docs: correct portal-prefetch root cause (h2, server-side queue) + measured outcome

The HTTP/1.1 / six-connection-cap claim was wrong — it came from the
Schannel curl build that cannot speak HTTP/2. ALPN (openssl s_client)
and .NET HttpClient confirm the portal negotiates h2; the queue is
server-side in the SWA SSR runtime. Doc, index, log and the
GlobalSidebar comment now describe the real mechanism.

Adds the 2026-07-28 outcome section: Standard plan changed nothing
(stratified p50s match, Mann-Whitney p=0.81); prefetch={false} removed
the freezes (worst totalDuration 225s -> 4.9s) and also removed an
accidental keep-alive (~150ms added to cold navigations).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/agent/autopilot-ztd-diagnostics.md

@@ -119,6 +119,19 @@ normal IME deployment flow. Spam containment, in order:
    payload; the event's own timestamp is the emission time, so the session's `StartedAt`
    (which the backend aligns to the earliest event) is not dragged backwards.
 
+Presentation (2026-07-28, customer feedback — an unannounced wall of pre-agent Error
+events read like a live failure):
+
+- The scan buffers the (capped) record set, first emits an **Info summary event**
+  (`modern_deployment_log`, payload `backfillSummary: true` + `replayedCount` /
+  `droppedOverCap` / `lookbackMinutes`) announcing the replay block, then replays the
+  records **oldest-first** so the timeline sequence follows event-log chronology.
+- The web timeline (`EventTimeline.tsx`) badges `backfilled: true` events („⟲ Backfilled",
+  slate, explanatory tooltip) and renders the original `timeCreated` as the row time with a
+  "(reported …)" suffix; the expanded metadata block gains a `Recorded` line. Severity is
+  deliberately **not** downgraded — unresolved pre-agent errors must still surface in the
+  Error filter.
+
 # Schema — Error codes (backend known-issue map)
 
 Codes documented in the known-issues / troubleshooting-FAQ pages that appear in ESP/enrollment

docs/agent/gather-rule-debug-log.md

@@ -0,0 +1,108 @@
+---
+type: Concept
+title: Gather Rule Debug Log — the per-tenant evaluation trace for rules that produce nothing
+description: EnableGatherRuleDebugLog (ConfigVersion 36) makes the agent write a local trace file explaining every gather-rule evaluation decision — scope skips, missing intervalSeconds, on_change suppression, empty collector results, logparser position/parse-mode/no-match outcomes — so customers can self-diagnose rules that never show up in the timeline.
+resource: /src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleDebugLog.cs
+tags:
+  - agent
+  - gather-rules
+  - diagnostics
+  - tenant-configuration
+timestamp: 2026-07-28T00:00:00+02:00
+---
+
+# Gather Rule Debug Log
+
+## Schema
+
+### The problem
+
+A gather rule that produces no timeline events is indistinguishable from a rule that
+never ran. The pipeline has many *silent-nothing* exits — before this feature, none of
+them were visible to the customer:
+
+| # | Decision point | Where |
+|---|---|---|
+| 1 | Rule delivered but `Enabled=false` | `GatherRuleExecutor.UpdateRules` |
+| 2 | `trigger=interval` without `intervalSeconds` — never runs | `UpdateRules` timer filter |
+| 3 | Interval timer's first tick comes only after one **full** interval | `UpdateRules` timer creation |
+| 4 | Out of phase scope (`activePhases` / `activeFromPhase` not latched); incl. `currentPhase=Unknown` before the first phase signal | `IsRuleInScopeLocked` |
+| 5 | phase_change / phase_exit dedup — once per (rule, phase) | `OnPhaseChanged` |
+| 6 | Collector returned an **empty** result (e.g. `emitOnlyIfExists=true` and target absent) | `ExecuteRule` |
+| 7 | `emit_mode=on_change` — result hash unchanged, emit suppressed | `ShouldEmitOnChange` |
+| 8 | Guard blocked the target (emits `security_warning`, but the rule yields no data) | `GatherRuleContext.EmitSecurityWarning` |
+| 9 | logparser: no files matched, position tracker says nothing new, regex no-match, plain-text file parsed in default `cmtrace` mode, `maxLines` cap, wildcard capped at 20 files | `LogParserCollector` |
+| 10 | Rule execution threw (agent log had only the message, no stack) | `ExecuteRule` catch |
+
+### The setting
+
+`TenantConfiguration.EnableGatherRuleDebugLog` (`bool?`, default null→false), served to the
+agent as `AgentConfigResponse.EnableGatherRuleDebugLog` — **ConfigVersion 36**. Portal:
+Settings → Agent → Settings, toggle "Gather Rule Debug Log", stored via the usual
+tenant-config roundtrip (`TableConfigRepository` Store+Map). Also shown in the admin
+tenant-config report.
+
+`RemoteConfigMerger` projects the bool onto a runtime path (same pattern as
+`EnableImeMatchLog`): `true` → `Constants.GatherRuleDebugLogPath` =
+`%ProgramData%\AutopilotMonitor\Logs\gather_rules_debug.log`; `false` → null, unless a
+`--gather-debug-log <path>` CLI override supplied a non-default path. The field is not
+security-sensitive and deliberately **survives the offline config cache**.
+
+### The trace file
+
+`GatherRuleDebugLog` is an append-only writer held by `GatherRuleExecutor` and exposed
+to collectors via `GatherRuleContext.DebugLog(ruleId, stage, message)` (null-safe no-op
+when disabled — zero cost on the normal path). Line format:
+
+```
+2026-07-28T09:15:02.123Z | RULE-ID | stage | message
+```
+
+Stages: `config` (registration summary per rule, header, zero-rules note), `trigger`
+(timer scheduled, phase/event fired, dedup), `scope` (skips with reason incl. current
+phase), `exec` (execution start), `collector` (null/empty results with likely cause),
+`guard` (allowlist block), `emit` (event emitted, hash change), `suppress` (on_change
+suppression with hash prefix + streak), `logparser` (per-file outcome: lines read,
+position range, match count, parse failures, regex timeouts, mode; plus the
+`format=text` hint when every line fails CMTrace parsing), `error` (full exception
+**with stack trace** — the agent log keeps only the message).
+
+Volume control: 10 MB cap with a single `.old` rotation generation (~20 MB worst case).
+Every write failure is swallowed — tracing must never break gathering. The trace never
+leaves the device on its own — but because it lives in the agent log folder
+(`Constants.LogDirectory`), the diagnostics package (`DiagnosticsPackageService`,
+`*.log` pattern, `AgentLogs/` section) picks it up automatically, so a customer-initiated
+diagnostics upload hands the trace to support without manual copying.
+
+### Semantics
+
+* **No hot-reload** — the flag is consumed once when `DefaultComponentFactory` builds
+  the `GatherRuleExecutorHost` at session start (per-enrollment lifecycle, same as
+  `EnableImeMatchLog`). Enable it in the tenant, then the *next* enrollment writes the
+  trace.
+* **Zero-rules case is traced too** — flag on + backend delivered no gather rules →
+  a one-shot standalone `config` line, so the file is never just absent.
+* **`--run-gather-rules` always traces** (operator diagnostic mode; CLI override or
+  default path) and mirrors every line to the console under `--console`.
+
+## Examples
+
+A logparser rule with `emit_mode=on_change` that "delivers nothing" becomes:
+
+```
+... | LP-01 | config | registered: trigger=interval, collector=logparser, target=C:\...\app.log, unscoped, emitMode=on_change, interval=300s
+... | LP-01 | trigger | interval timer scheduled every 300s (first run after one full interval — no immediate execution)
+... | LP-01 | exec | executing: collector=logparser, target=C:\...\app.log
+... | LP-01 | logparser | app.log: read 1000 lines from position 0->81234, matched 0, parseFailures=1000, regexTimeouts=0, mode=cmtrace
+... | LP-01 | logparser | every line failed CMTrace parsing — if this is a plain-text log, set parameter format=text
+```
+
+— the answer ("plain-text log parsed in CMTrace mode") is in the file.
+
+## Citations
+
+* Executor + trace points: `../../src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleExecutor.cs`
+* Writer: `../../src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleDebugLog.cs`
+* Config projection: `../../src/Agent/AutopilotMonitor.Agent.V2.Core/Configuration/RemoteConfigMerger.cs`
+* Backend serve + ConfigVersion: `../../src/Backend/AutopilotMonitor.Functions/Functions/Config/GetAgentConfigFunction.cs`
+* Phase scoping / emit mode background: `../rules/gather-rule-phase-scoping.md`

docs/backend/device-journeys.md

@@ -0,0 +1,122 @@
+---
+type: Concept
+title: Device Journeys & First-Time-Right (F2)
+description: How a device's terminal enrollment attempts are grouped into journeys (device key, junk-serial exclusion, first-success end, 30-day gap), where the DeviceHistories chain and the daily FTR aggregates are computed, stored and pruned, and which surfaces serve them.
+resource: src/Backend/AutopilotMonitor.Functions/Helpers/DeviceJourneyCalculator.cs
+tags:
+  - backend
+  - metrics
+  - device-history
+  - first-time-right
+  - insights
+timestamp: 2026-07-27T12:00:00+02:00
+---
+
+# Device Journeys & First-Time-Right (F2)
+
+Answers "how many devices enrolled right on the first try?" and "show me every attempt
+this device made". Session success rate hides wipe-and-retry loops — every retry that
+eventually succeeds counts as a success; First-Time-Right (FTR) exposes the real pain.
+All grouping semantics live server-side in `DeviceJourneyCalculator` (JourneyVersion 1);
+no consumer re-derives them.
+
+# Schema
+
+## Device key
+
+`(TenantId, normalized serial)` — normalization is trim + lower-case. Junk/placeholder
+serials are excluded entirely (never a chain, never in FTR, disclosed as a per-day
+exclusion count): `System Serial Number`, `To Be Filled By O.E.M.`, `Default string`,
+`0`, `None`, `INVALID`, `Unknown` (the agent's WMI-failure sentinel), empty, or shorter
+than 4 characters. A motherboard swap changes the serial and therefore the device key;
+re-enrollment under a different tenant is a separate key by design.
+
+## Journey
+
+Terminal sessions of a device key ordered by StartedAt. The terminal set is
+**Succeeded / Failed / Incomplete** — `Pending` (a sealed WhiteGlove part 1),
+`AwaitingUser`, `Stalled` and `InProgress` are OPEN sessions and never attempts.
+
+* A journey **ends** with the first terminal success; the next session starts a new
+  journey (redeployment).
+* A gap of **more than 30 days** since the previous attempt's terminal moment
+  (`CompletedAt`, fallback StartedAt) starts a new journey even without a success
+  (device shelved/repurposed). Constant, not a setting — production gaps: median 4.9 h,
+  92 % < 7 d.
+* WhiteGlove part 1 + part 2 share ONE session row, so a completed WG enrollment is ONE
+  attempt; a WG device still waiting for its user session leaves the journey open —
+  never a failed attempt.
+* **Attempt count** = terminal sessions in the journey (`Failed` and `Incomplete` are
+  non-successful attempts).
+* **FTR rate** = completed journeys with attempt count 1 ÷ all completed journeys.
+  Open and gap-abandoned journeys never enter numerator or denominator.
+
+Durations shown for attempts are the sessions' authoritative `DurationSeconds` verbatim
+(WhiteGlove pause excluded; `Incomplete` deliberately has none) — never
+`CompletedAt − StartedAt`, which is later in ~25 % of terminal sessions.
+
+## Persistence & compute
+
+* `DeviceHistories` (PK = TenantId, RK = percent-encoded normalized serial): the chain of
+  the device's terminal session refs `{sessionId, startedAt, completedAt, status,
+  enrollmentType, isPreProvisioned, durationSeconds, adminMarked}` capped at the 20 most
+  recent, plus derived `CurrentJourneyAttempts` (the LAST journey's attempts — the
+  banner's "Attempt N"), `JourneyCount` (chain-scoped) and `JourneyVersion`. Written
+  inline at the session-terminal single-writer seam
+  (`TableSessionRepository.UpdateSessionStatusAsync`, all three terminal statuses,
+  DeletionState-guarded) so the session banner is fresh; healed by the maintenance sweep.
+  Deliberately NOT part of the per-session deletion manifest — the row aggregates many
+  sessions. Wiped on tenant offboarding.
+* Sweep (`SweepDeviceJourneysAsync`, 30-day rolling window, 2h tick): (1) drops chain
+  refs of deleted sessions **tombstone-driven** — every session deletion (cascade and
+  retention both run through the cascade worker) leaves a `SessionTombstones` marker for
+  ~7 days, far longer than the sweep cadence, and even an expired-but-unpruned marker is
+  valid deletion evidence; a chain left empty deletes its row. (2) Merges the window's
+  terminal sessions into their chains (backfill, inline-miss healing, re-terminal
+  reclassifications). (3) Recomputes the daily FTR aggregates idempotently.
+* `DeviceJourneyAggregates` (PK = TenantId or `global`, RK = `{yyyy-MM-dd}`): per day —
+  completed journeys, first-time-right count, attempt histogram, junk-serial exclusion
+  count, `JourneyVersion`. A journey buckets on the StartedAt date of its completing
+  success session (the platform's StartedAt-date convention; late terminals converge via
+  the sweep). All counts are **additive**, so a window rate is the ratio of summed daily
+  rows — there is no rolling-window row (unlike the median-based time-attribution
+  aggregates, which cannot merge). 180-day retention. Rows exist below the ≥20 UI gate
+  on purpose (the UI needs the n for "insufficient data (n=…)").
+
+# Surfaces
+
+* `GET api/metrics/device-history?serialNumber=&sessionId=` (MemberRead + tenant query
+  param — the same route serves the web banner and MCP; a Global Admin passes `tenantId`)
+  — the chain plus, with `sessionId`, that session's server-computed attempt number
+  (live sessions get their would-be position via a virtual non-successful attempt, so the
+  redeploy and gap rules apply). `history: null` = no recorded history.
+* `GET api/metrics/device-journeys?days=` (MemberRead) /
+  `GET api/global/metrics/device-journeys?days=&tenantId=` (GlobalReadOrAdmin) —
+  `{ windowDays, totals, daily, repeatDevices }`. The days selector is honored because
+  counts are additive. Without `tenantId` the global variant serves the cross-tenant
+  aggregate rows and `repeatDevices: null` — a per-device list would require scanning
+  every tenant's partition.
+* Repeat devices (violator list, capped 10): devices whose LAST journey took ≥2 attempts
+  and whose newest terminal session falls inside the window, ordered by attempts then
+  recency; the failure reason comes from the newest failed attempt (bounded point-reads).
+* Web: "Attempt N for this device · View history" banner on session detail (expandable
+  chain); "First-time-right" section on Fleet Health (rate + weekly trend + attempt
+  histogram + repeat devices). MCP: `get_device_history` (serial mode / fleet FTR mode).
+
+# Examples
+
+A device fails ESP twice and succeeds on the third try within one week: one journey,
+three attempts, completed — counts once in the FTR denominator, not in the numerator,
+and the histogram's bucket `3` gains one. The same device redeployed a month later and
+succeeding immediately starts journey 2 with attempt count 1 — first-time-right. A
+device with `serialNumber = "Unknown"` (WMI failure) never gets a chain; its terminal
+sessions surface only as that day's disclosed exclusion count.
+
+# Citations
+
+* `src/Backend/AutopilotMonitor.Functions/Helpers/DeviceJourneyCalculator.cs` — device key, junk list, grouping, attempt numbers (JourneyVersion 1).
+* `src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.DeviceHistory.cs` — persistence + inline seam entry.
+* `src/Backend/AutopilotMonitor.Functions/Services/MaintenanceService.DeviceJourneys.cs` — sweep, tombstone pruning, daily aggregation.
+* `src/Backend/AutopilotMonitor.Functions/Functions/Metrics/GetDeviceJourneyFunctions.cs` — read surfaces.
+* `src/Backend/AutopilotMonitor.Functions.Tests/DeviceJourneyAndFtrTests.cs` — table-driven grouping/aggregation/attempt-number tests.
+* `tasks/insights-expansion-spec.md` — F2 specification and source-data audit (§0.5).

docs/backend/rule-regression-radar.md

@@ -0,0 +1,112 @@
+---
+type: Concept
+title: Rule Regression Radar (F3)
+description: How the radar detects analyze rules whose hit rate suddenly rose (7-day window vs 28-day baseline, Wilson-separated), which suppressions keep it quiet, how alert episodes live in the notification tracker, and which surfaces show them.
+resource: src/Backend/AutopilotMonitor.Functions/Helpers/RuleRegressionRadar.cs
+tags:
+  - backend
+  - rules
+  - regression-radar
+  - insights
+timestamp: 2026-07-27T16:00:00+02:00
+---
+
+# Rule Regression Radar (F3)
+
+Detects "this analyze rule suddenly fires much more often" before helpdesk volume does, and
+says what the spike correlates with — with honest statistics and honest wording. Analyze
+rules only in v1: their daily stats are audit-verified session-deduplicated
+(`FireCount` ≈ distinct sessions with a hit, `SessionsEvaluated` the same-source
+denominator). Gather rules are excluded until their per-batch stats dedup is fixed —
+never silently included with bad math.
+
+# Schema
+
+## Signal & detection
+
+Per (tenant, ruleId), daily hit rate = `FireCount ÷ SessionsEvaluated` from the
+`RuleStats` rows — RATES, not counts (absolute counts spike with every rollout wave).
+A regression fires only when ALL hold for the trailing 7-day window vs. the prior
+28-day baseline:
+
+1. window has ≥ 5 hit sessions AND ≥ 20 evaluated sessions;
+2. window rate ≥ 2× baseline rate;
+3. the Wilson 95 % intervals are disjoint in the increase direction
+   (`MetricsMath.WilsonInterval` / `RateIncreaseSeparated` — deterministic, unit-pinned),
+   so small-n noise never alerts.
+
+## Suppression (false positives are trust damage)
+
+* Rule entity missing (deleted) — never alerts.
+* Rule younger than baseline + window (`CreatedAt` within 35 days — grace period for new
+  rules; the entity timestamp is the honest gate, a stats-row count would fail on
+  low-volume tenants whose quiet days simply have no rows).
+* Rule edited inside the window (`UpdatedAt` ≥ window start) — edits legitimately change
+  hit rates.
+* Empty baseline denominator (rule disabled throughout the baseline).
+* Platform kill switch: app setting `RuleRegressionRadarDisabled=true` skips the radar
+  (fail-open — it only notifies, never mutates data).
+
+## Alert episodes (tracker keyspace)
+
+An episode lives as `ruleregression|{ruleId}` in the notification-tracker table
+(the `tpmpss|` pattern): the row IS the dedup (bell + ops event fire exactly once per
+episode), the badge state and the `regressions[]` payload — window/baseline counts,
+rates, lift (null for a zero-baseline "new signal" — no finite lift is invented), window
+dates, and the dimension concentration captured at first fire. Numbers refresh on every
+radar pass while the episode stays active; `FirstNotifiedAt` never moves. The episode
+closes (badge clears, dedup re-arms) when the window rate falls back under 1.5× baseline
+or fires stop entirely; the tracker's 30-day retention sweep also re-arms, so a
+month-old still-burning regression rings once more by design.
+
+## Dimension correlation (on fire only)
+
+Hit sessions (RuleResults scan: tenant partition range + RowKey = ruleId + DetectedAt in
+window, intersected with the window's sessions) are compared against all window sessions
+across `osBuild`, `model` (manufacturer + model), `agentVersion` and `imeVersion`. The
+top value by lift is reported with BOTH shares — wording contract: "X % of affected
+sessions are on … vs Y % of all sessions — correlated, not necessarily causal". No value
+with ≥ 5 hit sessions at ≥ 2× lift → "no clear dimension concentration"; a correlation
+failure also yields no claim. App-version correlation for `ANALYZE-APP-*` rules is a
+follow-up (needs rule→app matching semantics), tracked with the gather-rule fix.
+
+## Compute & alert path
+
+Runs in the daily maintenance pass right after the rule-stats aggregation
+(`RunRuleRegressionRadarAsync`), anchored on YESTERDAY — whole days only, a partial
+today would understate the window rate. One 35-day stats read covers all tenants;
+evaluation is the pure `RuleRegressionRadar` core. On a NEW episode:
+
+1. `RuleFrequencyRegression` ops event (category Tenant, Warning) with the full numbers
+   — dual-registered in the web `OPS_EVENT_TYPES` catalog for alert-rule routing.
+2. Tenant bell notification (type `rule_frequency_regression`, Admin audience) with the
+   same numbers and a deep link to the rule's card (`/analyze-rules#rule-card-{ruleId}`).
+   A sessions-list pre-filtered to rule hits needs a rule filter the session search does
+   not have yet — follow-up alongside the gather-rule work.
+3. v1 channel: bell + ops event only. Provider fan-out (webhook/Telegram) follows once
+   alert quality is proven — a noisy first version burns trust permanently.
+
+# Surfaces
+
+* `GET api/metrics/rule-stats` (and the global variant with `tenantId`) carries
+  `regressions[]` — the active episodes. MCP `get_rule_stats` inherits the block.
+* Analyze-rules page: per-rule 30-day fire-count sparkline (densified from the `trend`
+  rows the endpoint already served) and a red "↑ Regression" badge while an episode is
+  active, with the full numbers in the tooltip.
+
+# Examples
+
+A rule firing on 2 % of sessions for a month jumps to 15 % over a week (15/100 vs
+10/500): lift 7.5×, Wilson-separated → one bell, one ops event, badge until the rate
+falls back under 3 %. The same jump on 5/20 sessions with a 12 % baseline stays silent —
+the intervals overlap, so the spike is not statistically real yet. A rule that never
+fired in the baseline and now hits 15 % alerts as a "new signal" with no lift figure.
+
+# Citations
+
+* `src/Backend/AutopilotMonitor.Functions/Helpers/RuleRegressionRadar.cs` — gates, suppression, re-arm, dimension concentration.
+* `src/Backend/AutopilotMonitor.Functions/Helpers/MetricsMath.cs` — Wilson interval + separation primitive.
+* `src/Backend/AutopilotMonitor.Functions/Services/MaintenanceService.RuleRegression.cs` — sweep, episode reconcile, bell/ops wiring.
+* `src/Backend/AutopilotMonitor.Functions/DataAccess/TableStorage/TableHardwareRejectionNotificationTracker.cs` — episode keyspace.
+* `src/Backend/AutopilotMonitor.Functions.Tests/RuleRegressionRadarTests.cs` — hand-computed Wilson vectors + every suppression branch.
+* `tasks/insights-expansion-spec.md` — F3 specification and source-data audit (§0.5).

docs/backend/time-attribution.md

@@ -0,0 +1,124 @@
+---
+type: Concept
+title: Enrollment Time Attribution (F1)
+description: How a terminal session's wall clock is partitioned into named segments with an explicit unattributed remainder, how ESP-blocking apps and reboots are attributed, and where breakdowns and fleet aggregates are computed, stored and served.
+resource: src/Backend/AutopilotMonitor.Functions/Helpers/TimeAttributionCalculator.cs
+tags:
+  - backend
+  - metrics
+  - time-attribution
+  - insights
+timestamp: 2026-07-26T20:00:00+02:00
+---
+
+# Enrollment Time Attribution (F1)
+
+Answers "where did the 47 minutes go?" per session and per fleet. Every number is
+traceable to observed events; a missing signal produces "unknown" or an explicit
+unattributed remainder — never a guess, and the partition is never normalized to 100 %.
+
+# Schema
+
+## Invariant
+
+For every computed breakdown:
+
+```
+sum(span seconds) + UnattributedSeconds == WallClockSeconds == session DurationSeconds
+```
+
+`DurationSeconds` is the authoritative wall clock — for WhiteGlove it is part 1 + part 2
+WITHOUT the pause, and re-terminal stamps move `CompletedAt`, so `CompletedAt − StartedAt`
+is never used (it diverges in ~25 % of terminal sessions). Span seconds are floored;
+sub-second dust lands in the unattributed remainder.
+
+## Observation windows
+
+Windows are end-anchored on authoritative timestamps and constructed so their lengths sum
+exactly to `DurationSeconds`:
+
+* Non-WhiteGlove: one window `[CompletedAt − DurationSeconds, CompletedAt]`.
+* WhiteGlove (ONE session row, two windows): part 2 = `[ResumedAt, CompletedAt]`; part 1 =
+  `[part1End − (DurationSeconds − part2), part1End]` where `part1End` is anchored on the
+  `whiteglove_part1_complete` event. The pause between the windows is never attributed.
+  Fallback anchors set the `WhiteGloveAnchorsIncomplete` quality flag.
+
+## Segments
+
+Spans are sliced at phase-declaration events (only declaration events carry
+`Phase != Unknown`) plus `desktop_arrived`, in canonical Sequence order; anchors whose
+timestamp runs backward are dropped (`ClockSkewDropped`).
+
+| EnrollmentPhase | Segment key |
+|---|---|
+| Start / DevicePreparation / DeviceSetup | `device_prep` |
+| AppsDevice | `esp_apps` |
+| AccountSetup / FinalizingSetup | `identity_hello` |
+| AppsUser | `user_esp` |
+| Complete, `desktop_arrived` event | `desktop_handoff` |
+| Failed | attribution ends — tail stays unattributed |
+
+## ESP-blocking apps (positive evidence only)
+
+Per-app intervals use EVENT timestamps (first started/download event → LAST terminal
+event, covering IME retries) — never the agent payload timing, which freezes at the first
+terminal transition. Blocking membership joins the app id against the session's latest
+list-carrying `esp_config_detected` emission: listed ⇒ blocking; absent ⇒ unknown, never
+false (`BlockingSetUnknown` / `BlockingSetTruncated` flags). Critical-path occupancy =
+overlap-merged union of blocking intervals clipped to the `esp_apps` spans;
+`EspAppsOccupancySeconds` is null (unknown) when no lists were observed.
+
+The fleet what-if bound per app X is `max(0, cpEnd − cpEndWithoutX)` (latest interval end
+with vs. without X; the idle gap before X counts — the ESP also waits for X to start).
+It is an upper bound by construction; every consumer says "up to", never "you will save".
+
+## Reboots
+
+`system_reboot_detected` is detection-time-stamped by the NEXT agent run; the real boot
+moment is its `lastBootUtc` payload. Reboot spans are therefore the event-stream gap
+bracketing `lastBootUtc`, deduped per boot, clipped to the observation windows, and carried
+as a cross-cutting annotation (they overlap the segment they started in — never a slice of
+the partition).
+
+## Persistence & compute
+
+* `SessionTimeBreakdowns` (PK = TenantId, RK = SessionId): spans, reboot spans, blocking
+  intervals (top 20 + uncapped count), quality flags, `AttributionVersion`. Written once at
+  the session-terminal single-writer seam (`TableSessionRepository.UpdateSessionStatusAsync`,
+  Succeeded/Failed only — Incomplete deliberately has no duration). Deleted with its session
+  (deletion-manifest step) and on tenant offboarding.
+* Self-healing 30-day maintenance sweep (2h tick): backfills missing breakdowns, folds
+  late-terminating sessions into their StartedAt-date aggregates, and enforces version
+  purity — a stale-version row whose events aged out counts as missing, never mixed.
+* `TimeAttributionAggregates` (PK = TenantId or `global`, RK = `{yyyy-MM-dd}|{class}` and
+  `rolling30|{class}`): per enrollment class (`user_driven`, `whiteglove`, `self_deploying`,
+  `device_preparation` — never mixed) median/p75/p90 per segment over the fixed six-segment
+  stack (incl. `unattributed`; a session without a segment contributes 0), plus top blocking
+  apps (≥5 sessions per app row). Clean/flagged/missing counts are part of every row; rows
+  exist below the ≥20 UI gate on purpose (the UI needs the n for "insufficient data (n=…)").
+  Daily rows retain 180 days; `rolling30` rows are refreshed whole (a median of per-day
+  medians is not the range median — the rolling rows are the honest range statistics).
+
+## Surfaces
+
+* `GET api/sessions/{sessionId}/time-attribution` (MemberRead + tenant query param) —
+  breakdown row or `breakdown: null` (pre-feature / non-terminal / Incomplete = no lane).
+* `GET api/metrics/time-attribution` (MemberRead) / `GET api/global/metrics/time-attribution`
+  (GlobalReadOrAdmin, optional `tenantId`) — `{ windowDays, classes (rolling), daily }`.
+* Web: attribution lane under the session-detail phase timeline; "Time attribution" section
+  on Fleet Health. MCP: `get_time_attribution` (sessionId mode / fleet mode).
+
+# Examples
+
+A 30-minute user-driven session: `device_prep` 5m → `esp_apps` 10m (occupancy 4m by one
+blocking app) → `identity_hello` 8m → `user_esp` 5m → `desktop_handoff` 2m, unattributed 0.
+A WhiteGlove session with a 2-day pause reports wall clock = part1 + part2 only; the resume
+gap before the first part-2 phase declaration is unattributed, not guessed.
+
+# Citations
+
+* `src/Backend/AutopilotMonitor.Functions/Helpers/TimeAttributionCalculator.cs` — calculator + semantics (AttributionVersion 1).
+* `src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.TimeAttribution.cs` — persistence.
+* `src/Backend/AutopilotMonitor.Functions/Services/MaintenanceService.Aggregation.cs` — sweep + aggregation.
+* `src/Backend/AutopilotMonitor.Functions.Tests/TimeAttributionCalculatorTests.cs` — golden fixtures pinning the invariant.
+* `tasks/insights-expansion-spec.md` — F1 specification and source-data audit (§0.5).

docs/index.md

@@ -20,6 +20,7 @@ https://docs.autopilotmonitor.com (separate repository).
 * [V2 Agent](agent/index.md) - How the on-device agent works: [runtime overview](agent/overview.md), [decision engine](agent/decision-engine.md) (reducer, signals, completion arms), [logs & persistence](agent/logs-and-persistence.md) (signal log, snapshot, crash recovery), [Hello wizard un-skip](agent/hello-wizard-unskip.md) (why a single "WHfB disabled" read never decides completion), [Autopilot ZTD diagnostics](agent/autopilot-ztd-diagnostics.md) (event IDs, diagnostic registry, endpoints, error-code map).
 * [Build Counter Blob](agent/build-counter-blob.md) - How agent build numbers are minted: shared counter blob with ETag-CAS so local and CI builds never collide; CI additionally attests build provenance (Sigstore).
 * [Agent Endpoint Migration](agent/endpoint-migration.md) - How the backend re-homes agents to a new API base URL via the config channel (backend move or per-tenant region move): live-fetch-only, allowlist-validated on both sides, one hop, kill wins.
+* [Gather Rule Debug Log](agent/gather-rule-debug-log.md) - EnableGatherRuleDebugLog (ConfigVersion 36): the per-tenant local trace file that explains every gather-rule evaluation decision — scope skips, on_change suppression, empty collector results, logparser position/parse-mode outcomes — for rules that produce no timeline events.
 * [MDM Reboot Coalescing](agent/mdm-reboot-coalescing.md) - Attributing the mid-ESP coalesced reboot ("second sign-in") to the device-assigned policy URIs that forced it: aggregated DM-Enterprise 2800 observations (neutral, flush-time watermark) + the ANALYZE-ESP-005 advisory gated on an actually-observed reboot.
 * [Secure Boot CA-2023 Detection](agent/secureboot-ca2023-detection.md) - Why ANALYZE-SEC-001 v3 reads the UEFI db/KEK variables directly instead of trusting the SecureBoot\Servicing registry, and how the one-sided uefiCa2023FirmwareConfirmed marker plus a not_exists precondition give absence-tolerant suppression across old and new agents.
 * [ESP Policy-Provider Stall Detection](agent/esp-policy-provider-stall.md) - The EnrollmentStatusTracking CSP's no-timeout Setup/Apps wait is keyed to the Intune-registered "Sidecar" provider by NAME: co-management's "ConfigMgr" parks the user ESP at "Apps (Identifying)" for days even with TrackingPoliciesCreated=1 (issue #106); the always-on two-arm esp_policy_provider_stalled tripwire (provider_incomplete | sidecar_provider_missing) and the SOFTWARE\Microsoft\Windows\Autopilot gather-rule allowlist entry that surface it.
@@ -32,12 +33,19 @@ https://docs.autopilotmonitor.com (separate repository).
 # Backend
 
 * [Business Timestamps](backend/business-timestamps.md) - Why the Azure Tables system Timestamp is never authoritative (migrations reset it), and the OccurredUtc + RowKey-decode compensation for AuditLogs/OpsEvents/Events after the 2026-07-18 migration.
+* [Device Journeys & First-Time-Right](backend/device-journeys.md) - How a device's terminal enrollment attempts are grouped into journeys (trim+casefold device key with junk-serial exclusion, first-success end, 30-day gap, WhiteGlove = one attempt), the DeviceHistories chain with its tombstone-driven deleted-session pruning, the additive daily FTR aggregates, and the banner/fleet/MCP surfaces.
+* [Enrollment Time Attribution](backend/time-attribution.md) - How a terminal session's authoritative wall clock (DurationSeconds, WhiteGlove pause excluded) is partitioned into named segments with an explicit unattributed remainder, ESP-blocking apps as positive evidence with "up to" what-if bounds, reboot spans from event gaps, and the breakdown/aggregate tables the sweep maintains.
+* [Rule Regression Radar](backend/rule-regression-radar.md) - How analyze-rule hit-rate regressions are detected (7-day window ≥2× the 28-day baseline with disjoint Wilson intervals), which suppressions keep the radar quiet (grace period, edit-in-window, kill switch), how alert episodes live in the ruleregression tracker keyspace with re-arm semantics, and the on-fire dimension correlation with its "correlated, not necessarily causal" wording contract.
 * [ServerActions & On-Demand Diagnostics](backend/server-actions-on-demand-diagnostics.md) - The queue-on-session, deliver-on-ingest action channel, the TenantAdminOrOperator tier with in-function per-type re-gating, the portal's Collect Logs flow (quick-config orders rotate_config before request_diagnostics), and the hosted-prefix sweep in the offboarding cascade.
 
 # MCP Server
 
 * [MCP Docs Corpus](mcp/docs-corpus.md) - How the published customer documentation becomes the `search_docs` corpus: CRLF-safe heading chunking, build-time embedding as a third precomputed section, and why a docs edit needs an MCP redeploy.
 
+# Web Portal
+
+* [Portal Navigation Prefetch & the SWA Runtime Bottleneck](web/portal-navigation-prefetch.md) - Why every navigation Link sets `prefetch={false}`: the App Router's viewport prefetch fans out one RSC request per visible link and the Static Web Apps SSR runtime queues them server-side into a multi-minute tail. Records the follow-up measurement (the Standard plan changed nothing; the prefetch storm was an accidental keep-alive), where browser telemetry actually lives, and why this curl build cannot be trusted for HTTP versions.
+
 # Security & Identity
 
 * [MCP OAuth Flow](mcp-oauth-flow.md) - Who authenticates where when connecting an AI client to the MCP server; two identities, three parties plus Entra ID.

docs/log.md

@@ -1,5 +1,21 @@
 # Log
 
+## 2026-07-28
+
+* **Update**: `agent/autopilot-ztd-diagnostics.md` — presentation layer for the startup error backfill (customer feedback: an unannounced wall of pre-agent Error events with a single identical timestamp read like a live failure). Agent: the backfill scan now buffers the capped record set, emits an Info summary event first (`modern_deployment_log`, `backfillSummary: true` + `replayedCount`/`droppedOverCap`/`lookbackMinutes`), then replays oldest-first so the timeline sequence follows event-log chronology. Web: `EventTimeline.tsx` badges `backfilled: true` events („⟲ Backfilled", tooltip) and renders the original `timeCreated` as the row time with a "(reported …)" suffix plus a `Recorded` metadata line — works retroactively for already-stored events. Severity is deliberately not downgraded.
+
+* **Creation**: Added `agent/gather-rule-debug-log.md` — the new per-tenant setting `EnableGatherRuleDebugLog` (ConfigVersion 35 → 36, portal toggle under Settings → Agent, `EnableImeMatchLog`-style bool→path projection in `RemoteConfigMerger`). When enabled, the agent writes `%ProgramData%\AutopilotMonitor\Logs\gather_rules_debug.log`: one pipe-delimited line per evaluation decision across ten previously silent "produced nothing" exits — disabled rules, `interval` without `intervalSeconds` (never runs), the first-tick-after-one-full-interval window, phase-scope skips incl. `currentPhase=Unknown`, per-(rule, phase) dedup, empty collector results (`emitOnlyIfExists`), `on_change` hash suppression (hash prefix + streak), guard blocks, logparser per-file outcomes (position skips, parse failures with a `format=text` hint when every line fails CMTrace parsing, `maxLines`/wildcard caps), and full exception stacks that the agent log drops. 10 MB cap + one `.old` generation; no hot-reload (per-enrollment lifecycle); flag survives the offline config cache; `--run-gather-rules` always traces and echoes under `--console`; zero-rules delivery leaves a one-line file instead of nothing. Side fix: `GatherRuleExecutorHost` now passes the logger into `InformationalEventPost`, so gather-event emissions appear in the agent DEBUG log.
+
+* **Correction + Update**: `web/portal-navigation-prefetch.md`. The HTTP/1.1 claim in the 2026-07-27 entry below is **wrong** and has been struck from the document: `portal.autopilotmonitor.com` negotiates **h2**, verified by `openssl s_client -alpn h2,http/1.1` and a .NET `HttpClient` returning `HTTP/2.0`. The false reading came from the Windows/Schannel curl build in this environment, which has no HTTP/2 support and therefore always reports `1.1` — do not use it to determine HTTP versions. There is no six-connection cap in play; the queue is server-side in the SWA SSR runtime, which does not change the fix or the evidence, only the mechanism. Added an `Outcome` section with 20 h of post-change telemetry: the Free → Standard plan change (16:02:44 UTC) produced **no measurable latency gain** once stratified by the gap to the previous request (p50 Free → Standard: `<10s` 85 → 95 ms, `5-30min` 429 → 441 ms; tail rates 1.64 %/0.374 % over 2 s/10 s vs 6 and 1 events at n = 258 against 4.2 and 1.0 expected; `browserTimings` Mann-Whitney z = −0.24, p = 0.81). The freezes were removed by `prefetch={false}` (16:34:13 UTC): worst `browserTimings.totalDuration` 225,277 → 4,856 ms. The prefetch storm was also an **accidental keep-alive** — requests under 10 s apart fell from 85 % to 46 %, and on the identical never-cacheable `/sessions/{id}` route the median rose 87 → 211 ms and p90 465 → 1,480 ms, with one 11,441 ms abandoned request (`resultCode 0`) after 517 minutes idle. Synthetic bursts warm the runtime and must not be used to benchmark this (round 1 p50 288 ms vs rounds 4–25 p50 113 ms).
+
+## 2026-07-27
+
+* **Creation**: Added `web/portal-navigation-prefetch.md` (and a `Web Portal` section to the index) — root cause of the minute-long portal freezes. `GlobalSidebar` and `Navbar` render the whole navigation on every page, so the App Router's default viewport prefetch issued one `?_rsc=` request per visible link against `portal.autopilotmonitor.com` (~10,400 in 14 days). *(The original entry attributed the freeze to HTTP/1.1 and a six-connection-per-origin cap — see the 2026-07-28 correction; the queue is server-side.)* When the Static Web Apps managed runtime queued the prefetches (p50 91 ms, p95 896 ms, but max 234 s / 21 samples over 30 s), the navigation the user wanted was stuck behind that queue. Measured on the 2026-07-27 17:25 CEST incident: `/admin/presence?_rsc=` 151 s, three siblings finishing within 340 ms of each other at ~37.5 s, all `200`, while the backend API answered in 1.6–2.2 s and `browserTimings` showed `networkDuration` 16 ms against `processingDuration` 225 s. Every navigation Link now sets `prefetch={false}` — these routes are client components behind `ProtectedRoute` that fetch their own data, so the prefetched RSC payload carried no benefit. The doc also records that browser telemetry lives in a **separate** App Insights resource (`AUTOPILOT_MONITOR_WEB_APPINSIGHTS_ID`) that the MCP `query_backend_logs` tool cannot reach, which is why the freezes left no trace in the backend logs.
+
+* **Creation**: Added `backend/rule-regression-radar.md` — F3 regression radar (analyze rules only; gather rules wait for their per-batch stats dedup fix): per (tenant, rule) daily hit rate from `RuleStats`, firing only when the trailing 7-day window has ≥5 hit sessions and ≥20 evaluated sessions, the rate is ≥2× the prior 28-day baseline AND the Wilson 95 % intervals are disjoint (deterministic `MetricsMath` primitive with hand-computed test vectors). Suppressed for deleted rules, rules younger than baseline+window (`CreatedAt` grace), rules edited inside the window (`UpdatedAt`), empty baselines, and the `RuleRegressionRadarDisabled` app-setting kill switch. Alert episodes live as `ruleregression|{ruleId}` tracker rows (one bell + one `RuleFrequencyRegression` ops event per episode; numbers refreshed while active; re-armed under 1.5× baseline, on fire-stop, or by the 30-day tracker retention). On-fire dimension correlation over osBuild/model/agentVersion/imeVersion with the "correlated, not necessarily causal" wording contract. Surfaces: `regressions[]` in the rule-stats response (MCP inherits), the analyze-rules page's 30-day sparkline and regression badge.
+
+* **Creation**: Added `backend/device-journeys.md` — F2 device history / First-Time-Right: the device key (trim + case-fold serial, junk/placeholder exclusion incl. the agent's `Unknown` WMI sentinel), journey grouping over the terminal set Succeeded/Failed/Incomplete (first success ends a journey, a >30-day gap from the previous attempt's CompletedAt starts one, WhiteGlove's single session row is ONE attempt, open sessions are never attempts), the `DeviceHistories` chain (cap 20, written inline at the terminal seam, healed by the sweep, deleted-session refs pruned tombstone-driven, deliberately not in the per-session deletion manifest) and the additive `DeviceJourneyAggregates` daily rows (window rate = ratio of sums — no rolling row needed, 180-day retention). Surfaces: the session-detail "Attempt N" banner with server-computed attempt numbers (virtual-attempt rule for live sessions), the Fleet Health First-time-right section (≥20-journey gate, attempt histogram, repeat-devices violator list), and the MCP `get_device_history` tool (serial mode / fleet FTR mode).
+
 ## 2026-07-25
 
 * **Update**: `agent/secureboot-ca2023-detection.md` — review follow-up on 90012d9 hardened the privilege scope, the repo's only privilege-adjustment code and therefore the precedent for any future one. The process token moved from a raw `IntPtr` to a `SafeHandle` assigned by the P/Invoke marshaler, so the CLR owns it from the moment `OpenProcessToken` returns and the critical finalizer releases it even when `Dispose` never runs — previously an async exception between the successful open and the caller's `using` leaked the handle *with the privilege enabled and no owner left to restore it*. `Dispose` became idempotent and now releases the handle in a `finally`, so a throwing restore cannot strand it; the restore obligation is recorded immediately after the successful `AdjustTokenPrivileges` with nothing throwable in between. The whole enable → read → restore sequence runs under a static gate because the privilege is adjusted on the *process* token: a concurrent reader would see "already enabled", correctly skip its own restore, and then lose the privilege mid-read when the first reader disposed, reporting `privilege_denied` on a machine that holds it.
@@ -52,6 +68,10 @@
 
 * **Creation**: Added `agent/endpoint-migration.md` — config-channel agent re-home (`MigrateToApiBaseUrl` on `GET agent/config`, ConfigVersion 33): backend or per-tenant API-URL moves without DNS indirection (impossible due to mTLS/Flex-TLS). Live-fetch-only with cache strip, `AgentEndpointMigrationRules` allowlist validated on both sides, one hop, kill-switch wins. Built as the lesson from the 2026-07-18 WEU→GWC cutover, which hard-cut all in-flight agents.
 
+## 2026-07-26
+
+* **Creation**: Added `backend/time-attribution.md` — the F1 enrollment time attribution: exact-partition invariant against the session's authoritative DurationSeconds, two-window WhiteGlove model, segment mapping from phase-declaration events, positive-evidence ESP-blocking join with "up to" what-if bounds, reboot spans from event gaps around `lastBootUtc`, and the SessionTimeBreakdowns / TimeAttributionAggregates tables with their terminal-seam + maintenance-sweep compute paths and read surfaces (web lane, fleet panel, MCP `get_time_attribution`).
+
 ## 2026-07-17
 
 * **Creation**: Added `agent/build-counter-blob.md` — agent build numbers now come from a shared public counter blob (`buildcounter-v{N}.txt`, reserve-before-build with ETag-CAS) so local `build.ps1` and CI `build-agent.yml` builds can never mint the same number. Documents the CI parity fixes (SummaryDialog.exe.config in the ZIP, EXE-vs-manifest version check, hash-oracle update gated on stable cutover) and the Sigstore provenance attestation on CI-built ZIPs.

docs/web/portal-navigation-prefetch.md

@@ -0,0 +1,120 @@
+---
+type: Concept
+title: Portal Navigation Prefetch & the SWA Runtime Bottleneck
+description: Why every navigation Link in the portal sets prefetch={false} — the App Router's viewport prefetch fires one RSC request per visible link, and the Static Web Apps SSR runtime queues them server-side into a multi-minute latency tail. Also records what the follow-up measurement showed about the Standard SKU and the keep-alive side effect.
+resource: src/Web/autopilot-monitor-web/components/GlobalSidebar.tsx
+tags:
+  - web
+  - performance
+  - nextjs
+  - static-web-apps
+  - observability
+timestamp: 2026-07-27T18:00:00+02:00
+---
+
+# Context
+
+The portal is a Next.js 15 App Router application hosted on Azure Static Web Apps. Every page under
+the authenticated shell is a client component behind `ProtectedRoute` that fetches its own data from
+the Function App (`autopilotmonitor-api-eu`) after mount. The RSC payload a route returns on
+navigation therefore carries no page data — only the shell.
+
+`GlobalSidebar` and `Navbar` render the full navigation on every page. With the App Router's default
+prefetch behaviour, each visible `<Link>` triggers a background `GET /<route>?_rsc=<hash>` as soon as
+it enters the viewport.
+
+# Mechanism
+
+Two properties combine into a portal-wide freeze:
+
+1. **Fan-out.** The navigation is fully rendered on each page load, so a single navigation issues one
+   RSC request per visible link — measured at ~10,400 requests over 14 days.
+2. **A heavy latency tail on the SSR runtime.** RSC responses are prerendered and edge-cached
+   (`x-nextjs-cache: HIT`, `s-maxage=31536000`), so the median is fast. On a cache miss or cold start
+   the Static Web Apps managed runtime queues them **server-side**, and the queue drains all at once.
+
+The navigation the user wants is then stuck behind that queue and the tab shows a loading spinner or a
+blank page until it drains. Nothing fails — the requests eventually return `200`, which is why the
+failure leaves no error trace anywhere.
+
+> **Correction (2026-07-28).** The original version of this document named a third property: that
+> `portal.autopilotmonitor.com` negotiates HTTP/1.1 and the prefetches exhaust the six-connection
+> browser cap. **That is wrong.** It came from `curl -w '%{http_version}'` on a Windows build of curl
+> whose Schannel backend has no HTTP/2 support, so it can only ever report `1.1`. ALPN says otherwise:
+> `openssl s_client -alpn h2,http/1.1` negotiates **h2** on the portal host, confirmed by a .NET
+> `HttpClient` request returning `HTTP/2.0`. There is no six-connection cap and connection starvation
+> was never the mechanism — the queue is server-side. Verify HTTP versions with `openssl s_client
+> -alpn` or `HttpClient`, never with this curl build.
+
+# Evidence
+
+Incident of 2026-07-27, 17:25–17:29 CEST. Browser-side dependencies during the freeze:
+
+| Request | Duration | Status |
+| --- | --- | --- |
+| `/admin/presence?_rsc=…` | 151,461 ms | 200 |
+| `/gather-rules?_rsc=…` | 52,283 ms | 200 |
+| `/progress?_rsc=…` | 37,878 ms | 200 |
+| `/analyze-rules?_rsc=…` | 37,559 ms | 200 |
+| `/audit?_rsc=…` | 37,539 ms | 200 |
+| Backend API, same window | 1,600–2,200 ms | 200 |
+
+The three ~37.5 s responses complete within 340 ms of each other — a queue draining, not independent
+slow requests. The corresponding `browserTimings` row for `/geographic-performance` reports
+`networkDuration` = 16 ms against `processingDuration` = 225,095 ms: the network delivered the
+document immediately and the browser then waited nearly four minutes for the `load` event.
+
+Fourteen-day distribution of RSC prefetches: n = 10,428, p50 = 91 ms, p95 = 896 ms, max = 234,230 ms,
+38 over 10 s, 21 over 30 s.
+
+# Outcome, measured 2026-07-28
+
+Two changes landed within half an hour of each other on 2026-07-27: the SWA plan went Free → Standard
+at 16:02:44 UTC, and `prefetch={false}` went live at 16:34:13 UTC. Twenty hours of production
+telemetry separate their effects.
+
+**The Standard plan produced no measurable latency gain.** Latency is governed almost entirely by the
+gap to the previous request — the SSR runtime cools down — so raw percentiles only measure the traffic
+mix. Stratified by that gap, the two eras are indistinguishable (p50, Free → Standard): `<10s`
+85 → 95 ms · `10-60s` 100 → 117 ms · `1-5min` 295 → 310 ms · `5-30min` 429 → 441 ms. Tail rates match
+too: Free ran 1.64 % over 2 s and 0.374 % over 10 s (n = 10,163); Standard produced 6 and 1 events at
+n = 258 against 4.2 and 1.0 expected. `browserTimings.totalDuration` by Mann-Whitney: n = 436 vs 48,
+z = −0.24, **p = 0.81**.
+
+**The prefetch fix is what removed the freezes** — worst `browserTimings.totalDuration` fell from
+225,277 ms to 4,856 ms, and the 30-second events stopped.
+
+**It also removed an accidental keep-alive.** The prefetch storm kept the SSR runtime warm: 85 % of
+requests used to arrive less than 10 s apart, now 46 % do. On an identical never-cacheable route
+(`/sessions/{id}`) the median rose from 87 ms to 211 ms and p90 from 465 ms to 1,480 ms. After 517
+minutes idle, one request took 11,441 ms and was abandoned (`resultCode 0`). The trade — minute-long
+freezes gone, ~150 ms added to a cold navigation — is worth it, but it is a trade.
+
+Do not benchmark this with a synthetic burst. Firing requests in quick succession warms the runtime
+and measures the best case: in a 25-round `curl --parallel-max 6` run, round 1 came in at p50 288 ms
+and rounds 4–25 at p50 113 ms.
+
+# Diagnosing this class of problem
+
+The backend Application Insights resource is the wrong place to look — a freeze appears there as an
+*absence* of requests, never as an error. Browser telemetry lives in a **separate** Application
+Insights resource addressed by `AUTOPILOT_MONITOR_WEB_APPINSIGHTS_ID`, which the MCP
+`query_backend_logs` tool does not reach. Query it through
+`.claude/commands/scripts/query-appinsights.sh` with that ID exported, and read `dependencies`
+(client-side fetches, including RSC prefetches) and `browserTimings` (the network/processing split of
+a document load).
+
+# Contract
+
+Navigation `<Link>` elements in `GlobalSidebar` and `Navbar` set `prefetch={false}`. The prefetched
+RSC payload buys nothing for these routes, so the only remaining cost of a click is the route's JS
+chunk, which the browser caches after first use.
+
+Do not remove the prop to "speed up navigation" without first re-measuring the tail in the web
+Application Insights resource — the prefetch is cheap only while the runtime is warm.
+
+# Citations
+
+* `src/Web/autopilot-monitor-web/components/GlobalSidebar.tsx` — nav link rendering, rationale comment
+* `src/Web/autopilot-monitor-web/components/Navbar.tsx` — top-bar and notification links
+* [SWA and Oryx node pinning](../architecture.md) — hosting model for the web app

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Configuration/RemoteConfigMergerTests.cs

@@ -285,6 +285,54 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Configuration
             Assert.Equal(@"C:\Temp\custom-ime.log", agent.ImeMatchLogPath);
         }
 
+        [Fact]
+        public void Merge_maps_enable_gather_rule_debug_log_true_to_default_path()
+        {
+            var agent = NewAgentConfig();
+            agent.GatherRuleDebugLogPath = null;
+
+            var remote = FullRemote();
+            remote.EnableGatherRuleDebugLog = true;
+
+            RemoteConfigMerger.Merge(agent, remote);
+
+            Assert.False(string.IsNullOrEmpty(agent.GatherRuleDebugLogPath));
+            Assert.Equal(
+                Environment.ExpandEnvironmentVariables(Constants.GatherRuleDebugLogPath),
+                agent.GatherRuleDebugLogPath);
+        }
+
+        [Fact]
+        public void Merge_maps_enable_gather_rule_debug_log_false_clears_path()
+        {
+            var agent = NewAgentConfig();
+            agent.GatherRuleDebugLogPath = Environment.ExpandEnvironmentVariables(Constants.GatherRuleDebugLogPath);
+
+            var remote = FullRemote();
+            remote.EnableGatherRuleDebugLog = false;
+
+            RemoteConfigMerger.Merge(agent, remote);
+
+            Assert.Null(agent.GatherRuleDebugLogPath);
+        }
+
+        [Fact]
+        public void Merge_preserves_custom_gather_rule_debug_log_path_when_remote_disables()
+        {
+            // A dev-time --gather-debug-log <custom> override seeds a non-default path on the
+            // AgentConfiguration. When the tenant remote flips EnableGatherRuleDebugLog off we
+            // keep the custom path rather than clobbering a deliberate dev override.
+            var agent = NewAgentConfig();
+            agent.GatherRuleDebugLogPath = @"C:\Temp\custom-gather.log";
+
+            var remote = FullRemote();
+            remote.EnableGatherRuleDebugLog = false;
+
+            RemoteConfigMerger.Merge(agent, remote);
+
+            Assert.Equal(@"C:\Temp\custom-gather.log", agent.GatherRuleDebugLogPath);
+        }
+
         // ============================================================= Null / partial tolerance
 
         [Fact]

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/DeviceInfo/DeviceInfoCollectorEspRefreshTests.cs

@@ -0,0 +1,157 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Persistence;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using Xunit;
+using SharedEventTypes = AutopilotMonitor.Shared.Constants.EventTypes;
+using DeviceInfoCollector = AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo.DeviceInfoCollector;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.DeviceInfo
+{
+    /// <summary>
+    /// Audit Q2 — <see cref="DeviceInfoCollector.RefreshEspConfiguration"/>
+    /// re-reads the ESP blocking lists and re-emits <c>esp_config_detected</c> exactly when the
+    /// payload changed: the registry lists grow progressively (one timestamped subkey per CSP
+    /// status write) and the user-scope lists appear only after sign-in, so the early emissions
+    /// are structurally partial. The StartupEventGate keeps an unchanged re-read silent.
+    /// Probe overrides are static slots → serialized with the other probe-driven suites.
+    /// </summary>
+    [Collection("SerialThreading")]
+    public sealed class DeviceInfoCollectorEspRefreshTests
+    {
+        private static readonly DateTime T0 = new DateTime(2026, 7, 27, 10, 0, 0, DateTimeKind.Utc);
+
+        private const string DeviceApp1 = "11111111-1111-1111-1111-111111111111";
+        private const string DeviceApp2 = "22222222-2222-2222-2222-222222222222";
+        private const string UserApp1 = "33333333-3333-3333-3333-333333333333";
+
+        private static EspTrackingInfoSnapshot Snapshot(string[] deviceApps, string[] userApps)
+        {
+            var all = deviceApps.Concat(userApps).Distinct().ToArray();
+            return new EspTrackingInfoSnapshot(
+                msiProductCodes: Array.Empty<string>(),
+                modernAppPfns: Array.Empty<string>(),
+                win32AppIds: all,
+                userWin32AppIds: userApps,
+                msiCount: 0,
+                modernCount: 0,
+                win32Count: all.Length);
+        }
+
+        private static IReadOnlyList<FakeSignalIngressSink.PostedSignal> EspConfigEvents(FakeSignalIngressSink ingress) =>
+            ingress.Posted
+                .Where(p => p.Kind == DecisionSignalKind.InformationalEvent
+                            && p.Payload != null
+                            && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                            && et == SharedEventTypes.EspConfigDetected)
+                .ToList();
+
+        private static IReadOnlyList<string> TypedList(FakeSignalIngressSink.PostedSignal signal, string key)
+        {
+            var data = Assert.IsAssignableFrom<IReadOnlyDictionary<string, object>>(signal.TypedPayload);
+            return Assert.IsAssignableFrom<IReadOnlyList<string>>(data[key]);
+        }
+
+        [Fact]
+        public void Refresh_reemits_when_lists_grew_and_stays_silent_when_unchanged()
+        {
+            using var tmp = new TempDirectory();
+            var logger = new AgentLogger(tmp.Path, AgentLogLevel.Info);
+            var ingress = new FakeSignalIngressSink();
+            var clock = new VirtualClock(T0);
+            var collector = new DeviceInfoCollector(
+                "session-1", "tenant-1",
+                new InformationalEventPost(ingress, clock), logger,
+                signalIngress: null, clock: clock,
+                startupGate: new StartupEventGate(tmp.Path, logger));
+
+            using var skip = new EspSkipConfigurationProbe.ScopedFullOverride(
+                _ => new EspFirstSyncSnapshot(
+                    skipUser: false, skipDevice: false,
+                    blockInStatusPage: null, syncFailureTimeoutMinutes: null));
+
+            // Early read (agent start / DeviceSetup detection): partial device list, empty user list.
+            using (new EspTrackingInfoProbe.ScopedOverride(_ => Snapshot(new[] { DeviceApp1 }, Array.Empty<string>())))
+            {
+                collector.CollectEspConfiguration();
+            }
+            var afterEarly = EspConfigEvents(ingress);
+            Assert.Single(afterEarly);
+            Assert.Empty(TypedList(afterEarly[0], "espTrackedUserWin32AppIds"));
+
+            // Apps sub-phase opened: the device list grew and sign-in populated the user list.
+            using (new EspTrackingInfoProbe.ScopedOverride(_ => Snapshot(new[] { DeviceApp1, DeviceApp2 }, new[] { UserApp1 })))
+            {
+                collector.RefreshEspConfiguration(DeviceInfoHost.EspConfigTriggerAppsUser);
+            }
+            var afterGrowth = EspConfigEvents(ingress);
+            Assert.Equal(2, afterGrowth.Count);
+            Assert.Contains(DeviceApp2, TypedList(afterGrowth[1], "espTrackedWin32AppIds"));
+            Assert.Equal(new[] { UserApp1 }, TypedList(afterGrowth[1], "espTrackedUserWin32AppIds"));
+
+            // A later trigger with an UNCHANGED registry state re-reads but emits nothing —
+            // the StartupEventGate suppresses the identical payload.
+            using (new EspTrackingInfoProbe.ScopedOverride(_ => Snapshot(new[] { DeviceApp1, DeviceApp2 }, new[] { UserApp1 })))
+            {
+                collector.RefreshEspConfiguration(DeviceInfoHost.EspConfigTriggerAccountSetup);
+            }
+            Assert.Equal(2, EspConfigEvents(ingress).Count);
+        }
+
+        [Fact]
+        public async Task Concurrent_refreshes_never_emit_an_older_snapshot_after_a_newer_one()
+        {
+            // Codex review: the refresh triggers each run on their own Task.Run — without the
+            // collector-side lock, two collects can interleave read-before-emit and the LATER
+            // emission carries the OLDER (smaller) list. The backend keeps the latest
+            // list-bearing emission as positive evidence, so that would silently shrink it.
+            // The probe returns a strictly growing list per read; with the read→emit critical
+            // section, emission order must equal read order — sizes strictly ascending.
+            using var tmp = new TempDirectory();
+            var logger = new AgentLogger(tmp.Path, AgentLogLevel.Info);
+            var ingress = new FakeSignalIngressSink();
+            var clock = new VirtualClock(T0);
+            var collector = new DeviceInfoCollector(
+                "session-1", "tenant-1",
+                new InformationalEventPost(ingress, clock), logger,
+                signalIngress: null, clock: clock,
+                startupGate: new StartupEventGate(tmp.Path, logger));
+
+            using var skip = new EspSkipConfigurationProbe.ScopedFullOverride(
+                _ => new EspFirstSyncSnapshot(
+                    skipUser: false, skipDevice: false,
+                    blockInStatusPage: null, syncFailureTimeoutMinutes: null));
+
+            var readCounter = 0;
+            using var tracking = new EspTrackingInfoProbe.ScopedOverride(_ =>
+            {
+                var n = Interlocked.Increment(ref readCounter);
+                var ids = Enumerable.Range(1, n)
+                    .Select(i => $"{i:d8}-1111-2222-3333-444444444444")
+                    .ToArray();
+                return Snapshot(ids, Array.Empty<string>());
+            });
+
+            var tasks = Enumerable.Range(0, 12)
+                .Select(i => Task.Run(() => collector.RefreshEspConfiguration($"stress-{i}")))
+                .ToArray();
+            await Task.WhenAll(tasks);
+
+            var sizes = EspConfigEvents(ingress)
+                .Select(e => TypedList(e, "espTrackedWin32AppIds").Count)
+                .ToList();
+            // Every refresh saw a strictly larger list (gate never suppresses) and each
+            // read→emit is atomic, so the emission sequence is exactly 1..12.
+            Assert.Equal(Enumerable.Range(1, 12), sizes);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/GatherRuleDebugLogTests.cs

@@ -0,0 +1,104 @@
+using System;
+using System.IO;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
+{
+    /// <summary>
+    /// Writer unit tests for <see cref="GatherRuleDebugLog"/>: line format, lazy directory
+    /// creation, size-cap rotation, and the null-writer no-op path on the context.
+    /// </summary>
+    public sealed class GatherRuleDebugLogTests : IDisposable
+    {
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly AgentLogger _logger;
+
+        public GatherRuleDebugLogTests()
+        {
+            _logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
+        }
+
+        public void Dispose() => _tmp.Dispose();
+
+        private string LogPath => Path.Combine(_tmp.Path, "sub", "gather_rules_debug.log");
+
+        [Fact]
+        public void Write_produces_pipe_delimited_line_and_creates_directory_lazily()
+        {
+            var log = new GatherRuleDebugLog(LogPath, _logger);
+            Assert.False(File.Exists(LogPath)); // lazy — nothing until the first write
+
+            log.Write("RULE-1", GatherRuleDebugLog.StageScope, "skipped: out of scope");
+
+            var lines = File.ReadAllLines(LogPath);
+            Assert.Equal(2, lines.Length); // header + entry
+            Assert.Contains("| - | config | -- gather rule debug log started --", lines[0]);
+            var parts = lines[1].Split(new[] { " | " }, StringSplitOptions.None);
+            Assert.Equal(4, parts.Length);
+            Assert.Equal("RULE-1", parts[1]);
+            Assert.Equal("scope", parts[2]);
+            Assert.Equal("skipped: out of scope", parts[3]);
+        }
+
+        [Fact]
+        public void Write_flattens_newlines_except_for_error_stage()
+        {
+            var log = new GatherRuleDebugLog(LogPath, _logger);
+            log.Write("RULE-1", GatherRuleDebugLog.StageCollector, "line1\r\nline2");
+            log.Write("RULE-1", GatherRuleDebugLog.StageError, "boom\r\n   at Frame()");
+
+            var content = File.ReadAllText(LogPath);
+            Assert.Contains("line1 line2", content);
+            Assert.Contains("   at Frame()", content); // error stage keeps the stack multi-line
+        }
+
+        [Fact]
+        public void Write_null_ruleId_renders_dash()
+        {
+            var log = new GatherRuleDebugLog(LogPath, _logger);
+            log.Write(null, GatherRuleDebugLog.StageConfig, "no rules delivered");
+
+            Assert.Contains(" | - | config | no rules delivered", File.ReadAllText(LogPath));
+        }
+
+        [Fact]
+        public void Write_rotates_once_when_file_exceeds_cap()
+        {
+            var log = new GatherRuleDebugLog(LogPath, _logger, maxBytes: 512);
+            for (int i = 0; i < 20; i++)
+                log.Write("RULE-1", GatherRuleDebugLog.StageExec, new string('x', 100));
+
+            var oldPath = Path.Combine(Path.GetDirectoryName(LogPath), "gather_rules_debug.old.log");
+            Assert.True(File.Exists(oldPath), "expected one .old rotation generation");
+            Assert.True(File.Exists(LogPath));
+            Assert.Contains("-- rotated", File.ReadAllText(LogPath) + File.ReadAllText(oldPath));
+            // Never more than one .old generation
+            Assert.Single(Directory.GetFiles(Path.GetDirectoryName(LogPath), "*.old.log"));
+        }
+
+        [Fact]
+        public void WriteStandalone_writes_single_config_line()
+        {
+            GatherRuleDebugLog.WriteStandalone(LogPath, "no gather rules delivered by backend — nothing to execute", _logger);
+
+            var lines = File.ReadAllLines(LogPath);
+            Assert.Contains(lines, l => l.Contains("no gather rules delivered by backend"));
+        }
+
+        [Fact]
+        public void Context_DebugLog_is_noop_without_writer()
+        {
+            var context = new GatherRuleContext(
+                _logger, "sess", "tenant", _ => { }, null, new LogFilePositionTracker());
+
+            context.DebugLog("RULE-1", GatherRuleDebugLog.StageScope, "should not throw, should not write");
+
+            Assert.False(File.Exists(LogPath));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/GatherRuleExecutorDebugLogTests.cs

@@ -0,0 +1,156 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
+{
+    /// <summary>
+    /// Debug-trace coverage of <see cref="GatherRuleExecutor"/> (EnableGatherRuleDebugLog):
+    /// every "silently produced nothing" outcome must leave an explanatory line in the trace
+    /// file — registration summary, missing interval, scope skips, on_change suppression,
+    /// empty collector results.
+    /// </summary>
+    [Collection("SerialThreading")] // startup rules execute on the shared ThreadPool
+    public sealed class GatherRuleExecutorDebugLogTests : IDisposable
+    {
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly GatherRuleExecutor _executor;
+        private readonly string _debugLogPath;
+
+        private const string AbsentPath =
+            "HKLM\\SOFTWARE\\AutopilotMonitorTests\\DefinitelyAbsent_7e3a1f4b-0000-0000-0000-000000000000";
+
+        public GatherRuleExecutorDebugLogTests()
+        {
+            var logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
+            _debugLogPath = Path.Combine(_tmp.Path, "gather_rules_debug.log");
+            _executor = new GatherRuleExecutor(
+                "sess", "tenant", _ => { }, logger,
+                debugLogPath: _debugLogPath)
+            {
+                UnrestrictedMode = true
+            };
+        }
+
+        public void Dispose()
+        {
+            _executor.Dispose();
+            _tmp.Dispose();
+        }
+
+        private string TraceContent() => File.Exists(_debugLogPath) ? File.ReadAllText(_debugLogPath) : string.Empty;
+
+        private static GatherRule Rule(string id, Action<GatherRule>? mutate = null)
+        {
+            var rule = new GatherRule
+            {
+                RuleId = id,
+                Title = id,
+                CollectorType = "registry",
+                Target = AbsentPath,
+                Trigger = "startup",
+                OutputEventType = "gather_test",
+                Enabled = true,
+            };
+            mutate?.Invoke(rule);
+            return rule;
+        }
+
+        [Fact]
+        public void UpdateRules_writes_registration_summary_per_rule()
+        {
+            _executor.UpdateRules(new List<GatherRule>
+            {
+                Rule("GATHER-REG-001", r => { r.Trigger = "interval"; r.IntervalSeconds = 3600; r.EmitMode = "on_change"; }),
+                Rule("GATHER-REG-002", r => r.Enabled = false),
+            });
+            _executor.WaitForStartupRules(30);
+
+            var trace = TraceContent();
+            Assert.Contains("GATHER-REG-001 | config | registered: trigger=interval, collector=registry", trace);
+            Assert.Contains("emitMode=on_change", trace);
+            Assert.Contains("interval=3600s", trace);
+            Assert.Contains("GATHER-REG-002 | config | rule disabled — will never run", trace);
+            Assert.Contains("interval timer scheduled every 3600s (first run after one full interval", trace);
+        }
+
+        [Fact]
+        public void UpdateRules_flags_interval_rule_without_intervalSeconds()
+        {
+            _executor.UpdateRules(new List<GatherRule>
+            {
+                Rule("GATHER-NOINT-001", r => { r.Trigger = "interval"; r.IntervalSeconds = null; }),
+            });
+
+            Assert.Contains("GATHER-NOINT-001 | error | trigger=interval but intervalSeconds is missing — rule will NEVER run",
+                TraceContent());
+        }
+
+        [Fact]
+        public void ScopedRule_skip_traces_unknown_phase_reason()
+        {
+            var rule = Rule("GATHER-SCOPE-001", r => { r.Trigger = "interval"; r.IntervalSeconds = 3600; r.ActivePhases = new List<string> { "DeviceSetup" }; });
+            _executor.UpdateRules(new List<GatherRule> { rule });
+
+            // Synchronous internal check mirrors the timer-tick gate; the reason must name Unknown.
+            string reason;
+            Assert.False(_executor.IsRuleInScope(rule, out reason));
+            Assert.Contains("currentPhase=Unknown", reason);
+        }
+
+        [Fact]
+        public void ScopedStartupRule_deferral_is_traced()
+        {
+            _executor.UpdateRules(new List<GatherRule>
+            {
+                Rule("GATHER-DEFER-001", r => r.ActivePhases = new List<string> { "DeviceSetup" }),
+            });
+
+            Assert.Contains("GATHER-DEFER-001 | scope | startup rule deferred — currentPhase=Unknown", TraceContent());
+        }
+
+        [Fact]
+        public void OnChange_suppression_and_reemission_are_traced()
+        {
+            var rule = Rule("GATHER-OC-001", r => { r.Trigger = "interval"; r.IntervalSeconds = 3600; r.EmitMode = "on_change"; });
+            _executor.UpdateRules(new List<GatherRule> { rule });
+
+            string hashPrefix;
+            int streak;
+            var first = new Dictionary<string, object> { ["exists"] = false };
+            Assert.True(_executor.ShouldEmitOnChange(rule, first, out hashPrefix, out streak));
+            Assert.Equal(0, streak);
+            Assert.False(string.IsNullOrEmpty(hashPrefix));
+
+            Assert.False(_executor.ShouldEmitOnChange(rule, new Dictionary<string, object> { ["exists"] = false }, out hashPrefix, out streak));
+            Assert.Equal(1, streak);
+            Assert.False(_executor.ShouldEmitOnChange(rule, new Dictionary<string, object> { ["exists"] = false }, out hashPrefix, out streak));
+            Assert.Equal(2, streak);
+
+            var changed = new Dictionary<string, object> { ["exists"] = true };
+            Assert.True(_executor.ShouldEmitOnChange(rule, changed, out hashPrefix, out streak));
+            Assert.Equal(2, streak); // the streak that just ended
+            Assert.Equal(2, changed["suppressedPolls"]);
+        }
+
+        [Fact]
+        public void EmptyCollectorResult_is_traced_via_startup_execution()
+        {
+            _executor.UpdateRules(new List<GatherRule>
+            {
+                Rule("GATHER-EMPTY-001", r => r.Parameters = new Dictionary<string, string> { ["emitOnlyIfExists"] = "true" }),
+            });
+            Assert.True(_executor.WaitForStartupRules(30));
+
+            var trace = TraceContent();
+            Assert.Contains("GATHER-EMPTY-001 | exec | executing: collector=registry", trace);
+            Assert.Contains("GATHER-EMPTY-001 | collector | registry key/value not found", trace);
+            Assert.Contains("GATHER-EMPTY-001 | collector | collector returned EMPTY result — nothing emitted", trace);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Gather/LogParserCollectorDebugLogTests.cs

@@ -0,0 +1,121 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
+{
+    /// <summary>
+    /// Debug-trace coverage of <see cref="LogParserCollector"/>: the classic
+    /// "rule delivers nothing" cases must be explained in the trace — zero matches,
+    /// position-tracker skips, and plain-text logs parsed in the default cmtrace mode.
+    /// </summary>
+    public sealed class LogParserCollectorDebugLogTests : IDisposable
+    {
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly List<EnrollmentEvent> _events = new List<EnrollmentEvent>();
+        private readonly GatherRuleContext _context;
+        private readonly string _debugLogPath;
+
+        // %TEMP% lives under C:\Users (hard-blocked) — parse targets sit beside the
+        // test assembly instead, admitted via UnrestrictedMode.
+        private readonly string _outsideUsers = Path.Combine(
+            AppContext.BaseDirectory, "gather-debug-tests-" + Guid.NewGuid().ToString("N"));
+
+        public LogParserCollectorDebugLogTests()
+        {
+            Directory.CreateDirectory(_outsideUsers);
+            var logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
+            _debugLogPath = Path.Combine(_tmp.Path, "gather_rules_debug.log");
+            _context = new GatherRuleContext(
+                logger, "sess", "tenant",
+                evt => _events.Add(evt),
+                null,
+                new LogFilePositionTracker(),
+                new GatherRuleDebugLog(_debugLogPath, logger))
+            {
+                UnrestrictedMode = true
+            };
+        }
+
+        public void Dispose()
+        {
+            _tmp.Dispose();
+            try { Directory.Delete(_outsideUsers, recursive: true); } catch { /* best effort */ }
+        }
+
+        private string TraceContent() => File.Exists(_debugLogPath) ? File.ReadAllText(_debugLogPath) : string.Empty;
+
+        private static GatherRule Rule(string target, string pattern, string? format = null) => new GatherRule
+        {
+            RuleId = "GATHER-LP-DEBUG",
+            Title = "logparser debug test",
+            CollectorType = "logparser",
+            Target = target,
+            Parameters = format == null
+                ? new Dictionary<string, string> { ["pattern"] = pattern }
+                : new Dictionary<string, string> { ["pattern"] = pattern, ["format"] = format },
+            Trigger = "startup",
+            OutputEventType = "logparser_debug_test",
+        };
+
+        [Fact]
+        public void ZeroMatches_writes_per_file_outcome_line()
+        {
+            var path = Path.Combine(_outsideUsers, "app.log");
+            File.WriteAllText(path, "nothing interesting\nstill nothing\n");
+
+            new LogParserCollector().Execute(Rule(path, "WILL_NEVER_MATCH_[0-9]+", format: "text"), _context);
+
+            Assert.Empty(_events);
+            var trace = TraceContent();
+            Assert.Contains("app.log: read 2 lines", trace);
+            Assert.Contains("matched 0", trace);
+            Assert.Contains("mode=text", trace);
+        }
+
+        [Fact]
+        public void SecondRun_without_new_content_traces_position_skip()
+        {
+            var path = Path.Combine(_outsideUsers, "twice.log");
+            File.WriteAllText(path, "one line\n");
+            var rule = Rule(path, "one", format: "text");
+
+            var collector = new LogParserCollector();
+            collector.Execute(rule, _context);   // reads the file, advances the position
+            collector.Execute(rule, _context);   // nothing new
+
+            Assert.Contains("twice.log: no new content (position", TraceContent());
+        }
+
+        [Fact]
+        public void PlainTextFile_in_default_cmtrace_mode_gets_format_hint()
+        {
+            var path = Path.Combine(_outsideUsers, "plain.log");
+            File.WriteAllText(path, "plain line one\nplain line two\n");
+
+            new LogParserCollector().Execute(Rule(path, "plain"), _context); // default = cmtrace mode
+
+            Assert.Empty(_events);
+            var trace = TraceContent();
+            Assert.Contains("parseFailures=2", trace);
+            Assert.Contains("every line failed CMTrace parsing — if this is a plain-text log, set parameter format=text", trace);
+        }
+
+        [Fact]
+        public void MissingFile_traces_no_files_matched()
+        {
+            var path = Path.Combine(_outsideUsers, "does-not-exist.log");
+
+            new LogParserCollector().Execute(Rule(path, "x", format: "text"), _context);
+
+            Assert.Contains("no files matched target", TraceContent());
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Interop/NetshWifiFallbackTests.cs

@@ -0,0 +1,209 @@
+#nullable enable
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Interop;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Interop
+{
+    /// <summary>
+    /// Tests for the pure netsh-output parser of the WiFi fallback path. netsh labels follow
+    /// the OS UI language — the parser must extract SSID/signal/radio/channel from the label
+    /// variants of the languages commonly seen in enrollments, and degrade gracefully (fields
+    /// absent, never throw) on unrecognized ones.
+    /// </summary>
+    public sealed class NetshWifiFallbackTests
+    {
+        [Fact]
+        public void Parse_english_output_extracts_all_fields()
+        {
+            const string output = @"
+There is 1 interface on the system:
+
+    Name                   : Wi-Fi
+    Description            : Intel(R) Wi-Fi 6 AX201 160MHz
+    GUID                   : 754b6c07-5ae9-49d5-ba6c-4fbd6e38bbf6
+    State                  : connected
+    SSID                   : contoso-corp
+    AP BSSID               : 3c:37:12:53:c8:44
+    Band                   : 5 GHz
+    Channel                : 116
+    Radio type             : 802.11ax
+    Signal                 : 94%
+";
+            var r = NetshWifiFallback.Parse(output);
+
+            Assert.NotNull(r);
+            Assert.Equal("contoso-corp", r!.Ssid);
+            Assert.Equal(94, r.SignalPercent);
+            Assert.Equal("802.11ax", r.RadioType);
+            Assert.Equal(116, r.Channel);
+        }
+
+        [Fact]
+        public void Parse_german_output_extracts_all_fields()
+        {
+            const string output = @"
+Es ist 1 Schnittstelle auf dem System vorhanden:
+
+    Name                   : WLAN
+    Beschreibung           : Intel(R) Wi-Fi 6 AX201 160MHz
+    Status                 : Verbunden
+    SSID                   : fabrikam-wlan
+    Kanal                  : 44
+    Funktyp                : 802.11ac
+    Signal                 : 87%
+";
+            var r = NetshWifiFallback.Parse(output);
+
+            Assert.NotNull(r);
+            Assert.Equal("fabrikam-wlan", r!.Ssid);
+            Assert.Equal(87, r.SignalPercent);
+            Assert.Equal("802.11ac", r.RadioType);
+            Assert.Equal(44, r.Channel);
+        }
+
+        [Fact]
+        public void Parse_spanish_output_extracts_signal_and_channel()
+        {
+            const string output = @"
+    Nombre                 : Wi-Fi
+    SSID                   : contoso-es
+    Canal                  : 6
+    Tipo de radio          : 802.11n
+    Señal                  : 72%
+";
+            var r = NetshWifiFallback.Parse(output);
+
+            Assert.NotNull(r);
+            Assert.Equal("contoso-es", r!.Ssid);
+            Assert.Equal(72, r.SignalPercent);
+            Assert.Equal("802.11n", r.RadioType);
+            Assert.Equal(6, r.Channel);
+        }
+
+        [Fact]
+        public void Parse_chinese_simplified_output_extracts_all_fields()
+        {
+            const string output = @"
+    名称                   : WLAN
+    SSID                   : contoso-cn
+    信道                   : 149
+    无线电类型             : 802.11ac
+    信号                   : 68%
+";
+            var r = NetshWifiFallback.Parse(output);
+
+            Assert.NotNull(r);
+            Assert.Equal("contoso-cn", r!.Ssid);
+            Assert.Equal(68, r.SignalPercent);
+            Assert.Equal("802.11ac", r.RadioType);
+            Assert.Equal(149, r.Channel);
+        }
+
+        [Fact]
+        public void Parse_korean_output_extracts_all_fields()
+        {
+            const string output = @"
+    이름                   : Wi-Fi
+    SSID                   : contoso-kr
+    채널                   : 36
+    라디오 종류            : 802.11ax
+    신호                   : 91%
+";
+            var r = NetshWifiFallback.Parse(output);
+
+            Assert.NotNull(r);
+            Assert.Equal("contoso-kr", r!.Ssid);
+            Assert.Equal(91, r.SignalPercent);
+            Assert.Equal("802.11ax", r.RadioType);
+            Assert.Equal(36, r.Channel);
+        }
+
+        [Fact]
+        public void Parse_signal_with_space_before_percent_is_parsed()
+        {
+            var r = NetshWifiFallback.Parse("    Signal : 81 %\r\n    SSID : x\r\n");
+
+            Assert.NotNull(r);
+            Assert.Equal(81, r!.SignalPercent);
+        }
+
+        [Fact]
+        public void Parse_ap_bssid_does_not_overwrite_ssid()
+        {
+            const string output = @"
+    SSID                   : contoso-corp
+    AP BSSID               : aa:bb:cc:dd:ee:ff
+";
+            var r = NetshWifiFallback.Parse(output);
+
+            Assert.Equal("contoso-corp", r!.Ssid);
+        }
+
+        [Fact]
+        public void Parse_finnish_output_extracts_all_fields()
+        {
+            const string output = @"
+    Nimi                   : Wi-Fi
+    SSID                   : contoso-fi
+    Kanava                 : 100
+    Radiotyyppi            : 802.11ax
+    Signaali               : 79%
+";
+            var r = NetshWifiFallback.Parse(output);
+
+            Assert.NotNull(r);
+            Assert.Equal("contoso-fi", r!.Ssid);
+            Assert.Equal(79, r.SignalPercent);
+            Assert.Equal("802.11ax", r.RadioType);
+            Assert.Equal(100, r.Channel);
+        }
+
+        [Fact]
+        public void Parse_indonesian_output_extracts_all_fields()
+        {
+            const string output = @"
+    Nama                   : Wi-Fi
+    SSID                   : contoso-id
+    Saluran                : 11
+    Jenis radio            : 802.11n
+    Sinyal                 : 64%
+";
+            var r = NetshWifiFallback.Parse(output);
+
+            Assert.NotNull(r);
+            Assert.Equal("contoso-id", r!.Ssid);
+            Assert.Equal(64, r.SignalPercent);
+            Assert.Equal("802.11n", r.RadioType);
+            Assert.Equal(11, r.Channel);
+        }
+
+        [Fact]
+        public void Parse_unknown_language_without_ssid_returns_null()
+        {
+            // Greek is not in the enrollment-geography label set -> nothing to report.
+            var r = NetshWifiFallback.Parse("    Κατάσταση : συνδεδεμένο\r\n    Σήμα : 90%\r\n");
+
+            Assert.Null(r);
+        }
+
+        [Fact]
+        public void Parse_unknown_language_still_yields_ssid()
+        {
+            // SSID is untranslated in all locales — partial result beats none.
+            var r = NetshWifiFallback.Parse("    SSID : contoso-gr\r\n    Σήμα : 90%\r\n");
+
+            Assert.NotNull(r);
+            Assert.Equal("contoso-gr", r!.Ssid);
+            Assert.Null(r.SignalPercent);
+        }
+
+        [Theory]
+        [InlineData(null)]
+        [InlineData("")]
+        [InlineData("Der WLAN-AutoKonfig-Dienst (wlansvc) wird nicht ausgeführt.")]
+        public void Parse_empty_or_error_output_returns_null(string? output)
+        {
+            Assert.Null(NetshWifiFallback.Parse(output));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Interop/WifiInfoReaderTests.cs

@@ -0,0 +1,98 @@
+#nullable enable
+using System.Text;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Interop;
+using Xunit;
+using static AutopilotMonitor.Agent.V2.Core.Monitoring.Interop.WlanNativeMethods;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Interop
+{
+    /// <summary>
+    /// Tests for the native-WLAN-API WiFi reader. The WLAN state of the test machine is
+    /// unknown (CI runners/VMs have no WLAN service), so the live path only pins the
+    /// fail-soft contract; the pure helpers (SSID decode, PHY-type mapping) are pinned
+    /// exactly — their output feeds wifi_signal_info event payloads and must stay
+    /// consistent with the strings netsh historically reported.
+    /// </summary>
+    public sealed class WifiInfoReaderTests
+    {
+        [Fact]
+        public void TryGetCurrentConnection_never_throws_and_returns_sane_values()
+        {
+            var result = WifiInfoReader.TryGetCurrentConnection();
+
+            if (result != null)
+            {
+                Assert.True(result.SignalPercent.HasValue, "native API path must always carry signal quality");
+                Assert.InRange(result.SignalPercent.Value, 0, 100);
+                if (result.Channel.HasValue)
+                    Assert.True(result.Channel.Value > 0, "channel must be positive when present");
+            }
+        }
+
+        // ----- DecodeSsid ---------------------------------------------------
+
+        [Fact]
+        public void DecodeSsid_decodes_utf8_bytes()
+        {
+            var raw = new byte[32];
+            var ssid = Encoding.UTF8.GetBytes("Contoso-Büro");
+            ssid.CopyTo(raw, 0);
+
+            Assert.Equal("Contoso-Büro", WifiInfoReader.DecodeSsid(raw, (uint)ssid.Length));
+        }
+
+        [Fact]
+        public void DecodeSsid_returns_null_for_empty_or_missing()
+        {
+            Assert.Null(WifiInfoReader.DecodeSsid(null, 5));
+            Assert.Null(WifiInfoReader.DecodeSsid(new byte[32], 0));
+        }
+
+        [Fact]
+        public void DecodeSsid_clamps_length_to_buffer_size()
+        {
+            var raw = Encoding.UTF8.GetBytes("abc");
+
+            // A corrupt native length beyond the buffer must not throw.
+            Assert.Equal("abc", WifiInfoReader.DecodeSsid(raw, 200));
+        }
+
+        [Fact]
+        public void DecodeSsid_uses_only_declared_length()
+        {
+            var raw = new byte[32];
+            Encoding.UTF8.GetBytes("HomeNet-Rest-Ignored").CopyTo(raw, 0);
+
+            Assert.Equal("HomeNet", WifiInfoReader.DecodeSsid(raw, 7));
+        }
+
+        // ----- PhyTypeToRadioType -------------------------------------------
+
+        // int parameters (cast inside): DOT11_PHY_TYPE is internal and may not appear in a
+        // public test method signature (CS0051).
+        [Theory]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_ofdm, "802.11a")]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_hrdsss, "802.11b")]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_erp, "802.11g")]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_ht, "802.11n")]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_vht, "802.11ac")]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_dmg, "802.11ad")]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_he, "802.11ax")]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_eht, "802.11be")]
+        public void PhyTypeToRadioType_maps_known_generations(int phyType, string expected)
+        {
+            Assert.Equal(expected, WifiInfoReader.PhyTypeToRadioType((DOT11_PHY_TYPE)phyType));
+        }
+
+        [Theory]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_unknown)]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_fhss)]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_dsss)]
+        [InlineData((int)DOT11_PHY_TYPE.dot11_phy_type_irbaseband)]
+        [InlineData(9999)]
+        public void PhyTypeToRadioType_returns_null_for_legacy_or_unknown(int phyType)
+        {
+            Assert.Null(WifiInfoReader.PhyTypeToRadioType((DOT11_PHY_TYPE)phyType));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Runtime/DiagnosticsPackageServiceTests.cs

@@ -226,6 +226,95 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Runtime
             return archive.Entries.Select(e => e.FullName).ToArray();
         }
 
+        private static string ZipEntryText(byte[] zipBytes, string entryName)
+        {
+            using var ms = new MemoryStream(zipBytes);
+            using var archive = new ZipArchive(ms, ZipArchiveMode.Read);
+            var entry = archive.GetEntry(entryName);
+            Assert.NotNull(entry);
+            using var reader = new StreamReader(entry!.Open(), Encoding.UTF8);
+            return reader.ReadToEnd();
+        }
+
+        // ── Nullable outcome (on-demand mid-session) — gate + sessioninfo semantics ──
+
+        /// <summary>
+        /// Sentinel subclass: throws before any HTTP so gate-pass-through is observable as a
+        /// non-null error result (a skip returns null BEFORE the archive is ever built).
+        /// </summary>
+        private sealed class ThrowOnBuildService : DiagnosticsPackageService
+        {
+            public ThrowOnBuildService(AgentConfiguration cfg, AgentLogger logger, BackendApiClient api)
+                : base(cfg, logger, api) { }
+            internal override byte[] BuildArchiveBytes(bool? enrollmentSucceeded) =>
+                throw new System.InvalidOperationException("gate-passed-sentinel");
+        }
+
+        private static DiagnosticsPackageService BuildGateProbe(AgentLogger logger, string mode)
+        {
+            var cfg = Cfg();
+            cfg.DiagnosticsUploadEnabled = true;
+            cfg.DiagnosticsUploadMode = mode;
+            var apiClient = new BackendApiClient(
+                httpClient: new System.Net.Http.HttpClient(),
+                baseUrl: "http://localhost",
+                manufacturer: string.Empty,
+                model: string.Empty,
+                serialNumber: string.Empty,
+                useBootstrapTokenAuth: false,
+                bootstrapToken: null,
+                agentVersion: "0.0.0",
+                logger: logger);
+            return new ThrowOnBuildService(cfg, logger, apiClient);
+        }
+
+        [Fact]
+        public async System.Threading.Tasks.Task CreateAndUploadAsync_null_outcome_passes_OnFailure_gate()
+        {
+            // On-demand mid-session (no outcome yet): the OnFailure gate must NOT skip —
+            // there is no known success to skip on. Reaching the archive build (sentinel
+            // throw → error result) proves the gate was passed; a skip would return null.
+            using var rig = new Rig();
+            var result = await BuildGateProbe(rig.Logger, "OnFailure")
+                .CreateAndUploadAsync(enrollmentSucceeded: null, fileNameSuffix: "server-requested");
+
+            Assert.NotNull(result);
+            Assert.Equal("gate-passed-sentinel", result!.ErrorCode);
+        }
+
+        [Fact]
+        public async System.Threading.Tasks.Task CreateAndUploadAsync_known_success_still_skipped_by_OnFailure_gate()
+        {
+            using var rig = new Rig();
+            var result = await BuildGateProbe(rig.Logger, "OnFailure")
+                .CreateAndUploadAsync(enrollmentSucceeded: true);
+
+            Assert.Null(result);
+        }
+
+        [Fact]
+        public async System.Threading.Tasks.Task CreateAndUploadAsync_null_outcome_still_blocked_by_mode_Off()
+        {
+            using var rig = new Rig();
+            var result = await BuildGateProbe(rig.Logger, "Off")
+                .CreateAndUploadAsync(enrollmentSucceeded: null);
+
+            Assert.Null(result);
+        }
+
+        [Theory]
+        [InlineData(true, "Succeeded")]
+        [InlineData(false, "Failed")]
+        [InlineData(null, "In Progress")]
+        public void BuildArchiveBytes_sessioninfo_reflects_nullable_outcome(bool? outcome, string expected)
+        {
+            using var rig = new Rig();
+            var bytes = rig.Build().BuildArchiveBytes(outcome);
+
+            var sessionInfo = ZipEntryText(bytes, "sessioninfo.txt");
+            Assert.Contains($"Enrollment Result: {expected}", sessionInfo);
+        }
+
         // ── BuildBlobUploadUrl — destination-aware URL construction ─────────────────
 
         [Theory]

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/ModernDeploymentTrackerErrorBackfillTests.cs

@@ -112,6 +112,36 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
             Assert.Equal(false, data["backfilled"]);
         }
 
+        [Fact]
+        public void ErrorBackfillSummary_EmitsInfoLogEvent_AnnouncingTheReplayBlock()
+        {
+            _tracker.EmitErrorBackfillSummary(replayedCount: 6, droppedOverCap: 0);
+
+            var posted = _sink.Posted.Single(p => p.Kind == DecisionSignalKind.InformationalEvent);
+            Assert.Equal("modern_deployment_log", posted.Payload![SignalPayloadKeys.EventType]);
+
+            var data = Assert.IsAssignableFrom<IReadOnlyDictionary<string, object>>(posted.TypedPayload);
+            Assert.Equal(true, data["backfillSummary"]);
+            Assert.Equal(6, data["replayedCount"]);
+            Assert.Equal(0, data["droppedOverCap"]);
+            Assert.Equal(240, data["lookbackMinutes"]);
+
+            var message = (string)posted.Payload[SignalPayloadKeys.Message];
+            Assert.Contains("Replaying 6 error event(s)", message);
+            Assert.Contains("before the agent started", message);
+            Assert.DoesNotContain("cap", message);
+        }
+
+        [Fact]
+        public void ErrorBackfillSummary_MentionsDroppedRecords_WhenCapWasHit()
+        {
+            _tracker.EmitErrorBackfillSummary(replayedCount: 25, droppedOverCap: 7);
+
+            var posted = _sink.Posted.Single(p => p.Kind == DecisionSignalKind.InformationalEvent);
+            var message = (string)posted.Payload![SignalPayloadKeys.Message];
+            Assert.Contains("7 older record(s) beyond the 25-record cap", message);
+        }
+
         [Fact]
         public void BackfilledHarmlessId_StillRunsThroughRollupSuppression()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Orchestration/DeviceInfoHostTriggerTests.cs

@@ -37,5 +37,41 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
             Assert.False(DeviceInfoHost.IsEndTrigger(DecisionSignalKind.EspPhaseChanged, null));
             Assert.False(DeviceInfoHost.IsEndTrigger(DecisionSignalKind.InformationalEvent, Phase("FinalizingSetup")));
         }
+
+        // Audit Q2 — the payload shape the adapter's apps sub-phase declaration produces on the
+        // ingress rail (InformationalEventPost: eventType + declared phase enum name).
+        private static IReadOnlyDictionary<string, string> SubPhaseDeclaration(string declaredPhase) =>
+            new Dictionary<string, string>
+            {
+                { SignalPayloadKeys.EventType, AutopilotMonitor.Shared.Constants.EventTypes.PhaseTransition },
+                { AutopilotMonitor.Agent.V2.Core.Telemetry.Events.EventTimelineEmitter.PhaseParamKey, declaredPhase },
+            };
+
+        [Fact]
+        public void Apps_subphase_declarations_classify_as_esp_config_refresh_triggers()
+        {
+            Assert.Equal(DeviceInfoHost.EspConfigTriggerAppsDevice,
+                DeviceInfoHost.ClassifyEspConfigRefreshTrigger(DecisionSignalKind.InformationalEvent, SubPhaseDeclaration("AppsDevice")));
+            Assert.Equal(DeviceInfoHost.EspConfigTriggerAppsUser,
+                DeviceInfoHost.ClassifyEspConfigRefreshTrigger(DecisionSignalKind.InformationalEvent, SubPhaseDeclaration("AppsUser")));
+            // Non-apps phase declarations (e.g. the reducer's Finalizing entry) never classify.
+            Assert.Null(DeviceInfoHost.ClassifyEspConfigRefreshTrigger(DecisionSignalKind.InformationalEvent, SubPhaseDeclaration("FinalizingSetup")));
+            // A phase_transition without a declared phase never classifies.
+            Assert.Null(DeviceInfoHost.ClassifyEspConfigRefreshTrigger(DecisionSignalKind.InformationalEvent,
+                new Dictionary<string, string> { { SignalPayloadKeys.EventType, AutopilotMonitor.Shared.Constants.EventTypes.PhaseTransition } }));
+        }
+
+        [Fact]
+        public void AccountSetup_phase_classifies_as_the_user_setup_refresh_trigger()
+        {
+            Assert.Equal(DeviceInfoHost.EspConfigTriggerAccountSetup,
+                DeviceInfoHost.ClassifyEspConfigRefreshTrigger(DecisionSignalKind.EspPhaseChanged, Phase("AccountSetup")));
+            // DeviceSetup is the enrollment-start trigger, not an ESP-config refresh.
+            Assert.Null(DeviceInfoHost.ClassifyEspConfigRefreshTrigger(DecisionSignalKind.EspPhaseChanged, Phase("DeviceSetup")));
+            Assert.Null(DeviceInfoHost.ClassifyEspConfigRefreshTrigger(DecisionSignalKind.EspPhaseChanged, null));
+            // Unrelated informational events never classify.
+            Assert.Null(DeviceInfoHost.ClassifyEspConfigRefreshTrigger(DecisionSignalKind.InformationalEvent,
+                new Dictionary<string, string> { { SignalPayloadKeys.EventType, "esp_config_detected" } }));
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Security/HardwareInfoNormalizeTests.cs

@@ -0,0 +1,33 @@
+using AutopilotMonitor.Agent.V2.Core.Security;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Security
+{
+    /// <summary>
+    /// Audit Q5 — WMI hardware values are trimmed at the source. BIOS serials become device
+    /// identity keys downstream (F2 device history joins on TenantId + serial), so padding
+    /// must never leave the agent; whitespace-only values collapse to the "Unknown" sentinel
+    /// the retry logic already treats as unresolved.
+    /// </summary>
+    public sealed class HardwareInfoNormalizeTests
+    {
+        [Theory]
+        [InlineData(" PF60H941 ", "PF60H941")]
+        [InlineData("PF60H941", "PF60H941")]
+        [InlineData("\tLENOVO \r\n", "LENOVO")]
+        [InlineData("Unknown", "Unknown")]
+        public void Trims_whitespace_at_the_source(string raw, string expected)
+            => Assert.Equal(expected, HardwareInfo.NormalizeWmiValue(raw));
+
+        [Theory]
+        [InlineData("")]
+        [InlineData("   ")]
+        [InlineData("\t\r\n")]
+        public void Empty_and_whitespace_only_collapse_to_the_Unknown_sentinel(string raw)
+            => Assert.Equal("Unknown", HardwareInfo.NormalizeWmiValue(raw));
+
+        [Fact]
+        public void Null_collapses_to_the_Unknown_sentinel()
+            => Assert.Equal("Unknown", HardwareInfo.NormalizeWmiValue(null));
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/SignalAdapters/ImeLogTrackerAdapterTimingTests.cs

@@ -243,5 +243,87 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.SignalAdapters
 
             Assert.Equal(firstStamp, adapter.AppTimings["app-P"].StartedAtUtc);
         }
+
+        [Fact]
+        public void Terminal_to_active_retry_rearms_CompletedAt_and_final_terminal_covers_total_occupancy()
+        {
+            // Audit Q1: the IME retry path (Error -> Downloading -> Installed is permitted by
+            // AppPackageState.UpdateState). Pre-fix, CompletedAt froze at the first Error, so
+            // the final Installed payload carried the first failure's completedAt/duration.
+            using var f = new ImeLogTrackerAdapterFixture(T0);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+            var app = new AppPackageState("app-R", 0);
+
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Unknown, AppInstallationState.Installing);
+            f.Clock.Advance(TimeSpan.FromSeconds(5));
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Installing, AppInstallationState.Error);
+            f.Clock.Advance(TimeSpan.FromSeconds(10));
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Error, AppInstallationState.Downloading);
+
+            // Re-armed while active again: the retry's download event carries no completedAt,
+            // and the FIRST start stamp is kept.
+            Assert.Null(adapter.AppTimings["app-R"].CompletedAtUtc);
+            var retryDownload = f.InfoEvent(SharedEventTypes.AppDownloadStarted);
+            Assert.False(retryDownload.Payload!.ContainsKey("completedAt"));
+            Assert.False(retryDownload.Payload.ContainsKey("durationSeconds"));
+            Assert.Equal(T0.ToString("o"), retryDownload.Payload["startedAt"]);
+
+            f.Clock.Advance(TimeSpan.FromSeconds(20));
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Downloading, AppInstallationState.Installed);
+
+            var timing = adapter.AppTimings["app-R"];
+            Assert.Equal(T0, timing.StartedAtUtc);
+            Assert.Equal(T0.AddSeconds(35), timing.CompletedAtUtc);
+            Assert.Equal(35.0, timing.DurationSeconds);
+
+            var completed = Assert.Single(f.InfoEvents(SharedEventTypes.AppInstallComplete));
+            Assert.Equal("35.00", completed.Payload!["durationSeconds"]);
+            Assert.Equal(T0.AddSeconds(35).ToString("o"), completed.Payload["completedAt"]);
+        }
+
+        [Fact]
+        public void Skipped_then_retried_app_emits_positive_duration_from_retry_start()
+        {
+            // Production regression (session 66f1c5e1, audit Q1): a user-scope app evaluated
+            // Skipped during DeviceSetup (terminal, no start observed), retried after sign-in
+            // (Skipped -> Downloading is permitted), Installed later. Pre-fix payload:
+            // completedAt frozen at the early Skip + startedAt from the retry ->
+            // durationSeconds=-2342. Post-fix: retry re-arms, duration covers retry-start ->
+            // final terminal.
+            using var f = new ImeLogTrackerAdapterFixture(T0);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+            var app = new AppPackageState("app-S", 0);
+
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Unknown, AppInstallationState.Skipped);
+            Assert.Null(adapter.AppTimings["app-S"].StartedAtUtc);
+            Assert.Equal(T0, adapter.AppTimings["app-S"].CompletedAtUtc);
+
+            f.Clock.Advance(TimeSpan.FromSeconds(60));
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Skipped, AppInstallationState.Downloading);
+            f.Clock.Advance(TimeSpan.FromSeconds(30));
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Downloading, AppInstallationState.Installed);
+
+            var timing = adapter.AppTimings["app-S"];
+            Assert.Equal(T0.AddSeconds(60), timing.StartedAtUtc);
+            Assert.Equal(T0.AddSeconds(90), timing.CompletedAtUtc);
+            Assert.Equal(30.0, timing.DurationSeconds);
+
+            var completedEvents = f.InfoEvents(SharedEventTypes.AppInstallComplete);
+            Assert.Equal(2, completedEvents.Count);
+            Assert.Equal("30.00", completedEvents[1].Payload!["durationSeconds"]);
+        }
+
+        [Fact]
+        public void Inverted_endpoints_yield_null_DurationSeconds()
+        {
+            // Negative guard (audit Q1): endpoints stamped from out-of-order source lines must
+            // never surface as a negative durationSeconds (observed -2342s in production). The
+            // payload emitter omits the field when DurationSeconds is null.
+            var inverted = new AppInstallTiming(startedAtUtc: T0.AddSeconds(100), completedAtUtc: T0);
+            Assert.Null(inverted.DurationSeconds);
+
+            var wellOrdered = new AppInstallTiming(startedAtUtc: T0, completedAtUtc: T0.AddSeconds(100));
+            Assert.Equal(100.0, wellOrdered.DurationSeconds);
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Termination/EnrollmentTerminationHandlerTests.cs

@@ -511,6 +511,88 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Termination
                 $"network_bandwidth_estimate (@{bandwidthIdx}) must precede whiteglove_part1_complete (@{part1CompleteIdx}) so the straggler stays in Part 1.");
         }
 
+        // ===================================================== WG Part-1 preprov diagnostics
+        // V1 parity (restored 2026-07-28): the seal exit uploads the diagnostics package as a
+        // pre-provisioning intermediate under the SAME mode gating as the terminal path — the
+        // seal counts as a success, so Always uploads, OnFailure skips (a Part-1 failure
+        // terminates via the regular Failed path, which uploads), Off does nothing.
+
+        [Theory]
+        [InlineData("Always", true, 1)]
+        [InlineData("OnFailure", true, 0)]
+        [InlineData("Off", true, 0)]
+        [InlineData("Always", false, 0)]
+        public void Handle_whiteglove_part1_diagnostics_upload_respects_mode(
+            string mode, bool enabled, int expected)
+        {
+            using var rig = new Rig();
+            rig.State = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1")) { Stage = SessionStage.WhiteGloveSealed }.Build();
+            var cfg = rig.BuildConfig(diagEnabled: enabled, diagMode: mode);
+
+            rig.Build(cfg).Handle(sender: null!,
+                Args(EnrollmentTerminationReason.DecisionTerminalStage, EnrollmentTerminationOutcome.Succeeded, SessionStage.WhiteGloveSealed));
+
+            Assert.Equal(expected, rig.DiagnosticsUploads);
+        }
+
+        [Fact]
+        public void Handle_whiteglove_part1_diagnostics_upload_uses_preprov_suffix_and_succeeded_flag()
+        {
+            using var rig = new Rig();
+            rig.State = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1")) { Stage = SessionStage.WhiteGloveSealed }.Build();
+            var cfg = rig.BuildConfig(diagEnabled: true, diagMode: "Always");
+
+            rig.Build(cfg).Handle(sender: null!,
+                Args(EnrollmentTerminationReason.DecisionTerminalStage, EnrollmentTerminationOutcome.Succeeded, SessionStage.WhiteGloveSealed));
+
+            Assert.Equal(1, rig.DiagnosticsUploads);
+            Assert.Equal("preprov", rig.LastDiagnosticsSuffix);
+            Assert.Equal(true, rig.LastDiagnosticsSucceededFlag);
+        }
+
+        [Fact]
+        public void Handle_whiteglove_part1_diagnostics_events_precede_part1_complete_marker()
+        {
+            // whiteglove_part1_complete is the authoritative Part-1/Part-2 boundary for the
+            // web split (computeWhiteGloveSplitSequence) — diagnostics_collecting/uploaded
+            // must sequence BEFORE it or they get mis-filed into the resumed Part-2 block.
+            using var rig = new Rig();
+            rig.State = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1")) { Stage = SessionStage.WhiteGloveSealed }.Build();
+            rig.DiagnosticsResult = new DiagnosticsUploadResult { BlobName = "diag-preprov.zip" };
+            var cfg = rig.BuildConfig(diagEnabled: true, diagMode: "Always");
+
+            rig.Build(cfg).Handle(sender: null!,
+                Args(EnrollmentTerminationReason.DecisionTerminalStage, EnrollmentTerminationOutcome.Succeeded, SessionStage.WhiteGloveSealed));
+
+            var emitted = rig.EmittedEventTypes.ToList();
+            var collectingIdx = emitted.IndexOf("diagnostics_collecting");
+            var uploadedIdx = emitted.IndexOf("diagnostics_uploaded");
+            var part1CompleteIdx = emitted.IndexOf(Constants.EventTypes.WhiteGlovePart1Complete);
+
+            Assert.True(collectingIdx >= 0, "diagnostics_collecting must have been emitted.");
+            Assert.True(uploadedIdx >= 0, "diagnostics_uploaded must have been emitted.");
+            Assert.True(part1CompleteIdx >= 0, "whiteglove_part1_complete must have been emitted.");
+            Assert.True(uploadedIdx < part1CompleteIdx,
+                $"diagnostics_uploaded (@{uploadedIdx}) must precede whiteglove_part1_complete (@{part1CompleteIdx}) so the upload stays in Part 1.");
+        }
+
+        [Fact]
+        public void Handle_whiteglove_part1_still_skips_cleanup_and_marker_when_diagnostics_enabled()
+        {
+            // The preprov upload must not change the Part-1 exit contract: no self-destruct,
+            // no enrollment-complete.marker, whiteglove.complete still written.
+            using var rig = new Rig();
+            rig.State = new DecisionStateBuilder(DecisionState.CreateInitial("S1", "T1")) { Stage = SessionStage.WhiteGloveSealed }.Build();
+            var cfg = rig.BuildConfig(diagEnabled: true, diagMode: "Always");
+
+            rig.Build(cfg).Handle(sender: null!,
+                Args(EnrollmentTerminationReason.DecisionTerminalStage, EnrollmentTerminationOutcome.Succeeded, SessionStage.WhiteGloveSealed));
+
+            Assert.Equal(0, rig.CleanupService.Invocations);
+            Assert.False(File.Exists(Path.Combine(rig.StateDir, "enrollment-complete.marker")));
+            Assert.True(rig.SessionPersistence.IsWhiteGloveResume());
+        }
+
         [Fact]
         public void Handle_standalone_reboot_fires_when_reboot_enabled_and_no_self_destruct()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Termination/ObservationCoverageTests.cs

@@ -1,5 +1,7 @@
 using System;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
 using AutopilotMonitor.Agent.V2.Core.Termination;
+using AutopilotMonitor.Shared.Models;
 using Xunit;
 
 namespace AutopilotMonitor.Agent.V2.Core.Tests.Termination
@@ -70,5 +72,82 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Termination
             Assert.Equal(0, bootToStart, 0);
             Assert.Equal(10, uptime, 0);
         }
+
+        // --- DescribeLateStart: outcome-calibrated severity + phrasing (fleet 2026-07-28) ---
+
+        private static void Describe(
+            EnrollmentTerminationOutcome outcome, string oobeState,
+            out EventSeverity severity, out string message, out string note)
+            => ObservationCoverage.DescribeLateStart(
+                outcome, oobeState, bootToStartSeconds: 34 * 60, uptimeSeconds: 30,
+                out severity, out message, out note);
+
+        [Fact]
+        public void Failed_outcome_is_a_warning_with_the_hung_script_post_mortem_note()
+        {
+            Describe(EnrollmentTerminationOutcome.Failed, "in_progress",
+                out var severity, out var message, out var note);
+
+            Assert.Equal(EventSeverity.Warning, severity);
+            Assert.Contains("low coverage of the enrollment window", message);
+            Assert.Contains("post-mortem", note);
+            Assert.Contains("hung ahead of the bootstrap", note);
+        }
+
+        [Fact]
+        public void TimedOut_outcome_is_a_warning_like_a_failure()
+        {
+            Describe(EnrollmentTerminationOutcome.TimedOut, "in_progress",
+                out var severity, out _, out var note);
+
+            Assert.Equal(EventSeverity.Warning, severity);
+            Assert.Contains("post-mortem", note);
+        }
+
+        [Fact]
+        public void Succeeded_outcome_is_an_info_about_tail_only_coverage_without_alarm_framing()
+        {
+            // The 659c3a90 shape: healthy enrollment, bootstrap merely ran late in the ESP queue.
+            Describe(EnrollmentTerminationOutcome.Succeeded, "in_progress",
+                out var severity, out _, out var note);
+
+            Assert.Equal(EventSeverity.Info, severity);
+            Assert.Contains("succeeded", note);
+            Assert.Contains("IME log replay", note);
+            Assert.DoesNotContain("post-mortem", note);
+            Assert.DoesNotContain("hung", note);
+        }
+
+        [Fact]
+        public void Oobe_completed_at_start_phrases_a_pure_post_mortem()
+        {
+            Describe(EnrollmentTerminationOutcome.Failed, "completed",
+                out _, out var message, out _);
+
+            Assert.Contains("OOBE was already completed when the agent started", message);
+        }
+
+        [Fact]
+        public void Oobe_in_progress_at_start_phrases_the_live_tail()
+        {
+            Describe(EnrollmentTerminationOutcome.Failed, "in_progress",
+                out _, out var message, out _);
+
+            Assert.Contains("OOBE was still in progress at agent start", message);
+            Assert.Contains("final 30s live", message);
+        }
+
+        [Theory]
+        [InlineData("not_started")]  // flips in after a mid-OOBE reboot — not interpretable
+        [InlineData("unavailable")]  // WinRT contract absent / read failed
+        [InlineData("unknown_3")]    // unexpected enum value
+        public void Uninterpretable_oobe_states_add_no_claim_to_the_message(string oobeState)
+        {
+            Describe(EnrollmentTerminationOutcome.Failed, oobeState,
+                out _, out var message, out _);
+
+            Assert.DoesNotContain("OOBE", message);
+            Assert.EndsWith("low coverage of the enrollment window.", message);
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core/Configuration/AgentConfiguration.cs

@@ -121,6 +121,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Configuration
         /// </summary>
         public string ImeMatchLogPath { get; set; }
 
+        /// <summary>
+        /// Optional path to write a gather-rule evaluation trace (for debugging).
+        /// If empty, no trace is written. Set from remote config (EnableGatherRuleDebugLog)
+        /// or the --gather-debug-log CLI override.
+        /// </summary>
+        public string GatherRuleDebugLogPath { get; set; }
+
         /// <summary>
         /// Path to directory with real IME log files for log replay.
         /// When set, the agent replays these logs with time compression instead of reading live logs.

src/Agent/AutopilotMonitor.Agent.V2.Core/Configuration/RemoteConfigMerger.cs

@@ -135,6 +135,24 @@ namespace AutopilotMonitor.Agent.V2.Core.Configuration
                 }
             }
 
+            // ---------------- GatherRuleDebugLog: same bool→path projection as ImeMatchLog
+            //                  above. `true` expands Constants.GatherRuleDebugLogPath, `false`
+            //                  nulls the runtime path unless a --gather-debug-log CLI override
+            //                  supplied a non-default path.
+            if (remoteConfig.EnableGatherRuleDebugLog)
+            {
+                agentConfig.GatherRuleDebugLogPath = Environment.ExpandEnvironmentVariables(Constants.GatherRuleDebugLogPath);
+            }
+            else
+            {
+                var defaultGatherDebugPath = Environment.ExpandEnvironmentVariables(Constants.GatherRuleDebugLogPath);
+                if (string.IsNullOrEmpty(agentConfig.GatherRuleDebugLogPath)
+                    || string.Equals(agentConfig.GatherRuleDebugLogPath, defaultGatherDebugPath, StringComparison.OrdinalIgnoreCase))
+                {
+                    agentConfig.GatherRuleDebugLogPath = null;
+                }
+            }
+
             // ---------------- Upload interval / batch — direct, V1 parity (no > 0 gate so a
             //                  misconfigured tenant can in theory break uploads, but this
             //                  surfaces the config bug instead of silently masking it).

src/Agent/AutopilotMonitor.Agent.V2.Core/Configuration/RemoteConfigService.cs

@@ -327,6 +327,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Configuration
                 KeepLogFile = false,
                 EnableGeoLocation = true,
                 EnableImeMatchLog = false,
+                EnableGatherRuleDebugLog = false,
                 Collectors = CollectorConfiguration.CreateDefault(),
                 GatherRules = new System.Collections.Generic.List<GatherRule>(),
                 ImeLogPatterns = new System.Collections.Generic.List<ImeLogPattern>()

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/AppInstallTiming.cs

@@ -10,9 +10,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
     /// the <c>app_tracking_summary</c> terminal event.
     /// <para>
     /// <b>StartedAtUtc</b> is recorded on the first lifecycle transition into Downloading /
-    /// Installing / InProgress. <b>CompletedAtUtc</b> is recorded on the first transition to a
-    /// terminal state (Installed / Skipped / Postponed / Error). Both are "set-once" — subsequent
-    /// identical-state events do not overwrite an earlier stamp.
+    /// Installing / InProgress and never overwritten. <b>CompletedAtUtc</b> is recorded on a
+    /// transition to a terminal state (Installed / Skipped / Postponed / Error) and re-armed
+    /// to <c>null</c> when the app goes terminal → active again (IME retry / re-evaluation,
+    /// audit Q1) — so the final terminal event carries first-start → last-terminal.
     /// </para>
     /// </summary>
     public sealed class AppInstallTiming
@@ -30,10 +31,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// <summary>
         /// Elapsed time from first Downloading/Installing transition to terminal state, in
         /// seconds. <c>null</c> when either endpoint is missing (e.g. app still installing,
-        /// or the adapter missed the start event because it came online mid-install).
+        /// or the adapter missed the start event because it came online mid-install) — and
+        /// <c>null</c> when the endpoints are inverted (CompletedAt before StartedAt: log lines
+        /// from different source files can be processed out of chronological order; observed in
+        /// production as durationSeconds=-2342 on a Skipped-then-retried user-scope app,
+        /// audit Q1). A negative duration is never a real measurement, so it is not emitted.
         /// </summary>
         public double? DurationSeconds =>
-            StartedAtUtc.HasValue && CompletedAtUtc.HasValue
+            StartedAtUtc.HasValue && CompletedAtUtc.HasValue && CompletedAtUtc.Value >= StartedAtUtc.Value
                 ? (CompletedAtUtc.Value - StartedAtUtc.Value).TotalSeconds
                 : (double?)null;
     }

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/ModernDeploymentTracker.cs

@@ -631,10 +631,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// the regular <see cref="ProcessRecord"/> pipeline with isBackfill=true, so they arrive
         /// as modern_deployment_error events carrying backfilled=true plus the original
         /// timeCreated; the event's own timestamp is emission time, so session StartedAt is not
-        /// dragged backwards. Newest-first, capped, watermark-deduped across restarts.
+        /// dragged backwards. The scan reads newest-first (the cap keeps the newest records),
+        /// but replay is buffered so an Info summary event announces the block BEFORE the errors
+        /// hit the timeline (customer feedback 2026-07-28: an unannounced wall of pre-agent
+        /// Error events reads like a live failure) and the records emit oldest-first, giving the
+        /// timeline sequence the original event-log chronology. Watermark-deduped across restarts.
         /// </summary>
         private void BackfillAutopilotErrors()
         {
+            var buffered = new List<EventRecord>();
             try
             {
                 long watermark;
@@ -649,7 +654,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                     ReverseDirection = true
                 };
 
-                int processed = 0, skippedWatermark = 0, droppedOverCap = 0;
+                int skippedWatermark = 0, droppedOverCap = 0;
                 long maxSeen = watermark;
 
                 using (var reader = new EventLogReader(query))
@@ -657,37 +662,48 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                     EventRecord record;
                     while ((record = reader.ReadEvent()) != null)
                     {
-                        using (record)
+                        var recordId = record.RecordId ?? 0;
+                        if (recordId > maxSeen) maxSeen = recordId;
+
+                        if (recordId != 0 && recordId <= watermark)
                         {
-                            var recordId = record.RecordId ?? 0;
-                            if (recordId > maxSeen) maxSeen = recordId;
-
-                            if (recordId != 0 && recordId <= watermark)
-                            {
-                                skippedWatermark++;
-                                continue;
-                            }
-
-                            if (processed >= ErrorBackfillMaxRecords)
-                            {
-                                droppedOverCap++;
-                                continue;
-                            }
-
-                            processed++;
-                            ProcessRecord(record, "Autopilot", AutopilotChannel, isBackfill: true);
+                            skippedWatermark++;
+                            record.Dispose();
+                            continue;
                         }
+
+                        if (buffered.Count >= ErrorBackfillMaxRecords)
+                        {
+                            droppedOverCap++;
+                            record.Dispose();
+                            continue;
+                        }
+
+                        buffered.Add(record);
                     }
                 }
 
                 if (maxSeen > watermark)
                     AdvanceAutopilotErrorWatermark(maxSeen);
 
-                if (processed == 0 && droppedOverCap == 0)
+                if (buffered.Count == 0 && droppedOverCap == 0)
+                {
                     _logger.Debug($"ModernDeployment error backfill: nothing new (skippedByWatermark={skippedWatermark})");
+                }
                 else
-                    _logger.Info($"ModernDeployment error backfill: forwarded {processed} record(s) " +
+                {
+                    EmitErrorBackfillSummary(buffered.Count, droppedOverCap);
+
+                    // Scan buffered newest-first — replay in reverse so the emitted sequence
+                    // follows the original event-log chronology.
+                    for (var i = buffered.Count - 1; i >= 0; i--)
+                    {
+                        ProcessRecord(buffered[i], "Autopilot", AutopilotChannel, isBackfill: true);
+                    }
+
+                    _logger.Info($"ModernDeployment error backfill: forwarded {buffered.Count} record(s) " +
                         $"(skippedByWatermark={skippedWatermark}, droppedOverCap={droppedOverCap})");
+                }
             }
             catch (EventLogNotFoundException)
             {
@@ -701,6 +717,49 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             {
                 _logger.Warning($"ModernDeployment error backfill failed: {ex.Message}");
             }
+            finally
+            {
+                foreach (var record in buffered)
+                {
+                    try { record.Dispose(); } catch { }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Announces the error-backfill block on the session timeline BEFORE the replayed
+        /// errors, so pre-agent Error events are readable as history rather than a live
+        /// failure. The web timeline additionally badges each replayed event via its
+        /// backfilled=true payload marker; this summary carries backfillSummary=true instead —
+        /// it is a live emission, not a replayed record.
+        /// </summary>
+        internal void EmitErrorBackfillSummary(int replayedCount, int droppedOverCap)
+        {
+            var message = $"[Autopilot] Replaying {replayedCount} error event(s) recorded in the Autopilot event log " +
+                $"before the agent started (lookback {ErrorBackfillLookbackMinutes / 60}h). " +
+                "These predate monitoring — if enrollment progressed afterwards, they were already resolved by a retry.";
+            if (droppedOverCap > 0)
+            {
+                message += $" {droppedOverCap} older record(s) beyond the {ErrorBackfillMaxRecords}-record cap were not replayed.";
+            }
+
+            _post.Emit(new EnrollmentEvent
+            {
+                SessionId = _sessionId,
+                TenantId = _tenantId,
+                EventType = Constants.EventTypes.ModernDeploymentLog,
+                Severity = EventSeverity.Info,
+                Source = "ModernDeploymentWatcher",
+                Phase = EnrollmentPhase.Unknown,
+                Message = message,
+                Data = new Dictionary<string, object>
+                {
+                    { "backfillSummary", true },
+                    { "replayedCount", replayedCount },
+                    { "droppedOverCap", droppedOverCap },
+                    { "lookbackMinutes", ErrorBackfillLookbackMinutes }
+                }
+            });
         }
 
         /// <summary>

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Interop/NetshWifiFallback.cs

@@ -0,0 +1,221 @@
+using System;
+using System.Diagnostics;
+using AutopilotMonitor.Agent.V2.Core.Security;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Interop
+{
+    /// <summary>
+    /// Fallback WiFi reader via <c>netsh wlan show interfaces</c> output parsing, used ONLY
+    /// when <see cref="WifiInfoReader"/> (native WLAN API) yields nothing on a WiFi-connected
+    /// device. Field evidence 2026-07-28: the WLAN API can return nothing in the OOBE/SYSTEM
+    /// context on builds where inbox netsh still reports the connection — until that is fully
+    /// root-caused (suspect: Wi-Fi location gating, 24H2+), netsh stays as the safety net.
+    /// <para>
+    /// netsh labels follow the OS UI language, so the parser matches the label variants of
+    /// every language implied by the enrollment geography seen to date (see the comment on
+    /// the key arrays for the country→language derivation). Unknown-language labels fall
+    /// through harmlessly — the affected field is simply absent, same as before. "SSID"
+    /// itself is untranslated in all known locales.
+    /// </para>
+    /// </summary>
+    internal static class NetshWifiFallback
+    {
+        private const int NetshTimeoutMs = 5000;
+
+        // Label variants per field, by OS UI language. Matched case-insensitively against the
+        // full text left of the colon, so acronym-suffixed keys ("AP BSSID") never collide.
+        // Language set derived from enrollment geography (get_geographic_metrics, 365d):
+        // US/GB/AU/CA/IE/SG/IN/ZA/NG/PH en · DE/AT/CH de · BE/NL nl · BE/FR/CH fr · DK da ·
+        // SE sv · PL pl · TR tr · CN zh-CN · HK zh-TW · ES/MX/PE/PY es · CZ cs · SK sk ·
+        // IT/CH it · ID id · MY ms · FI fi · LT lt · LV lv · HU hu · BR/PT pt · JP ja ·
+        // KR ko · TH th · VN vi · RO/MD ro · BG bg · BA/HR hr · AE/SA/EG/JO ar ·
+        // MN/GE/AZ usually en/ru images → ru.
+        private static readonly string[] SignalKeys =
+        {
+            "Signal",     // en, de, fr, sv, da, nb, hr
+            "Señal",      // es
+            "Sinal",      // pt
+            "Segnale",    // it
+            "Signaal",    // nl
+            "Sygnał",     // pl
+            "Signál",     // cs, sk
+            "Sinyal",     // tr, id
+            "Isyarat",    // ms
+            "Signaali",   // fi
+            "Signalas",   // lt
+            "Signāls",    // lv
+            "Jel",        // hu
+            "Semnal",     // ro
+            "Tín hiệu",   // vi
+            "สัญญาณ",     // th
+            "الإشارة",    // ar
+            "إشارة",      // ar (variant without article)
+            "Сигнал",     // ru, bg
+            "シグナル",    // ja
+            "信号",        // zh-CN
+            "訊號",        // zh-TW
+            "신호",        // ko
+        };
+
+        private static readonly string[] RadioTypeKeys =
+        {
+            "Radio type",      // en
+            "Funktyp",         // de
+            "Type de radio",   // fr
+            "Tipo de radio",   // es
+            "Tipo de rádio",   // pt
+            "Tipo di radio",   // it
+            "Radiotype",       // nl, da
+            "Radiotyp",        // sv
+            "Typ radia",       // pl
+            "Typ rádia",       // cs, sk
+            "Radyo türü",      // tr
+            "Jenis radio",     // id, ms
+            "Radiotyyppi",     // fi
+            "Radijo tipas",    // lt
+            "Radio tips",      // lv
+            "Rádió típusa",    // hu
+            "Tip radio",       // ro
+            "Vrsta radija",    // hr, bs
+            "Loại radio",      // vi
+            "ชนิดวิทยุ",        // th
+            "نوع الراديو",     // ar
+            "Тип радио",       // ru
+            "Тип на радиото",  // bg
+            "無線の種類",       // ja
+            "无线电类型",       // zh-CN
+            "無線電類型",       // zh-TW
+            "라디오 종류",      // ko
+            "무선 종류",        // ko (variant)
+        };
+
+        private static readonly string[] ChannelKeys =
+        {
+            "Channel",     // en
+            "Kanal",       // de, sv, da, nb, tr, hr
+            "Canal",       // fr, es, pt, ro
+            "Canale",      // it
+            "Kanaal",      // nl
+            "Kanał",       // pl
+            "Kanál",       // cs, sk
+            "Saluran",     // id, ms
+            "Kanava",      // fi
+            "Kanalas",     // lt
+            "Kanāls",      // lv
+            "Csatorna",    // hu
+            "Kênh",        // vi
+            "ช่องสัญญาณ",   // th
+            "ช่อง",         // th (variant)
+            "القناة",      // ar
+            "قناة",        // ar (variant without article)
+            "Канал",       // ru, bg
+            "チャネル",     // ja
+            "信道",         // zh-CN
+            "通道",         // zh-TW / zh-CN (variant)
+            "채널",         // ko
+        };
+
+        /// <summary>
+        /// Runs <c>netsh wlan show interfaces</c> and parses its output. Returns a
+        /// <see cref="WifiConnectionInfo"/> with the fields that could be parsed, or null when
+        /// nothing was found (no WLAN, netsh failure, timeout, or unrecognized localized
+        /// labels). Never throws.
+        /// </summary>
+        internal static WifiConnectionInfo TryRead()
+        {
+            try
+            {
+                var psi = new ProcessStartInfo
+                {
+                    FileName = SystemPaths.Netsh,
+                    Arguments = "wlan show interfaces",
+                    UseShellExecute = false,
+                    RedirectStandardOutput = true,
+                    RedirectStandardError = true,
+                    CreateNoWindow = true
+                };
+
+                string output;
+                using (var process = Process.Start(psi))
+                {
+                    output = process.StandardOutput.ReadToEnd();
+                    if (!process.WaitForExit(NetshTimeoutMs))
+                    {
+                        try { process.Kill(); } catch { }
+                        return null;
+                    }
+                }
+
+                return Parse(output);
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// Pure parser over the netsh output text. Internal for direct unit-testing via
+        /// InternalsVisibleTo (TryRead itself spawns a process and stays untested).
+        /// </summary>
+        internal static WifiConnectionInfo Parse(string output)
+        {
+            if (string.IsNullOrEmpty(output))
+                return null;
+
+            string ssid = null, radioType = null;
+            int? signal = null, channel = null;
+
+            foreach (var line in output.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries))
+            {
+                var trimmed = line.Trim();
+                var colonIndex = trimmed.IndexOf(':');
+                if (colonIndex < 0) continue;
+
+                var key = trimmed.Substring(0, colonIndex).Trim();
+                var value = trimmed.Substring(colonIndex + 1).Trim();
+
+                if (key.Equals("SSID", StringComparison.OrdinalIgnoreCase))
+                {
+                    ssid = value;
+                }
+                else if (MatchesAny(key, SignalKeys))
+                {
+                    // Value formats seen: "94%", "94% " (trailing space), "94 %".
+                    if (int.TryParse(value.TrimEnd('%', ' '), out var sig))
+                        signal = sig;
+                }
+                else if (MatchesAny(key, RadioTypeKeys))
+                {
+                    radioType = value;
+                }
+                else if (MatchesAny(key, ChannelKeys))
+                {
+                    if (int.TryParse(value, out var ch))
+                        channel = ch;
+                }
+            }
+
+            if (ssid == null && signal == null && radioType == null && channel == null)
+                return null;
+
+            return new WifiConnectionInfo
+            {
+                Ssid = ssid,
+                SignalPercent = signal,
+                RadioType = radioType,
+                Channel = channel,
+            };
+        }
+
+        private static bool MatchesAny(string key, string[] candidates)
+        {
+            foreach (var candidate in candidates)
+            {
+                if (key.Equals(candidate, StringComparison.OrdinalIgnoreCase))
+                    return true;
+            }
+            return false;
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Interop/WifiInfoReader.cs

@@ -0,0 +1,234 @@
+using System;
+using System.Runtime.InteropServices;
+using System.Text;
+using static AutopilotMonitor.Agent.V2.Core.Monitoring.Interop.WlanNativeMethods;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Interop
+{
+    /// <summary>
+    /// Current WiFi connection details as read from the native WLAN API.
+    /// </summary>
+    public sealed class WifiConnectionInfo
+    {
+        /// <summary>SSID of the connected network; null when the AP broadcasts an empty SSID.</summary>
+        public string Ssid { get; internal set; }
+
+        /// <summary>
+        /// Signal quality 0–100 (same semantics as the netsh "Signal" percentage). Always set
+        /// on the native WLAN API path; null only when the netsh fallback could not parse it.
+        /// </summary>
+        public int? SignalPercent { get; internal set; }
+
+        /// <summary>Human-readable PHY generation ("802.11ax" …); null for exotic/unknown PHYs.</summary>
+        public string RadioType { get; internal set; }
+
+        /// <summary>Current 802.11 channel number; null when the channel query fails.</summary>
+        public int? Channel { get; internal set; }
+    }
+
+    /// <summary>
+    /// Fail-soft reader over <see cref="WlanNativeMethods"/>: returns the current WiFi
+    /// connection or null — never throws, never blocks on a child process. Machines without
+    /// the WLAN AutoConfig service (VMs, wired-only devices) simply return null.
+    /// </summary>
+    public static class WifiInfoReader
+    {
+        /// <summary>
+        /// Reads the current WiFi connection. When <paramref name="preferredInterfaceId"/> is
+        /// given (the adapter GUID from <c>NetworkInterface.Id</c>), that interface is queried
+        /// first; otherwise — or when it is not connected — the first connected WLAN interface
+        /// wins. Returns null when no interface has an active connection.
+        /// </summary>
+        public static WifiConnectionInfo TryGetCurrentConnection(Guid? preferredInterfaceId = null)
+            => TryGetCurrentConnection(preferredInterfaceId, out _);
+
+        /// <summary>
+        /// Same as <see cref="TryGetCurrentConnection(Guid?)"/> but reports WHY the read
+        /// yielded nothing via <paramref name="diagnostics"/> (native return codes per step).
+        /// The WLAN API can fail in ways that are invisible from the outside (e.g. per-process
+        /// access gating on newer Windows builds) — callers log this at Debug so field issues
+        /// are explainable from the agent log instead of a silent missing event.
+        /// </summary>
+        public static WifiConnectionInfo TryGetCurrentConnection(Guid? preferredInterfaceId, out string diagnostics)
+        {
+            var diag = new StringBuilder();
+            var clientHandle = IntPtr.Zero;
+            try
+            {
+                var rc = WlanOpenHandle(WLAN_CLIENT_VERSION, IntPtr.Zero, out _, out clientHandle);
+                if (rc != ERROR_SUCCESS)
+                {
+                    diagnostics = $"WlanOpenHandle rc={rc}";
+                    return null;
+                }
+
+                var interfaceList = IntPtr.Zero;
+                try
+                {
+                    rc = WlanEnumInterfaces(clientHandle, IntPtr.Zero, out interfaceList);
+                    if (rc != ERROR_SUCCESS)
+                    {
+                        diagnostics = $"WlanEnumInterfaces rc={rc}";
+                        return null;
+                    }
+
+                    var count = (uint)Marshal.ReadInt32(interfaceList);
+                    if (count == 0)
+                    {
+                        diagnostics = "no WLAN interfaces";
+                        return null;
+                    }
+
+                    var infoSize = Marshal.SizeOf(typeof(WLAN_INTERFACE_INFO));
+                    // List header: DWORD dwNumberOfItems + DWORD dwIndex, then the info array.
+                    var firstEntry = new IntPtr(interfaceList.ToInt64() + 8);
+
+                    WifiConnectionInfo fallback = null;
+                    for (var i = 0; i < count; i++)
+                    {
+                        var entryPtr = new IntPtr(firstEntry.ToInt64() + i * infoSize);
+                        var info = (WLAN_INTERFACE_INFO)Marshal.PtrToStructure(entryPtr, typeof(WLAN_INTERFACE_INFO));
+
+                        var connection = QueryCurrentConnection(clientHandle, info.InterfaceGuid, diag);
+                        if (connection == null)
+                            continue;
+
+                        if (preferredInterfaceId.HasValue && info.InterfaceGuid == preferredInterfaceId.Value)
+                        {
+                            diagnostics = null;
+                            return connection;
+                        }
+
+                        if (fallback == null)
+                            fallback = connection;
+                    }
+
+                    diagnostics = fallback == null ? diag.ToString() : null;
+                    return fallback;
+                }
+                finally
+                {
+                    if (interfaceList != IntPtr.Zero)
+                        WlanFreeMemory(interfaceList);
+                }
+            }
+            catch (Exception ex)
+            {
+                diagnostics = $"exception {ex.GetType().Name}: {ex.Message}";
+                return null;
+            }
+            finally
+            {
+                if (clientHandle != IntPtr.Zero)
+                    WlanCloseHandle(clientHandle, IntPtr.Zero);
+            }
+        }
+
+        private static WifiConnectionInfo QueryCurrentConnection(IntPtr clientHandle, Guid interfaceGuid, StringBuilder diag)
+        {
+            var dataPtr = IntPtr.Zero;
+            try
+            {
+                var rc = WlanQueryInterface(clientHandle, ref interfaceGuid,
+                        WLAN_INTF_OPCODE.wlan_intf_opcode_current_connection,
+                        IntPtr.Zero, out _, out dataPtr, IntPtr.Zero);
+                if (rc != ERROR_SUCCESS)
+                {
+                    diag.Append($"[{interfaceGuid:D}] query(current_connection) rc={rc}; ");
+                    return null;
+                }
+
+                var attributes = (WLAN_CONNECTION_ATTRIBUTES)Marshal.PtrToStructure(
+                    dataPtr, typeof(WLAN_CONNECTION_ATTRIBUTES));
+
+                if (attributes.isState != WLAN_INTERFACE_STATE.wlan_interface_state_connected)
+                {
+                    diag.Append($"[{interfaceGuid:D}] state={attributes.isState}; ");
+                    return null;
+                }
+
+                var assoc = attributes.wlanAssociationAttributes;
+                return new WifiConnectionInfo
+                {
+                    Ssid = DecodeSsid(assoc.dot11Ssid.ucSSID, assoc.dot11Ssid.uSSIDLength),
+                    SignalPercent = (int)Math.Min(assoc.wlanSignalQuality, 100),
+                    RadioType = PhyTypeToRadioType(assoc.dot11PhyType),
+                    Channel = QueryChannel(clientHandle, interfaceGuid),
+                };
+            }
+            finally
+            {
+                if (dataPtr != IntPtr.Zero)
+                    WlanFreeMemory(dataPtr);
+            }
+        }
+
+        private static int? QueryChannel(IntPtr clientHandle, Guid interfaceGuid)
+        {
+            var dataPtr = IntPtr.Zero;
+            try
+            {
+                if (WlanQueryInterface(clientHandle, ref interfaceGuid,
+                        WLAN_INTF_OPCODE.wlan_intf_opcode_channel_number,
+                        IntPtr.Zero, out var dataSize, out dataPtr, IntPtr.Zero) != ERROR_SUCCESS)
+                    return null;
+
+                if (dataSize < sizeof(uint) || dataPtr == IntPtr.Zero)
+                    return null;
+
+                return Marshal.ReadInt32(dataPtr);
+            }
+            catch
+            {
+                return null;
+            }
+            finally
+            {
+                if (dataPtr != IntPtr.Zero)
+                    WlanFreeMemory(dataPtr);
+            }
+        }
+
+        /// <summary>
+        /// Decodes a raw DOT11_SSID (UTF-8 by convention) into a string; null for empty SSIDs.
+        /// Internal for direct unit-testing via InternalsVisibleTo.
+        /// </summary>
+        internal static string DecodeSsid(byte[] raw, uint length)
+        {
+            if (raw == null || length == 0)
+                return null;
+
+            var byteCount = (int)Math.Min(length, (uint)raw.Length);
+            try
+            {
+                var ssid = Encoding.UTF8.GetString(raw, 0, byteCount);
+                return string.IsNullOrEmpty(ssid) ? null : ssid;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// Maps a DOT11 PHY type to the same strings netsh historically reported as
+        /// "Radio type" — keeps event payloads consistent across the netsh→WLAN-API switch.
+        /// Internal for direct unit-testing via InternalsVisibleTo.
+        /// </summary>
+        internal static string PhyTypeToRadioType(DOT11_PHY_TYPE phyType)
+        {
+            switch (phyType)
+            {
+                case DOT11_PHY_TYPE.dot11_phy_type_ofdm: return "802.11a";
+                case DOT11_PHY_TYPE.dot11_phy_type_hrdsss: return "802.11b";
+                case DOT11_PHY_TYPE.dot11_phy_type_erp: return "802.11g";
+                case DOT11_PHY_TYPE.dot11_phy_type_ht: return "802.11n";
+                case DOT11_PHY_TYPE.dot11_phy_type_vht: return "802.11ac";
+                case DOT11_PHY_TYPE.dot11_phy_type_dmg: return "802.11ad";
+                case DOT11_PHY_TYPE.dot11_phy_type_he: return "802.11ax";
+                case DOT11_PHY_TYPE.dot11_phy_type_eht: return "802.11be";
+                default: return null;
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Interop/WlanNativeMethods.cs

@@ -0,0 +1,142 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Interop
+{
+    /// <summary>
+    /// Native WLAN API interop (<c>wlanapi.dll</c>) used to read the current WiFi connection
+    /// (SSID, signal quality, PHY type, channel) without spawning <c>netsh</c>.
+    /// <para>
+    /// The WLAN API is language-neutral — unlike parsing <c>netsh wlan show interfaces</c>
+    /// output, whose labels follow the OS UI language and silently drop fields on
+    /// non-English images. On machines without the WLAN AutoConfig service (VMs, servers,
+    /// wired-only devices) <c>WlanOpenHandle</c>/<c>WlanEnumInterfaces</c> fail with a
+    /// non-zero error code; callers treat that as "no WiFi" (see <see cref="WifiInfoReader"/>).
+    /// </para>
+    /// </summary>
+    internal static class WlanNativeMethods
+    {
+        internal const uint ERROR_SUCCESS = 0;
+
+        /// <summary>Client version 2 = Vista and later (the only relevant range).</summary>
+        internal const uint WLAN_CLIENT_VERSION = 2;
+
+        internal enum WLAN_INTF_OPCODE : uint
+        {
+            wlan_intf_opcode_current_connection = 7,
+            wlan_intf_opcode_channel_number = 8,
+        }
+
+        internal enum WLAN_INTERFACE_STATE
+        {
+            wlan_interface_state_not_ready = 0,
+            wlan_interface_state_connected = 1,
+            wlan_interface_state_ad_hoc_network_formed = 2,
+            wlan_interface_state_disconnecting = 3,
+            wlan_interface_state_disconnected = 4,
+            wlan_interface_state_associating = 5,
+            wlan_interface_state_discovering = 6,
+            wlan_interface_state_authenticating = 7,
+        }
+
+        internal enum DOT11_PHY_TYPE : uint
+        {
+            dot11_phy_type_unknown = 0,
+            dot11_phy_type_fhss = 1,
+            dot11_phy_type_dsss = 2,
+            dot11_phy_type_irbaseband = 3,
+            dot11_phy_type_ofdm = 4,    // 802.11a
+            dot11_phy_type_hrdsss = 5,  // 802.11b
+            dot11_phy_type_erp = 6,     // 802.11g
+            dot11_phy_type_ht = 7,      // 802.11n
+            dot11_phy_type_vht = 8,     // 802.11ac
+            dot11_phy_type_dmg = 9,     // 802.11ad
+            dot11_phy_type_he = 10,     // 802.11ax
+            dot11_phy_type_eht = 11,    // 802.11be
+        }
+
+        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+        internal struct WLAN_INTERFACE_INFO
+        {
+            public Guid InterfaceGuid;
+            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
+            public string strInterfaceDescription;
+            public WLAN_INTERFACE_STATE isState;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct DOT11_SSID
+        {
+            public uint uSSIDLength;
+            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
+            public byte[] ucSSID;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct WLAN_ASSOCIATION_ATTRIBUTES
+        {
+            public DOT11_SSID dot11Ssid;
+            public int dot11BssType;
+            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)]
+            public byte[] dot11Bssid;
+            public DOT11_PHY_TYPE dot11PhyType;
+            public uint uDot11PhyIndex;
+            public uint wlanSignalQuality; // 0..100, same semantics as netsh "Signal"
+            public uint ulRxRate;
+            public uint ulTxRate;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct WLAN_SECURITY_ATTRIBUTES
+        {
+            [MarshalAs(UnmanagedType.Bool)]
+            public bool bSecurityEnabled;
+            [MarshalAs(UnmanagedType.Bool)]
+            public bool bOneXEnabled;
+            public int dot11AuthAlgorithm;
+            public int dot11CipherAlgorithm;
+        }
+
+        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+        internal struct WLAN_CONNECTION_ATTRIBUTES
+        {
+            public WLAN_INTERFACE_STATE isState;
+            public int wlanConnectionMode;
+            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
+            public string strProfileName;
+            public WLAN_ASSOCIATION_ATTRIBUTES wlanAssociationAttributes;
+            public WLAN_SECURITY_ATTRIBUTES wlanSecurityAttributes;
+        }
+
+        [DllImport("wlanapi.dll")]
+        internal static extern uint WlanOpenHandle(
+            uint dwClientVersion,
+            IntPtr pReserved,
+            out uint pdwNegotiatedVersion,
+            out IntPtr phClientHandle);
+
+        [DllImport("wlanapi.dll")]
+        internal static extern uint WlanCloseHandle(
+            IntPtr hClientHandle,
+            IntPtr pReserved);
+
+        [DllImport("wlanapi.dll")]
+        internal static extern uint WlanEnumInterfaces(
+            IntPtr hClientHandle,
+            IntPtr pReserved,
+            out IntPtr ppInterfaceList);
+
+        [DllImport("wlanapi.dll")]
+        internal static extern uint WlanQueryInterface(
+            IntPtr hClientHandle,
+            [In] ref Guid pInterfaceGuid,
+            WLAN_INTF_OPCODE OpCode,
+            IntPtr pReserved,
+            out uint pdwDataSize,
+            out IntPtr ppData,
+            IntPtr pWlanOpcodeValueType);
+
+        [DllImport("wlanapi.dll")]
+        internal static extern void WlanFreeMemory(IntPtr pMemory);
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Runtime/DiagnosticsPackageService.cs

@@ -218,15 +218,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
         /// This method is non-fatal: all exceptions are caught and logged.
         /// </summary>
         /// <param name="enrollmentSucceeded">
-        /// True for a successful enrollment (affects OnFailure mode check and sessioninfo.txt content).
-        /// Pass true for WhiteGlove pre-provisioning (it succeeded up to this point).
+        /// True for a successful enrollment, false for a failed one (drives the OnFailure mode
+        /// check and sessioninfo.txt content). Pass true for WhiteGlove pre-provisioning (it
+        /// succeeded up to this point). Pass <b>null</b> when the session has no outcome yet
+        /// (on-demand server-requested collection mid-enrollment): the OnFailure gate does not
+        /// apply — there is no success to skip on — and sessioninfo.txt records "In Progress".
         /// </param>
         /// <param name="fileNameSuffix">
         /// Optional suffix inserted before the .zip extension.
         /// Example: "preprov" → AgentDiagnostics-{sessionId}-{timestamp}-preprov.zip
         /// Null (default) → AgentDiagnostics-{sessionId}-{timestamp}.zip
         /// </param>
-        public virtual async Task<DiagnosticsUploadResult> CreateAndUploadAsync(bool enrollmentSucceeded, string fileNameSuffix = null)
+        public virtual async Task<DiagnosticsUploadResult> CreateAndUploadAsync(bool? enrollmentSucceeded, string fileNameSuffix = null)
         {
             try
             {
@@ -244,13 +247,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
                     return null;
                 }
 
-                if (string.Equals(mode, "OnFailure", StringComparison.OrdinalIgnoreCase) && enrollmentSucceeded)
+                // Null outcome (on-demand mid-session) passes through: the OnFailure gate only
+                // skips a KNOWN success — an in-flight session has nothing to skip on.
+                if (string.Equals(mode, "OnFailure", StringComparison.OrdinalIgnoreCase) && enrollmentSucceeded == true)
                 {
                     _logger.Info("Diagnostics upload skipped: enrollment succeeded and mode=OnFailure");
                     return null;
                 }
 
-                _logger.Info($"Creating diagnostics package (mode={mode}, enrollmentSucceeded={enrollmentSucceeded}{(fileNameSuffix != null ? $", suffix={fileNameSuffix}" : "")})...");
+                _logger.Info($"Creating diagnostics package (mode={mode}, enrollmentSucceeded={(enrollmentSucceeded.HasValue ? enrollmentSucceeded.ToString() : "n/a")}{(fileNameSuffix != null ? $", suffix={fileNameSuffix}" : "")})...");
 
                 // Build ZIP in memory
                 var timestamp = DateTime.UtcNow.ToString("yyyyMMddHHmmss");
@@ -343,7 +348,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
 
         // Builds the diagnostics ZIP body in-memory. Extracted from CreateAndUploadAsync so
         // tests can assert archive contents without going through the upload path.
-        internal virtual byte[] BuildArchiveBytes(bool enrollmentSucceeded)
+        internal virtual byte[] BuildArchiveBytes(bool? enrollmentSucceeded)
         {
             var tracker = new BudgetTracker(Budget);
             using (var ms = new MemoryStream())
@@ -414,14 +419,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
             }
         }
 
-        private void AddSessionInfo(ZipArchive archive, bool enrollmentSucceeded)
+        private void AddSessionInfo(ZipArchive archive, bool? enrollmentSucceeded)
         {
             var sb = new StringBuilder();
             sb.AppendLine($"Session ID: {_configuration.SessionId}");
             sb.AppendLine($"Tenant ID: {_configuration.TenantId}");
             sb.AppendLine($"Device Name: {Environment.MachineName}");
             sb.AppendLine($"Timestamp: {DateTime.UtcNow:O}");
-            sb.AppendLine($"Enrollment Result: {(enrollmentSucceeded ? "Succeeded" : "Failed")}");
+            sb.AppendLine($"Enrollment Result: {(enrollmentSucceeded == null ? "In Progress" : enrollmentSucceeded.Value ? "Succeeded" : "Failed")}");
 
             // Hardware info via existing DeviceInfoProvider (WMI)
             sb.AppendLine($"Manufacturer: {DeviceInfoProvider.GetManufacturer()}");

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/DeviceInfo/DeviceInfoCollector.NetworkAndSecurity.cs

@@ -706,10 +706,27 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo
         /// the desktop via "Continue anyway".
         /// </para>
         /// </summary>
+        // Serializes the ESP-config read+emit across ALL callers (CollectAll on the startup
+        // ThreadPool task, CollectAtEnrollmentStart and RefreshEspConfiguration on their own
+        // Task.Run) — without it, two concurrent collects can interleave read-before-emit and
+        // the LATER emission can carry the OLDER (smaller) registry snapshot. The backend keeps
+        // the latest list-bearing emission as positive blocking evidence, so an out-of-order
+        // emission would silently shrink it (Codex review). Inside the lock each collect is
+        // read→emit atomic: a later emission always carries an equal-or-newer snapshot.
+        private readonly object _espConfigCollectLock = new object();
+
         // Internal (not private) as a test seam: unlike CollectAll/CollectAtEnrollmentStart this
         // method touches no live system state once both probes are overridden, so tests can
         // drive the esp_config_detected event surface in isolation (InternalsVisibleTo).
         internal (bool? skipUserStatusPage, bool? skipDeviceStatusPage) CollectEspConfiguration()
+        {
+            lock (_espConfigCollectLock)
+            {
+                return CollectEspConfigurationLocked();
+            }
+        }
+
+        private (bool? skipUserStatusPage, bool? skipDeviceStatusPage) CollectEspConfigurationLocked()
         {
             bool? skipUser = null;
             bool? skipDevice = null;
@@ -798,7 +815,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo
         /// Collects active network interface details (name, type, link speed, MAC) using
         /// System.Net.NetworkInformation — instant, no process spawn.
         /// If the active interface is WiFi, fires off a separate async task to collect
-        /// WiFi signal info via netsh (fire-and-forget, never blocks).
+        /// WiFi signal info via the native WLAN API (fire-and-forget, never blocks).
         /// </summary>
         private void CollectActiveNetworkInterfaceInfo()
         {
@@ -841,7 +858,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo
                 // Fire-and-forget WiFi signal collection — separate event, never blocks
                 if (isWifi)
                 {
-                    Task.Run(() => CollectWiFiSignalInfo());
+                    Guid? nicGuid = Guid.TryParse(activeNic.Id, out var parsedGuid) ? parsedGuid : (Guid?)null;
+                    Task.Run(() => CollectWiFiSignalInfo(nicGuid));
                 }
             }
             catch (Exception ex)
@@ -882,78 +900,41 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo
         }
 
         /// <summary>
-        /// Collects WiFi signal info via netsh wlan show interfaces and emits a separate
-        /// wifi_signal_info event. Designed to run as fire-and-forget via Task.Run —
-        /// never blocks other collection. VMs without WiFi service simply get no event.
+        /// Collects WiFi signal info via the native WLAN API (<see cref="WifiInfoReader"/>,
+        /// language-neutral, no process spawn) and emits a separate wifi_signal_info event.
+        /// Designed to run as fire-and-forget via Task.Run — never blocks other collection.
+        /// VMs without WiFi service simply get no event.
         /// </summary>
-        private void CollectWiFiSignalInfo()
+        private void CollectWiFiSignalInfo(Guid? interfaceGuid)
         {
             try
             {
-                var psi = new ProcessStartInfo
+                var wifi = WifiInfoReader.TryGetCurrentConnection(interfaceGuid, out var wifiDiag);
+                if (wifi == null)
                 {
-                    FileName = SystemPaths.Netsh,
-                    Arguments = "wlan show interfaces",
-                    UseShellExecute = false,
-                    RedirectStandardOutput = true,
-                    RedirectStandardError = true,
-                    CreateNoWindow = true
-                };
-
-                string output;
-                using (var process = Process.Start(psi))
-                {
-                    output = process.StandardOutput.ReadToEnd();
-                    process.WaitForExit(5000);
+                    _logger.Debug($"EnrollmentTracker: native WLAN API returned no WiFi info ({wifiDiag ?? "no connected WLAN interface"}) — trying netsh fallback");
+                    wifi = NetshWifiFallback.TryRead();
+                    if (wifi == null)
+                        return;
                 }
 
-                if (string.IsNullOrEmpty(output))
-                    return;
-
                 var data = new Dictionary<string, object>();
+                if (wifi.Ssid != null)
+                    data["wifiSsid"] = wifi.Ssid;
+                if (wifi.SignalPercent.HasValue)
+                    data["wifiSignalPercent"] = wifi.SignalPercent.Value;
+                if (wifi.RadioType != null)
+                    data["wifiRadioType"] = wifi.RadioType;
+                if (wifi.Channel.HasValue)
+                    data["wifiChannel"] = wifi.Channel.Value;
 
-                foreach (var line in output.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries))
-                {
-                    var trimmed = line.Trim();
-                    var colonIndex = trimmed.IndexOf(':');
-                    if (colonIndex < 0) continue;
+                var message = wifi.Ssid != null ? $"WiFi: {wifi.Ssid}" : "WiFi signal info";
+                if (wifi.SignalPercent.HasValue)
+                    message += $", Signal: {wifi.SignalPercent.Value}%";
+                if (wifi.RadioType != null)
+                    message += $" ({wifi.RadioType})";
 
-                    var key = trimmed.Substring(0, colonIndex).Trim();
-                    var value = trimmed.Substring(colonIndex + 1).Trim();
-
-                    if (key.Equals("SSID", StringComparison.OrdinalIgnoreCase) &&
-                        !key.Equals("BSSID", StringComparison.OrdinalIgnoreCase))
-                    {
-                        data["wifiSsid"] = value;
-                    }
-                    else if (key.Equals("Signal", StringComparison.OrdinalIgnoreCase))
-                    {
-                        if (int.TryParse(value.TrimEnd('%'), out var signal))
-                            data["wifiSignalPercent"] = signal;
-                    }
-                    else if (key.Equals("Radio type", StringComparison.OrdinalIgnoreCase))
-                    {
-                        data["wifiRadioType"] = value;
-                    }
-                    else if (key.Equals("Channel", StringComparison.OrdinalIgnoreCase))
-                    {
-                        if (int.TryParse(value, out var channel))
-                            data["wifiChannel"] = channel;
-                    }
-                }
-
-                if (data.Count > 0)
-                {
-                    var message = data.ContainsKey("wifiSsid")
-                        ? $"WiFi: {data["wifiSsid"]}"
-                        : "WiFi signal info";
-                    if (data.ContainsKey("wifiSignalPercent"))
-                        message += $", Signal: {data["wifiSignalPercent"]}%";
-                    if (data.ContainsKey("wifiRadioType"))
-                        message += $" ({data["wifiRadioType"]})";
-
-                    EmitDeviceInfoEvent(Constants.EventTypes.WifiSignalInfo, message, data);
-                }
+                EmitDeviceInfoEvent(Constants.EventTypes.WifiSignalInfo, message, data);
             }
             catch (Exception ex)
             {

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/DeviceInfo/DeviceInfoCollector.cs

@@ -114,6 +114,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo
             CollectTpmStatus();
         }
 
+        /// <summary>
+        /// Re-reads the ESP configuration (skip flags + ESPTrackingInfo blocking lists) and
+        /// re-emits <c>esp_config_detected</c> when the payload changed. Audit Q2: the earlier
+        /// emissions (agent start, DeviceSetup detection) fire before the registry lists are
+        /// complete — the ESP writes one timestamped subkey per CSP status write, so the
+        /// device-scope list grows progressively and the user-scope <c>S-&lt;SID&gt;</c> lists
+        /// appear only after sign-in. Called by <see cref="Orchestration.DeviceInfoHost"/> as
+        /// phase-driven one-shots (apps sub-phase opened, AccountSetup detected) — never on a
+        /// timer. The StartupEventGate keeps an unchanged payload silent, so a re-collect that
+        /// found nothing new emits nothing.
+        /// </summary>
+        public void RefreshEspConfiguration(string trigger)
+        {
+            _logger.Info($"EnrollmentTracker: re-collecting ESP configuration (trigger={trigger})");
+            CollectEspConfiguration();
+        }
+
         /// <summary>
         /// Re-collects device info that may change during enrollment (e.g. BitLocker enabled via policy).
         /// Called at enrollment complete / FinalizingSetup transition to capture final state.

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/Collectors/LogParserCollector.cs

@@ -25,14 +25,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
         {
             var filePath = rule.Target;
             if (string.IsNullOrEmpty(filePath))
+            {
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser, "empty target — nothing to parse");
                 return null;
+            }
 
             // Expand custom tokens (%LOGGED_ON_USER_PROFILE%) and standard environment variables
             var userProfilePath = UserProfileResolver.ContainsUserProfileToken(filePath)
                 ? UserProfileResolver.GetLoggedOnUserProfilePath() : null;
             filePath = UserProfileResolver.ExpandCustomTokens(filePath);
             if (filePath == null)
+            {
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                    "target contains %LOGGED_ON_USER_PROFILE% but no user is logged on — skipped this run");
                 return null; // Token present but no user logged on — skip silently
+            }
 
             // Apply IME log path override if set. The override comes from the local
             // --ime-log-path flag only (never from remote config), so the operator
@@ -66,6 +73,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
                 string.IsNullOrEmpty(patternStr))
             {
                 context.Logger.Warning($"LogParser rule {rule.RuleId} has no 'pattern' parameter");
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageError,
+                    "missing 'pattern' parameter — rule can never match");
                 return null;
             }
 
@@ -93,6 +102,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             catch (Exception ex)
             {
                 context.Logger.Warning($"LogParser rule {rule.RuleId} has invalid regex: {ex.Message}");
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageError,
+                    $"invalid regex pattern — rule can never match: {ex.Message}");
                 return null;
             }
 
@@ -101,6 +112,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             if (resolvedPaths.Count == 0)
             {
                 context.Logger.Debug($"LogParser rule {rule.RuleId}: no files found for: {filePath}");
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                    $"no files matched target {filePath}" + (HasWildcard(Path.GetFileName(filePath)) ? " (wildcard)" : "") + " — nothing to parse");
                 return null;
             }
 
@@ -144,7 +157,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             try
             {
                 // Return matched files sorted by last write time (newest first), capped at 20
-                return Directory.GetFiles(directory, fileNamePart)
+                var allMatches = Directory.GetFiles(directory, fileNamePart);
+                if (allMatches.Length > 20)
+                    context.DebugLog(ruleId, GatherRuleDebugLog.StageLogParser,
+                        $"wildcard matched {allMatches.Length} files — capped to the 20 newest");
+                return allMatches
                     .OrderByDescending(f => new FileInfo(f).LastWriteTimeUtc)
                     .Take(20)
                     .ToList();
@@ -152,6 +169,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
             catch (Exception ex)
             {
                 context.Logger.Warning($"LogParser rule {ruleId}: wildcard expansion failed for {filePath}: {ex.Message}");
+                context.DebugLog(ruleId, GatherRuleDebugLog.StageError, $"wildcard expansion failed for {filePath}: {ex.Message}");
                 return new List<string>();
             }
         }
@@ -168,10 +186,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
 
                 // Nothing new to read
                 if (startPosition >= fileInfo.Length)
+                {
+                    context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                        $"{Path.GetFileName(filePath)}: no new content (position {startPosition} >= length {fileInfo.Length}) — trackPosition=true, nothing re-read");
                     return;
+                }
 
                 int matchCount = 0;
                 int linesRead = 0;
+                int parseFailCount = 0;
+                int timeoutCount = 0;
                 long endPosition = startPosition;
 
                 using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
@@ -195,6 +219,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
                                 }
                                 catch (RegexMatchTimeoutException)
                                 {
+                                    timeoutCount++;
                                     continue;
                                 }
                                 if (!match.Success)
@@ -239,7 +264,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
                                 // CMTrace mode: parse line as CMTrace format, match regex against message
                                 CmTraceLogEntry entry;
                                 if (!CmTraceLogParser.TryParseLine(line, out entry))
+                                {
+                                    parseFailCount++;
                                     continue;
+                                }
 
                                 Match match;
                                 try
@@ -248,6 +276,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
                                 }
                                 catch (RegexMatchTimeoutException)
                                 {
+                                    timeoutCount++;
                                     continue;
                                 }
                                 if (!match.Success)
@@ -301,10 +330,24 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
 
                 if (matchCount > 0)
                     context.Logger.Debug($"LogParser rule {rule.RuleId}: {matchCount} matches from {linesRead} lines in {Path.GetFileName(filePath)}");
+
+                // Per-file outcome — always written so a "matched 0" run is visible too.
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                    $"{Path.GetFileName(filePath)}: read {linesRead} lines from position {startPosition}->{endPosition}, " +
+                    $"matched {matchCount}, parseFailures={parseFailCount}, regexTimeouts={timeoutCount}, mode={(isTextMode ? "text" : "cmtrace")}");
+
+                if (!isTextMode && linesRead > 0 && parseFailCount == linesRead)
+                    context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                        "every line failed CMTrace parsing — if this is a plain-text log, set parameter format=text");
+
+                if (linesRead == maxLines)
+                    context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageLogParser,
+                        $"stopped at maxLines={maxLines} — remaining content is deferred to the next run");
             }
             catch (Exception ex)
             {
                 context.Logger.Warning($"LogParser rule {rule.RuleId} failed reading {filePath}: {ex.Message}");
+                context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageError, $"failed reading {filePath}: {ex}");
             }
         }
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/Collectors/RegistryCollector.cs

@@ -113,7 +113,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
 
                         // Suppress the "not found" event when the rule only wants a positive signal.
                         if (emitOnlyIfExists)
+                        {
+                            context.DebugLog(rule.RuleId, GatherRuleDebugLog.StageCollector,
+                                $"registry key/value not found: {path} — emitOnlyIfExists=true, empty result");
                             return new Dictionary<string, object>(); // empty → executor emits nothing
+                        }
 
                         data["exists"] = false;
                         data["path"] = path;

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleContext.cs

@@ -22,13 +22,20 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
         public LogFilePositionTracker FilePositionTracker { get; }
         public bool UnrestrictedMode { get; set; }
 
+        /// <summary>
+        /// Optional gather-rule debug trace writer (EnableGatherRuleDebugLog). Null when
+        /// tracing is disabled — use <see cref="DebugLog"/> for null-safe writes.
+        /// </summary>
+        public GatherRuleDebugLog DebugWriter { get; }
+
         public GatherRuleContext(
             AgentLogger logger,
             string sessionId,
             string tenantId,
             Action<EnrollmentEvent> onEventCollected,
             string imeLogPathOverride,
-            LogFilePositionTracker filePositionTracker)
+            LogFilePositionTracker filePositionTracker,
+            GatherRuleDebugLog debugLog = null)
         {
             Logger = logger ?? throw new ArgumentNullException(nameof(logger));
             SessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
@@ -36,8 +43,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             OnEventCollected = onEventCollected ?? throw new ArgumentNullException(nameof(onEventCollected));
             ImeLogPathOverride = imeLogPathOverride;
             FilePositionTracker = filePositionTracker ?? throw new ArgumentNullException(nameof(filePositionTracker));
+            DebugWriter = debugLog;
         }
 
+        /// <summary>
+        /// Null-safe write to the gather-rule debug trace. No-op when tracing is disabled.
+        /// </summary>
+        public void DebugLog(string ruleId, string stage, string message) => DebugWriter?.Write(ruleId, stage, message);
+
         /// <summary>
         /// Emits a security_warning event and returns an empty result dictionary.
         /// Called when a gather rule targets a path/query not on the allowlist.
@@ -45,6 +58,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
         public Dictionary<string, object> EmitSecurityWarning(GatherRule rule, string collectorType, string target)
         {
             Logger.Warning($"SECURITY: {collectorType} path blocked by guard: {target} (Rule: {rule.RuleId})");
+            DebugLog(rule.RuleId, GatherRuleDebugLog.StageGuard,
+                $"{collectorType} target blocked by allowlist guard: {target} — security_warning emitted, rule produced no data");
 
             var data = new Dictionary<string, object>
             {

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleDebugLog.cs

@@ -0,0 +1,115 @@
+using System;
+using System.IO;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
+{
+    /// <summary>
+    /// Append-only trace file for gather-rule evaluation, enabled per tenant via
+    /// EnableGatherRuleDebugLog (or --gather-debug-log). Explains every evaluation
+    /// decision — including the outcomes that produce no event — so customers can
+    /// diagnose rules that never show up in the timeline. Every write failure is
+    /// swallowed: tracing must never break gathering.
+    /// </summary>
+    public sealed class GatherRuleDebugLog
+    {
+        public const string StageConfig = "config";
+        public const string StageTrigger = "trigger";
+        public const string StageScope = "scope";
+        public const string StageExec = "exec";
+        public const string StageCollector = "collector";
+        public const string StageGuard = "guard";
+        public const string StageEmit = "emit";
+        public const string StageSuppress = "suppress";
+        public const string StageLogParser = "logparser";
+        public const string StageError = "error";
+
+        private const long DefaultMaxBytes = 10 * 1024 * 1024;
+
+        private readonly string _path;
+        private readonly long _maxBytes;
+        private readonly Action<string> _echo;
+        private readonly object _lock = new object();
+        private bool _headerWritten;
+
+        public GatherRuleDebugLog(string path, AgentLogger logger, Action<string> echo = null, long maxBytes = DefaultMaxBytes)
+        {
+            if (string.IsNullOrEmpty(path)) throw new ArgumentNullException(nameof(path));
+            _path = path;
+            _maxBytes = maxBytes;
+            _echo = echo;
+            logger?.Info($"GatherRuleDebugLog: enabled -> {path}");
+        }
+
+        /// <summary>
+        /// Writes one trace line: <c>{utc} | {ruleId} | {stage} | {message}</c>.
+        /// Newlines in <paramref name="message"/> are flattened except for the error
+        /// stage, where exception stack traces stay multi-line.
+        /// </summary>
+        public void Write(string ruleId, string stage, string message)
+        {
+            try
+            {
+                if (stage != StageError && message != null && message.IndexOf('\n') >= 0)
+                    message = message.Replace("\r", "").Replace('\n', ' ');
+
+                var line = $"{DateTime.UtcNow:yyyy-MM-ddTHH:mm:ss.fffZ} | {ruleId ?? "-"} | {stage} | {message}";
+
+                lock (_lock)
+                {
+                    EnsureFileReadyLocked();
+                    File.AppendAllText(_path, line + Environment.NewLine);
+                }
+
+                _echo?.Invoke(line);
+            }
+            catch { }
+        }
+
+        /// <summary>
+        /// One-shot helper for callers that have no executor (e.g. the flag is on but the
+        /// backend delivered zero gather rules) — the customer's trace file should explain
+        /// that too instead of silently not existing.
+        /// </summary>
+        public static void WriteStandalone(string path, string message, AgentLogger logger)
+        {
+            if (string.IsNullOrEmpty(path)) return;
+            try
+            {
+                new GatherRuleDebugLog(path, logger).Write(null, StageConfig, message);
+            }
+            catch { }
+        }
+
+        // Lazy on first write: create the directory and emit a header line. Before every
+        // append, rotate when the file exceeds maxBytes — keeping exactly one .old
+        // generation (worst case ~2x maxBytes on disk).
+        private void EnsureFileReadyLocked()
+        {
+            if (!_headerWritten)
+            {
+                var dir = Path.GetDirectoryName(_path);
+                if (!string.IsNullOrEmpty(dir))
+                    Directory.CreateDirectory(dir);
+            }
+
+            var info = new FileInfo(_path);
+            if (info.Exists && info.Length > _maxBytes)
+            {
+                var oldPath = Path.ChangeExtension(_path, null) + ".old.log";
+                if (File.Exists(oldPath))
+                    File.Delete(oldPath);
+                File.Move(_path, oldPath);
+                File.AppendAllText(_path,
+                    $"{DateTime.UtcNow:yyyy-MM-ddTHH:mm:ss.fffZ} | - | {StageConfig} | -- rotated (previous file exceeded {_maxBytes} bytes) --" + Environment.NewLine);
+            }
+
+            if (!_headerWritten)
+            {
+                File.AppendAllText(_path,
+                    $"{DateTime.UtcNow:yyyy-MM-ddTHH:mm:ss.fffZ} | - | {StageConfig} | -- gather rule debug log started --" + Environment.NewLine);
+                _headerWritten = true;
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Gather/GatherRuleExecutor.cs

@@ -22,6 +22,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
     public class GatherRuleExecutor : IDisposable
     {
         private readonly AgentLogger _logger;
+        private readonly GatherRuleDebugLog _debug;   // null unless EnableGatherRuleDebugLog / --gather-debug-log
         private readonly GatherRuleContext _context;
         private readonly Dictionary<string, IGatherRuleCollector> _collectors;
 
@@ -61,7 +62,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
         }
 
         public GatherRuleExecutor(string sessionId, string tenantId, Action<EnrollmentEvent> onEventCollected,
-            AgentLogger logger, string imeLogPathOverride = null)
+            AgentLogger logger, string imeLogPathOverride = null, string debugLogPath = null,
+            Action<string> debugEcho = null)
         {
             if (sessionId == null) throw new ArgumentNullException(nameof(sessionId));
             if (tenantId == null) throw new ArgumentNullException(nameof(tenantId));
@@ -69,9 +71,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             if (logger == null) throw new ArgumentNullException(nameof(logger));
 
             _logger = logger;
+            _debug = string.IsNullOrEmpty(debugLogPath) ? null : new GatherRuleDebugLog(debugLogPath, logger, debugEcho);
 
             var filePositionTracker = new LogFilePositionTracker();
-            _context = new GatherRuleContext(logger, sessionId, tenantId, onEventCollected, imeLogPathOverride, filePositionTracker);
+            _context = new GatherRuleContext(logger, sessionId, tenantId, onEventCollected, imeLogPathOverride, filePositionTracker, _debug);
 
             // Register all collector strategies
             var collectorList = new IGatherRuleCollector[]
@@ -96,6 +99,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             _collectors["command"] = _collectors["command_allowlisted"];
         }
 
+        /// <summary>
+        /// Null-safe write to the gather-rule debug trace. Never call while holding
+        /// <see cref="_scopeLock"/> — capture the message under the lock, write after release.
+        /// </summary>
+        private void DebugLog(string ruleId, string stage, string message) => _debug?.Write(ruleId, stage, message);
+
         /// <summary>
         /// Updates the active rules and starts/stops execution accordingly
         /// </summary>
@@ -111,11 +120,43 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
 
             _activeRules = rules.Where(r => r.Enabled).ToList();
 
+            // Registration summary for the debug trace: one line per delivered rule so the
+            // customer can see exactly what the agent received and how it will be triggered.
+            if (_debug != null)
+            {
+                foreach (var rule in rules)
+                {
+                    if (!rule.Enabled)
+                    {
+                        DebugLog(rule.RuleId, GatherRuleDebugLog.StageConfig, "rule disabled — will never run");
+                        continue;
+                    }
+
+                    var scope = rule.ActivePhases != null && rule.ActivePhases.Count > 0
+                        ? $"activePhases=[{string.Join(",", rule.ActivePhases)}]"
+                        : !string.IsNullOrEmpty(rule.ActiveFromPhase)
+                            ? $"activeFromPhase={rule.ActiveFromPhase}"
+                            : "unscoped";
+                    DebugLog(rule.RuleId, GatherRuleDebugLog.StageConfig,
+                        $"registered: trigger={rule.Trigger}" +
+                        (string.IsNullOrEmpty(rule.TriggerPhase) ? "" : $" triggerPhase={rule.TriggerPhase}") +
+                        (string.IsNullOrEmpty(rule.TriggerEventType) ? "" : $" triggerEventType={rule.TriggerEventType}") +
+                        $", collector={rule.CollectorType}, target={rule.Target}, {scope}" +
+                        $", emitMode={(string.IsNullOrEmpty(rule.EmitMode) ? "always" : rule.EmitMode)}" +
+                        (rule.IntervalSeconds.HasValue ? $", interval={rule.IntervalSeconds}s" : ""));
+
+                    if (rule.Trigger == "interval" && !rule.IntervalSeconds.HasValue)
+                        DebugLog(rule.RuleId, GatherRuleDebugLog.StageError,
+                            "trigger=interval but intervalSeconds is missing — rule will NEVER run");
+                }
+            }
+
             // Execute startup rules — track completion via CountdownEvent so callers can wait.
             // Scoped startup rules that are not yet in scope are deferred: they run once from
             // OnPhaseChanged when their scope activates (same _startupRulesExecuted dedup — a
             // rule runs either here or there, never both). Unscoped rules behave as before.
             List<GatherRule> pendingStartup;
+            var deferredTraces = _debug != null ? new List<KeyValuePair<string, string>>() : null;
             lock (_scopeLock)
             {
                 // A config refresh may deliver new from-phase rules after their phase was
@@ -124,7 +165,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
 
                 pendingStartup = _activeRules
                     .Where(r => r.Trigger == "startup" && !_startupRulesExecuted.Contains(r.RuleId))
-                    .Where(r => IsRuleInScopeLocked(r))
+                    .Where(r =>
+                    {
+                        string reason;
+                        var inScope = IsRuleInScopeLocked(r, out reason);
+                        if (!inScope && deferredTraces != null)
+                            deferredTraces.Add(new KeyValuePair<string, string>(r.RuleId,
+                                $"startup rule deferred — {reason}; runs once when its scope activates"));
+                        return inScope;
+                    })
                     .ToList();
 
                 foreach (var rule in pendingStartup)
@@ -133,6 +182,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                 }
             }
 
+            if (deferredTraces != null)
+            {
+                foreach (var trace in deferredTraces)
+                    DebugLog(trace.Key, GatherRuleDebugLog.StageScope, trace.Value);
+            }
+
             if (pendingStartup.Count > 0)
             {
                 _startupRulesLatch?.Dispose();
@@ -158,8 +213,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                 var timer = new Timer(
                     _ =>
                     {
-                        if (!IsRuleInScope(intervalRule))
+                        string skipReason;
+                        if (!IsRuleInScope(intervalRule, out skipReason))
+                        {
+                            DebugLog(intervalRule.RuleId, GatherRuleDebugLog.StageScope, $"interval tick skipped: {skipReason}");
                             return;
+                        }
                         ExecuteRule(intervalRule);
                     },
                     null,
@@ -168,6 +227,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                 );
                 _intervalTimers[intervalRule.RuleId] = timer;
                 _logger.Info($"  Interval rule {intervalRule.RuleId} scheduled every {intervalRule.IntervalSeconds}s");
+                DebugLog(intervalRule.RuleId, GatherRuleDebugLog.StageTrigger,
+                    $"interval timer scheduled every {intervalRule.IntervalSeconds}s (first run after one full interval — no immediate execution)");
             }
 
             _logger.Info($"GatherRuleExecutor: {_activeRules.Count(r => r.Trigger == "startup")} startup, " +
@@ -187,6 +248,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             // _currentPhase moves below. A transition INTO Failed still fires the exit rules of the
             // phase that failed — that snapshot is the whole point at a failure boundary.
             List<GatherRule> exitRules = null;
+            var exitTraces = _debug != null ? new List<KeyValuePair<string, string>>() : null;
             lock (_scopeLock)
             {
                 var previousPhase = _currentPhase;
@@ -204,12 +266,22 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
 
                         // Scope gate before the dedup add — an out-of-scope pass must not consume
                         // the once-per-(rule, phase) slot. IsRuleInScopeLocked still sees the old phase.
-                        if (!IsRuleInScopeLocked(rule)) continue;
+                        string scopeReason;
+                        if (!IsRuleInScopeLocked(rule, out scopeReason))
+                        {
+                            if (exitTraces != null)
+                                exitTraces.Add(new KeyValuePair<string, string>(rule.RuleId,
+                                    $"phase_exit of {previousPhaseName} skipped: {scopeReason}"));
+                            continue;
+                        }
 
                         // "exit:" prefix keeps this key space disjoint from the phase_change keys.
                         if (!_phaseRulesExecuted.Add($"exit:{rule.RuleId}|{previousPhaseName}"))
                         {
                             _logger.Debug($"Phase-exit rule {rule.RuleId} already executed for exit of {previousPhaseName}, skipping");
+                            if (exitTraces != null)
+                                exitTraces.Add(new KeyValuePair<string, string>(rule.RuleId,
+                                    $"phase_exit already executed for exit of {previousPhaseName} — once per (rule, phase)"));
                             continue;
                         }
 
@@ -219,6 +291,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                 }
             }
 
+            if (exitTraces != null)
+            {
+                foreach (var trace in exitTraces)
+                    DebugLog(trace.Key, GatherRuleDebugLog.StageScope, trace.Value);
+            }
+
             if (exitRules != null)
             {
                 foreach (var rule in exitRules)
@@ -252,6 +330,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             {
                 var deferredRule = rule;
                 _logger.Info($"Phase {phaseName} activated deferred startup rule {deferredRule.RuleId}");
+                DebugLog(deferredRule.RuleId, GatherRuleDebugLog.StageTrigger,
+                    $"phase {phaseName} activated deferred startup rule");
                 ThreadPool.QueueUserWorkItem(_ => ExecuteRule(deferredRule));
             }
 
@@ -262,18 +342,26 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                 {
                     // Scope gate BEFORE the dedup add — an out-of-scope pass must not consume
                     // the once-per-(rule, phase) execution slot.
-                    if (!IsRuleInScope(rule))
+                    string scopeReason;
+                    if (!IsRuleInScope(rule, out scopeReason))
+                    {
+                        DebugLog(rule.RuleId, GatherRuleDebugLog.StageScope,
+                            $"phase_change to {phaseName} skipped: {scopeReason}");
                         continue;
+                    }
 
                     // Deduplicate: only fire once per (ruleId, phase) combination
                     var deduplicationKey = $"{rule.RuleId}|{phaseName}";
                     if (!_phaseRulesExecuted.Add(deduplicationKey))
                     {
                         _logger.Debug($"Phase rule {rule.RuleId} already executed for phase {phaseName}, skipping");
+                        DebugLog(rule.RuleId, GatherRuleDebugLog.StageTrigger,
+                            $"phase_change already executed for phase {phaseName} — once per (rule, phase)");
                         continue;
                     }
 
                     _logger.Info($"Phase change triggered rule {rule.RuleId} (phase: {phaseName})");
+                    DebugLog(rule.RuleId, GatherRuleDebugLog.StageTrigger, $"phase_change to {phaseName} fired");
                     ThreadPool.QueueUserWorkItem(_ => ExecuteRule(rule));
                 }
             }
@@ -288,10 +376,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             {
                 if (string.Equals(rule.TriggerEventType, eventType, StringComparison.OrdinalIgnoreCase))
                 {
-                    if (!IsRuleInScope(rule))
+                    string scopeReason;
+                    if (!IsRuleInScope(rule, out scopeReason))
+                    {
+                        DebugLog(rule.RuleId, GatherRuleDebugLog.StageScope,
+                            $"on_event {eventType} skipped: {scopeReason}");
                         continue;
+                    }
 
                     _logger.Info($"Event triggered rule {rule.RuleId} (event: {eventType})");
+                    DebugLog(rule.RuleId, GatherRuleDebugLog.StageTrigger, $"on_event {eventType} fired");
                     ThreadPool.QueueUserWorkItem(_ => ExecuteRule(rule));
                 }
             }
@@ -302,6 +396,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
             try
             {
                 _logger.Info($"Executing gather rule: {rule.RuleId} ({rule.Title})");
+                DebugLog(rule.RuleId, GatherRuleDebugLog.StageExec, $"executing: collector={rule.CollectorType}, target={rule.Target}");
 
                 var collectorType = rule.CollectorType?.ToLower();
 
@@ -309,6 +404,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                 if (collectorType == null || !_collectors.TryGetValue(collectorType, out collector))
                 {
                     _logger.Warning($"Unknown collector type: {rule.CollectorType} for rule {rule.RuleId}");
+                    DebugLog(rule.RuleId, GatherRuleDebugLog.StageError, $"unknown collector type '{rule.CollectorType}' — nothing emitted");
                     return;
                 }
 
@@ -316,7 +412,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
 
                 // LogParser (and potentially others) emit events directly and return null
                 if (result == null)
+                {
+                    DebugLog(rule.RuleId, GatherRuleDebugLog.StageCollector,
+                        collectorType == "logparser"
+                            ? "logparser emits per-match events directly — see logparser lines above for the per-file outcome"
+                            : "collector returned null — nothing emitted");
                     return;
+                }
+
+                if (result.Count == 0)
+                {
+                    DebugLog(rule.RuleId, GatherRuleDebugLog.StageCollector,
+                        "collector returned EMPTY result — nothing emitted (typical causes: target not found with emitOnlyIfExists, or guard block — see guard line if present)");
+                }
 
                 if (result.Count > 0)
                 {
@@ -325,8 +433,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                     // empty result never reaches this point, so an emitOnlyIfExists miss neither
                     // emits nor updates the hash — composing to "one event on appearance, then
                     // only on change".
-                    if (IsOnChangeMode(rule) && !ShouldEmitOnChange(rule, result))
-                        return;
+                    if (IsOnChangeMode(rule))
+                    {
+                        string hashPrefix;
+                        int suppressedStreak;
+                        if (!ShouldEmitOnChange(rule, result, out hashPrefix, out suppressedStreak))
+                        {
+                            DebugLog(rule.RuleId, GatherRuleDebugLog.StageSuppress,
+                                $"result unchanged (hash {hashPrefix}) — emit suppressed (on_change), suppressed streak={suppressedStreak}");
+                            return;
+                        }
+                        DebugLog(rule.RuleId, GatherRuleDebugLog.StageEmit,
+                            $"result changed (hash {hashPrefix})" + (suppressedStreak > 0 ? $" after {suppressedStreak} suppressed polls" : ""));
+                    }
 
                     result["ruleId"] = rule.RuleId;
                     result["ruleTitle"] = rule.Title;
@@ -357,11 +476,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                         Message = $"Gather: {rule.Title}",
                         Data = result
                     });
+                    DebugLog(rule.RuleId, GatherRuleDebugLog.StageEmit,
+                        $"emitted {eventType} (severity={severity}, {result.Count} fields)");
                 }
             }
             catch (Exception ex)
             {
                 _logger.Warning($"Gather rule {rule.RuleId} failed: {ex.Message}");
+                // Full exception incl. stack trace only in the debug trace — the agent log stays terse.
+                DebugLog(rule.RuleId, GatherRuleDebugLog.StageError, $"rule execution failed: {ex}");
             }
         }
 
@@ -375,15 +498,33 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
 
         // Internal so the scope matrix is testable synchronously (no timer/ThreadPool races).
         internal bool IsRuleInScope(GatherRule rule)
+        {
+            string reason;
+            return IsRuleInScope(rule, out reason);
+        }
+
+        /// <summary>
+        /// Scope gate with a human-readable skip reason for the debug trace. The reason is
+        /// captured under the lock but must be WRITTEN outside it (never trace under _scopeLock).
+        /// </summary>
+        internal bool IsRuleInScope(GatherRule rule, out string reason)
         {
             lock (_scopeLock)
             {
-                return IsRuleInScopeLocked(rule);
+                return IsRuleInScopeLocked(rule, out reason);
             }
         }
 
         private bool IsRuleInScopeLocked(GatherRule rule)
         {
+            string reason;
+            return IsRuleInScopeLocked(rule, out reason);
+        }
+
+        private bool IsRuleInScopeLocked(GatherRule rule, out string reason)
+        {
+            reason = null;
+
             if (!HasPhaseScope(rule))
                 return true; // unscoped — legacy behavior
 
@@ -400,7 +541,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                 // No phase signal yet (or scope tokens that never match, e.g. "Unknown"):
                 // scoped rules stay inactive.
                 if (_currentPhase == EnrollmentPhase.Unknown)
+                {
+                    reason = "currentPhase=Unknown — scoped rules stay inactive until the first phase signal";
                     return false;
+                }
 
                 var phaseName = _currentPhase.ToString();
                 foreach (var phase in rule.ActivePhases)
@@ -408,10 +552,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                     if (string.Equals(phase, phaseName, StringComparison.OrdinalIgnoreCase))
                         return true;
                 }
+                reason = $"out of scope (currentPhase={phaseName}, activePhases=[{string.Join(",", rule.ActivePhases)}])";
                 return false;
             }
 
-            return _fromPhaseLatched.Contains(rule.RuleId);
+            if (_fromPhaseLatched.Contains(rule.RuleId))
+                return true;
+
+            reason = $"activeFromPhase={rule.ActiveFromPhase} not latched yet (currentPhase={_currentPhase})";
+            return false;
         }
 
         /// <summary>
@@ -457,8 +606,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
         /// Internal so the state machine is testable synchronously (no timer/ThreadPool races).
         /// </summary>
         internal bool ShouldEmitOnChange(GatherRule rule, Dictionary<string, object> result)
+        {
+            string hashPrefix;
+            int suppressedStreak;
+            return ShouldEmitOnChange(rule, result, out hashPrefix, out suppressedStreak);
+        }
+
+        /// <summary>
+        /// Overload exposing the hash prefix and suppression streak for the debug trace:
+        /// on suppress, <paramref name="suppressedStreak"/> is the updated streak count;
+        /// on emit, it is the streak that just ended (0 when none).
+        /// </summary>
+        internal bool ShouldEmitOnChange(GatherRule rule, Dictionary<string, object> result,
+            out string hashPrefix, out int suppressedStreak)
         {
             var hash = ComputeCanonicalHash(result);
+            hashPrefix = hash.Length > 8 ? hash.Substring(0, 8) : hash;
+            suppressedStreak = 0;
             bool emit;
             lock (_scopeLock)
             {
@@ -469,6 +633,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                     _suppressed[rule.RuleId] = _suppressed.TryGetValue(rule.RuleId, out streak)
                         ? (streak.Count + 1, streak.SinceUtc)
                         : (1, DateTime.UtcNow);
+                    suppressedStreak = _suppressed[rule.RuleId].Count;
                     emit = false;
                 }
                 else
@@ -479,6 +644,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                     {
                         result["suppressedPolls"] = streak.Count;
                         result["suppressedSinceUtc"] = streak.SinceUtc.ToString("o", CultureInfo.InvariantCulture);
+                        suppressedStreak = streak.Count;
                     }
                     _suppressed.Remove(rule.RuleId);
                     emit = true;

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Periodic/AgentSelfMetricsCollector.cs

@@ -77,11 +77,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
 
         protected override void Collect()
         {
-            // Full path writes 18 keys: agent_version + process metrics (5: cpu, ws, private,
-            // threads, handles) + spool stats (4) + network delta (8: requests, failures,
-            // bytes_up/down, avg_latency, total_up/down/requests). cap=18 → HashHelpers.GetPrime(18)=23
-            // buckets → no resize on the 18th key (cap=16 would land at 17 buckets and resize).
-            var data = new Dictionary<string, object>(capacity: 18, StringComparer.Ordinal)
+            // Full path writes 19 keys: agent_version + process metrics (5: cpu, ws, private,
+            // threads, handles) + spool stats (4) + network delta (9: requests, failures,
+            // bytes_up/down, avg_latency, total_up/down/requests/latency). cap=19 →
+            // HashHelpers.GetPrime(19)=23 buckets → no resize on the 19th key.
+            var data = new Dictionary<string, object>(capacity: 19, StringComparer.Ordinal)
             {
                 { "agent_version", _agentVersion }
             };
@@ -164,6 +164,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
                 data["net_total_bytes_up"] = currentNet.TotalBytesUp;
                 data["net_total_bytes_down"] = currentNet.TotalBytesDown;
                 data["net_total_requests"] = currentNet.RequestCount;
+                // Cumulative latency sum: total/requests = session-wide average HTTP
+                // round-trip. The backend projects that average onto the Session row
+                // (AvgApiLatencyMs) — cumulative counters make the write idempotent.
+                data["net_total_latency_ms"] = currentNet.TotalLatencyMs;
             }
             catch (Exception ex)
             {

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Periodic/NetworkChangeDetector.cs

@@ -8,8 +8,8 @@ using System.Net.Sockets;
 using System.Threading;
 using System.Threading.Tasks;
 using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Interop;
 using AutopilotMonitor.Agent.V2.Core.Orchestration;
-using AutopilotMonitor.Agent.V2.Core.Security;
 using AutopilotMonitor.Shared;
 using AutopilotMonitor.Shared.Models;
 
@@ -37,7 +37,6 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
         private const int DebounceDelayMs = 3000;
         private const int ConnectivityCheckDelayMs = 5000;
         private const int ConnectivityCheckTimeoutMs = 8000;
-        private const int WifiCollectTimeoutMs = 3000;
         private const string Source = "NetworkChangeDetector";
 
         /// <summary>
@@ -374,7 +373,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
                 // Collect WiFi SSID synchronously (needed for before/after comparison)
                 if (isWifi)
                 {
-                    var wifiInfo = CollectWiFiInfo();
+                    Guid? nicGuid = Guid.TryParse(activeNic.Id, out var parsedGuid) ? parsedGuid : (Guid?)null;
+                    var wifiInfo = CollectWiFiInfo(nicGuid);
                     snapshot.WifiSsid = wifiInfo.ssid;
                     snapshot.WifiSignalPercent = wifiInfo.signal;
                     snapshot.WifiRadioType = wifiInfo.radioType;
@@ -390,73 +390,30 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
         }
 
         /// <summary>
-        /// Collects WiFi SSID, signal, and radio type via netsh wlan show interfaces.
-        /// Synchronous with timeout — needed before emitting the event.
+        /// Collects WiFi SSID, signal, and radio type via the native WLAN API
+        /// (<see cref="WifiInfoReader"/> — language-neutral, no process spawn).
+        /// Synchronous — needed before emitting the event.
         /// </summary>
-        private (string ssid, int? signal, string radioType) CollectWiFiInfo()
+        private (string ssid, int? signal, string radioType) CollectWiFiInfo(Guid? interfaceGuid)
         {
-            string ssid = null;
-            int? signal = null;
-            string radioType = null;
-
             try
             {
-                var psi = new ProcessStartInfo
+                var wifi = WifiInfoReader.TryGetCurrentConnection(interfaceGuid, out var wifiDiag);
+                if (wifi == null)
                 {
-                    FileName = SystemPaths.Netsh,
-                    Arguments = "wlan show interfaces",
-                    UseShellExecute = false,
-                    RedirectStandardOutput = true,
-                    RedirectStandardError = true,
-                    CreateNoWindow = true
-                };
-
-                string output;
-                using (var process = Process.Start(psi))
-                {
-                    output = process.StandardOutput.ReadToEnd();
-                    if (!process.WaitForExit(WifiCollectTimeoutMs))
-                    {
-                        try { process.Kill(); } catch { }
-                        _logger.Debug("NetworkChangeDetector: netsh timed out");
-                        return (null, null, null);
-                    }
+                    _logger.Debug($"NetworkChangeDetector: native WLAN API returned no WiFi info ({wifiDiag ?? "no connected WLAN interface"}) — trying netsh fallback");
+                    wifi = NetshWifiFallback.TryRead();
                 }
 
-                if (string.IsNullOrEmpty(output))
-                    return (null, null, null);
-
-                foreach (var line in output.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries))
-                {
-                    var trimmed = line.Trim();
-                    var colonIndex = trimmed.IndexOf(':');
-                    if (colonIndex < 0) continue;
-
-                    var key = trimmed.Substring(0, colonIndex).Trim();
-                    var value = trimmed.Substring(colonIndex + 1).Trim();
-
-                    if (key.Equals("SSID", StringComparison.OrdinalIgnoreCase) &&
-                        !key.Equals("BSSID", StringComparison.OrdinalIgnoreCase))
-                    {
-                        ssid = value;
-                    }
-                    else if (key.Equals("Signal", StringComparison.OrdinalIgnoreCase))
-                    {
-                        if (int.TryParse(value.TrimEnd('%'), out var sig))
-                            signal = sig;
-                    }
-                    else if (key.Equals("Radio type", StringComparison.OrdinalIgnoreCase))
-                    {
-                        radioType = value;
-                    }
-                }
+                if (wifi != null)
+                    return (wifi.Ssid, wifi.SignalPercent, wifi.RadioType);
             }
             catch (Exception ex)
             {
                 _logger.Debug($"NetworkChangeDetector: WiFi info collection failed: {ex.Message}");
             }
 
-            return (ssid, signal, radioType);
+            return (null, null, null);
         }
 
         // -------------------------------------------------------------------

src/Agent/AutopilotMonitor.Agent.V2.Core/Orchestration/DefaultComponentFactory.cs

@@ -483,7 +483,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                     logger: logger,
                     rules: _remoteConfig.GatherRules,
                     imeLogPathOverride: _agentConfig.ImeLogPathOverride,
-                    unrestrictedMode: _agentConfig.UnrestrictedMode));
+                    unrestrictedMode: _agentConfig.UnrestrictedMode,
+                    gatherDebugLogPath: _agentConfig.GatherRuleDebugLogPath));
+            }
+            else if (!string.IsNullOrEmpty(_agentConfig.GatherRuleDebugLogPath))
+            {
+                // Debug trace is on but the backend delivered zero gather rules — the trace
+                // file must say so instead of silently not existing.
+                Monitoring.Telemetry.Gather.GatherRuleDebugLog.WriteStandalone(
+                    _agentConfig.GatherRuleDebugLogPath,
+                    "no gather rules delivered by backend — nothing to execute", logger);
             }
 
             return new CollectorSurfaces(hosts, imeLogHost, espAndHelloHost, aadJoinHost);

src/Agent/AutopilotMonitor.Agent.V2.Core/Orchestration/Hosts/DeviceInfoHost.cs

@@ -36,6 +36,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
     ///   <item><c>CollectAtEnd</c> — once, on <c>FinalizingSetup</c> or desktop arrival
     ///   (whichever comes first; desktop arrival also covers no-ESP / WDP v2). Re-fetches
     ///   BitLocker (commonly enabled via policy DURING enrollment) + the active NIC.</item>
+    ///   <item><c>RefreshEspConfiguration</c> — audit Q2, one-shot per trigger: the ESP
+    ///   blocking lists in the registry grow progressively (device scope) and the user-scope
+    ///   lists appear only after sign-in, so the early emissions are structurally partial.
+    ///   Re-collected when the apps sub-phase opens (first app activity in DeviceSetup /
+    ///   AccountSetup — the adapter's <c>phase_transition</c> declaration) and when the
+    ///   AccountSetup ESP phase itself is detected. Phase-driven one-shots, never a timer
+    ///   (no-heartbeat policy).</item>
     /// </list>
     /// <para>
     /// Duplicate-event cost is zero: every re-collected event runs through the collector's
@@ -46,6 +53,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
     {
         public string Name => "DeviceInfoCollector";
 
+        // ESP-config refresh trigger labels (audit Q2) — also the values passed to
+        // DeviceInfoCollector.RefreshEspConfiguration for the agent-log line.
+        internal const string EspConfigTriggerAppsDevice = "apps_phase_device";
+        internal const string EspConfigTriggerAppsUser = "apps_phase_user";
+        internal const string EspConfigTriggerAccountSetup = "account_setup_detected";
+
         private readonly Monitoring.Telemetry.DeviceInfo.DeviceInfoCollector _collector;
         private readonly AgentLogger _logger;
 
@@ -58,6 +71,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
         private int _endCollected;
         private int _disposed;
 
+        // Audit Q2 — fire-once latches per ESP-config refresh trigger. Guarded by _espConfigLock
+        // instead of three Interlocked ints so the membership test + add stays one atomic step.
+        private readonly object _espConfigLock = new object();
+        private readonly HashSet<string> _espConfigRefreshesFired = new HashSet<string>(StringComparer.Ordinal);
+
         public DeviceInfoHost(
             string sessionId,
             string tenantId,
@@ -100,6 +118,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
 
         private void OnSignalPosted(DecisionSignalKind kind, IReadOnlyDictionary<string, string>? payload)
         {
+            HandleEspConfigRefreshTrigger(kind, payload);
+
             var startTrigger = IsEnrollmentStartTrigger(kind, payload);
             var endTrigger = IsEndTrigger(kind, payload);
             if (!startTrigger && !endTrigger) return;
@@ -111,10 +131,6 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             var runEndCollect = endTrigger && Interlocked.Exchange(ref _endCollected, 1) == 0;
             if (!runStartRefresh && !runEndCollect) return;
 
-            // Both one-shots done → nothing left to observe.
-            if (Volatile.Read(ref _enrollmentStartCollected) == 1 && Volatile.Read(ref _endCollected) == 1)
-                Unsubscribe();
-
             var trigger = kind == DecisionSignalKind.DesktopArrived ? "desktop_arrived" : "esp_phase_changed";
             _logger.Info($"DeviceInfoHost: trigger '{trigger}' — scheduling re-collect (enrollmentStart={runStartRefresh}, end={runEndCollect}).");
 
@@ -134,6 +150,32 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             });
         }
 
+        /// <summary>
+        /// Audit Q2 — ESP-config refresh one-shots. Each trigger label fires at most once per
+        /// agent run; the collector's StartupEventGate keeps an unchanged payload silent, so
+        /// the worst case is one silent registry re-read per trigger. The subscription stays
+        /// armed for the host's lifetime (unlike the start/end pair there is no "all triggers
+        /// seen" point that is guaranteed to arrive — SkipUser enrollments never enter
+        /// AccountSetup); the per-signal cost is a few dictionary lookups.
+        /// </summary>
+        private void HandleEspConfigRefreshTrigger(DecisionSignalKind kind, IReadOnlyDictionary<string, string>? payload)
+        {
+            var trigger = ClassifyEspConfigRefreshTrigger(kind, payload);
+            if (trigger == null) return;
+
+            lock (_espConfigLock)
+            {
+                if (!_espConfigRefreshesFired.Add(trigger)) return;
+            }
+
+            _logger.Info($"DeviceInfoHost: ESP-config refresh trigger '{trigger}' — scheduling re-collect.");
+            Task.Run(() =>
+            {
+                try { _collector.RefreshEspConfiguration(trigger); }
+                catch (Exception ex) { _logger.Warning($"DeviceInfoHost: ESP-config refresh threw: {ex.Message}"); }
+            });
+        }
+
         /// <summary>First DeviceSetup phase signal — MDM enrollment has populated the registry surface.</summary>
         internal static bool IsEnrollmentStartTrigger(DecisionSignalKind kind, IReadOnlyDictionary<string, string>? payload)
         {
@@ -156,6 +198,45 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                 && string.Equals(phase, nameof(EnrollmentPhase.FinalizingSetup), StringComparison.Ordinal);
         }
 
+        /// <summary>
+        /// Audit Q2 — maps a posted signal to an ESP-config refresh trigger label, or
+        /// <c>null</c> when the signal is not one. Two trigger families:
+        /// <list type="bullet">
+        ///   <item>The adapter's apps sub-phase declaration (<c>phase_transition</c>
+        ///   InformationalEvent with phase AppsDevice/AppsUser — fired on the first app
+        ///   activity in an ESP phase): by then IME is actively processing the blocking set,
+        ///   so the device-scope ESPTrackingInfo lists are as complete as they get.</item>
+        ///   <item>The AccountSetup ESP phase (UserSetup detection): sign-in has happened, so
+        ///   the user-scope <c>S-&lt;SID&gt;</c> lists exist now — production showed 88 of 89
+        ///   sessions with an EMPTY user list at the last pre-fix emission.</item>
+        /// </list>
+        /// </summary>
+        internal static string? ClassifyEspConfigRefreshTrigger(DecisionSignalKind kind, IReadOnlyDictionary<string, string>? payload)
+        {
+            if (payload == null) return null;
+
+            if (kind == DecisionSignalKind.InformationalEvent
+                && payload.TryGetValue(SignalPayloadKeys.EventType, out var eventType)
+                && string.Equals(eventType, AutopilotMonitor.Shared.Constants.EventTypes.PhaseTransition, StringComparison.Ordinal)
+                && payload.TryGetValue(Telemetry.Events.EventTimelineEmitter.PhaseParamKey, out var declaredPhase))
+            {
+                if (string.Equals(declaredPhase, nameof(EnrollmentPhase.AppsDevice), StringComparison.Ordinal))
+                    return EspConfigTriggerAppsDevice;
+                if (string.Equals(declaredPhase, nameof(EnrollmentPhase.AppsUser), StringComparison.Ordinal))
+                    return EspConfigTriggerAppsUser;
+                return null;
+            }
+
+            if (kind == DecisionSignalKind.EspPhaseChanged
+                && payload.TryGetValue(SignalPayloadKeys.EspPhase, out var espPhase)
+                && string.Equals(espPhase, nameof(EnrollmentPhase.AccountSetup), StringComparison.Ordinal))
+            {
+                return EspConfigTriggerAccountSetup;
+            }
+
+            return null;
+        }
+
         public void Stop() => Unsubscribe();
 
         public void Dispose()

src/Agent/AutopilotMonitor.Agent.V2.Core/Orchestration/Hosts/GatherRuleExecutorHost.cs

@@ -39,7 +39,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             AgentLogger logger,
             List<GatherRule> rules,
             string? imeLogPathOverride,
-            bool unrestrictedMode = false)
+            bool unrestrictedMode = false,
+            string? gatherDebugLogPath = null)
         {
             if (ingress == null) throw new ArgumentNullException(nameof(ingress));
             if (clock == null) throw new ArgumentNullException(nameof(clock));
@@ -55,9 +56,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             // session mode we wrap post.Emit so every session-mode gather event still
             // flows through the InformationalEvent ingress pipe before hitting the
             // telemetry spool — Rail-A semantics for ordering / replay determinism.
-            var post = new InformationalEventPost(ingress, clock);
+            var post = new InformationalEventPost(ingress, clock, logger);
             _executor = new Monitoring.Telemetry.Gather.GatherRuleExecutor(
-                sessionId, tenantId, evt => post.Emit(evt), logger, imeLogPathOverride);
+                sessionId, tenantId, evt => post.Emit(evt), logger, imeLogPathOverride,
+                debugLogPath: gatherDebugLogPath);
             _observableIngress = ingress as SignalIngress;
         }
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Security/HardwareInfo.cs

@@ -93,7 +93,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Security
                     {
                         using (obj)
                         {
-                            manufacturer = obj["Manufacturer"]?.ToString() ?? Unknown;
+                            manufacturer = NormalizeWmiValue(obj["Manufacturer"]?.ToString());
                             if (manufacturer.IndexOf("lenovo", StringComparison.OrdinalIgnoreCase) >= 0)
                             {
                                 using (var lenovoSearcher = new ManagementObjectSearcher("SELECT Version FROM Win32_ComputerSystemProduct"))
@@ -103,7 +103,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Security
                                     {
                                         using (lenovoObj)
                                         {
-                                            model = lenovoObj["Version"]?.ToString() ?? Unknown;
+                                            model = NormalizeWmiValue(lenovoObj["Version"]?.ToString());
                                         }
                                         break;
                                     }
@@ -111,7 +111,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Security
                             }
                             else
                             {
-                                model = obj["Model"]?.ToString() ?? Unknown;
+                                model = NormalizeWmiValue(obj["Model"]?.ToString());
                             }
                         }
                     }
@@ -132,7 +132,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Security
                     {
                         using (obj)
                         {
-                            serialNumber = obj["SerialNumber"]?.ToString() ?? Unknown;
+                            serialNumber = NormalizeWmiValue(obj["SerialNumber"]?.ToString());
                         }
                     }
                 }
@@ -154,5 +154,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Security
         private static bool IsResolved(string value)
             => !string.IsNullOrWhiteSpace(value)
                && !string.Equals(value, Unknown, StringComparison.OrdinalIgnoreCase);
+
+        /// <summary>
+        /// Trims a raw WMI string value at the source (audit Q5: BIOS serials are used as device
+        /// identity keys downstream — F2 device history joins on them — so padding must never
+        /// leave the agent). Whitespace-only and empty values collapse to the "Unknown" sentinel,
+        /// matching the null fallback so the retry logic treats them as unresolved.
+        /// </summary>
+        internal static string NormalizeWmiValue(string raw)
+        {
+            if (string.IsNullOrWhiteSpace(raw)) return Unknown;
+            return raw.Trim();
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core/SignalAdapters/ImeLogTrackerAdapter.cs

@@ -132,7 +132,9 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
 
         // Plan §5 Fix 4c — per-app install-lifecycle timing captured from state transitions.
         // StartedAtUtc on first Downloading/Installing/InProgress transition (set-once);
-        // CompletedAtUtc on first terminal transition (Installed/Skipped/Postponed/Error).
+        // CompletedAtUtc on terminal transition (Installed/Skipped/Postponed/Error), re-armed
+        // to null on a terminal→active transition (IME retry, audit Q1) so the final terminal
+        // stamp reflects the last outcome instead of freezing at the first one.
         // Surfaced via <see cref="AppTimings"/> to peripheral consumers (FinalStatusBuilder,
         // app_tracking_summary emission in EnrollmentTerminationHandler).
         private readonly Dictionary<string, (DateTime? Started, DateTime? Completed)> _appTimings =
@@ -691,10 +693,20 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
         }
 
         /// <summary>
-        /// Plan §5 Fix 4c — set-once per-app install-lifecycle timing. Called for every
-        /// state transition, no-op for duplicate stamps. Returns the up-to-date
+        /// Plan §5 Fix 4c — per-app install-lifecycle timing. Called for every state
+        /// transition, no-op for duplicate stamps. Returns the up-to-date
         /// <see cref="AppInstallTiming"/> so the emitter can inline the values on the
         /// current event's payload without a second dictionary lookup.
+        /// <para>
+        /// Audit Q1: a terminal→active transition (the IME retry path — <see
+        /// cref="AppPackageState.UpdateState"/> permits e.g. Error→Downloading and
+        /// Skipped→Downloading) re-arms <c>Completed</c> to <c>null</c>, so the NEXT terminal
+        /// transition stamps a fresh CompletedAt. StartedAt keeps its first value — the final
+        /// terminal payload then covers first-start → last-terminal (total occupancy across
+        /// attempts) instead of freezing at the first failure. Observed pre-fix: a user-scope
+        /// app Skipped early in DeviceSetup, retried after sign-in, emitted its final
+        /// Installed event with the stale early CompletedAt (durationSeconds=-2342).
+        /// </para>
         /// </summary>
         private AppInstallTiming UpdateAppTiming(string appId, AppInstallationState newState, DateTime now)
         {
@@ -702,13 +714,20 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
             {
                 _appTimings.TryGetValue(appId, out var current);
 
+                // Terminal→active (retry): the earlier terminal stamp no longer describes this
+                // app's outcome — re-arm so the next terminal transition stamps fresh.
+                if (current.Completed != null && IsLifecycleActive(newState))
+                {
+                    current.Completed = null;
+                }
+
                 // First lifecycle-active transition → record StartedAt.
                 if (current.Started == null && IsLifecycleActive(newState))
                 {
                     current.Started = now;
                 }
 
-                // First terminal transition → record CompletedAt.
+                // Terminal transition → record CompletedAt (fresh after a re-arm).
                 if (current.Completed == null && IsCompletedState(newState))
                 {
                     current.Completed = now;

src/Agent/AutopilotMonitor.Agent.V2.Core/Termination/EnrollmentTerminationHandler.cs

@@ -39,8 +39,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
     ///     <see cref="SessionStage.WhiteGloveSealed"/> (Part-1 exit, session resumes Part 2).</item>
     ///   <item>WhiteGlove Part-1 path: stop peripheral collectors first (so their stop-time
     ///     stragglers — e.g. <c>network_bandwidth_estimate</c> — sequence BEFORE the marker),
-    ///     then emit <c>whiteglove_part1_complete</c>, drain spool, and write
-    ///     <c>whiteglove.complete</c> marker via <see cref="SessionIdPersistence.SaveWhiteGloveComplete"/>
+    ///     upload the diagnostics package as a pre-provisioning intermediate (suffix
+    ///     <c>preprov</c>, same mode gating as the terminal path — the seal counts as a
+    ///     success, so <c>OnFailure</c> skips), then emit <c>whiteglove_part1_complete</c>,
+    ///     drain spool, and write <c>whiteglove.complete</c> marker via
+    ///     <see cref="SessionIdPersistence.SaveWhiteGloveComplete"/>
     ///     so Part-2 resume is detected on the next boot.</item>
     ///   <item>Signal the caller-owned shutdown <see cref="ManualResetEventSlim"/>.</item>
     /// </list>
@@ -241,6 +244,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
                     // the full Stop() later is a no-op for the hosts.
                     StopPeripheralCollectorsBestEffort();
 
+                    // V1 parity (restored 2026-07-28) — upload the diagnostics package as a
+                    // pre-provisioning intermediate. Between reseal and user OOBE the device
+                    // may sit boxed for weeks, and if Part 2 never uploads (never runs, or
+                    // OnFailure + success) the Part-1 forensics would be lost to self-destruct.
+                    // No dedicated flag: the existing mode semantics apply — Always uploads,
+                    // OnFailure skips (the seal is a success; a Part-1 failure terminates via
+                    // the regular Failed path below, which uploads), Off does nothing. Must run
+                    // BEFORE the whiteglove_part1_complete emit so diagnostics_* events keep a
+                    // lower sequence than the Part-1/Part-2 boundary marker. Best-effort: a
+                    // reseal-reboot racing the upload just loses the intermediate package.
+                    RunUploadDiagnosticsWithEvents(args, suffixOverride: "preprov");
+
                     EmitEventSafe(new EnrollmentEvent
                     {
                         SessionId = _configuration.SessionId,
@@ -623,12 +638,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
         }
 
         /// <summary>
-        /// Emits a one-shot <c>agent_late_start</c> Warning when the agent had low observation
+        /// Emits a one-shot <c>agent_late_start</c> event when the agent had low observation
         /// coverage: it started a long time after device boot AND lived only briefly before this
         /// terminal outcome (gate in <see cref="ObservationCoverage"/>). Such a session looks like a
         /// normal multi-minute failure in the list (StartedAt is back-dated to the earliest replayed
-        /// IME-log event) but the agent actually observed only the end-state — so the operator should
-        /// read the diagnosis as a post-mortem reconstruction, not live evidence. No state mutation.
+        /// IME-log event) but the agent actually observed only the end-state. Severity and phrasing
+        /// are outcome-calibrated via <see cref="ObservationCoverage.DescribeLateStart"/>: a failure
+        /// stays a Warning with the post-mortem/hung-script note, a success is an Info about
+        /// tail-only coverage (fleet 2026-07-28: tenant 659c3a90 collected 12 Warnings on healthy
+        /// enrollments whose bootstrap merely ran late). No state mutation.
         /// </summary>
         private void MaybeEmitAgentLateStart(EnrollmentTerminatedEventArgs args)
         {
@@ -642,21 +660,24 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
                         out var bootToStartSeconds, out var uptimeSeconds))
                     return;
 
+                ObservationCoverage.DescribeLateStart(
+                    args.Outcome, _oobeStateAtAgentStart, bootToStartSeconds, uptimeSeconds,
+                    out var severity, out var message, out var note);
+
                 _logger.Info(
                     $"EnrollmentTerminationHandler: low observation coverage — agent started " +
                     $"{bootToStartSeconds / 60.0:F1} min after boot and lived {uptimeSeconds:F0}s; " +
-                    $"emitting agent_late_start.");
+                    $"emitting agent_late_start ({severity}, outcome {args.Outcome}).");
 
                 _post.Emit(new EnrollmentEvent
                 {
                     SessionId = _configuration.SessionId,
                     TenantId = _configuration.TenantId,
                     EventType = Constants.EventTypes.AgentLateStart,
-                    Severity = EventSeverity.Warning,
+                    Severity = severity,
                     Source = "EnrollmentTerminationHandler",
                     Phase = EnrollmentPhase.Unknown,
-                    Message = $"Agent started {bootToStartSeconds / 60.0:F0} min after boot and observed only " +
-                              $"{uptimeSeconds:F0}s before terminating ({args.Outcome}) — low coverage of the enrollment window.",
+                    Message = message,
                     Data = new Dictionary<string, object>
                     {
                         { "bootToAgentStartSeconds", Math.Round(bootToStartSeconds, 1) },
@@ -665,7 +686,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
                         { "agentStartUtc", _agentStartTimeUtc.ToString("o") },
                         { "oobeStateAtAgentStart", _oobeStateAtAgentStart },
                         { "outcome", args.Outcome.ToString() },
-                        { "note", "The agent's bootstrap (an Intune platform script) ran only near the end of the enrollment, so the agent observed the already-decided end-state rather than the failure window. Treat the diagnosis as a post-mortem; check for a platform/remediation script that hung ahead of the bootstrap (see script_timeout_suspected)." },
+                        { "note", note },
                     },
                     ImmediateUpload = true,
                 });
@@ -771,7 +792,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
                 StringComparison.Ordinal);
         }
 
-        private void RunUploadDiagnosticsWithEvents(EnrollmentTerminatedEventArgs args)
+        /// <param name="args">Termination payload — outcome drives the OnFailure gate.</param>
+        /// <param name="suffixOverride">
+        /// Blob-name suffix override. Null (terminal path) derives "success"/"failure" from
+        /// the outcome; the WhiteGlove Part-1 seal passes "preprov" so the intermediate
+        /// package is distinguishable from the later Part-2 terminal upload.
+        /// </param>
+        private void RunUploadDiagnosticsWithEvents(EnrollmentTerminatedEventArgs args, string suffixOverride = null)
         {
             var mode = _configuration.DiagnosticsUploadMode ?? "Off";
             if (!_configuration.DiagnosticsUploadEnabled || string.Equals(mode, "Off", StringComparison.OrdinalIgnoreCase))
@@ -807,7 +834,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
             DiagnosticsUploadResult result = null;
             try
             {
-                var suffix = enrollmentSucceeded ? "success" : "failure";
+                var suffix = suffixOverride ?? (enrollmentSucceeded ? "success" : "failure");
                 result = _uploadDiagnosticsAsync(enrollmentSucceeded, suffix).GetAwaiter().GetResult();
             }
             catch (Exception ex)

src/Agent/AutopilotMonitor.Agent.V2.Core/Termination/ObservationCoverage.cs

@@ -1,6 +1,8 @@
 #nullable enable
 using System;
 using System.Runtime.InteropServices;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Shared.Models;
 
 namespace AutopilotMonitor.Agent.V2.Core.Termination
 {
@@ -76,5 +78,57 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
             uptimeSeconds = Math.Max(0, uptime.TotalSeconds);
             return bootToStart >= LateStartBootThreshold && uptime <= LowCoverageUptime;
         }
+
+        /// <summary>
+        /// Severity + operator-facing phrasing for the <c>agent_late_start</c> event, calibrated
+        /// by fleet data (2026-07-28): the gate alone is outcome-blind and attached a
+        /// "post-mortem / check for a hung script" Warning to sessions that in fact succeeded —
+        /// there the late bootstrap is deployment hygiene, not an alarm. The OOBE state refines
+        /// the phrasing but must never gate: the canonical hung-script failure terminates on the
+        /// still-shown ESP screen, i.e. with OOBE reading <c>in_progress</c>.
+        /// </summary>
+        /// <param name="outcome">Terminal outcome the enrollment reached.</param>
+        /// <param name="oobeStateAtAgentStart"><see cref="Monitoring.Interop.OobeStateReader"/>
+        /// sample taken at THIS process's start. Only <c>completed</c> / <c>in_progress</c> are
+        /// interpreted; <c>not_started</c> flips in after mid-OOBE reboots and <c>completed</c> is
+        /// routine for post-desktop restarts, so no claim is phrased from the other values.</param>
+        /// <param name="bootToStartSeconds">From <see cref="IsLowObservationCoverage"/>.</param>
+        /// <param name="uptimeSeconds">From <see cref="IsLowObservationCoverage"/>.</param>
+        internal static void DescribeLateStart(
+            EnrollmentTerminationOutcome outcome,
+            string oobeStateAtAgentStart,
+            double bootToStartSeconds,
+            double uptimeSeconds,
+            out EventSeverity severity,
+            out string message,
+            out string note)
+        {
+            var succeeded = outcome == EnrollmentTerminationOutcome.Succeeded;
+            severity = succeeded ? EventSeverity.Info : EventSeverity.Warning;
+
+            message = $"Agent started {bootToStartSeconds / 60.0:F0} min after boot and observed only " +
+                      $"{uptimeSeconds:F0}s before terminating ({outcome}) — low coverage of the enrollment window.";
+            switch (oobeStateAtAgentStart)
+            {
+                case "completed":
+                    message += " OOBE was already completed when the agent started — the diagnosis is a " +
+                               "post-mortem reconstruction, not live observation.";
+                    break;
+                case "in_progress":
+                    message += $" OOBE was still in progress at agent start — the agent did observe the " +
+                               $"final {uptimeSeconds:F0}s live.";
+                    break;
+            }
+
+            note = succeeded
+                ? "The agent's bootstrap (an Intune platform script) ran late in the enrollment, so only the " +
+                  "final stretch was observed live; earlier timeline entries are reconstructed from IME log " +
+                  "replay. The enrollment itself succeeded. If this recurs across sessions, review which " +
+                  "platform/remediation scripts run ahead of the bootstrap (see script_timeout_suspected)."
+                : "The agent's bootstrap (an Intune platform script) ran only near the end of the enrollment, " +
+                  "so the agent observed the already-decided end-state rather than the failure window. Treat " +
+                  "the diagnosis as a post-mortem; check for a platform/remediation script that hung ahead of " +
+                  "the bootstrap (see script_timeout_suspected).";
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2/Program.GatherRulesMode.cs

@@ -221,8 +221,18 @@ namespace AutopilotMonitor.Agent.V2
                         },
                     });
 
-                    // Step 4 — run the executor and wait.
-                    using (var executor = new GatherRuleExecutor(sessionId, tenantId, emitEvent, logger, config.ImeLogPathOverride))
+                    // Step 4 — run the executor and wait. Diagnostic mode always writes the
+                    // gather-rule debug trace (CLI override or default path) and mirrors it
+                    // to the console in --console mode.
+                    var gatherDebugLogPath = !string.IsNullOrEmpty(config.GatherRuleDebugLogPath)
+                        ? config.GatherRuleDebugLogPath
+                        : Environment.ExpandEnvironmentVariables(Constants.GatherRuleDebugLogPath);
+                    logger.Info($"--run-gather-rules: debug trace -> {gatherDebugLogPath}");
+                    if (consoleMode) Console.WriteLine($"Debug trace: {gatherDebugLogPath}");
+
+                    using (var executor = new GatherRuleExecutor(sessionId, tenantId, emitEvent, logger, config.ImeLogPathOverride,
+                        debugLogPath: gatherDebugLogPath,
+                        debugEcho: consoleMode ? (Action<string>)(line => Console.WriteLine($"  {line}")) : null))
                     {
                         // Diagnostic mode has no enrollment phase context — scoped rules
                         // (activePhases / activeFromPhase) execute unconditionally here.

src/Agent/AutopilotMonitor.Agent.V2/Program.cs

@@ -303,6 +303,7 @@ namespace AutopilotMonitor.Agent.V2
             var apiBaseUrl = GetArgValue(args, "--api-url", "--backend-api") ?? Constants.ApiBaseUrl;
             var imeLogPathOverride = GetArgValue(args, "--ime-log-path");
             var imeMatchLogPath = GetArgValue(args, "--ime-match-log");
+            var gatherDebugLogPath = GetArgValue(args, "--gather-debug-log");
 
             // Dev / test — IME log replay (V1 compat mode). Feeds ImeLogTracker.SimulationMode
             // + SpeedFactor so recorded raw IME logs are replayed at an accelerated rate; signal
@@ -373,6 +374,7 @@ namespace AutopilotMonitor.Agent.V2
                 EnableGeoLocation = !disableGeoLocation,
                 ImeLogPathOverride = imeLogPathOverride,
                 ImeMatchLogPath = imeMatchLogPath,
+                GatherRuleDebugLogPath = gatherDebugLogPath,
                 KeepLogFile = keepLogFile,
                 SelfDestructOnComplete = !noCleanup,
                 CommandLineArgs = FormatArgsForLog(args),
@@ -485,6 +487,7 @@ namespace AutopilotMonitor.Agent.V2
             Console.Out.WriteLine("  --api-url <URL>                   Override backend API base URL (alias: --backend-api)");
             Console.Out.WriteLine("  --ime-log-path <PATH>             Override IME logs directory");
             Console.Out.WriteLine("  --ime-match-log <PATH>            Write matched IME log lines to file (debug)");
+            Console.Out.WriteLine("  --gather-debug-log <PATH>         Write gather-rule evaluation trace to file (debug)");
             Console.Out.WriteLine();
             Console.Out.WriteLine("Dev / Test:");
             Console.Out.WriteLine("  --replay-log-dir <PATH>           Replay IME logs from this directory (simulation mode)");

src/Agent/AutopilotMonitor.Agent.V2/Runtime/ServerControlPlane.cs

@@ -46,8 +46,12 @@ namespace AutopilotMonitor.Agent.V2.Runtime
                     try { var _ = await remoteConfigService.FetchConfigAsync(); return true; }
                     catch (Exception ex) { logger.Warning($"ServerAction rotate_config failed: {ex.Message}"); return false; }
                 },
+                // On-demand request mid-enrollment — the session has no outcome yet. Null keeps
+                // sessioninfo.txt honest ("In Progress") and passes the OnFailure gate by
+                // semantics (there is no success to skip on) instead of the former
+                // enrollmentSucceeded:false workaround that stamped in-flight packages "Failed".
                 uploadDiagnosticsAsync: async (suffix) =>
-                    await diagnosticsService.CreateAndUploadAsync(enrollmentSucceeded: false, fileNameSuffix: suffix),
+                    await diagnosticsService.CreateAndUploadAsync(enrollmentSucceeded: null, fileNameSuffix: suffix),
                 onTerminateRequested: action => OnTerminateRequested(
                     action, agentConfig, orchestrator, terminationHandler, shutdown, shutdownComplete, logger),
                 post: post);

src/Backend/AutopilotMonitor.Functions.Tests/AppInstallIdentityAndEspBlockingTests.cs

@@ -0,0 +1,333 @@
+using System.Text.Json;
+using Azure.Data.Tables;
+using AutopilotMonitor.Functions.Functions.Apps;
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.DataAccess;
+using AutopilotMonitor.Shared.Models;
+using Moq;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// F1 PR1 (insights spec §F1, source-data audit Q2/Q3): app identity on the name-keyed
+/// summary row and the ESP-blocking join.
+///
+/// Ingest side: <c>appId</c> is adopted from the app events; a second appId under the same
+/// name flags the row (<see cref="AppInstallSummary.AppIdCollision"/>) — in-batch and
+/// cross-batch. Store side: sentinel-gated columns + sticky collision. Join side:
+/// <see cref="EspBlockingSets"/> is positive evidence only, and
+/// <see cref="TableStorageService.ShouldStampEspBlocking"/> never stamps collision rows,
+/// id-less rows, or non-members. Aggregate side: collision rows leave every per-app fleet
+/// aggregate with a disclosed exclusion count.
+/// </summary>
+public class AppInstallIdentityAndEspBlockingTests
+{
+    private static readonly DateTime T0 = new(2026, 7, 26, 10, 0, 0, DateTimeKind.Utc);
+
+    private const string IdA = "aaaaaaaa-1111-2222-3333-444444444444";
+    private const string IdB = "bbbbbbbb-1111-2222-3333-444444444444";
+
+    // ── ingest fold: appId adoption + in-batch collision ────────────────────
+
+    private static Dictionary<string, AppInstallAggregationState> Aggregate(params EnrollmentEvent[] events)
+    {
+        var summaries = new Dictionary<string, AppInstallAggregationState>(StringComparer.OrdinalIgnoreCase);
+        foreach (var evt in events)
+            EventIngestProcessor.AggregateAppInstallEvent(evt, "tenant", "session", summaries);
+        return summaries;
+    }
+
+    private static EnrollmentEvent AppEvent(string eventType, string? appId = null, string appName = "App")
+    {
+        var evt = new EnrollmentEvent
+        {
+            EventType = eventType,
+            Timestamp = T0,
+            Data = new Dictionary<string, object> { ["appName"] = appName },
+        };
+        if (appId != null) evt.Data["appId"] = appId;
+        return evt;
+    }
+
+    [Fact]
+    public void Ingest_AdoptsAppId_FromFirstObservingEvent()
+    {
+        var s = Aggregate(
+            AppEvent("app_install_started", IdA),
+            AppEvent("app_install_completed", IdA))["App"].Summary;
+
+        Assert.Equal(IdA, s.AppId);
+        Assert.False(s.AppIdCollision);
+    }
+
+    [Fact]
+    public void Ingest_SameName_DifferentAppId_FlagsCollision_FirstSeenIdWins()
+    {
+        // Device- + user-scope assignment of the same display name in one batch (audit Q3:
+        // observed in production as two "Company Portal" appIds in one session).
+        var s = Aggregate(
+            AppEvent("app_install_started", IdA),
+            AppEvent("app_install_started", IdB))["App"].Summary;
+
+        Assert.True(s.AppIdCollision);
+        Assert.Equal(IdA, s.AppId);
+    }
+
+    [Fact]
+    public void Ingest_AppIdCaseDrift_IsNotACollision()
+    {
+        var s = Aggregate(
+            AppEvent("app_install_started", IdA),
+            AppEvent("app_install_completed", IdA.ToUpperInvariant()))["App"].Summary;
+
+        Assert.False(s.AppIdCollision);
+    }
+
+    [Fact]
+    public void Ingest_EventsWithoutAppId_LeaveSentinelEmpty()
+    {
+        var s = Aggregate(AppEvent("app_install_completed"))["App"].Summary;
+        Assert.Equal(string.Empty, s.AppId);
+        Assert.False(s.AppIdCollision);
+    }
+
+    // ── reconcile: cross-batch identity ─────────────────────────────────────
+
+    [Fact]
+    public void Reconcile_AdoptsStoredAppId_WhenIncomingBatchHasNone()
+    {
+        var existing = new TableEntity("tenant", "session_App") { ["AppId"] = IdA };
+        var summary = new AppInstallSummary { AppName = "App", StartedAt = T0 };
+
+        TableStorageService.ReconcileAppInstallSummaryWithExisting(summary, existing);
+
+        Assert.Equal(IdA, summary.AppId);
+        Assert.False(summary.AppIdCollision);
+    }
+
+    [Fact]
+    public void Reconcile_CrossBatchDifferentAppId_FlagsCollision_StoredIdWins()
+    {
+        var existing = new TableEntity("tenant", "session_App") { ["AppId"] = IdA };
+        var summary = new AppInstallSummary { AppName = "App", AppId = IdB, StartedAt = T0 };
+
+        TableStorageService.ReconcileAppInstallSummaryWithExisting(summary, existing);
+
+        Assert.True(summary.AppIdCollision);
+        Assert.Equal(IdA, summary.AppId); // first-seen (stored) identity wins, matching the fold rule
+    }
+
+    [Fact]
+    public void Reconcile_CollisionIsSticky_AndEspBlockingVerdictIsAdopted()
+    {
+        var existing = new TableEntity("tenant", "session_App")
+        {
+            ["AppId"] = IdA,
+            ["AppIdCollision"] = true,
+            ["EspBlocking"] = true,
+        };
+        var summary = new AppInstallSummary { AppName = "App", AppId = IdA, StartedAt = T0 };
+
+        TableStorageService.ReconcileAppInstallSummaryWithExisting(summary, existing);
+
+        Assert.True(summary.AppIdCollision);       // one-way sticky
+        Assert.True(summary.EspBlocking);          // terminal-path verdict survives late batches
+    }
+
+    // ── entity builder: sentinel gating ─────────────────────────────────────
+
+    [Fact]
+    public void EntityBuilder_IdentityColumns_AreSentinelGated()
+    {
+        var empty = TableStorageService.BuildAppInstallSummaryEntity(
+            new AppInstallSummary { AppName = "App" }, "rk");
+        // Absent columns → Merge-mode preserves prior values / stays unknown.
+        Assert.False(empty.ContainsKey("AppId"));
+        Assert.False(empty.ContainsKey("EspBlocking"));
+        Assert.False(empty.ContainsKey("AppIdCollision"));
+
+        var full = TableStorageService.BuildAppInstallSummaryEntity(
+            new AppInstallSummary { AppName = "App", AppId = IdA, EspBlocking = true, AppIdCollision = true }, "rk");
+        Assert.Equal(IdA, full.GetString("AppId"));
+        Assert.True(full.GetBoolean("EspBlocking"));
+        Assert.True(full.GetBoolean("AppIdCollision"));
+    }
+
+    // ── EspBlockingSets: positive-evidence parsing ──────────────────────────
+
+    private static Dictionary<string, object> Lists(
+        object? win32 = null, object? userWin32 = null, object? msi = null, object? pfn = null,
+        long? win32Count = null)
+    {
+        var d = new Dictionary<string, object> { ["source"] = "registry_firstsync" };
+        if (win32 != null) d["espTrackedWin32AppIds"] = win32;
+        if (userWin32 != null) d["espTrackedUserWin32AppIds"] = userWin32;
+        if (msi != null) d["espTrackedMsiProductCodes"] = msi;
+        if (pfn != null) d["espTrackedModernAppPfns"] = pfn;
+        if (win32Count.HasValue) d["espTrackedWin32Count"] = win32Count.Value;
+        return d;
+    }
+
+    [Fact]
+    public void Sets_PayloadWithoutListKeys_YieldsNull_NoListsIsNotEmptyLists()
+    {
+        Assert.Null(EspBlockingSets.FromEventData(null));
+        Assert.Null(EspBlockingSets.FromEventData(Lists())); // probe found no Diagnostics key
+    }
+
+    [Fact]
+    public void Sets_MembershipIsCaseInsensitive_AcrossAllFourLists()
+    {
+        // Storage rehydration shape: List<object> (EventDataNormalizer).
+        var sets = EspBlockingSets.FromEventData(Lists(
+            win32: new List<object> { IdA },
+            msi: new List<object> { "{11111111-2222-3333-4444-555555555555}" },
+            pfn: new List<object> { "Contoso.App_abc123" }))!;
+
+        Assert.True(sets.Contains(IdA.ToUpperInvariant()));
+        Assert.True(sets.Contains("{11111111-2222-3333-4444-555555555555}"));
+        Assert.True(sets.Contains("Contoso.App_abc123"));
+        Assert.False(sets.Contains(IdB));           // absent ⇒ unknown at the caller, never false here
+        Assert.False(sets.Contains(null));
+        Assert.Equal(3, sets.ListedCount);
+        Assert.False(sets.IsTruncated);
+    }
+
+    [Fact]
+    public void Sets_EmittedCountAboveListLength_MeansTruncated()
+    {
+        var sets = EspBlockingSets.FromEventData(Lists(
+            win32: new List<object> { IdA }, win32Count: 60))!;
+
+        Assert.True(sets.IsTruncated);
+    }
+
+    [Fact]
+    public void Sets_UserScopeSubset_IsExposedForCoverageLabeling()
+    {
+        var sets = EspBlockingSets.FromEventData(Lists(
+            win32: new List<object> { IdA, IdB },
+            userWin32: new List<object> { IdB }))!;
+
+        Assert.Contains(IdB, sets.UserWin32AppIds);
+        Assert.DoesNotContain(IdA, sets.UserWin32AppIds);
+    }
+
+    // ── terminal-path stamping predicate ────────────────────────────────────
+
+    private static TableEntity Row(string? appId = null, bool? collision = null, bool? espBlocking = null)
+    {
+        var row = new TableEntity("tenant", "session_App");
+        if (appId != null) row["AppId"] = appId;
+        if (collision.HasValue) row["AppIdCollision"] = collision.Value;
+        if (espBlocking.HasValue) row["EspBlocking"] = espBlocking.Value;
+        return row;
+    }
+
+    [Fact]
+    public void Stamp_OnlyPositiveMembers_NeverIdlessCollidedOrAlreadyStamped()
+    {
+        var sets = EspBlockingSets.FromEventData(Lists(win32: new List<object> { IdA }))!;
+
+        Assert.True(TableStorageService.ShouldStampEspBlocking(Row(IdA), sets));
+        Assert.False(TableStorageService.ShouldStampEspBlocking(Row(), sets));                    // no identity → unknown
+        Assert.False(TableStorageService.ShouldStampEspBlocking(Row(IdB), sets));                 // absent ⇒ unknown, never false
+        Assert.False(TableStorageService.ShouldStampEspBlocking(Row(IdA, collision: true), sets)); // ambiguous identity
+        Assert.False(TableStorageService.ShouldStampEspBlocking(Row(IdA, espBlocking: true), sets)); // idempotent
+    }
+
+    // ── per-app fleet aggregates: collision rows leave, disclosed ───────────
+
+    private static AppInstallSummary Summary(
+        string appName, string status = "Succeeded", bool collision = false, int duration = 30)
+        => new()
+        {
+            TenantId = "00000000-0000-0000-0000-000000000fa1",
+            SessionId = "s-1",
+            AppName = appName,
+            Status = status,
+            TerminalState = status == "Succeeded" ? "Installed" : "Error",
+            DurationSeconds = duration,
+            StartedAt = DateTime.UtcNow.AddHours(-2),
+            AppIdCollision = collision,
+        };
+
+    [Fact]
+    public void AppMetricsPayload_ExcludesCollisionRowsFromGroups_DisclosesCount()
+    {
+        var summaries = new List<AppInstallSummary>
+        {
+            Summary("Clean App"),
+            Summary("Clean App"),
+            Summary("Company Portal", collision: true),
+            Summary("Company Portal", status: "Failed", collision: true),
+        };
+
+        var root = JsonSerializer.SerializeToElement(MetricsMath.BuildAppMetricsPayload(summaries));
+
+        Assert.Equal(1, root.GetProperty("totalApps").GetInt32());          // collided name forms no group
+        Assert.Equal(4, root.GetProperty("totalInstalls").GetInt32());      // raw row count unchanged
+        Assert.Equal(2, root.GetProperty("totalCollisionExcluded").GetInt32());
+        Assert.Empty(root.GetProperty("topFailingApps").EnumerateArray());  // the collided Failed row ranks nowhere
+    }
+
+    [Fact]
+    public void AppsList_ExcludesCollisionRows_DisclosesCount()
+    {
+        var summaries = new List<AppInstallSummary>
+        {
+            Summary("Clean App"),
+            Summary("Company Portal", collision: true),
+        };
+
+        var root = JsonSerializer.SerializeToElement(
+            AppsAnalyticsHelper.BuildAppsListResponse(summaries, days: 30));
+
+        var apps = root.GetProperty("apps").EnumerateArray().ToList();
+        Assert.Single(apps);
+        Assert.Equal("Clean App", apps[0].GetProperty("appName").GetString());
+        Assert.Equal(2, root.GetProperty("totalInstalls").GetInt32());
+        Assert.Equal(1, root.GetProperty("collisionExcluded").GetInt32());
+    }
+
+    [Fact]
+    public async Task AppAnalytics_ExcludesCollisionRows_DisclosesCount()
+    {
+        var repo = new Mock<ISessionRepository>();
+        repo.Setup(r => r.GetSessionAsync(It.IsAny<string>(), It.IsAny<string>()))
+            .ReturnsAsync((SessionSummary?)null);
+
+        var summaries = new List<AppInstallSummary>
+        {
+            Summary("Company Portal"),
+            Summary("Company Portal", status: "Failed", collision: true), // the second identity's failure
+        };
+
+        var root = JsonSerializer.SerializeToElement(await AppsAnalyticsHelper.BuildAnalyticsResponseAsync(
+            summaries, repo.Object, "Company Portal", days: 30));
+
+        Assert.Equal(1, root.GetProperty("collisionExcluded").GetInt32());
+        var stats = root.GetProperty("summary");
+        Assert.Equal(1, stats.GetProperty("totalInstalls").GetInt32());
+        Assert.Equal(0, stats.GetProperty("failed").GetInt32());            // ambiguous failure not attributed
+        Assert.Equal(0d, stats.GetProperty("failureRate").GetDouble());
+    }
+
+    [Fact]
+    public async Task AppAnalytics_AllRowsCollided_ReturnsEmptyShape_WithDisclosure()
+    {
+        var repo = new Mock<ISessionRepository>();
+        repo.Setup(r => r.GetSessionAsync(It.IsAny<string>(), It.IsAny<string>()))
+            .ReturnsAsync((SessionSummary?)null);
+
+        var summaries = new List<AppInstallSummary> { Summary("Company Portal", collision: true) };
+
+        var root = JsonSerializer.SerializeToElement(await AppsAnalyticsHelper.BuildAnalyticsResponseAsync(
+            summaries, repo.Object, "Company Portal", days: 30));
+
+        Assert.Equal(1, root.GetProperty("collisionExcluded").GetInt32());
+        Assert.Equal(0, root.GetProperty("summary").GetProperty("totalInstalls").GetInt32());
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/AppInstallTerminalStateAndReconcileTests.cs

@@ -0,0 +1,201 @@
+using Azure.Data.Tables;
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// PR0 (2026-07-26, source-data audit §0.5 of tasks/insights-expansion-spec.md).
+///
+/// Ingest side: the agent emits <c>app_install_completed</c> for EVERY terminal transition —
+/// including Skipped/Postponed no-ops (V1 wire parity; production: 78 % of zero-duration rows
+/// were skips). The payload's <c>state</c> field must be persisted as
+/// <see cref="AppInstallSummary.TerminalState"/> so metrics can exclude skips from durations
+/// and rates.
+///
+/// Store side: <see cref="TableStorageService.ReconcileAppInstallSummaryWithExisting"/> pins the
+/// cross-batch contract — earliest StartedAt wins, terminal status is sticky, and the Q4
+/// out-of-order case (terminal batch first, started batch later) recomputes the duration.
+/// </summary>
+public class AppInstallTerminalStateAndReconcileTests
+{
+    private static readonly DateTime T0 = new(2026, 7, 26, 10, 0, 0, DateTimeKind.Utc);
+
+    // ── ingest: TerminalState fold ──────────────────────────────────────────
+
+    private static Dictionary<string, AppInstallAggregationState> Aggregate(params EnrollmentEvent[] events)
+    {
+        var summaries = new Dictionary<string, AppInstallAggregationState>(StringComparer.OrdinalIgnoreCase);
+        foreach (var evt in events)
+            EventIngestProcessor.AggregateAppInstallEvent(evt, "tenant", "session", summaries);
+        return summaries;
+    }
+
+    private static EnrollmentEvent AppEvent(string eventType, DateTime ts, string? state = null, string appName = "App")
+    {
+        var evt = new EnrollmentEvent
+        {
+            EventType = eventType,
+            Timestamp = ts,
+            Data = new Dictionary<string, object> { ["appName"] = appName },
+        };
+        if (state != null) evt.Data["state"] = state;
+        return evt;
+    }
+
+    [Theory]
+    [InlineData("Installed")]
+    [InlineData("Skipped")]
+    [InlineData("Postponed")]
+    public void Completed_PersistsPayloadState(string state)
+    {
+        var s = Aggregate(AppEvent("app_install_completed", T0, state))["App"].Summary;
+
+        Assert.Equal("Succeeded", s.Status);          // backward-compatible status
+        Assert.Equal(state, s.TerminalState);          // new precision column
+    }
+
+    [Fact]
+    public void Completed_WithoutState_LeavesSentinelEmpty_NeverGuessed()
+    {
+        var s = Aggregate(AppEvent("app_install_completed", T0))["App"].Summary;
+        Assert.Equal(string.Empty, s.TerminalState);
+    }
+
+    [Fact]
+    public void Completed_WithNonTerminalOrGarbageState_LeavesSentinelEmpty()
+    {
+        // A payload state outside the terminal set (bug or drift) must not be persisted.
+        var s = Aggregate(AppEvent("app_install_completed", T0, "Downloading"))["App"].Summary;
+        Assert.Equal(string.Empty, s.TerminalState);
+    }
+
+    [Fact]
+    public void Failed_SetsError()
+    {
+        var s = Aggregate(AppEvent("app_install_failed", T0))["App"].Summary;
+        Assert.Equal("Failed", s.Status);
+        Assert.Equal("Error", s.TerminalState);
+    }
+
+    [Fact]
+    public void FailedThenCompleted_RetrySucceeds_LastTerminalWins()
+    {
+        // IME retry path (audit Q1): Error → retry → Installed. The later completed event is
+        // the authoritative outcome for Status AND TerminalState.
+        var s = Aggregate(
+            AppEvent("app_install_failed", T0),
+            AppEvent("app_install_completed", T0.AddMinutes(10), "Installed"))["App"].Summary;
+
+        Assert.Equal("Succeeded", s.Status);
+        Assert.Equal("Installed", s.TerminalState);
+    }
+
+    [Fact]
+    public void SkippedEvent_SetsSkipped_ButNeverOverridesStrongerTerminal()
+    {
+        var fresh = Aggregate(AppEvent("app_install_skipped", T0))["App"].Summary;
+        Assert.Equal("Succeeded", fresh.Status);
+        Assert.Equal("Skipped", fresh.TerminalState);
+
+        var afterFailure = Aggregate(
+            AppEvent("app_install_failed", T0),
+            AppEvent("app_install_skipped", T0.AddSeconds(5)))["App"].Summary;
+        Assert.Equal("Error", afterFailure.TerminalState);
+    }
+
+    // ── store: cross-batch reconcile ────────────────────────────────────────
+
+    [Fact]
+    public void Reconcile_Q4_OutOfOrder_RecomputesDurationFromStoredCompletedAt()
+    {
+        // Terminal batch landed first: row has CompletedAt but no usable duration.
+        var existing = new TableEntity("tenant", "session_App")
+        {
+            ["Status"] = "Succeeded",
+            ["StartedAt"] = new DateTimeOffset(T0.AddMinutes(5)),   // late (completed-event) stamp
+            ["CompletedAt"] = new DateTimeOffset(T0.AddMinutes(5)),
+        };
+        // Started batch arrives now with the true (earlier) start.
+        var summary = new AppInstallSummary
+        {
+            AppName = "App", SessionId = "session", TenantId = "tenant",
+            Status = "InProgress", StartedAt = T0,
+        };
+
+        TableStorageService.ReconcileAppInstallSummaryWithExisting(summary, existing);
+
+        Assert.Equal(T0, summary.StartedAt);                        // earlier start kept
+        Assert.Equal(T0.AddMinutes(5), summary.CompletedAt);        // endpoint adopted from the row
+        Assert.Equal(300, summary.DurationSeconds);                 // recomputed — was permanently unset before PR0
+        Assert.Equal("Succeeded", summary.Status);                  // sticky terminal (below)
+    }
+
+    [Fact]
+    public void Reconcile_TerminalStatusIsSticky_AgainstLateInProgressBatch()
+    {
+        var existing = new TableEntity("tenant", "session_App") { ["Status"] = "Failed" };
+        var summary = new AppInstallSummary { AppName = "App", Status = "InProgress", StartedAt = T0 };
+
+        TableStorageService.ReconcileAppInstallSummaryWithExisting(summary, existing);
+
+        Assert.Equal("Failed", summary.Status);
+    }
+
+    [Fact]
+    public void Reconcile_TerminalToTerminal_StaysWithIncomingEvidence()
+    {
+        // Failed row + succeeded batch (successful retry) → the new terminal wins.
+        var existing = new TableEntity("tenant", "session_App") { ["Status"] = "Failed" };
+        var summary = new AppInstallSummary { AppName = "App", Status = "Succeeded", StartedAt = T0 };
+
+        TableStorageService.ReconcileAppInstallSummaryWithExisting(summary, existing);
+
+        Assert.Equal("Succeeded", summary.Status);
+    }
+
+    [Fact]
+    public void Reconcile_Q4Guard_DoesNotFireWithoutStoredCompletedAt()
+    {
+        var existing = new TableEntity("tenant", "session_App") { ["Status"] = "InProgress" };
+        var summary = new AppInstallSummary { AppName = "App", Status = "InProgress", StartedAt = T0 };
+
+        TableStorageService.ReconcileAppInstallSummaryWithExisting(summary, existing);
+
+        Assert.Null(summary.CompletedAt);
+        Assert.Equal(0, summary.DurationSeconds);
+    }
+
+    [Fact]
+    public void Reconcile_Q4Guard_IgnoresStoredCompletedAtBeforeIncomingStart()
+    {
+        // Negative interval (clock mess) must not produce a negative duration.
+        var existing = new TableEntity("tenant", "session_App")
+        {
+            ["Status"] = "Succeeded",
+            ["CompletedAt"] = new DateTimeOffset(T0.AddMinutes(-10)),
+        };
+        var summary = new AppInstallSummary { AppName = "App", Status = "InProgress", StartedAt = T0 };
+
+        TableStorageService.ReconcileAppInstallSummaryWithExisting(summary, existing);
+
+        Assert.Null(summary.CompletedAt);
+        Assert.Equal(0, summary.DurationSeconds);
+    }
+
+    // ── entity builder: sentinel gating for the new column ─────────────────
+
+    [Fact]
+    public void EntityBuilder_TerminalState_IsSentinelGated()
+    {
+        var withState = new AppInstallSummary { AppName = "App", TerminalState = "Skipped" };
+        var entity = TableStorageService.BuildAppInstallSummaryEntity(withState, "rk");
+        Assert.Equal("Skipped", entity.GetString("TerminalState"));
+
+        var withoutState = new AppInstallSummary { AppName = "App" };
+        var empty = TableStorageService.BuildAppInstallSummaryEntity(withoutState, "rk");
+        // Column absent → Merge-mode preserves a prior batch's terminal state.
+        Assert.False(empty.ContainsKey("TerminalState"));
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/AppsAnalyticsFailureRateTests.cs

@@ -162,6 +162,58 @@ public class AppsAnalyticsFailureRateTests
         Assert.Equal(50d, todayBucket.GetProperty("failureRate").GetDouble());
     }
 
+    // ── PR0 (2026-07-26): skip / unmeasured classification ──────────────────
+
+    [Fact]
+    public void List_Skips_LeaveRateAndDurations_AndAreReportedSeparately()
+    {
+        var skip = A("Succeeded");
+        skip.TerminalState = "Skipped";
+        skip.DurationSeconds = 0;
+        var unmeasured = A("Succeeded");
+        unmeasured.TerminalState = "Installed";
+        unmeasured.DurationSeconds = 0;
+
+        var summaries = new List<AppInstallSummary> { A("Failed"), A("Succeeded"), skip, unmeasured };
+
+        var root = JsonSerializer.SerializeToElement(
+            AppsAnalyticsHelper.BuildAppsListResponse(summaries, days: 30));
+        var app = root.GetProperty("apps")[0];
+
+        Assert.Equal(4, app.GetProperty("totalInstalls").GetInt32());
+        Assert.Equal(2, app.GetProperty("succeeded").GetInt32());          // real install + unmeasured
+        Assert.Equal(1, app.GetProperty("skipped").GetInt32());
+        Assert.Equal(1, app.GetProperty("unmeasured").GetInt32());
+        // 1 / (1 + 2) — the skip is not an attempt.
+        Assert.Equal(33.3d, app.GetProperty("failureRate").GetDouble());
+        // avg over the single measured row (30s) — the zero must not drag it to 15.
+        Assert.Equal(30d, app.GetProperty("avgDurationSeconds").GetDouble());
+    }
+
+    [Fact]
+    public async Task Analytics_Summary_CarriesSkippedAndUnmeasured_AndP95OverMeasuredOnly()
+    {
+        var skip = A("Succeeded");
+        skip.TerminalState = "Skipped";
+        skip.DurationSeconds = 0;
+        var unmeasured = A("Succeeded");
+        unmeasured.TerminalState = "Installed";
+        unmeasured.DurationSeconds = 0;
+        var measured = A("Succeeded");
+        measured.TerminalState = "Installed";
+        measured.DurationSeconds = 100;
+
+        var root = await BuildAnalyticsAsync(new List<AppInstallSummary> { skip, unmeasured, measured });
+        var summary = root.GetProperty("summary");
+
+        Assert.Equal(2, summary.GetProperty("succeeded").GetInt32());
+        Assert.Equal(1, summary.GetProperty("skipped").GetInt32());
+        Assert.Equal(1, summary.GetProperty("unmeasured").GetInt32());
+        Assert.Equal(100d, summary.GetProperty("avgDurationSeconds").GetDouble());
+        Assert.Equal(100, summary.GetProperty("p95DurationSeconds").GetInt32());
+        Assert.Equal(0d, summary.GetProperty("failureRate").GetDouble());
+    }
+
     [Fact]
     public async Task Analytics_DeviceModelBreakdown_RatesAndSampleFloor_UseFinishedInstalls()
     {

src/Backend/AutopilotMonitor.Functions.Tests/AppsProjectionEquivalenceTests.cs

@@ -34,6 +34,14 @@ public class AppsProjectionEquivalenceTests
             ["AppType"] = "Win32",
             ["AppVersion"] = "2.1.0",
             ["Status"] = "Failed",
+            // PR0/PR1 classification columns. The fixture MUST populate every column a Build*
+            // method reads: a column absent here passes the equivalence assert trivially (both
+            // sides map to default) — exactly how the missing TerminalState projection slipped
+            // through and zeroed totalSkipped in production (2026-07-27).
+            ["TerminalState"] = "Skipped",
+            ["AppId"] = "9e8d7c6b-5a49-4832-9182-736451234567",
+            ["EspBlocking"] = true,
+            ["AppIdCollision"] = true,
             ["StartedAt"] = new DateTimeOffset(DateTime.UtcNow.AddHours(-6)),
             ["CompletedAt"] = new DateTimeOffset(DateTime.UtcNow.AddHours(-5)),
             ["DurationSeconds"] = 340,
@@ -83,6 +91,9 @@ public class AppsProjectionEquivalenceTests
 
         Assert.Equal(fromFull.AppName, fromProjected.AppName);
         Assert.Equal(fromFull.Status, fromProjected.Status);
+        // IsSkipTerminalState / skip classification input — see the fixture comment.
+        Assert.Equal(fromFull.TerminalState, fromProjected.TerminalState);
+        Assert.Equal(fromFull.AppIdCollision, fromProjected.AppIdCollision);
         Assert.Equal(fromFull.StartedAt, fromProjected.StartedAt);
         Assert.Equal(fromFull.DurationSeconds, fromProjected.DurationSeconds);
         Assert.Equal(fromFull.DownloadBytes, fromProjected.DownloadBytes);
@@ -122,6 +133,10 @@ public class AppsProjectionEquivalenceTests
         Assert.Equal(fromFull.FailureMessage, fromProjected.FailureMessage);
         Assert.Equal(fromFull.ExitCode, fromProjected.ExitCode);
         Assert.Equal(fromFull.DetectionResult, fromProjected.DetectionResult);
+        Assert.Equal(fromFull.TerminalState, fromProjected.TerminalState);
+        Assert.Equal(fromFull.AppId, fromProjected.AppId);
+        Assert.Equal(fromFull.EspBlocking, fromProjected.EspBlocking);
+        Assert.Equal(fromFull.AppIdCollision, fromProjected.AppIdCollision);
     }
 
     [Fact]

src/Backend/AutopilotMonitor.Functions.Tests/AzureMonitorAlertWebhookFunctionTests.cs

@@ -0,0 +1,172 @@
+using AutopilotMonitor.Functions.Functions.Infrastructure;
+using AutopilotMonitor.Shared.DataAccess;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Pins the pure helpers of <see cref="AzureMonitorAlertWebhookFunction"/> — the anonymous,
+/// secret-gated bridge that turns Azure Monitor Common Alert Schema notifications into ops
+/// events. Load-bearing bits: the secret gate is fail-closed (an unset app setting rejects
+/// everything), severity mapping can never escalate on schema drift (unknown → Info), and
+/// parsing is defensive (only the alert rule name is mandatory).
+/// </summary>
+public class AzureMonitorAlertWebhookFunctionTests
+{
+    // ── SecretMatches ──────────────────────────────────────────────────────
+
+    [Fact]
+    public void SecretMatches_accepts_equal_secrets()
+    {
+        Assert.True(AzureMonitorAlertWebhookFunction.SecretMatches("s3cret-value", "s3cret-value"));
+    }
+
+    [Theory]
+    [InlineData("wrong", "right")]
+    [InlineData("right-but-longer", "right")]
+    [InlineData("", "configured")]
+    [InlineData(null, "configured")]
+    public void SecretMatches_rejects_mismatch_or_missing_provided(string? provided, string configured)
+    {
+        Assert.False(AzureMonitorAlertWebhookFunction.SecretMatches(provided, configured));
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    public void SecretMatches_fails_closed_when_not_configured(string? configured)
+    {
+        // While the app setting is unset, NOTHING matches — not even an empty provided value.
+        Assert.False(AzureMonitorAlertWebhookFunction.SecretMatches("anything", configured));
+        Assert.False(AzureMonitorAlertWebhookFunction.SecretMatches("", configured));
+        Assert.False(AzureMonitorAlertWebhookFunction.SecretMatches(null, configured));
+    }
+
+    // ── MapSeverity ────────────────────────────────────────────────────────
+
+    [Theory]
+    [InlineData("Sev0", OpsEventSeverity.Critical)]
+    [InlineData("Sev1", OpsEventSeverity.Error)]
+    [InlineData("Sev2", OpsEventSeverity.Warning)]
+    [InlineData("Sev3", OpsEventSeverity.Info)]
+    [InlineData("Sev4", OpsEventSeverity.Info)]
+    public void MapSeverity_maps_azure_scale_to_ops_scale(string azure, string expected)
+    {
+        Assert.Equal(expected, AzureMonitorAlertWebhookFunction.MapSeverity(azure));
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("Sev5")]
+    [InlineData("Critical")] // someone posting the ops scale directly must not pass through
+    public void MapSeverity_falls_back_to_info_on_unknown_values(string? azure)
+    {
+        Assert.Equal(OpsEventSeverity.Info, AzureMonitorAlertWebhookFunction.MapSeverity(azure));
+    }
+
+    // ── TryParse ───────────────────────────────────────────────────────────
+
+    private const string FullPayload = """
+        {
+          "schemaId": "azureMonitorCommonAlertSchema",
+          "data": {
+            "essentials": {
+              "alertId": "/subscriptions/xxx/providers/Microsoft.AlertsManagement/alerts/abc",
+              "alertRule": "Portal RSC prefetch tail",
+              "severity": "Sev2",
+              "signalType": "Log",
+              "monitorCondition": "Fired",
+              "monitoringService": "Log Alerts V2",
+              "alertTargetIDs": [
+                "/subscriptions/xxx/resourcegroups/rg-autopilotmonitor-prd-gwc/providers/microsoft.insights/components/autopilotmonitorweb"
+              ],
+              "description": "RSC prefetches exceeding 10s",
+              "firedDateTime": "2026-07-27T15:30:00.000Z"
+            },
+            "alertContext": {
+              "condition": {
+                "windowSize": "PT1H",
+                "allOf": [
+                  {
+                    "searchQuery": "dependencies | where name contains '_rsc='",
+                    "metricValue": 18.0,
+                    "operator": "GreaterThan",
+                    "threshold": "0"
+                  }
+                ]
+              }
+            }
+          }
+        }
+        """;
+
+    [Fact]
+    public void TryParse_extracts_essentials_and_metric_value()
+    {
+        var alert = AzureMonitorAlertWebhookFunction.TryParse(FullPayload);
+
+        Assert.NotNull(alert);
+        Assert.Equal("Portal RSC prefetch tail", alert!.AlertRule);
+        Assert.Equal("Sev2", alert.Severity);
+        Assert.Equal("Fired", alert.MonitorCondition);
+        Assert.Equal("RSC prefetches exceeding 10s", alert.Description);
+        Assert.Equal("Log Alerts V2", alert.MonitoringService);
+        // No targetResourceName in the payload → resource name segment of the first target ID.
+        Assert.Equal("autopilotmonitorweb", alert.TargetResource);
+        Assert.Equal(18.0, alert.MetricValue);
+    }
+
+    [Fact]
+    public void TryParse_prefers_explicit_target_resource_name()
+    {
+        const string payload = """
+            {"data":{"essentials":{"alertRule":"r","targetResourceName":"explicit-name",
+            "alertTargetIDs":["/sub/x/other-name"]}}}
+            """;
+        var alert = AzureMonitorAlertWebhookFunction.TryParse(payload);
+        Assert.Equal("explicit-name", alert!.TargetResource);
+    }
+
+    [Fact]
+    public void TryParse_minimal_payload_needs_only_the_alert_rule()
+    {
+        var alert = AzureMonitorAlertWebhookFunction.TryParse(
+            """{"data":{"essentials":{"alertRule":"minimal"}}}""");
+
+        Assert.NotNull(alert);
+        Assert.Equal("minimal", alert!.AlertRule);
+        Assert.Null(alert.Severity);
+        Assert.Equal("Fired", alert.MonitorCondition); // default when absent
+        Assert.Null(alert.Description);
+        Assert.Null(alert.MetricValue);
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData("not json at all")]
+    [InlineData("{}")]                                          // no data
+    [InlineData("""{"data":{}}""")]                             // no essentials
+    [InlineData("""{"data":{"essentials":{}}}""")]              // no alertRule
+    [InlineData("""{"data":{"essentials":{"alertRule":""}}}""")] // empty alertRule
+    [InlineData("""{"data":{"essentials":{"alertRule":123}}}""")] // wrong type
+    public void TryParse_rejects_unusable_payloads(string? body)
+    {
+        Assert.Null(AzureMonitorAlertWebhookFunction.TryParse(body!));
+    }
+
+    [Fact]
+    public void TryParse_tolerates_malformed_alert_context()
+    {
+        // alertContext with unexpected shapes must not break essentials extraction.
+        const string payload = """
+            {"data":{"essentials":{"alertRule":"r","severity":"Sev0"},
+            "alertContext":{"condition":{"allOf":"not-an-array"}}}}
+            """;
+        var alert = AzureMonitorAlertWebhookFunction.TryParse(payload);
+        Assert.NotNull(alert);
+        Assert.Equal("Sev0", alert!.Severity);
+        Assert.Null(alert.MetricValue);
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/ConnectionTypeFilterTests.cs

@@ -0,0 +1,48 @@
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Cover for the ConnectionType predicate used on every search path that does NOT push the
+/// filter to OData — the deviceProperties batch-get (<c>ApplyBasicFilters</c>) and the legacy
+/// unpaged scan. Sessions that predate the projection (null ConnectionType) must never match
+/// a set filter; an unset filter matches everything.
+/// </summary>
+public class ConnectionTypeFilterTests
+{
+    private static SessionSummary Session(string? connectionType) =>
+        new() { SessionId = "s", TenantId = "t", ConnectionType = connectionType };
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("WiFi")]
+    [InlineData("Ethernet")]
+    public void NoFilter_AlwaysMatches(string? connectionType)
+    {
+        var filter = new SessionSearchFilter();
+        Assert.True(TableStorageService.MatchesConnectionType(Session(connectionType), filter));
+    }
+
+    [Theory]
+    [InlineData("Ethernet", true)]
+    [InlineData("ethernet", true)]  // case-insensitive, matching the other string filters
+    [InlineData("WiFi", false)]
+    [InlineData(null, false)]       // legacy session without the projected column
+    public void EthernetFilter_MatchesOnlyEthernet(string? connectionType, bool expected)
+    {
+        var filter = new SessionSearchFilter { ConnectionType = "Ethernet" };
+        Assert.Equal(expected, TableStorageService.MatchesConnectionType(Session(connectionType), filter));
+    }
+
+    [Theory]
+    [InlineData("WiFi", true)]
+    [InlineData("Ethernet", false)]
+    [InlineData(null, false)]
+    public void WiFiFilter_MatchesOnlyWiFi(string? connectionType, bool expected)
+    {
+        var filter = new SessionSearchFilter { ConnectionType = "WiFi" };
+        Assert.Equal(expected, TableStorageService.MatchesConnectionType(Session(connectionType), filter));
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/DeletionManifestBuilderTests.cs

@@ -75,8 +75,9 @@ public class DeletionManifestBuilderTests
         Assert.Equal(2,  c["classifierVerdictsByIdLevel"]);
         Assert.Equal(11, c["signalsByKind"]);
 
-        // 15 cascade tables + tombstone = 16 steps; no inventory steps when no contributions row.
-        Assert.Equal(16, manifest.Steps.Count);
+        // 16 cascade tables (incl. SessionTimeBreakdowns, F1 PR2) + tombstone = 17 steps;
+        // no inventory steps when no contributions row.
+        Assert.Equal(17, manifest.Steps.Count);
         Assert.Equal(DeletionStepClass.Final, manifest.Steps.Last().Class);
     }
 
@@ -102,7 +103,8 @@ public class DeletionManifestBuilderTests
             .WithSessionsByStage(1, propValue: "stage_marker")
             .WithDeadEndsByReason(1, propValue: "deadend_marker")
             .WithClassifierVerdictsByIdLevel(1, propValue: "classifier_marker")
-            .WithSignalsByKind(1, propValue: "signalkind_marker"));
+            .WithSignalsByKind(1, propValue: "signalkind_marker")
+            .WithSessionTimeBreakdown(propValue: "breakdown_marker"));
 
         var manifest = await NewBuilder(reader).BuildAsync(
             TenantId, SessionId, "admin_delete",
@@ -145,8 +147,8 @@ public class DeletionManifestBuilderTests
             new DeletionRetentionContext { TenantRetentionDays = 90 });
 
         var nonTombstoneSteps = manifest.Steps.Where(s => s.Class != DeletionStepClass.Final).ToList();
-        // Without a contributions row, neither inventory step is emitted → exactly 15 cascade-table steps.
-        Assert.Equal(15, nonTombstoneSteps.Count);
+        // Without a contributions row, neither inventory step is emitted → exactly 16 cascade-table steps.
+        Assert.Equal(16, nonTombstoneSteps.Count);
         foreach (var step in nonTombstoneSteps)
         {
             Assert.Equal(0, step.RowCount);
@@ -175,8 +177,8 @@ public class DeletionManifestBuilderTests
             new DeletionActor { Type = "admin", Actor = "alice@example.com" },
             new DeletionRetentionContext { TenantRetentionDays = 90 });
 
-        // Expect: 15 cascade + 2 inventory + 1 tombstone = 18 steps.
-        Assert.Equal(18, manifest.Steps.Count);
+        // Expect: 16 cascade + 2 inventory + 1 tombstone = 19 steps.
+        Assert.Equal(19, manifest.Steps.Count);
 
         var aggregate = manifest.Steps.Single(s => s.Class == DeletionStepClass.Aggregate);
         Assert.Equal(DeletionStepNames.SoftwareInventoryDecrement, aggregate.Step);
@@ -640,6 +642,7 @@ public class DeletionManifestBuilderTests
         private TableEntity? _vulnerabilityReport;
         private TableEntity? _deviceSnapshot;
         private TableEntity? _eventSessionIndex;
+        private TableEntity? _sessionTimeBreakdown;
         private TableEntity? _sessionInventoryContributions;
         private string _sessionsIndexRowKey = "INDEX_" + SessionId;
 
@@ -719,6 +722,16 @@ public class DeletionManifestBuilderTests
             return this;
         }
 
+        public ReaderSeed WithSessionTimeBreakdown(string propValue = "tab")
+        {
+            _sessionTimeBreakdown = new TableEntity(TenantId, SessionId)
+            {
+                ["Marker"] = propValue,
+            };
+            _sessionTimeBreakdown.ETag = new ETag("0xTAB");
+            return this;
+        }
+
         public ReaderSeed WithEventTypeIndex(int n, string propValue = "eti")
         {
             // PK = {tenantId}_{eventType}, RK ends with _{sessionId}.
@@ -796,6 +809,8 @@ public class DeletionManifestBuilderTests
                   .ReturnsAsync(_deviceSnapshot);
             reader.Setup(r => r.GetEntityOrNullAsync(Constants.TableNames.EventSessionIndex, TenantId, SessionId, It.IsAny<CancellationToken>()))
                   .ReturnsAsync(_eventSessionIndex);
+            reader.Setup(r => r.GetEntityOrNullAsync(Constants.TableNames.SessionTimeBreakdowns, TenantId, SessionId, It.IsAny<CancellationToken>()))
+                  .ReturnsAsync(_sessionTimeBreakdown);
             reader.Setup(r => r.GetEntityOrNullAsync(Constants.TableNames.SessionInventoryContributions, TenantId, SessionId, It.IsAny<CancellationToken>()))
                   .ReturnsAsync(_sessionInventoryContributions);
 

src/Backend/AutopilotMonitor.Functions.Tests/DeviceJourneyAndFtrTests.cs

@@ -0,0 +1,809 @@
+using AutopilotMonitor.Functions.Functions.Metrics;
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// F2 PR4 (insights spec §F2): device-key normalization (junk serials), terminal-only chain
+/// maintenance (upsert, cap, deletion-ref pruning), journey grouping (first-success end,
+/// 30-day gap, Incomplete attempts, WG-Pending stays open), the pure daily FTR aggregation
+/// core (<see cref="MaintenanceService.BuildDeviceJourneyAggregates"/>) and the persistence
+/// round-trips (table-storage-serialization rule — every property must survive Store→Map).
+/// </summary>
+public class DeviceJourneyAndFtrTests
+{
+    private static readonly DateTime T0 = new(2026, 7, 20, 10, 0, 0, DateTimeKind.Utc);
+    private const string TenantA = "aaaaaaaa-0000-0000-0000-000000000001";
+    private const string TenantB = "bbbbbbbb-0000-0000-0000-000000000002";
+
+    private static SessionSummary Session(
+        string sessionId,
+        SessionStatus status = SessionStatus.Succeeded,
+        DateTime? startedAt = null,
+        DateTime? completedAt = null,
+        int? durationSeconds = 1800,
+        string? serial = "PF4X1ABC",
+        string tenantId = TenantA,
+        bool wg = false,
+        string enrollmentType = "v1",
+        string? adminMarkedAction = null)
+        => new()
+        {
+            TenantId = tenantId,
+            SessionId = sessionId,
+            SerialNumber = serial!,
+            Status = status,
+            StartedAt = startedAt ?? T0,
+            CompletedAt = completedAt ?? (startedAt ?? T0).AddSeconds(durationSeconds ?? 0),
+            DurationSeconds = durationSeconds,
+            IsPreProvisioned = wg,
+            EnrollmentType = enrollmentType,
+            AdminMarkedAction = adminMarkedAction,
+            Manufacturer = "Contoso",
+            Model = "Laptop 5",
+        };
+
+    private static DeviceSessionRef Ref(
+        string sessionId, SessionStatus status, DateTime startedAt, DateTime? completedAt = null)
+        => new()
+        {
+            SessionId = sessionId,
+            Status = status.ToString(),
+            StartedAt = startedAt,
+            CompletedAt = completedAt ?? startedAt.AddMinutes(30),
+        };
+
+    // ── serial normalization / junk exclusion ───────────────────────────────
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData("abc")]                      // shorter than 4 chars
+    [InlineData("0")]
+    [InlineData("None")]
+    [InlineData("INVALID")]
+    [InlineData("Unknown")]                  // the agent's WMI-failure sentinel (audit Q5)
+    [InlineData("unknown")]
+    [InlineData("System Serial Number")]
+    [InlineData("TO BE FILLED BY O.E.M.")]
+    [InlineData("Default String")]
+    [InlineData("  Default string  ")]       // junk match happens after trim + case-fold
+    public void NormalizeSerial_JunkAndPlaceholders_YieldNull(string? raw)
+    {
+        Assert.Null(DeviceJourneyCalculator.NormalizeSerial(raw));
+    }
+
+    [Theory]
+    [InlineData("PF4X1ABC", "pf4x1abc")]
+    [InlineData("  PF4X1ABC  ", "pf4x1abc")] // trim
+    [InlineData("pf4x1abc", "pf4x1abc")]
+    [InlineData("1234", "1234")]             // exactly 4 chars is a valid identity
+    public void NormalizeSerial_RealSerials_TrimAndCaseFold(string raw, string expected)
+    {
+        Assert.Equal(expected, DeviceJourneyCalculator.NormalizeSerial(raw));
+    }
+
+    // ── terminal set / ref building ─────────────────────────────────────────
+
+    [Theory]
+    [InlineData(SessionStatus.Succeeded, true)]
+    [InlineData(SessionStatus.Failed, true)]
+    [InlineData(SessionStatus.Incomplete, true)]
+    [InlineData(SessionStatus.InProgress, false)]
+    [InlineData(SessionStatus.Pending, false)]      // WG part 1 sealed — an OPEN session
+    [InlineData(SessionStatus.Stalled, false)]
+    [InlineData(SessionStatus.AwaitingUser, false)]
+    [InlineData(SessionStatus.Unknown, false)]
+    public void IsTerminal_MatchesTheF2TerminalSet(SessionStatus status, bool expected)
+    {
+        Assert.Equal(expected, DeviceJourneyCalculator.IsTerminal(status));
+    }
+
+    [Fact]
+    public void BuildSessionRef_MapsAllFields_DurationIsAuthoritativeDurationSeconds()
+    {
+        // CompletedAt deliberately diverges from StartedAt + DurationSeconds (25 % of terminal
+        // sessions in production) — the ref must carry DurationSeconds verbatim.
+        var session = Session("s-1", startedAt: T0, completedAt: T0.AddHours(5), durationSeconds: 1800,
+            wg: true, enrollmentType: "v1", adminMarkedAction: "Succeeded");
+
+        var reference = DeviceJourneyCalculator.BuildSessionRef(session)!;
+
+        Assert.Equal("s-1", reference.SessionId);
+        Assert.Equal(T0, reference.StartedAt);
+        Assert.Equal(T0.AddHours(5), reference.CompletedAt);
+        Assert.Equal("Succeeded", reference.Status);
+        Assert.Equal("v1", reference.EnrollmentType);
+        Assert.True(reference.IsPreProvisioned);
+        Assert.Equal(1800, reference.DurationSeconds);
+        Assert.True(reference.AdminMarked);
+    }
+
+    [Fact]
+    public void BuildSessionRef_WhiteGlovePending_YieldsNull_NeverAnAttempt()
+    {
+        var pending = Session("s-1", status: SessionStatus.Pending, wg: true, durationSeconds: null);
+        Assert.Null(DeviceJourneyCalculator.BuildSessionRef(pending));
+    }
+
+    [Fact]
+    public void BuildSessionRef_Incomplete_KeepsNullDuration()
+    {
+        var incomplete = Session("s-1", status: SessionStatus.Incomplete, durationSeconds: null);
+        var reference = DeviceJourneyCalculator.BuildSessionRef(incomplete)!;
+        Assert.Equal("Incomplete", reference.Status);
+        Assert.Null(reference.DurationSeconds);
+        Assert.False(reference.AdminMarked);
+    }
+
+    // ── chain maintenance ───────────────────────────────────────────────────
+
+    [Fact]
+    public void MergeChain_UpsertsBySessionId_ReclassificationReplacesTheEntry()
+    {
+        var existing = new List<DeviceSessionRef> { Ref("s-1", SessionStatus.Incomplete, T0) };
+        var update = Ref("s-1", SessionStatus.Succeeded, T0);
+
+        var merged = DeviceJourneyCalculator.MergeChain(existing, new[] { update });
+
+        var entry = Assert.Single(merged);
+        Assert.Equal("Succeeded", entry.Status);
+    }
+
+    [Fact]
+    public void MergeChain_OrdersByStartedAt_TiebreakSessionId_AndCapsToMostRecent()
+    {
+        var refs = new List<DeviceSessionRef>();
+        for (var i = 0; i < 25; i++)
+            refs.Add(Ref($"s-{i:D2}", SessionStatus.Failed, T0.AddDays(i)));
+        // Same StartedAt as s-24 — the ordinal sessionId tiebreak must keep the order stable.
+        refs.Add(Ref("s-00-twin", SessionStatus.Failed, T0.AddDays(24)));
+
+        var merged = DeviceJourneyCalculator.MergeChain(null, refs);
+
+        Assert.Equal(20, merged.Count);                       // cap 20 most recent
+        Assert.Equal("s-06", merged[0].SessionId);            // s-00..s-05 dropped (oldest)
+        Assert.Equal(T0.AddDays(24), merged[^1].StartedAt);
+        Assert.Equal("s-24", merged[^1].SessionId);           // "s-00-twin" < "s-24" ordinal → sorts first
+        Assert.Equal("s-00-twin", merged[^2].SessionId);
+    }
+
+    [Fact]
+    public void MergeChain_DropsNonTerminalRefs_Defensively()
+    {
+        var corrupt = new List<DeviceSessionRef>
+        {
+            Ref("s-1", SessionStatus.Succeeded, T0),
+            new() { SessionId = "s-2", Status = "Pending", StartedAt = T0.AddDays(1) },
+            new() { SessionId = "s-3", Status = "garbage", StartedAt = T0.AddDays(2) },
+        };
+
+        var merged = DeviceJourneyCalculator.MergeChain(corrupt, Array.Empty<DeviceSessionRef>());
+
+        Assert.Equal("s-1", Assert.Single(merged).SessionId);
+    }
+
+    [Fact]
+    public void RemoveSessionRefs_DropsDeletedSessions_EmptyChainSignalsRowDeletion()
+    {
+        var chain = new List<DeviceSessionRef>
+        {
+            Ref("s-1", SessionStatus.Failed, T0),
+            Ref("s-2", SessionStatus.Succeeded, T0.AddDays(1)),
+        };
+
+        var partial = DeviceJourneyCalculator.RemoveSessionRefs(
+            chain, new HashSet<string>(StringComparer.Ordinal) { "s-1" });
+        Assert.Equal("s-2", Assert.Single(partial).SessionId);
+
+        var empty = DeviceJourneyCalculator.RemoveSessionRefs(
+            chain, new HashSet<string>(StringComparer.Ordinal) { "s-1", "s-2" });
+        Assert.Empty(empty);
+    }
+
+    // ── journey grouping ────────────────────────────────────────────────────
+
+    [Fact]
+    public void GroupJourneys_SingleSuccess_IsOneCompletedFirstTimeRightJourney()
+    {
+        var journeys = DeviceJourneyCalculator.GroupJourneys(
+            new[] { Ref("s-1", SessionStatus.Succeeded, T0) });
+
+        var journey = Assert.Single(journeys);
+        Assert.True(journey.Completed);
+        Assert.Single(journey.Attempts);
+        Assert.Equal("s-1", journey.CompletingRef!.SessionId);
+    }
+
+    [Fact]
+    public void GroupJourneys_FailAndIncompleteAreAttempts_JourneyEndsWithFirstSuccess()
+    {
+        var journeys = DeviceJourneyCalculator.GroupJourneys(new[]
+        {
+            Ref("s-1", SessionStatus.Failed, T0),
+            Ref("s-2", SessionStatus.Incomplete, T0.AddHours(2)),
+            Ref("s-3", SessionStatus.Succeeded, T0.AddHours(4)),
+        });
+
+        var journey = Assert.Single(journeys);
+        Assert.True(journey.Completed);
+        Assert.Equal(3, journey.Attempts.Count); // Incomplete is a non-successful attempt
+    }
+
+    [Fact]
+    public void GroupJourneys_SessionAfterSuccess_StartsANewJourney_Redeployment()
+    {
+        var journeys = DeviceJourneyCalculator.GroupJourneys(new[]
+        {
+            Ref("s-1", SessionStatus.Succeeded, T0),
+            Ref("s-2", SessionStatus.Failed, T0.AddDays(2)),
+        });
+
+        Assert.Equal(2, journeys.Count);
+        Assert.True(journeys[0].Completed);
+        Assert.False(journeys[1].Completed);   // open — no failed verdict, just not done yet
+        Assert.Null(journeys[1].CompletingRef);
+    }
+
+    [Fact]
+    public void GroupJourneys_FailuresOnly_JourneyStaysOpen_NeverCompleted()
+    {
+        var journeys = DeviceJourneyCalculator.GroupJourneys(new[]
+        {
+            Ref("s-1", SessionStatus.Failed, T0),
+            Ref("s-2", SessionStatus.Failed, T0.AddDays(1)),
+        });
+
+        var journey = Assert.Single(journeys);
+        Assert.False(journey.Completed);
+        Assert.Equal(2, journey.Attempts.Count);
+    }
+
+    [Fact]
+    public void GroupJourneys_GapOver30Days_StartsANewJourney_AbandonedStaysUncompleted()
+    {
+        var journeys = DeviceJourneyCalculator.GroupJourneys(new[]
+        {
+            Ref("s-1", SessionStatus.Failed, T0, completedAt: T0.AddHours(1)),
+            Ref("s-2", SessionStatus.Failed, T0.AddHours(1).AddDays(31)),
+            Ref("s-3", SessionStatus.Succeeded, T0.AddHours(1).AddDays(31).AddHours(3)),
+        });
+
+        Assert.Equal(2, journeys.Count);
+        Assert.False(journeys[0].Completed);            // shelved/abandoned — never counts for FTR
+        Assert.Single(journeys[0].Attempts);
+        Assert.True(journeys[1].Completed);
+        Assert.Equal(2, journeys[1].Attempts.Count);
+    }
+
+    [Fact]
+    public void GroupJourneys_GapBoundary_Exactly30DaysStaysOneJourney_StrictlyMoreSplits()
+    {
+        var prevEnd = T0.AddHours(1);
+
+        var exactly30 = DeviceJourneyCalculator.GroupJourneys(new[]
+        {
+            Ref("s-1", SessionStatus.Failed, T0, completedAt: prevEnd),
+            Ref("s-2", SessionStatus.Failed, prevEnd.AddDays(30)),
+        });
+        Assert.Single(exactly30); // spec: "> 30 days" — the boundary itself does not split
+
+        var over30 = DeviceJourneyCalculator.GroupJourneys(new[]
+        {
+            Ref("s-1", SessionStatus.Failed, T0, completedAt: prevEnd),
+            Ref("s-2", SessionStatus.Failed, prevEnd.AddDays(30).AddHours(1)),
+        });
+        Assert.Equal(2, over30.Count);
+    }
+
+    [Fact]
+    public void GroupJourneys_GapMeasuredFromCompletedAt_NotStartedAt()
+    {
+        // Previous attempt STARTED 40 days before the next one but went terminal only 10 days
+        // before it — the gap is 10 days, one journey. StartedAt-based measuring would split.
+        var journeys = DeviceJourneyCalculator.GroupJourneys(new[]
+        {
+            Ref("s-1", SessionStatus.Failed, T0.AddDays(-40), completedAt: T0.AddDays(-10)),
+            Ref("s-2", SessionStatus.Succeeded, T0),
+        });
+
+        var journey = Assert.Single(journeys);
+        Assert.Equal(2, journey.Attempts.Count);
+    }
+
+    [Fact]
+    public void GroupJourneys_WhiteGloveIsOneSessionRow_OneAttempt_NoStitching()
+    {
+        // WG part 1 + part 2 share one session row (second-sweep finding): a completed WG
+        // enrollment is exactly one ref and one first-time-right attempt.
+        var wg = Session("s-1", wg: true, durationSeconds: 5400, completedAt: T0.AddDays(6));
+        var reference = DeviceJourneyCalculator.BuildSessionRef(wg)!;
+
+        var journeys = DeviceJourneyCalculator.GroupJourneys(new[] { reference });
+
+        var journey = Assert.Single(journeys);
+        Assert.True(journey.Completed);
+        Assert.Single(journey.Attempts);
+        Assert.Equal(5400, journey.Attempts[0].DurationSeconds); // pause-free combined duration, verbatim
+    }
+
+    [Fact]
+    public void Derive_CurrentJourneyAttempts_IsTheLastJourneys_OpenOrCompleted()
+    {
+        var (journeyCount, currentAttempts) = DeviceJourneyCalculator.Derive(new[]
+        {
+            Ref("s-1", SessionStatus.Succeeded, T0),
+            Ref("s-2", SessionStatus.Failed, T0.AddDays(1)),
+            Ref("s-3", SessionStatus.Failed, T0.AddDays(2)),
+        });
+
+        Assert.Equal(2, journeyCount);
+        Assert.Equal(2, currentAttempts); // the open redeployment journey has 2 attempts so far
+
+        Assert.Equal((0, 0), DeviceJourneyCalculator.Derive(Array.Empty<DeviceSessionRef>()));
+    }
+
+    // ── history row assembly (display precedence) ───────────────────────────
+
+    [Fact]
+    public void BuildDeviceHistoryRow_DisplayFields_FollowTheNewestChainEntry()
+    {
+        var newest = Session("s-2", serial: " PF4X1ABC ", startedAt: T0.AddDays(1));
+        var chain = new List<DeviceSessionRef>
+        {
+            Ref("s-1", SessionStatus.Failed, T0),
+            Ref("s-2", SessionStatus.Succeeded, T0.AddDays(1)),
+        };
+
+        var row = TableStorageService.BuildDeviceHistoryRow(TenantA, "pf4x1abc", chain, existing: null, newest);
+
+        Assert.Equal("PF4X1ABC", row.SerialNumber); // trimmed original casing
+        Assert.Equal("Contoso", row.Manufacturer);
+        Assert.Equal("Laptop 5", row.Model);
+        Assert.Equal(2, row.CurrentJourneyAttempts);
+        Assert.Equal(1, row.JourneyCount);
+        Assert.Equal(DeviceJourneyCalculator.CurrentVersion, row.JourneyVersion);
+    }
+
+    [Fact]
+    public void BuildDeviceHistoryRow_BackfillingAnOlderSession_KeepsExistingDisplayFields()
+    {
+        var older = Session("s-1", serial: "pf4x1abc", startedAt: T0);
+        older.Model = "Laptop 4"; // stale model from the older enrollment
+        var chain = new List<DeviceSessionRef>
+        {
+            Ref("s-1", SessionStatus.Failed, T0),
+            Ref("s-2", SessionStatus.Succeeded, T0.AddDays(1)),
+        };
+        var existing = new DeviceHistory
+        {
+            TenantId = TenantA, SerialKey = "pf4x1abc",
+            SerialNumber = "PF4X1ABC", Manufacturer = "Contoso", Model = "Laptop 5",
+        };
+
+        var row = TableStorageService.BuildDeviceHistoryRow(TenantA, "pf4x1abc", chain, existing, older);
+
+        Assert.Equal("PF4X1ABC", row.SerialNumber); // not regressed to the older session's data
+        Assert.Equal("Laptop 5", row.Model);
+    }
+
+    // ── persistence round-trips ─────────────────────────────────────────────
+
+    [Fact]
+    public void DeviceHistoryEntity_RoundTripsAllFields_IncludingChainJson()
+    {
+        var history = new DeviceHistory
+        {
+            TenantId = TenantA,
+            SerialKey = "pf4x1abc",
+            SerialNumber = "PF4X1ABC",
+            Manufacturer = "Contoso",
+            Model = "Laptop 5",
+            CurrentJourneyAttempts = 2,
+            JourneyCount = 3,
+            JourneyVersion = 1,
+            LastUpdated = T0,
+            Chain = new List<DeviceSessionRef>
+            {
+                new()
+                {
+                    SessionId = "s-1", StartedAt = T0, CompletedAt = T0.AddHours(5),
+                    Status = "Succeeded", EnrollmentType = "v2", IsPreProvisioned = true,
+                    DurationSeconds = 1800, AdminMarked = true,
+                },
+                new()
+                {
+                    SessionId = "s-2", StartedAt = T0.AddDays(1), CompletedAt = null,
+                    Status = "Incomplete", EnrollmentType = "v1", DurationSeconds = null,
+                },
+            },
+        };
+
+        var mapped = TableStorageService.MapToDeviceHistory(
+            TableStorageService.BuildDeviceHistoryEntity(history));
+
+        Assert.Equal(TenantA, mapped.TenantId);
+        Assert.Equal("pf4x1abc", mapped.SerialKey);
+        Assert.Equal("PF4X1ABC", mapped.SerialNumber);
+        Assert.Equal("Contoso", mapped.Manufacturer);
+        Assert.Equal("Laptop 5", mapped.Model);
+        Assert.Equal(2, mapped.CurrentJourneyAttempts);
+        Assert.Equal(3, mapped.JourneyCount);
+        Assert.Equal(1, mapped.JourneyVersion);
+        Assert.Equal(T0, mapped.LastUpdated);
+
+        Assert.Equal(2, mapped.Chain.Count);
+        var first = mapped.Chain[0];
+        Assert.Equal("s-1", first.SessionId);
+        Assert.Equal(T0, first.StartedAt);
+        Assert.Equal(T0.AddHours(5), first.CompletedAt);
+        Assert.Equal("Succeeded", first.Status);
+        Assert.Equal("v2", first.EnrollmentType);
+        Assert.True(first.IsPreProvisioned);
+        Assert.Equal(1800, first.DurationSeconds);
+        Assert.True(first.AdminMarked);
+        var second = mapped.Chain[1];
+        Assert.Null(second.CompletedAt);      // Incomplete: no terminal timestamp requirement
+        Assert.Null(second.DurationSeconds);  // Incomplete: deliberately no duration — stays null
+        Assert.False(second.AdminMarked);
+    }
+
+    [Fact]
+    public void DeviceHistoryEntity_RowKeyEncoding_MakesForbiddenKeyCharsSafe_AndRoundTrips()
+    {
+        // '/', '\', '#', '?' are forbidden in Table Storage keys — a defensive encoding keeps a
+        // pathological serial writable, and the mapper restores the exact normalized serial.
+        var weird = "ab/cd\\ef#1?x";
+        var history = new DeviceHistory { TenantId = TenantA, SerialKey = weird };
+
+        var entity = TableStorageService.BuildDeviceHistoryEntity(history);
+        Assert.All(new[] { "/", "\\", "#", "?" }, c => Assert.DoesNotContain(c, entity.RowKey));
+
+        Assert.Equal(weird, TableStorageService.MapToDeviceHistory(entity).SerialKey);
+
+        // Ordinary serials stay human-readable.
+        Assert.Equal("pf4x1abc", TableStorageService.SerialRowKey("pf4x1abc"));
+    }
+
+    [Fact]
+    public void DeviceJourneyAggregateEntity_RoundTripsAllFields_RowKeyIsTheDate()
+    {
+        var aggregate = new DeviceJourneyDailyAggregate
+        {
+            TenantId = TenantA,
+            Date = "2026-07-20",
+            JourneyVersion = 1,
+            CompletedJourneyCount = 23,
+            FirstTimeRightCount = 19,
+            ExcludedSessionCount = 2,
+            ComputedAt = T0,
+            AttemptHistogram = new List<DeviceJourneyAttemptBucket>
+            {
+                new() { Attempts = 1, JourneyCount = 19 },
+                new() { Attempts = 2, JourneyCount = 3 },
+                new() { Attempts = 4, JourneyCount = 1 },
+            },
+        };
+
+        var entity = TableStorageService.BuildDeviceJourneyAggregateEntity(aggregate);
+        Assert.Equal("2026-07-20", entity.RowKey);
+
+        var mapped = TableStorageService.MapToDeviceJourneyAggregate(entity);
+        Assert.Equal(TenantA, mapped.TenantId);
+        Assert.Equal("2026-07-20", mapped.Date);
+        Assert.Equal(1, mapped.JourneyVersion);
+        Assert.Equal(23, mapped.CompletedJourneyCount);
+        Assert.Equal(19, mapped.FirstTimeRightCount);
+        Assert.Equal(2, mapped.ExcludedSessionCount);
+        Assert.Equal(T0, mapped.ComputedAt);
+        Assert.Equal(3, mapped.AttemptHistogram.Count);
+        Assert.Equal(1, mapped.AttemptHistogram[0].Attempts);
+        Assert.Equal(19, mapped.AttemptHistogram[0].JourneyCount);
+        Assert.Equal(4, mapped.AttemptHistogram[2].Attempts);
+    }
+
+    // ── daily FTR aggregation core ──────────────────────────────────────────
+
+    private static readonly DateTime WindowStart = T0.Date.AddDays(-30);
+    private static readonly DateTime WindowEnd = T0.Date.AddDays(1);
+
+    private static DeviceHistory History(string tenantId, params DeviceSessionRef[] chain)
+        => new() { TenantId = tenantId, SerialKey = Guid.NewGuid().ToString("N"), Chain = chain.ToList() };
+
+    [Fact]
+    public void FtrAggregates_BucketByCompletingSessionsStartDate_AndMirrorGlobal()
+    {
+        var histories = new List<DeviceHistory>
+        {
+            // Tenant A device 1: fail → success (2 attempts, completes on T0 date).
+            History(TenantA,
+                Ref("a1-1", SessionStatus.Failed, T0.AddDays(-1)),
+                Ref("a1-2", SessionStatus.Succeeded, T0)),
+            // Tenant A device 2: first-time right on the same date.
+            History(TenantA, Ref("a2-1", SessionStatus.Succeeded, T0.AddHours(2))),
+            // Tenant B device: first-time right on a different date.
+            History(TenantB, Ref("b1-1", SessionStatus.Succeeded, T0.AddDays(-3))),
+        };
+
+        var rows = MaintenanceService.BuildDeviceJourneyAggregates(
+            histories, Array.Empty<SessionSummary>(), WindowStart, WindowEnd, T0);
+
+        // Tenant A (1 date) + Tenant B (1 date) + global (2 dates) = 4 rows.
+        Assert.Equal(4, rows.Count);
+
+        var tenantARow = rows.Single(r => r.TenantId == TenantA);
+        Assert.Equal(T0.ToString("yyyy-MM-dd"), tenantARow.Date);
+        Assert.Equal(2, tenantARow.CompletedJourneyCount);
+        Assert.Equal(1, tenantARow.FirstTimeRightCount);
+        Assert.Equal(DeviceJourneyCalculator.CurrentVersion, tenantARow.JourneyVersion);
+        Assert.Equal(2, tenantARow.AttemptHistogram.Count);
+        Assert.Equal(1, tenantARow.AttemptHistogram[0].Attempts);
+        Assert.Equal(1, tenantARow.AttemptHistogram[0].JourneyCount);
+        Assert.Equal(2, tenantARow.AttemptHistogram[1].Attempts);
+
+        var globalOnT0 = rows.Single(r => r.TenantId == "global" && r.Date == T0.ToString("yyyy-MM-dd"));
+        Assert.Equal(2, globalOnT0.CompletedJourneyCount); // tenant B's journey sits on its own date
+    }
+
+    [Fact]
+    public void FtrAggregates_OpenAndAbandonedJourneys_NeverCount()
+    {
+        var histories = new List<DeviceHistory>
+        {
+            // Open journey: failures only (e.g. a WG device still waiting for its user session
+            // has, at most, prior failed attempts in the chain — the Pending row itself never
+            // becomes a ref).
+            History(TenantA, Ref("a1-1", SessionStatus.Failed, T0)),
+            // Abandoned journey (31d gap, no success) followed by a completed journey.
+            History(TenantA,
+                Ref("a2-1", SessionStatus.Failed, T0.AddDays(-20), completedAt: T0.AddDays(-20).AddHours(1)),
+                Ref("a2-2", SessionStatus.Succeeded, T0.AddDays(11).AddHours(2))),
+        };
+
+        var rows = MaintenanceService.BuildDeviceJourneyAggregates(
+            histories, Array.Empty<SessionSummary>(), WindowStart, T0.Date.AddDays(12), T0);
+
+        // Only the completed journey produced rows: tenant + global on one date.
+        Assert.Equal(2, rows.Count);
+        var tenantRow = rows.Single(r => r.TenantId == TenantA);
+        Assert.Equal(1, tenantRow.CompletedJourneyCount);
+        Assert.Equal(1, tenantRow.FirstTimeRightCount); // the abandoned attempt belongs to a DIFFERENT journey
+        Assert.Equal(T0.AddDays(11).ToString("yyyy-MM-dd"), tenantRow.Date);
+    }
+
+    [Fact]
+    public void FtrAggregates_JourneysCompletedOutsideTheWindow_AreSkipped()
+    {
+        var histories = new List<DeviceHistory>
+        {
+            History(TenantA, Ref("a1-1", SessionStatus.Succeeded, WindowStart.AddDays(-1))),
+        };
+
+        var rows = MaintenanceService.BuildDeviceJourneyAggregates(
+            histories, Array.Empty<SessionSummary>(), WindowStart, WindowEnd, T0);
+
+        Assert.Empty(rows);
+    }
+
+    [Fact]
+    public void FtrAggregates_JunkSerialExclusions_ProduceDisclosureRows()
+    {
+        var excluded = new List<SessionSummary>
+        {
+            Session("x-1", serial: "Unknown", startedAt: T0),
+            Session("x-2", serial: "Unknown", startedAt: T0.AddHours(1)),
+            Session("x-3", serial: "Unknown", startedAt: WindowStart.AddDays(-2)), // outside window — ignored
+        };
+
+        var rows = MaintenanceService.BuildDeviceJourneyAggregates(
+            Array.Empty<DeviceHistory>(), excluded, WindowStart, WindowEnd, T0);
+
+        Assert.Equal(2, rows.Count); // tenant + global disclosure rows, no journey claim
+        var tenantRow = rows.Single(r => r.TenantId == TenantA);
+        Assert.Equal(0, tenantRow.CompletedJourneyCount);
+        Assert.Equal(0, tenantRow.FirstTimeRightCount);
+        Assert.Empty(tenantRow.AttemptHistogram);
+        Assert.Equal(2, tenantRow.ExcludedSessionCount);
+        Assert.Equal(2, rows.Single(r => r.TenantId == "global").ExcludedSessionCount);
+    }
+
+    [Fact]
+    public void FtrAggregates_TwoCompletedJourneysOfOneDevice_SameDay_BothCount()
+    {
+        // Redeploy on the same day: success closes journey 1, the next success closes journey 2.
+        var histories = new List<DeviceHistory>
+        {
+            History(TenantA,
+                Ref("a1-1", SessionStatus.Succeeded, T0),
+                Ref("a1-2", SessionStatus.Succeeded, T0.AddHours(3))),
+        };
+
+        var rows = MaintenanceService.BuildDeviceJourneyAggregates(
+            histories, Array.Empty<SessionSummary>(), WindowStart, WindowEnd, T0);
+
+        var tenantRow = rows.Single(r => r.TenantId == TenantA);
+        Assert.Equal(2, tenantRow.CompletedJourneyCount);
+        Assert.Equal(2, tenantRow.FirstTimeRightCount);
+    }
+
+    // ── attempt number (session banner, PR5) ────────────────────────────────
+
+    [Fact]
+    public void ComputeAttemptNumber_TerminalSessionInChain_ReturnsPositionWithinItsJourney()
+    {
+        var chain = new[]
+        {
+            Ref("s-1", SessionStatus.Failed, T0),
+            Ref("s-2", SessionStatus.Succeeded, T0.AddHours(2)),
+            Ref("s-3", SessionStatus.Failed, T0.AddDays(5)), // redeployment → new journey
+        };
+
+        Assert.Equal(1, DeviceJourneyCalculator.ComputeAttemptNumber(chain, "s-1", T0));
+        Assert.Equal(2, DeviceJourneyCalculator.ComputeAttemptNumber(chain, "s-2", T0.AddHours(2)));
+        Assert.Equal(1, DeviceJourneyCalculator.ComputeAttemptNumber(chain, "s-3", T0.AddDays(5)));
+    }
+
+    [Fact]
+    public void ComputeAttemptNumber_LiveSession_ContinuesTheOpenJourney()
+    {
+        var chain = new[] { Ref("s-1", SessionStatus.Failed, T0) };
+        // s-2 is still InProgress — not a chain ref; the virtual-attempt rule places it.
+        Assert.Equal(2, DeviceJourneyCalculator.ComputeAttemptNumber(chain, "s-2", T0.AddDays(1)));
+    }
+
+    [Fact]
+    public void ComputeAttemptNumber_LiveSession_AfterCompletedJourney_IsAttemptOne()
+    {
+        var chain = new[] { Ref("s-1", SessionStatus.Succeeded, T0) };
+        Assert.Equal(1, DeviceJourneyCalculator.ComputeAttemptNumber(chain, "s-2", T0.AddDays(2)));
+    }
+
+    [Fact]
+    public void ComputeAttemptNumber_LiveSession_AfterThirtyDayGap_IsAttemptOne()
+    {
+        var prevEnd = T0.AddHours(1);
+        var chain = new[] { Ref("s-1", SessionStatus.Failed, T0, completedAt: prevEnd) };
+        Assert.Equal(1, DeviceJourneyCalculator.ComputeAttemptNumber(chain, "s-2", prevEnd.AddDays(31)));
+        // Inside the gap boundary the open journey continues instead.
+        Assert.Equal(2, DeviceJourneyCalculator.ComputeAttemptNumber(chain, "s-3", prevEnd.AddDays(29)));
+    }
+
+    [Fact]
+    public void ComputeAttemptNumber_EmptyChain_YieldsNull_NoGuessedPosition()
+    {
+        Assert.Null(DeviceJourneyCalculator.ComputeAttemptNumber(
+            Array.Empty<DeviceSessionRef>(), "s-1", T0));
+    }
+
+    // ── fleet response helpers (PR5) ────────────────────────────────────────
+
+    [Fact]
+    public void SumAggregates_SumsAdditiveCounts_AndMergesHistograms()
+    {
+        var daily = new List<DeviceJourneyDailyAggregate>
+        {
+            new()
+            {
+                CompletedJourneyCount = 2, FirstTimeRightCount = 1, ExcludedSessionCount = 1,
+                AttemptHistogram = new List<DeviceJourneyAttemptBucket>
+                {
+                    new() { Attempts = 1, JourneyCount = 1 },
+                    new() { Attempts = 2, JourneyCount = 1 },
+                },
+            },
+            new()
+            {
+                CompletedJourneyCount = 1, FirstTimeRightCount = 1, ExcludedSessionCount = 0,
+                AttemptHistogram = new List<DeviceJourneyAttemptBucket> { new() { Attempts = 1, JourneyCount = 1 } },
+            },
+        };
+
+        var totals = DeviceJourneyMetricsResponse.SumAggregates(daily);
+
+        Assert.Equal(3, totals.CompletedJourneys);
+        Assert.Equal(2, totals.FirstTimeRight);
+        Assert.Equal(66.7, totals.FtrRatePct);
+        Assert.Equal(1, totals.ExcludedSessions);
+        Assert.Equal(2, totals.AttemptHistogram.Count);
+        Assert.Equal(2, totals.AttemptHistogram.Single(b => b.Attempts == 1).JourneyCount);
+        Assert.Equal(1, totals.AttemptHistogram.Single(b => b.Attempts == 2).JourneyCount);
+    }
+
+    [Fact]
+    public void SumAggregates_NoCompletedJourneys_RateIsNull_NeverZero()
+    {
+        var totals = DeviceJourneyMetricsResponse.SumAggregates(new List<DeviceJourneyDailyAggregate>
+        {
+            new() { CompletedJourneyCount = 0, FirstTimeRightCount = 0, ExcludedSessionCount = 3 },
+        });
+
+        Assert.Equal(0, totals.CompletedJourneys);
+        Assert.Null(totals.FtrRatePct);
+        Assert.Equal(3, totals.ExcludedSessions);
+    }
+
+    [Theory]
+    [InlineData(null, 30)]     // default window
+    [InlineData("garbage", 30)]
+    [InlineData("7", 7)]
+    [InlineData("0", 1)]       // clamped low
+    [InlineData("999", 180)]   // clamped to aggregate retention
+    public void ClampDays_DefaultsAndClamps(string? raw, int expected)
+    {
+        Assert.Equal(expected, DeviceJourneyMetricsResponse.ClampDays(raw));
+    }
+
+    [Fact]
+    public void InclusiveWindowStart_YieldsExactlyNCalendarDays()
+    {
+        // Codex review: both range ends are inclusive, so "today - days" returned N+1 keys —
+        // days=1 summed yesterday AND today.
+        var today = new DateTime(2026, 7, 27);
+        Assert.Equal(today, DeviceJourneyMetricsResponse.InclusiveWindowStart(today, 1));
+        Assert.Equal(today.AddDays(-29), DeviceJourneyMetricsResponse.InclusiveWindowStart(today, 30));
+    }
+
+    private static DeviceHistory RepeaterHistory(
+        string serial, int attempts, params DeviceSessionRef[] chain)
+        => new()
+        {
+            TenantId = TenantA,
+            SerialKey = serial,
+            SerialNumber = serial.ToUpperInvariant(),
+            Chain = chain.ToList(),
+            CurrentJourneyAttempts = attempts,
+            JourneyCount = 1,
+        };
+
+    [Fact]
+    public void SelectRepeatDevices_FiltersGate_WindowsOnNewestRef_AndPicksNewestFailure()
+    {
+        var histories = new List<DeviceHistory>
+        {
+            // Single attempt — not a repeat device.
+            RepeaterHistory("clean-1", attempts: 1, Ref("c1", SessionStatus.Succeeded, T0)),
+            // Repeat device, active in window: newest failed ref carries the reason lookup.
+            RepeaterHistory("hot-1", attempts: 3,
+                Ref("h1", SessionStatus.Failed, T0.AddDays(-2)),
+                Ref("h2", SessionStatus.Failed, T0.AddDays(-1)),
+                Ref("h3", SessionStatus.Incomplete, T0)),
+            // Repeat device, but its pain is OLDER than the window — current lists only.
+            RepeaterHistory("old-1", attempts: 4,
+                Ref("o1", SessionStatus.Failed, T0.AddDays(-40))),
+            // Lower attempt count → sorts after hot-1.
+            RepeaterHistory("warm-1", attempts: 2,
+                Ref("w1", SessionStatus.Failed, T0.AddDays(-3)),
+                Ref("w2", SessionStatus.Succeeded, T0.AddDays(-2))),
+        };
+
+        var selected = DeviceJourneyMetricsResponse.SelectRepeatDevices(histories, T0.AddDays(-30));
+
+        Assert.Equal(2, selected.Count);
+        Assert.Equal("hot-1", selected[0].History.SerialKey);   // attempts desc
+        Assert.Equal("h3", selected[0].Newest.SessionId);
+        Assert.Equal("h2", selected[0].NewestFailed!.SessionId); // last FAILED, not last ref
+        Assert.Equal("warm-1", selected[1].History.SerialKey);
+    }
+
+    [Fact]
+    public void SelectRepeatDevices_CapsAtTen_ByAttemptsThenRecency()
+    {
+        var histories = new List<DeviceHistory>();
+        for (var i = 0; i < 12; i++)
+        {
+            histories.Add(RepeaterHistory($"dev-{i:D2}", attempts: 2 + i,
+                Ref($"r-{i}", SessionStatus.Failed, T0.AddDays(-i))));
+        }
+
+        var selected = DeviceJourneyMetricsResponse.SelectRepeatDevices(histories, T0.AddDays(-30));
+
+        Assert.Equal(10, selected.Count);
+        Assert.Equal("dev-11", selected[0].History.SerialKey); // highest attempts first
+        Assert.DoesNotContain(selected, c => c.History.SerialKey == "dev-00");
+        Assert.DoesNotContain(selected, c => c.History.SerialKey == "dev-01");
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/GeoMetricsProjectionEquivalenceTests.cs

@@ -50,6 +50,8 @@ public class GeoMetricsProjectionEquivalenceTests
             ["GeoCity"] = "Frankfurt",
             ["GeoLoc"] = "50.11,8.68",
             ["IsPreProvisioned"] = false,
+            ["AvgApiLatencyMs"] = 217.4,
+            ["ApiRequestCount"] = 270,
             // Noise the geo aggregation never reads.
             ["SerialNumber"] = "SN-FULL",
             ["Manufacturer"] = "Contoso",
@@ -76,6 +78,8 @@ public class GeoMetricsProjectionEquivalenceTests
         Assert.Equal(fromFull.GeoRegion, fromProjected.GeoRegion);
         Assert.Equal(fromFull.GeoCity, fromProjected.GeoCity);
         Assert.Equal(fromFull.GeoLoc, fromProjected.GeoLoc);
+        Assert.Equal(fromFull.AvgApiLatencyMs, fromProjected.AvgApiLatencyMs);
+        Assert.Equal(fromFull.ApiRequestCount, fromProjected.ApiRequestCount);
 
         // The grouping key must be identical too — it is composed from the Geo* fields.
         Assert.Equal(

src/Backend/AutopilotMonitor.Functions.Tests/GeographicMetricsApiLatencyTests.cs

@@ -0,0 +1,124 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.Functions.Functions.Metrics;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Pins the API-latency aggregation of
+/// <see cref="GetGeographicMetricsFunction.ComputeGeographicMetrics"/> (2026-07-28): both the
+/// per-location and the global figure are REQUEST-WEIGHTED averages —
+/// Σ(sessionAvg·requests)/Σ(requests) — not averages of session averages, so a long session
+/// with many uploads counts proportionally. Sessions without latency data (agents predating
+/// <c>AvgApiLatencyMs</c>) drop out of the weighting entirely.
+/// </summary>
+public class GeographicMetricsApiLatencyTests
+{
+    private static SessionSummary S(string country, string city, double? avgLatencyMs, int? requestCount)
+        => new()
+        {
+            TenantId = "00000000-0000-0000-0000-000000000fe0",
+            SessionId = Guid.NewGuid().ToString(),
+            Status = SessionStatus.Succeeded,
+            StartedAt = DateTime.UtcNow.AddHours(-2),
+            GeoCountry = country,
+            GeoRegion = country,
+            GeoCity = city,
+            GeoLoc = "0,0",
+            AvgApiLatencyMs = avgLatencyMs,
+            ApiRequestCount = requestCount,
+        };
+
+    [Fact]
+    public void LocationLatency_IsRequestWeighted_NotAverageOfAverages()
+    {
+        var sessions = new List<SessionSummary>
+        {
+            S("ID", "Jakarta", 1000, 300),
+            S("ID", "Jakarta", 500, 100),
+        };
+
+        var result = GetGeographicMetricsFunction.ComputeGeographicMetrics(
+            sessions, new List<AppInstallSummary>(), "country");
+
+        var loc = Assert.Single(result.Locations);
+        // (1000·300 + 500·100) / 400 = 875 — an unweighted mean would say 750.
+        Assert.Equal(875d, loc.AvgApiLatencyMs);
+        Assert.Equal(2, loc.ApiLatencySessionCount);
+    }
+
+    [Fact]
+    public void SessionsWithoutLatencyData_DropOutOfWeighting_ButStayInSessionCount()
+    {
+        var sessions = new List<SessionSummary>
+        {
+            S("DE", "Frankfurt", 200, 100),
+            S("DE", "Frankfurt", avgLatencyMs: null, requestCount: null), // pre-feature agent
+            S("DE", "Frankfurt", avgLatencyMs: 0, requestCount: 50),      // zero = no signal
+        };
+
+        var result = GetGeographicMetricsFunction.ComputeGeographicMetrics(
+            sessions, new List<AppInstallSummary>(), "country");
+
+        var loc = Assert.Single(result.Locations);
+        Assert.Equal(3, loc.SessionCount);
+        Assert.Equal(1, loc.ApiLatencySessionCount);
+        Assert.Equal(200d, loc.AvgApiLatencyMs);
+    }
+
+    [Fact]
+    public void NoLatencyDataAnywhere_YieldsZeroes_NotDivisionByZero()
+    {
+        var sessions = new List<SessionSummary> { S("DE", "Frankfurt", null, null) };
+
+        var result = GetGeographicMetricsFunction.ComputeGeographicMetrics(
+            sessions, new List<AppInstallSummary>(), "country");
+
+        var loc = Assert.Single(result.Locations);
+        Assert.Equal(0d, loc.AvgApiLatencyMs);
+        Assert.Equal(0, loc.ApiLatencySessionCount);
+        Assert.Equal(0d, loc.ApiLatencyVsGlobalPct);
+        Assert.Equal(0d, result.GlobalAverages.AvgApiLatencyMs);
+    }
+
+    [Fact]
+    public void GlobalLatency_WeightsAcrossLocations_AndVsGlobalPctCompares()
+    {
+        var sessions = new List<SessionSummary>
+        {
+            S("DE", "Frankfurt", 200, 100),
+            S("ID", "Jakarta", 800, 100),
+        };
+
+        var result = GetGeographicMetricsFunction.ComputeGeographicMetrics(
+            sessions, new List<AppInstallSummary>(), "country");
+
+        // Equal request weights → global = (200 + 800) / 2 = 500.
+        Assert.Equal(500d, result.GlobalAverages.AvgApiLatencyMs);
+
+        var de = result.Locations.Single(l => l.Country == "DE");
+        var id = result.Locations.Single(l => l.Country == "ID");
+        Assert.Equal(-60d, de.ApiLatencyVsGlobalPct); // 200 vs 500
+        Assert.Equal(60d, id.ApiLatencyVsGlobalPct);  // 800 vs 500
+    }
+
+    [Fact]
+    public void LocationWithoutData_KeepsZeroPct_EvenWhenGlobalHasData()
+    {
+        var sessions = new List<SessionSummary>
+        {
+            S("DE", "Frankfurt", 200, 100),
+            S("FR", "Paris", null, null),
+        };
+
+        var result = GetGeographicMetricsFunction.ComputeGeographicMetrics(
+            sessions, new List<AppInstallSummary>(), "country");
+
+        var fr = result.Locations.Single(l => l.Country == "FR");
+        Assert.Equal(0d, fr.AvgApiLatencyMs);
+        Assert.Equal(0d, fr.ApiLatencyVsGlobalPct); // no data ≠ "0 ms fast"
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/GetImeVersionHistoryRedactionTests.cs

@@ -0,0 +1,189 @@
+using System.Text.Json;
+using AutopilotMonitor.Functions.Functions.Metrics;
+using AutopilotMonitor.Shared.Models;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Guards the cross-tenant redaction on GET metrics/ime-versions.
+///
+/// The route is <c>MemberRead</c> (EndpointAccessPolicyCatalog) and the archive itself is a
+/// single global partition — every tenant member reads the SAME platform-wide rows. The only
+/// thing standing between an ordinary tenant user and another tenant's identifiers is the
+/// projection in <see cref="GetImeVersionHistoryFunction.BuildResponsePayload"/>. That made it
+/// worth pinning: the redaction had no test at all, and a boundary nobody asserts is one a
+/// later refactor can open without a single failure.
+///
+/// The JSON tests are the ones that matter — a property dropped from an anonymous type is only
+/// a real redaction once it is also absent from the wire, and the wire is what the customer's
+/// MCP client receives. camelCase mirrors Program.cs's PropertyNamingPolicy.
+/// </summary>
+public class GetImeVersionHistoryRedactionTests
+{
+    private static readonly DateTime First = new(2026, 7, 8, 3, 18, 13, DateTimeKind.Utc);
+    private static readonly DateTime Last = new(2026, 7, 27, 16, 59, 34, DateTimeKind.Utc);
+
+    private static readonly JsonSerializerOptions CamelCase =
+        new() { PropertyNamingPolicy = JsonNamingPolicy.CamelCase };
+
+    // =========================================================================
+    // Non-global caller (ordinary tenant member) — the redaction
+    // =========================================================================
+
+    [Fact]
+    public void NonGlobalCaller_DropsForeignTenantAndSessionIds()
+    {
+        var json = SerializeFor(hasGlobalScope: false, MakeEntry());
+
+        Assert.DoesNotContain("firstSeenTenantId", json, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("firstSeenSessionId", json, StringComparison.OrdinalIgnoreCase);
+    }
+
+    /// <summary>
+    /// The values, not just the property names: a rename of the model property must not let the
+    /// identifier survive under a different key. Asserting on the GUIDs catches that.
+    /// </summary>
+    [Fact]
+    public void NonGlobalCaller_ForeignIdentifierValuesAppearNowhereInThePayload()
+    {
+        var json = SerializeFor(hasGlobalScope: false, MakeEntry());
+
+        Assert.DoesNotContain("57f34dd1-6a42-47f9-9bc0-b921fa6caa30", json, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("baae0453-6d19-47b5-aa58-8bed5a572fc8", json, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void NonGlobalCaller_ExposesExactlyTheFourAllowedProperties()
+    {
+        using var doc = JsonDocument.Parse(SerializeFor(hasGlobalScope: false, MakeEntry()));
+
+        var keys = doc.RootElement[0].EnumerateObject().Select(p => p.Name).OrderBy(n => n).ToArray();
+
+        Assert.Equal(new[] { "firstSeenAt", "lastSeenAt", "sessionCount", "version" }, keys);
+    }
+
+    /// <summary>
+    /// SessionCount stays on purpose — it is a platform-wide total, and the route exists so any
+    /// tenant member can track Microsoft's IME rollout. Pinned so that "the counts are global"
+    /// stays a decision someone made rather than something that quietly drifts either way.
+    /// </summary>
+    [Fact]
+    public void NonGlobalCaller_KeepsVersionDatesAndGlobalSessionCount()
+    {
+        using var doc = JsonDocument.Parse(SerializeFor(hasGlobalScope: false, MakeEntry()));
+
+        var row = doc.RootElement[0];
+        Assert.Equal("1.103.101.0", row.GetProperty("version").GetString());
+        Assert.Equal(First, row.GetProperty("firstSeenAt").GetDateTime());
+        Assert.Equal(Last, row.GetProperty("lastSeenAt").GetDateTime());
+        Assert.Equal(3109, row.GetProperty("sessionCount").GetInt32());
+    }
+
+    // =========================================================================
+    // Global caller (Global Admin or Global Reader) — full archive
+    // =========================================================================
+
+    [Fact]
+    public void GlobalCaller_KeepsTenantAndSessionIds()
+    {
+        using var doc = JsonDocument.Parse(SerializeFor(hasGlobalScope: true, MakeEntry()));
+
+        var row = doc.RootElement[0];
+        Assert.Equal("57f34dd1-6a42-47f9-9bc0-b921fa6caa30", row.GetProperty("firstSeenTenantId").GetString());
+        Assert.Equal("baae0453-6d19-47b5-aa58-8bed5a572fc8", row.GetProperty("firstSeenSessionId").GetString());
+    }
+
+    [Fact]
+    public void GlobalCaller_ExposesTheFullEntry()
+    {
+        using var doc = JsonDocument.Parse(SerializeFor(hasGlobalScope: true, MakeEntry()));
+
+        var keys = doc.RootElement[0].EnumerateObject().Select(p => p.Name).OrderBy(n => n).ToArray();
+
+        Assert.Equal(
+            new[] { "firstSeenAt", "firstSeenSessionId", "firstSeenTenantId", "lastSeenAt", "sessionCount", "version" },
+            keys);
+    }
+
+    // =========================================================================
+    // Shape-preserving properties of the projection
+    // =========================================================================
+
+    [Fact]
+    public void BothScopes_EmitAJsonArray_EvenForASingleRow()
+    {
+        foreach (var scope in new[] { true, false })
+        {
+            using var doc = JsonDocument.Parse(SerializeFor(scope, MakeEntry()));
+            Assert.Equal(JsonValueKind.Array, doc.RootElement.ValueKind);
+            Assert.Equal(1, doc.RootElement.GetArrayLength());
+        }
+    }
+
+    [Fact]
+    public void BothScopes_EmptyArchive_SerializesAsEmptyArray()
+    {
+        foreach (var scope in new[] { true, false })
+        {
+            using var doc = JsonDocument.Parse(SerializeFor(scope));
+            Assert.Equal(JsonValueKind.Array, doc.RootElement.ValueKind);
+            Assert.Equal(0, doc.RootElement.GetArrayLength());
+        }
+    }
+
+    /// <summary>
+    /// The repository orders by FirstSeenAt descending; the projection must not reshuffle, or a
+    /// redacted caller would see a different sequence than a Global Admin for the same archive.
+    /// </summary>
+    [Fact]
+    public void NonGlobalCaller_PreservesRowOrderAndCount()
+    {
+        var newest = MakeEntry("1.103.101.0", First);
+        var older = MakeEntry("1.101.111.0", First.AddDays(-48));
+        var oldest = MakeEntry("1.99.101.0", First.AddDays(-131));
+
+        using var doc = JsonDocument.Parse(SerializeFor(false, newest, older, oldest));
+
+        Assert.Equal(3, doc.RootElement.GetArrayLength());
+        Assert.Equal("1.103.101.0", doc.RootElement[0].GetProperty("version").GetString());
+        Assert.Equal("1.101.111.0", doc.RootElement[1].GetProperty("version").GetString());
+        Assert.Equal("1.99.101.0", doc.RootElement[2].GetProperty("version").GetString());
+    }
+
+    /// <summary>
+    /// BuildResponsePayload returns `object`; the branch that keeps everything hands back the
+    /// entries themselves. System.Text.Json resolves an `object` declared type via the runtime
+    /// type, which is what keeps the wire format identical to the pre-extraction inline code —
+    /// assert it rather than trust it, since a regression here would silently emit "{}" rows.
+    /// </summary>
+    [Fact]
+    public void GlobalPayload_SerializedAsObject_StillEmitsPopulatedRows()
+    {
+        var payload = GetImeVersionHistoryFunction.BuildResponsePayload([MakeEntry()], hasGlobalScope: true);
+
+        var json = JsonSerializer.Serialize(payload, CamelCase);
+
+        Assert.Contains("1.103.101.0", json, StringComparison.Ordinal);
+        Assert.NotEqual("[{}]", json);
+    }
+
+    // =========================================================================
+    // Helpers
+    // =========================================================================
+
+    private static string SerializeFor(bool hasGlobalScope, params ImeVersionHistoryEntry[] versions) =>
+        JsonSerializer.Serialize(
+            GetImeVersionHistoryFunction.BuildResponsePayload(versions, hasGlobalScope),
+            CamelCase);
+
+    private static ImeVersionHistoryEntry MakeEntry(string version = "1.103.101.0", DateTime? firstSeenAt = null) =>
+        new()
+        {
+            Version = version,
+            FirstSeenAt = firstSeenAt ?? First,
+            FirstSeenSessionId = "baae0453-6d19-47b5-aa58-8bed5a572fc8",
+            FirstSeenTenantId = "57f34dd1-6a42-47f9-9bc0-b921fa6caa30",
+            LastSeenAt = Last,
+            SessionCount = 3109,
+        };
+}

src/Backend/AutopilotMonitor.Functions.Tests/HardwareRejectionNotificationTrackerDedupTests.cs

@@ -135,8 +135,64 @@ public class HardwareRejectionNotificationTrackerDedupTests
         Assert.Equal(2, harness.Store.Count);
     }
 
+    // ── F3 rule regression: one bell per episode, keyspaces stay independent ──────
+
+    [Fact]
+    public async Task RuleRegression_SecondRegister_SameRule_ReturnsFalse_OneBellPerEpisode()
+    {
+        var harness = new Harness();
+        var alert = new AutopilotMonitor.Shared.Models.RuleRegressionAlert
+        {
+            TenantId = TenantId, RuleId = "ANALYZE-NET-001",
+            FirstNotifiedAt = DateTime.UtcNow, LastEvaluatedAt = DateTime.UtcNow,
+        };
+
+        Assert.True(await harness.Sut.TryRegisterRuleRegressionAsync(TenantId, alert));
+        Assert.False(await harness.Sut.TryRegisterRuleRegressionAsync(TenantId, alert));
+
+        var entity = Assert.Single(harness.Store.Values);
+        Assert.Equal("ruleregression|analyze-net-001", entity.RowKey);
+        Assert.NotNull(entity.GetDateTime("FirstNotifiedAt")); // the retention sweep depends on it
+    }
+
+    [Fact]
+    public async Task RuleRegression_DeleteReArms_AndDoesNotTouchOtherKeyspaces()
+    {
+        var harness = new Harness();
+        var alert = new AutopilotMonitor.Shared.Models.RuleRegressionAlert
+        {
+            TenantId = TenantId, RuleId = "ANALYZE-NET-001",
+            FirstNotifiedAt = DateTime.UtcNow, LastEvaluatedAt = DateTime.UtcNow,
+        };
+        Assert.True(await harness.Sut.TryRegisterRuleRegressionAsync(TenantId, alert));
+        Assert.True(await harness.Sut.TryRegisterFirstTpmPssNotificationAsync(TenantId, Serial));
+
+        await harness.Sut.DeleteRuleRegressionAsync(TenantId, "ANALYZE-NET-001");
+
+        // The episode re-arms; the unrelated tpmpss row survives.
+        Assert.Equal("tpmpss|s4sq8685", Assert.Single(harness.Store.Values).RowKey);
+        Assert.True(await harness.Sut.TryRegisterRuleRegressionAsync(TenantId, alert));
+    }
+
     // ── Retention sweep ───────────────────────────────────────────────────────────
 
+    [Fact]
+    public async Task DeleteOlderThanAsync_PrunesRuleRegressionRows_ReArmingLongBurningEpisodes()
+    {
+        var harness = new Harness();
+        Assert.True(await harness.Sut.TryRegisterRuleRegressionAsync(TenantId,
+            new AutopilotMonitor.Shared.Models.RuleRegressionAlert
+            {
+                TenantId = TenantId, RuleId = "ANALYZE-NET-001",
+                FirstNotifiedAt = DateTime.UtcNow, LastEvaluatedAt = DateTime.UtcNow,
+            }));
+        harness.AgeRows(TimeSpan.FromDays(31));
+
+        // Spec §F3: retention cleanup re-arms — a month-old still-burning regression rings again.
+        Assert.Equal(1, await harness.Sut.DeleteOlderThanAsync(DateTime.UtcNow.AddDays(-30)));
+        Assert.Empty(harness.Store);
+    }
+
     [Fact]
     public async Task DeleteOlderThanAsync_PrunesTpmPssRows_AndReArmsThatDevicesBell()
     {

src/Backend/AutopilotMonitor.Functions.Tests/IngestApiLatencyProjectionTests.cs

@@ -0,0 +1,165 @@
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Pins the per-session API-latency projection (2026-07-28): the V2 agent emits cumulative
+/// counters <c>net_total_latency_ms</c> / <c>net_total_requests</c> in every
+/// <c>agent_metrics_snapshot</c>; ingest derives the session-wide average from the LAST
+/// snapshot of the batch and persists it via <c>UpdateSessionNetworkLatencyAsync</c>
+/// (last-write-wins on cumulative counters → replay-idempotent).
+/// Wire-format note: the ingest body is parsed with Newtonsoft into
+/// <c>Dictionary&lt;string, object&gt;</c>, so integer JSON numbers arrive as boxed
+/// <c>long</c> — fixtures mirror that, not the agent's in-memory types.
+/// </summary>
+public class IngestApiLatencyProjectionTests
+{
+    private static EnrollmentEvent Snapshot(object? totalLatencyMs, object? totalRequests)
+    {
+        var evt = new EnrollmentEvent
+        {
+            EventType = "agent_metrics_snapshot",
+            Data = new Dictionary<string, object>
+            {
+                ["agent_cpu_percent"] = 3.62,
+                ["net_requests"] = 50L,
+                ["net_avg_latency_ms"] = 513.0,
+            },
+        };
+        if (totalLatencyMs != null) evt.Data["net_total_latency_ms"] = totalLatencyMs;
+        if (totalRequests != null) evt.Data["net_total_requests"] = totalRequests;
+        return evt;
+    }
+
+    [Fact]
+    public void CumulativeCounters_YieldSessionAverage()
+    {
+        var events = new List<EnrollmentEvent> { Snapshot(51_300L, 100L) };
+
+        Assert.True(EventIngestProcessor.TryComputeSessionApiLatency(events, out var avg, out var count));
+        Assert.Equal(513.0, avg);
+        Assert.Equal(100, count);
+    }
+
+    [Fact]
+    public void AverageIsRounded_ToOneDecimal()
+    {
+        var events = new List<EnrollmentEvent> { Snapshot(1_000L, 3L) };
+
+        Assert.True(EventIngestProcessor.TryComputeSessionApiLatency(events, out var avg, out _));
+        Assert.Equal(333.3, avg);
+    }
+
+    [Fact]
+    public void LastSnapshotOfBatch_Wins()
+    {
+        // Cumulative counters grow monotonically — the last snapshot carries the most
+        // complete session average.
+        var events = new List<EnrollmentEvent>
+        {
+            Snapshot(51_300L, 100L),
+            new EnrollmentEvent { EventType = "download_progress" },
+            Snapshot(120_000L, 200L),
+        };
+
+        Assert.True(EventIngestProcessor.TryComputeSessionApiLatency(events, out var avg, out var count));
+        Assert.Equal(600.0, avg);
+        Assert.Equal(200, count);
+    }
+
+    [Fact]
+    public void OldAgentSnapshot_WithoutTotalLatencyField_DoesNotMatch()
+    {
+        // Agents predating net_total_latency_ms emit net_total_requests only.
+        var events = new List<EnrollmentEvent> { Snapshot(totalLatencyMs: null, totalRequests: 100L) };
+
+        Assert.False(EventIngestProcessor.TryComputeSessionApiLatency(events, out _, out _));
+    }
+
+    [Fact]
+    public void SnapshotWithLatencyButMissingRequests_DoesNotMatch()
+    {
+        var events = new List<EnrollmentEvent> { Snapshot(51_300L, totalRequests: null) };
+
+        Assert.False(EventIngestProcessor.TryComputeSessionApiLatency(events, out _, out _));
+    }
+
+    [Fact]
+    public void ZeroRequests_DoesNotMatch()
+    {
+        // No requests yet (first snapshot before the first upload completes) — no division.
+        var events = new List<EnrollmentEvent> { Snapshot(0L, 0L) };
+
+        Assert.False(EventIngestProcessor.TryComputeSessionApiLatency(events, out _, out _));
+    }
+
+    [Fact]
+    public void MatchingLastSnapshot_SkipsOlderAgentSnapshotAfterIt()
+    {
+        // A field-less (old-schema) snapshot later in the batch must not shadow an earlier
+        // one that carries the counters — the predicate selects the last MATCHING snapshot.
+        var events = new List<EnrollmentEvent>
+        {
+            Snapshot(51_300L, 100L),
+            Snapshot(totalLatencyMs: null, totalRequests: 150L),
+        };
+
+        Assert.True(EventIngestProcessor.TryComputeSessionApiLatency(events, out var avg, out var count));
+        Assert.Equal(513.0, avg);
+        Assert.Equal(100, count);
+    }
+
+    [Fact]
+    public void BatchWithoutSnapshots_DoesNotMatch()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            new EnrollmentEvent { EventType = "esp_phase_changed" },
+            new EnrollmentEvent { EventType = "app_install_started" },
+        };
+
+        Assert.False(EventIngestProcessor.TryComputeSessionApiLatency(events, out _, out _));
+    }
+
+    // -------- TryGetDouble coercion ladder (mirrors PlatformMetricsService.GetDouble) --------
+
+    [Theory]
+    [InlineData(513.5)]         // double — decimal JSON number
+    [InlineData(513)]           // int — in-memory constructed events (tests, V1 paths)
+    [InlineData(513L)]          // long — Newtonsoft wire form for integer JSON numbers
+    [InlineData(513f)]          // float
+    public void TryGetDouble_CoercesBoxedNumericPrimitives(object boxed)
+    {
+        var data = new Dictionary<string, object> { ["k"] = boxed };
+
+        Assert.True(EventIngestProcessor.TryGetDouble(data, "k", out var value));
+        Assert.Equal(Convert.ToDouble(boxed), value);
+    }
+
+    [Fact]
+    public void TryGetDouble_ParsesStrings_InvariantCulture()
+    {
+        var data = new Dictionary<string, object> { ["k"] = "513.5" };
+
+        Assert.True(EventIngestProcessor.TryGetDouble(data, "k", out var value));
+        Assert.Equal(513.5, value);
+    }
+
+    [Theory]
+    [InlineData("not-a-number")]
+    [InlineData("")]
+    public void TryGetDouble_RejectsUnparseableStrings(string raw)
+    {
+        var data = new Dictionary<string, object> { ["k"] = raw };
+
+        Assert.False(EventIngestProcessor.TryGetDouble(data, "k", out _));
+    }
+
+    [Fact]
+    public void TryGetDouble_MissingKey_ReturnsFalse()
+    {
+        Assert.False(EventIngestProcessor.TryGetDouble(new Dictionary<string, object>(), "k", out _));
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/IngestConnectionTypeProjectionTests.cs

@@ -0,0 +1,124 @@
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Pins the per-session connection-type projection (2026-07-28): the agent stamps
+/// <c>connectionType</c> ("WiFi"/"Ethernet") into every <c>network_interface_info</c>
+/// emission (initial collect + re-collect on change); ingest takes the LAST matching
+/// event of the batch and persists it via <c>UpdateSessionConnectionTypeAsync</c>
+/// (last-write-wins → a device that switches media mid-enrollment is relabeled).
+/// The no-NIC payload ({"status":"no_active_interface"}) carries no connectionType
+/// and must never match.
+/// </summary>
+public class IngestConnectionTypeProjectionTests
+{
+    private static EnrollmentEvent NicInfo(string? connectionType)
+    {
+        var evt = new EnrollmentEvent
+        {
+            EventType = "network_interface_info",
+            Data = new Dictionary<string, object>
+            {
+                ["adapterName"] = "Ethernet 2",
+                ["linkSpeedMbps"] = 1000L,
+            },
+        };
+        if (connectionType != null) evt.Data["connectionType"] = connectionType;
+        return evt;
+    }
+
+    [Fact]
+    public void EthernetEmission_IsExtracted()
+    {
+        var events = new List<EnrollmentEvent> { NicInfo("Ethernet") };
+
+        Assert.True(EventIngestProcessor.TryExtractConnectionType(events, out var type));
+        Assert.Equal("Ethernet", type);
+    }
+
+    [Fact]
+    public void LastEmissionOfBatch_Wins()
+    {
+        // Media switch mid-batch (dock removed → WiFi) — the most recent state wins.
+        var events = new List<EnrollmentEvent>
+        {
+            NicInfo("Ethernet"),
+            new EnrollmentEvent { EventType = "download_progress" },
+            NicInfo("WiFi"),
+        };
+
+        Assert.True(EventIngestProcessor.TryExtractConnectionType(events, out var type));
+        Assert.Equal("WiFi", type);
+    }
+
+    [Fact]
+    public void NoActiveInterfacePayload_DoesNotMatch()
+    {
+        // The no-NIC emission carries only {"status":"no_active_interface"}.
+        var events = new List<EnrollmentEvent>
+        {
+            new EnrollmentEvent
+            {
+                EventType = "network_interface_info",
+                Data = new Dictionary<string, object> { ["status"] = "no_active_interface" },
+            },
+        };
+
+        Assert.False(EventIngestProcessor.TryExtractConnectionType(events, out _));
+    }
+
+    [Fact]
+    public void NoActiveInterfaceAfterValidEmission_DoesNotShadowIt()
+    {
+        // The predicate selects the last event that CARRIES connectionType.
+        var events = new List<EnrollmentEvent>
+        {
+            NicInfo("WiFi"),
+            new EnrollmentEvent
+            {
+                EventType = "network_interface_info",
+                Data = new Dictionary<string, object> { ["status"] = "no_active_interface" },
+            },
+        };
+
+        Assert.True(EventIngestProcessor.TryExtractConnectionType(events, out var type));
+        Assert.Equal("WiFi", type);
+    }
+
+    [Theory]
+    [InlineData("Cellular")]
+    [InlineData("wifi")]      // agent emits exact casing — anything else is unexpected
+    [InlineData("")]
+    public void UnexpectedValues_AreDroppedDefensively(string raw)
+    {
+        var events = new List<EnrollmentEvent> { NicInfo(raw) };
+
+        Assert.False(EventIngestProcessor.TryExtractConnectionType(events, out _));
+    }
+
+    [Fact]
+    public void BatchWithoutNicEvents_DoesNotMatch()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            new EnrollmentEvent { EventType = "esp_phase_changed" },
+            new EnrollmentEvent { EventType = "agent_metrics_snapshot" },
+        };
+
+        Assert.False(EventIngestProcessor.TryExtractConnectionType(events, out _));
+    }
+
+    [Fact]
+    public void NullData_DoesNotMatch()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            new EnrollmentEvent { EventType = "network_interface_info", Data = null! },
+        };
+
+        Assert.False(EventIngestProcessor.TryExtractConnectionType(events, out _));
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/MetricsMathAppPayloadTests.cs

@@ -137,6 +137,120 @@ public class MetricsMathAppPayloadTests
         Assert.Equal(50d, app.GetProperty("failureRate").GetDouble());
     }
 
+    // ── PR0 (2026-07-26): skip/unmeasured classification ────────────────────
+
+    [Fact]
+    public void Skips_LeaveTheFailureRate_AndAreReportedSeparately()
+    {
+        // 1 Failed + 1 real install + 3 skips ("Update for X" not applicable).
+        // Rate must be 1/(1+1) = 50%, NOT 1/(1+4) = 20% — skips are not attempts.
+        var summaries = new List<AppInstallSummary>
+        {
+            new() { AppName = "App A", Status = "Failed", TerminalState = "Error" },
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 30 },
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Skipped" },
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Skipped" },
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Postponed" },
+        };
+
+        var root = Build(summaries);
+        var app = root.GetProperty("topFailingApps")[0];
+
+        Assert.Equal(50d, app.GetProperty("failureRate").GetDouble());
+        Assert.Equal(1, app.GetProperty("succeeded").GetInt32());
+        Assert.Equal(3, app.GetProperty("skipped").GetInt32());
+        Assert.Equal(0, app.GetProperty("unmeasured").GetInt32());
+        Assert.Equal(3, root.GetProperty("totalSkipped").GetInt32());
+    }
+
+    [Fact]
+    public void ZeroDurations_AreExcludedFromAverages_AndCountedAsUnmeasured()
+    {
+        // Two measured installs (100s, 200s) + one whose start was never observed (audit §0.5:
+        // agent attach window — duration UNKNOWN). avg must be 150, not (100+200+0)/3 = 100.
+        var summaries = new List<AppInstallSummary>
+        {
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 100 },
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 200 },
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 0 },
+        };
+
+        var root = Build(summaries);
+        Assert.Equal(1, root.GetProperty("totalUnmeasured").GetInt32());
+
+        // Rebuild with a third measured row to clear the sample floor and read the average.
+        summaries.Add(new AppInstallSummary { AppName = "App A", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 150 });
+        var slowest = Build(summaries).GetProperty("slowestApps");
+        Assert.Equal(1, slowest.GetArrayLength());
+        Assert.Equal(150d, slowest[0].GetProperty("avgDurationSeconds").GetDouble());
+        Assert.Equal(1, slowest[0].GetProperty("unmeasured").GetInt32());
+    }
+
+    [Fact]
+    public void LegacyZeroDurationRows_StayInRate_ButNeverInDurations()
+    {
+        // Rows written before TerminalState existed: cannot be classified as skip vs unmeasured.
+        // They keep the legacy rate behavior (counted as succeeded) and are excluded from
+        // durations (counted as unmeasured — duration genuinely not measured).
+        var summaries = new List<AppInstallSummary>
+        {
+            new() { AppName = "App A", Status = "Failed" },
+            new() { AppName = "App A", Status = "Succeeded", DurationSeconds = 0 },   // legacy, no TerminalState
+            new() { AppName = "App A", Status = "Succeeded", DurationSeconds = 60, TerminalState = "Installed" },
+        };
+
+        var app = Build(summaries).GetProperty("topFailingApps")[0];
+
+        Assert.Equal(2, app.GetProperty("succeeded").GetInt32());      // legacy row stays in the rate
+        Assert.Equal(33.3d, app.GetProperty("failureRate").GetDouble());
+        Assert.Equal(1, app.GetProperty("unmeasured").GetInt32());
+        Assert.Equal(0, app.GetProperty("skipped").GetInt32());
+    }
+
+    [Fact]
+    public void ImplausibleDurations_AreExcludedFromAverages_AndCountedAsUnmeasured()
+    {
+        // A duration beyond the agent's max observation lifetime is a back-stamped emission
+        // artifact (CompletedAt pinned at session end — production: 60 175 s app rows inside a
+        // 2 697 s session), not a slow install. It must fall out of the averages exactly like
+        // an unobserved start. Boundary: exactly 6 h is still plausible/measured.
+        var summaries = new List<AppInstallSummary>
+        {
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 100 },
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 200 },
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Installed",
+                    DurationSeconds = MetricsMath.MaxPlausibleInstallDurationSeconds },       // boundary: measured
+            new() { AppName = "App A", Status = "Succeeded", TerminalState = "Installed",
+                    DurationSeconds = MetricsMath.MaxPlausibleInstallDurationSeconds + 1 },   // artifact: unmeasured
+        };
+
+        var root = Build(summaries);
+        Assert.Equal(1, root.GetProperty("totalUnmeasured").GetInt32());
+
+        var slowest = root.GetProperty("slowestApps");
+        Assert.Equal(1, slowest.GetArrayLength());
+        Assert.Equal(3, slowest[0].GetProperty("measuredInstalls").GetInt32());
+        // avg over {100, 200, 21600} — the 21601 artifact contributes nothing.
+        Assert.Equal(7300d, slowest[0].GetProperty("avgDurationSeconds").GetDouble());
+        Assert.Equal(MetricsMath.MaxPlausibleInstallDurationSeconds, slowest[0].GetProperty("maxDurationSeconds").GetInt32());
+    }
+
+    [Fact]
+    public void SlowestApps_GateOnMeasuredInstalls_NotOnSucceededCount()
+    {
+        // 3 succeeded but only 2 measured → below the floor; an app must not rank "fast"
+        // (or at all) on a handful of unobserved zeros.
+        var summaries = new List<AppInstallSummary>
+        {
+            new() { AppName = "Mostly Unmeasured", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 5 },
+            new() { AppName = "Mostly Unmeasured", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 5 },
+            new() { AppName = "Mostly Unmeasured", Status = "Succeeded", TerminalState = "Installed", DurationSeconds = 0 },
+        };
+
+        var slowest = Build(summaries).GetProperty("slowestApps");
+        Assert.Equal(0, slowest.GetArrayLength());
+    }
+
     [Fact]
     public void SlowestApps_DropsAppsBelowSampleFloor()
     {

src/Backend/AutopilotMonitor.Functions.Tests/OffboardingSessionEnumeratorTests.cs

@@ -125,5 +125,6 @@ public class OffboardingSessionEnumeratorTests
         public Task<bool> IsSessionIndexEmptyAsync() => throw new NotImplementedException();
         public Task<List<OrphanedEventSession>> GetOrphanedEventSessionsAsync(TimeSpan gracePeriod) => throw new NotImplementedException();
         public Task DeleteEventSessionIndexEntryAsync(string tenantId, string sessionId) => throw new NotImplementedException();
+        public Task<List<(string TenantId, string SessionId)>> GetAllSessionTombstoneKeysAsync() => throw new NotImplementedException();
     }
 }

src/Backend/AutopilotMonitor.Functions.Tests/RuleRegressionRadarTests.cs

@@ -0,0 +1,405 @@
+using AutopilotMonitor.Functions.DataAccess.TableStorage;
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// F3 PR6 (insights spec §F3): the Wilson primitive (hand-computed vectors), the radar's
+/// detection gates and EVERY suppression branch (table-driven), the re-arm rule, the
+/// dimension-concentration gates, the tracker keyspace round-trip (tri-states included)
+/// and the alert wording contracts ("correlated, not necessarily causal").
+/// </summary>
+public class RuleRegressionRadarTests
+{
+    private static readonly DateTime Target = new(2026, 7, 26, 0, 0, 0, DateTimeKind.Utc);
+    private const string TenantA = "aaaaaaaa-0000-0000-0000-000000000001";
+    private const string RuleX = "ANALYZE-NET-001";
+
+    // ── Wilson interval (MetricsMath) — hand-computed 95 % vectors ──────────
+
+    [Theory]
+    [InlineData(10, 20, 0.2993, 0.7007)]  // symmetric mid-range
+    [InlineData(0, 20, 0.0000, 0.1611)]   // zero successes: lower pinned at 0
+    [InlineData(5, 25, 0.0886, 0.3913)]
+    public void WilsonInterval_MatchesHandComputedVectors(int successes, int trials, double lower, double upper)
+    {
+        var (l, u) = MetricsMath.WilsonInterval(successes, trials);
+        Assert.Equal(lower, l, 3);
+        Assert.Equal(upper, u, 3);
+    }
+
+    [Fact]
+    public void WilsonInterval_ZeroTrials_IsUninformative_NeverClaimsSeparation()
+    {
+        Assert.Equal((0.0, 1.0), MetricsMath.WilsonInterval(0, 0));
+        // A zero-denominator window can never be "separated" from anything.
+        Assert.False(MetricsMath.RateIncreaseSeparated(0, 0, 10, 500));
+    }
+
+    [Fact]
+    public void RateIncreaseSeparated_DisjointIntervals_True_OverlappingFalse()
+    {
+        // 15 % on n=100 (lower ≈ 0.093) vs 2 % baseline on n=500 (upper ≈ 0.036) → separated.
+        Assert.True(MetricsMath.RateIncreaseSeparated(15, 100, 10, 500));
+        // 5 % on n=100 vs 4 % baseline on n=500 → intervals overlap → noise, not a regression.
+        Assert.False(MetricsMath.RateIncreaseSeparated(5, 100, 20, 500));
+    }
+
+    // ── radar evaluation — gates + suppression branches ─────────────────────
+
+    private static RuleStatsEntry Entry(
+        string date, int fire, int sessions, string ruleId = RuleX, string ruleType = "analyze")
+        => new()
+        {
+            TenantId = TenantA,
+            Date = date,
+            RuleId = ruleId,
+            RuleType = ruleType,
+            RuleTitle = "Network check",
+            Category = "network",
+            Severity = "warning",
+            FireCount = fire,
+            EvaluationCount = sessions,
+            SessionsEvaluated = sessions,
+        };
+
+    private static string Day(int daysBeforeTarget) => Target.AddDays(-daysBeforeTarget).ToString("yyyy-MM-dd");
+
+    /// <summary>Window fire=15/100 across two days; baseline fire=10/500 across three days — fires all gates.</summary>
+    private static List<RuleStatsEntry> RegressedEntries() => new()
+    {
+        Entry(Day(0), 10, 60),
+        Entry(Day(6), 5, 40),      // windowStart boundary — still window
+        Entry(Day(7), 4, 200),     // first baseline day
+        Entry(Day(20), 4, 200),
+        Entry(Day(34), 2, 100),    // baselineStart boundary — still baseline
+    };
+
+    private static Dictionary<string, RuleRegressionRadar.RuleTimestamps> OldRule(
+        DateTime? createdAt = null, DateTime? updatedAt = null, string ruleId = RuleX)
+        => new(StringComparer.OrdinalIgnoreCase)
+        {
+            [ruleId] = new RuleRegressionRadar.RuleTimestamps(
+                createdAt ?? Target.AddDays(-100), updatedAt ?? Target.AddDays(-50)),
+        };
+
+    [Fact]
+    public void Evaluate_AllGatesPass_FiresWithFullNumbers()
+    {
+        var findings = RuleRegressionRadar.Evaluate(RegressedEntries(), Target, OldRule());
+
+        var finding = Assert.Single(findings);
+        Assert.Equal(RuleX, finding.RuleId);
+        Assert.Equal(15, finding.WindowFireCount);
+        Assert.Equal(100, finding.WindowSessionCount);
+        Assert.Equal(10, finding.BaselineFireCount);
+        Assert.Equal(500, finding.BaselineSessionCount);
+        Assert.Equal(15.0, finding.WindowRatePct);
+        Assert.Equal(2.0, finding.BaselineRatePct);
+        Assert.Equal(7.5, finding.Lift);
+        Assert.Equal(Day(6), finding.WindowStartDate);
+        Assert.Equal(Day(0), finding.WindowEndDate);
+    }
+
+    [Fact]
+    public void Evaluate_ZeroBaselineFires_FiresAsNewSignal_WithNullLift()
+    {
+        var entries = new List<RuleStatsEntry>
+        {
+            Entry(Day(0), 15, 100),
+            Entry(Day(10), 0, 500),
+        };
+
+        var finding = Assert.Single(RuleRegressionRadar.Evaluate(entries, Target, OldRule()));
+        Assert.Null(finding.Lift); // no finite lift is ever invented (truthfulness rule 1)
+        Assert.Equal(0.0, finding.BaselineRatePct);
+    }
+
+    public static TheoryData<string, List<RuleStatsEntry>> SuppressedByCounts() => new()
+    {
+        // Below the ≥5 hit-session gate.
+        { "below hit gate", new List<RuleStatsEntry> { Entry(Day(0), 4, 100), Entry(Day(10), 1, 500) } },
+        // Below the ≥20 evaluated-session gate.
+        { "below session gate", new List<RuleStatsEntry> { Entry(Day(0), 5, 19), Entry(Day(10), 1, 500) } },
+        // No baseline denominator at all (rule disabled through the baseline, re-enabled recently).
+        { "no baseline sessions", new List<RuleStatsEntry> { Entry(Day(0), 15, 100) } },
+        // Lift below 2× (10 % vs 6 %).
+        { "lift below 2x", new List<RuleStatsEntry> { Entry(Day(0), 10, 100), Entry(Day(10), 30, 500) } },
+        // Lift 2.1× but Wilson intervals overlap (5/20 vs 60/500) — small-n noise never alerts.
+        { "not separated", new List<RuleStatsEntry> { Entry(Day(0), 5, 20), Entry(Day(10), 60, 500) } },
+        // Gather rows are ignored entirely (audit Q6: per-batch dedup — bad math until fixed).
+        { "gather ignored", new List<RuleStatsEntry>
+            { Entry(Day(0), 50, 60, ruleType: "gather"), Entry(Day(10), 1, 500, ruleType: "gather") } },
+    };
+
+    [Theory]
+    [MemberData(nameof(SuppressedByCounts))]
+    public void Evaluate_SuppressionBranches_ProduceNoFinding(string branch, List<RuleStatsEntry> entries)
+    {
+        Assert.True(RuleRegressionRadar.Evaluate(entries, Target, OldRule()).Count == 0,
+            $"branch '{branch}' must not fire");
+    }
+
+    [Fact]
+    public void Evaluate_RuleEntityGates_Suppress()
+    {
+        var entries = RegressedEntries();
+
+        // Deleted rule (no entity) never alerts.
+        Assert.Empty(RuleRegressionRadar.Evaluate(
+            entries, Target, new Dictionary<string, RuleRegressionRadar.RuleTimestamps>()));
+
+        // Grace period: created inside baseline+window (< 34 days before target).
+        Assert.Empty(RuleRegressionRadar.Evaluate(
+            entries, Target, OldRule(createdAt: Target.AddDays(-20))));
+
+        // Edited inside the 7-day window — edits legitimately change hit rates.
+        Assert.Empty(RuleRegressionRadar.Evaluate(
+            entries, Target, OldRule(updatedAt: Target.AddDays(-2))));
+
+        // Edited just BEFORE the window → not suppressed.
+        Assert.Single(RuleRegressionRadar.Evaluate(
+            entries, Target, OldRule(updatedAt: Target.AddDays(-8))));
+    }
+
+    [Fact]
+    public void SumWindows_BoundaryDates_LandInTheRightBucket()
+    {
+        var entries = new List<RuleStatsEntry>
+        {
+            Entry(Target.AddDays(1).ToString("yyyy-MM-dd"), 100, 100), // future — ignored
+            Entry(Day(0), 1, 10),
+            Entry(Day(6), 2, 20),   // last window day
+            Entry(Day(7), 4, 40),   // first baseline day
+            Entry(Day(34), 8, 80),  // last baseline day
+            Entry(Day(35), 100, 100), // beyond horizon — ignored
+        };
+
+        var sums = RuleRegressionRadar.SumWindows(entries, Target);
+        Assert.Equal(3, sums.WindowFire);
+        Assert.Equal(30, sums.WindowSessions);
+        Assert.Equal(12, sums.BaselineFire);
+        Assert.Equal(120, sums.BaselineSessions);
+    }
+
+    // ── re-arm rule ─────────────────────────────────────────────────────────
+
+    [Fact]
+    public void ShouldReArm_FiresStopped_OrRateBackUnderOnePointFive()
+    {
+        // Nothing fired in the window anymore → re-arm (also covers "no stats rows at all").
+        Assert.True(RuleRegressionRadar.ShouldReArm(new List<RuleStatsEntry>(), Target));
+        Assert.True(RuleRegressionRadar.ShouldReArm(
+            new List<RuleStatsEntry> { Entry(Day(0), 0, 100), Entry(Day(10), 10, 500) }, Target));
+
+        // 2 % window vs 2 % baseline → 1.0× < 1.5 → re-arm.
+        Assert.True(RuleRegressionRadar.ShouldReArm(
+            new List<RuleStatsEntry> { Entry(Day(0), 2, 100), Entry(Day(10), 10, 500) }, Target));
+
+        // 4 % window vs 2 % baseline → 2.0× ≥ 1.5 → still elevated, keep the episode.
+        Assert.False(RuleRegressionRadar.ShouldReArm(
+            new List<RuleStatsEntry> { Entry(Day(0), 4, 100), Entry(Day(10), 10, 500) }, Target));
+
+        // Zero-baseline episode ("new signal"): no rate threshold to fall under — only the
+        // fires-stopped branch re-arms it.
+        Assert.False(RuleRegressionRadar.ShouldReArm(
+            new List<RuleStatsEntry> { Entry(Day(0), 3, 100), Entry(Day(10), 0, 500) }, Target));
+    }
+
+    // ── dimension concentration ─────────────────────────────────────────────
+
+    private static SessionSummary DimSession(string osBuild = "", string model = "", string agentVersion = "")
+        => new()
+        {
+            TenantId = TenantA,
+            SessionId = Guid.NewGuid().ToString(),
+            SerialNumber = "PF4X1ABC",
+            OsBuild = osBuild,
+            Manufacturer = "Contoso",
+            Model = model,
+            AgentVersion = agentVersion,
+            ImeAgentVersion = "",
+            StartedAt = Target,
+        };
+
+    [Fact]
+    public void DimensionConcentration_DominantOsBuild_ReportsBothShares()
+    {
+        var all = new List<SessionSummary>();
+        for (var i = 0; i < 20; i++) all.Add(DimSession(osBuild: "26100.4652"));
+        for (var i = 0; i < 80; i++) all.Add(DimSession(osBuild: "22631.3880"));
+        var hits = all.Take(16).Concat(all.Skip(20).Take(4)).ToList(); // 16 on the new build, 4 on the old
+
+        var result = RuleRegressionRadar.ComputeDimensionConcentration(hits, all)!;
+
+        Assert.Equal("osBuild", result.Dimension);
+        Assert.Equal("26100.4652", result.Value);
+        Assert.Equal(16, result.HitCount);
+        Assert.Equal(80.0, result.HitSharePct);
+        Assert.Equal(20.0, result.AllSharePct);
+        Assert.Equal(4.0, result.Lift);
+    }
+
+    [Fact]
+    public void DimensionConcentration_BelowGates_YieldsNull_NeverStretched()
+    {
+        var all = Enumerable.Range(0, 100).Select(_ => DimSession(osBuild: "26100.1")).ToList();
+
+        // Every session shares the build → lift 1.0 < 2 → no claim.
+        Assert.Null(RuleRegressionRadar.ComputeDimensionConcentration(all.Take(10).ToList(), all));
+
+        // Concentrated but only 4 hit sessions (< 5) → no claim.
+        var mixed = Enumerable.Range(0, 96).Select(_ => DimSession(osBuild: "22631.1"))
+            .Concat(Enumerable.Range(0, 4).Select(_ => DimSession(osBuild: "26100.9")))
+            .ToList();
+        var hits4 = mixed.Skip(96).ToList();
+        Assert.Null(RuleRegressionRadar.ComputeDimensionConcentration(hits4, mixed));
+
+        // No hit sessions at all → no claim.
+        Assert.Null(RuleRegressionRadar.ComputeDimensionConcentration(new List<SessionSummary>(), all));
+    }
+
+    [Fact]
+    public void DimensionConcentration_PicksTheHighestLiftAcrossDimensions()
+    {
+        var all = new List<SessionSummary>();
+        for (var i = 0; i < 25; i++) all.Add(DimSession(osBuild: "26100.1", model: "Laptop 5"));
+        for (var i = 0; i < 75; i++) all.Add(DimSession(osBuild: "22631.1", model: i < 25 ? "Laptop 5" : "Laptop 4"));
+        // Hits: 8 of 10 on the new build (lift 80/25 = 3.2); model "Contoso Laptop 5" is 50 % of
+        // fleet and 80 % of hits (lift 1.6 — below gate).
+        var hits = all.Take(8).Concat(all.Skip(25).Take(2)).ToList();
+
+        var result = RuleRegressionRadar.ComputeDimensionConcentration(hits, all)!;
+        Assert.Equal("osBuild", result.Dimension);
+        Assert.Equal(3.2, result.Lift);
+    }
+
+    // ── tracker keyspace (round-trip + key shape) ───────────────────────────
+
+    [Fact]
+    public void RuleRegressionRowKey_PrefixedAndCaseFolded()
+    {
+        Assert.Equal("ruleregression|analyze-net-001",
+            TableHardwareRejectionNotificationTracker.BuildRuleRegressionRowKey("  ANALYZE-NET-001 "));
+    }
+
+    [Fact]
+    public void RuleRegressionEntity_RoundTripsAllFields_IncludingDimension()
+    {
+        var alert = new RuleRegressionAlert
+        {
+            TenantId = TenantA,
+            RuleId = RuleX,
+            RuleTitle = "Network check",
+            WindowFireCount = 15,
+            WindowSessionCount = 100,
+            BaselineFireCount = 10,
+            BaselineSessionCount = 500,
+            WindowRatePct = 15.0,
+            BaselineRatePct = 2.0,
+            Lift = 7.5,
+            WindowStartDate = "2026-07-20",
+            WindowEndDate = "2026-07-26",
+            Dimension = new RuleRegressionDimension
+            {
+                Dimension = "osBuild", Value = "26100.4652",
+                HitCount = 12, HitSharePct = 80.0, AllSharePct = 20.0, Lift = 4.0,
+            },
+            FirstNotifiedAt = Target,
+            LastEvaluatedAt = Target.AddHours(2),
+        };
+
+        var entity = TableHardwareRejectionNotificationTracker.BuildRuleRegressionEntity(TenantA, alert);
+        Assert.Equal(TenantA.ToLowerInvariant(), entity.PartitionKey);
+        Assert.Equal("ruleregression|analyze-net-001", entity.RowKey);
+
+        var mapped = TableHardwareRejectionNotificationTracker.MapToRuleRegressionAlert(entity);
+        Assert.Equal(RuleX, mapped.RuleId);
+        Assert.Equal("Network check", mapped.RuleTitle);
+        Assert.Equal(15, mapped.WindowFireCount);
+        Assert.Equal(100, mapped.WindowSessionCount);
+        Assert.Equal(10, mapped.BaselineFireCount);
+        Assert.Equal(500, mapped.BaselineSessionCount);
+        Assert.Equal(15.0, mapped.WindowRatePct);
+        Assert.Equal(2.0, mapped.BaselineRatePct);
+        Assert.Equal(7.5, mapped.Lift);
+        Assert.Equal("2026-07-20", mapped.WindowStartDate);
+        Assert.Equal("2026-07-26", mapped.WindowEndDate);
+        Assert.Equal(Target, mapped.FirstNotifiedAt);
+        Assert.Equal(Target.AddHours(2), mapped.LastEvaluatedAt);
+        Assert.NotNull(mapped.Dimension);
+        Assert.Equal("osBuild", mapped.Dimension!.Dimension);
+        Assert.Equal(4.0, mapped.Dimension.Lift);
+    }
+
+    [Fact]
+    public void RuleRegressionEntity_TriStates_AbsentColumnsMapToNull_NeverInvented()
+    {
+        var alert = new RuleRegressionAlert
+        {
+            TenantId = TenantA, RuleId = RuleX,
+            Lift = null,       // new signal — no finite lift
+            Dimension = null,  // no clear concentration
+            FirstNotifiedAt = Target, LastEvaluatedAt = Target,
+        };
+
+        var entity = TableHardwareRejectionNotificationTracker.BuildRuleRegressionEntity(TenantA, alert);
+        Assert.False(entity.ContainsKey("Lift"));
+        Assert.False(entity.ContainsKey("DimensionJson"));
+
+        var mapped = TableHardwareRejectionNotificationTracker.MapToRuleRegressionAlert(entity);
+        Assert.Null(mapped.Lift);
+        Assert.Null(mapped.Dimension);
+    }
+
+    // ── wording contracts ───────────────────────────────────────────────────
+
+    [Fact]
+    public void DescribeDimension_UsesCorrelationWording_NeverCausal()
+    {
+        var text = MaintenanceService.DescribeDimension(new RuleRegressionDimension
+        {
+            Dimension = "osBuild", Value = "26100.4652",
+            HitCount = 12, HitSharePct = 87.0, AllSharePct = 22.0, Lift = 4.0,
+        })!;
+
+        Assert.Contains("87% of affected sessions are on osBuild 26100.4652", text);
+        Assert.Contains("vs 22% of all sessions (lift 4x)", text);
+        Assert.Contains("correlated, not necessarily causal", text);
+        Assert.Null(MaintenanceService.DescribeDimension(null));
+    }
+
+    [Fact]
+    public void BuildRegressionMessage_CarriesFullNumbers_AndHonestNoDimensionFallback()
+    {
+        var finding = new RuleRegressionFinding
+        {
+            TenantId = TenantA, RuleId = RuleX, RuleTitle = "Network check",
+            WindowFireCount = 15, WindowSessionCount = 100, WindowRatePct = 15.0,
+            BaselineFireCount = 10, BaselineSessionCount = 500, BaselineRatePct = 2.0,
+            Lift = 7.5, WindowStartDate = "2026-07-20", WindowEndDate = "2026-07-26",
+        };
+
+        var message = MaintenanceService.BuildRegressionMessage(finding, dimensionSummary: null);
+        Assert.Contains("15 of 100 evaluated sessions", message);
+        Assert.Contains("(15%)", message);
+        Assert.Contains("baseline 2% (10/500 over the prior 28 days)", message);
+        Assert.Contains("lift 7.5x", message);
+        Assert.Contains("No clear dimension concentration.", message);
+
+        var newSignal = MaintenanceService.BuildRegressionMessage(
+            new RuleRegressionFinding
+            {
+                RuleId = RuleX, RuleTitle = "Network check",
+                WindowFireCount = 15, WindowSessionCount = 100, WindowRatePct = 15.0,
+                BaselineFireCount = 0, BaselineSessionCount = 500, BaselineRatePct = 0.0,
+                Lift = null, WindowStartDate = "2026-07-20", WindowEndDate = "2026-07-26",
+            },
+            dimensionSummary: "dim summary");
+        Assert.Contains("new signal", newSignal);
+        Assert.Contains("dim summary.", newSignal);
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/SessionIndexProjectionTests.cs

@@ -45,6 +45,12 @@ public class SessionIndexProjectionTests
             ["IsSelfDeployingProfile"] = true,
             // Device-validation path recorded at registration — shown on the session detail page.
             ["ValidatedBy"] = "AutopilotV1",
+            // Agent→backend HTTP latency projection (UpdateSessionNetworkLatencyAsync merges these).
+            ["AvgApiLatencyMs"] = 513.5,
+            ["ApiRequestCount"] = 100,
+            // Connection-type projection (UpdateSessionConnectionTypeAsync merges this) —
+            // search-filterable (connectionType= pushes an OData eq on the index).
+            ["ConnectionType"] = "Ethernet",
         };
 
         var idx = TableStorageService.BuildSessionIndexEntity(session, IndexRowKey, StartedAt);
@@ -67,6 +73,9 @@ public class SessionIndexProjectionTests
         Assert.True(idx.GetBoolean("ExcessiveEventsAutoActioned"));
         Assert.True(idx.GetBoolean("IsSelfDeployingProfile"));
         Assert.Equal("AutopilotV1", idx.GetString("ValidatedBy"));
+        Assert.Equal(513.5, idx.GetDouble("AvgApiLatencyMs"));
+        Assert.Equal(100, idx.GetInt32("ApiRequestCount"));
+        Assert.Equal("Ethernet", idx.GetString("ConnectionType"));
     }
 
     [Fact]
@@ -86,6 +95,8 @@ public class SessionIndexProjectionTests
         Assert.False(idx.ContainsKey("FailureSource"));
         Assert.False(idx.ContainsKey("StalledAt"));
         Assert.False(idx.ContainsKey("ValidatedBy"));
+        Assert.False(idx.ContainsKey("AvgApiLatencyMs"));
+        Assert.False(idx.ContainsKey("ConnectionType"));
         // Always-present counts/flags mirror the Sessions defaults.
         Assert.Equal(0, idx.GetInt32("PlatformScriptCount"));
         Assert.Equal(0, idx.GetInt32("RemediationScriptCount"));

src/Backend/AutopilotMonitor.Functions.Tests/StoreSessionReregistrationPreserveTests.cs

@@ -40,6 +40,7 @@ public class StoreSessionReregistrationPreserveTests
             ["PlatformScriptCount"]    = 3,
             ["RemediationScriptCount"] = 5,
             ["RebootCount"]            = 7,
+            ["ConnectionType"]         = "Ethernet",
         };
         existing.ETag = new ETag("0xEXISTING");
 
@@ -71,6 +72,9 @@ public class StoreSessionReregistrationPreserveTests
         Assert.Equal(7, harness.Written.GetInt32("RebootCount"));
         // EventCount preservation is the established sibling behaviour — assert it as a sanity anchor.
         Assert.Equal(42, harness.Written.GetInt32("EventCount"));
+        // Merge-mode field (UpdateSessionConnectionTypeAsync) — must survive the Replace so the
+        // value isn't lost in the window until the restarted agent re-emits network_interface_info.
+        Assert.Equal("Ethernet", harness.Written.GetString("ConnectionType"));
     }
 
     [Fact]

src/Backend/AutopilotMonitor.Functions.Tests/TimeAttributionCalculatorTests.cs

@@ -0,0 +1,562 @@
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Golden fixtures for <see cref="TimeAttributionCalculator"/> (F1 PR1, insights spec §F1) —
+/// synthetic sessions only (no customer data), each pinning one semantic decision:
+/// linear phase partition, clock skew, late start, WhiteGlove two-window split, missing /
+/// truncated blocking lists, IME retry occupancy, and reboot gaps. EVERY fixture asserts the
+/// exact-partition invariant: sum(span seconds) + unattributed == wall clock ==
+/// the session's DurationSeconds (truthfulness rule 2 — never normalized, never interpolated).
+/// </summary>
+public class TimeAttributionCalculatorTests
+{
+    private static readonly DateTime T0 = new(2026, 7, 26, 10, 0, 0, DateTimeKind.Utc);
+
+    private const string AppA = "aaaaaaaa-1111-2222-3333-444444444444"; // in blocking list
+    private const string AppB = "bbbbbbbb-1111-2222-3333-444444444444"; // in blocking list, never observed
+    private const string AppC = "cccccccc-1111-2222-3333-444444444444"; // observed, NOT listed
+
+    private static long _seq;
+
+    private static EnrollmentEvent Evt(
+        DateTime ts, string eventType,
+        EnrollmentPhase phase = EnrollmentPhase.Unknown,
+        Dictionary<string, object>? data = null)
+        => new()
+        {
+            EventType = eventType,
+            Timestamp = ts,
+            Sequence = ++_seq,
+            Phase = phase,
+            Data = data ?? new Dictionary<string, object>(),
+        };
+
+    private static Dictionary<string, object> AppData(string appId, string appName, string? state = null)
+    {
+        var d = new Dictionary<string, object> { ["appId"] = appId, ["appName"] = appName };
+        if (state != null) d["state"] = state;
+        return d;
+    }
+
+    /// <summary>Storage-shape blocking lists (EventDataNormalizer yields List&lt;object&gt;).</summary>
+    private static Dictionary<string, object> EspLists(long? win32Count = null, params string[] win32Ids)
+        => new()
+        {
+            ["espTrackedWin32AppIds"] = new List<object>(win32Ids),
+            ["espTrackedUserWin32AppIds"] = new List<object>(),
+            ["espTrackedMsiProductCodes"] = new List<object>(),
+            ["espTrackedModernAppPfns"] = new List<object>(),
+            ["espTrackedWin32Count"] = win32Count ?? win32Ids.Length,
+            ["espTrackedMsiCount"] = 0L,
+            ["espTrackedModernCount"] = 0L,
+        };
+
+    private static TimeAttributionInput Input(
+        List<EnrollmentEvent> events, DateTime completedAt, int durationSeconds,
+        string status = "Succeeded", bool wg = false, DateTime? resumedAt = null)
+        => new()
+        {
+            TenantId = "00000000-0000-0000-0000-0000000000t1",
+            SessionId = "00000000-0000-0000-0000-0000000000s1",
+            Status = status,
+            StartedAt = T0,
+            CompletedAt = completedAt,
+            DurationSeconds = durationSeconds,
+            IsPreProvisioned = wg,
+            ResumedAt = resumedAt,
+            Events = events,
+        };
+
+    /// <summary>The invariant every fixture must satisfy exactly (spec §0 rule 2).</summary>
+    private static void AssertExactPartition(SessionTimeBreakdown b)
+    {
+        Assert.Equal(b.WallClockSeconds, b.Segments.Sum(s => s.Seconds) + b.UnattributedSeconds);
+        Assert.True(b.UnattributedSeconds >= 0, "unattributed must never be negative");
+    }
+
+    // ── golden: linear UDE session ──────────────────────────────────────────
+
+    private static List<EnrollmentEvent> LinearSession()
+        => new()
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(2), "esp_config_detected", data: EspLists(win32Ids: new[] { AppA, AppB })),
+            Evt(T0.AddMinutes(5), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(T0.AddMinutes(6), "app_install_started", data: AppData(AppA, "App A")),
+            Evt(T0.AddMinutes(10), "app_install_completed", data: AppData(AppA, "App A", "Installed")),
+            Evt(T0.AddMinutes(11), "app_install_started", data: AppData(AppC, "Untracked App")),
+            Evt(T0.AddMinutes(13), "app_install_completed", data: AppData(AppC, "Untracked App", "Installed")),
+            Evt(T0.AddMinutes(15), "esp_phase_changed", EnrollmentPhase.AccountSetup),
+            Evt(T0.AddMinutes(20), "esp_phase_changed", EnrollmentPhase.AppsUser),
+            Evt(T0.AddMinutes(25), "esp_phase_changed", EnrollmentPhase.FinalizingSetup),
+            Evt(T0.AddMinutes(28), "desktop_arrived"),
+            Evt(T0.AddMinutes(30), "enrollment_complete"),
+        };
+
+    [Fact]
+    public void Linear_Session_PartitionsIntoAllFiveSegments_Exactly()
+    {
+        var b = TimeAttributionCalculator.Compute(
+            Input(LinearSession(), completedAt: T0.AddMinutes(30), durationSeconds: 1800))!;
+
+        AssertExactPartition(b);
+        Assert.Equal(1800, b.WallClockSeconds);
+        Assert.Equal(0, b.UnattributedSeconds);
+        Assert.Equal(TimeAttributionFlags.None, b.QualityFlags);
+        Assert.Equal(TimeAttributionCalculator.CurrentVersion, b.AttributionVersion);
+
+        var totals = b.GetSegmentTotals();
+        Assert.Equal(300, totals[TimeAttributionSegments.DevicePrep]);      // T0 → apps entry (+5m)
+        Assert.Equal(600, totals[TimeAttributionSegments.EspApps]);         // +5m → +15m
+        Assert.Equal(480, totals[TimeAttributionSegments.IdentityHello]);   // AccountSetup 300 + Finalizing 180
+        Assert.Equal(300, totals[TimeAttributionSegments.UserEsp]);         // +20m → +25m
+        Assert.Equal(120, totals[TimeAttributionSegments.DesktopHandoff]);  // desktop_arrived → terminal
+    }
+
+    [Fact]
+    public void Linear_Session_BlockingJoin_IsPositiveEvidenceOnly()
+    {
+        var b = TimeAttributionCalculator.Compute(
+            Input(LinearSession(), completedAt: T0.AddMinutes(30), durationSeconds: 1800))!;
+
+        // App A is listed → blocking, interval from EVENT timestamps (started → completed).
+        var interval = Assert.Single(b.BlockingApps);
+        Assert.Equal(AppA, interval.AppId);
+        Assert.Equal(240, interval.Seconds); // +6m → +10m
+        // App C installed fine but is NOT in the lists → unknown, NEVER "not blocking":
+        // it appears nowhere (no negative claim), and only App A counts as matched.
+        Assert.Equal(1, b.BlockingAppCount);
+        // Occupancy = App A's interval clipped to the esp_apps span.
+        Assert.Equal(240, b.EspAppsOccupancySeconds);
+    }
+
+    // ── skew: backward anchor is dropped, dust stays honest ─────────────────
+
+    [Fact]
+    public void BackwardPhaseAnchor_IsDropped_WithClockSkewFlag()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(10), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            // Replayed declaration whose timestamp runs BACKWARD in canonical order.
+            Evt(T0.AddMinutes(3), "esp_phase_changed", EnrollmentPhase.AccountSetup),
+            Evt(T0.AddMinutes(30), "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddMinutes(30), durationSeconds: 1800))!;
+
+        AssertExactPartition(b);
+        Assert.True(b.QualityFlags.HasFlag(TimeAttributionFlags.ClockSkewDropped));
+        var totals = b.GetSegmentTotals();
+        Assert.Equal(600, totals[TimeAttributionSegments.DevicePrep]);
+        Assert.Equal(1200, totals[TimeAttributionSegments.EspApps]); // runs to window end — no phantom AccountSetup
+        Assert.False(totals.ContainsKey(TimeAttributionSegments.IdentityHello));
+    }
+
+    [Fact]
+    public void SubSecondBoundaries_FloorIntoUnattributedDust_NeverInvented()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddSeconds(90.5), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddSeconds(300), durationSeconds: 300))!;
+
+        AssertExactPartition(b);
+        var totals = b.GetSegmentTotals();
+        Assert.Equal(90, totals[TimeAttributionSegments.DevicePrep]);   // floor(90.5)
+        Assert.Equal(209, totals[TimeAttributionSegments.EspApps]);     // floor(209.5)
+        Assert.Equal(1, b.UnattributedSeconds);                          // the dust, disclosed
+    }
+
+    // ── late start ──────────────────────────────────────────────────────────
+
+    [Fact]
+    public void AgentLateStart_SetsPartialObservation()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddSeconds(1), "agent_late_start"),
+            Evt(T0.AddMinutes(10), "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddMinutes(10), durationSeconds: 600))!;
+
+        AssertExactPartition(b);
+        Assert.True(b.QualityFlags.HasFlag(TimeAttributionFlags.PartialObservation));
+    }
+
+    // ── WhiteGlove: two windows in ONE session, pause never attributed ──────
+
+    [Fact]
+    public void WhiteGlove_SplitsIntoTwoWindows_PauseExcluded_WallClockIsDurationSeconds()
+    {
+        var part1End = T0.AddMinutes(20);
+        var resumedAt = T0.AddDays(2);                 // 2-day pause
+        var completedAt = resumedAt.AddMinutes(10);    // part 2 = 600 s
+        // Stored combined duration: part1 (1200 s) + part2 (600 s) — pause excluded by design.
+        const int duration = 1800;
+
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(1), "esp_config_detected", data: EspLists(win32Ids: new[] { AppA })),
+            Evt(T0.AddMinutes(2), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(part1End, "whiteglove_part1_complete"),
+            // — pause —
+            Evt(resumedAt.AddSeconds(30), "agent_started", EnrollmentPhase.AccountSetup),
+            Evt(resumedAt.AddMinutes(5), "esp_phase_changed", EnrollmentPhase.FinalizingSetup),
+            Evt(resumedAt.AddMinutes(8), "desktop_arrived"),
+            Evt(completedAt, "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt, duration, wg: true, resumedAt: resumedAt))!;
+
+        AssertExactPartition(b);
+        // Wall clock is the stored DurationSeconds — NOT CompletedAt − StartedAt (≈ 2 days).
+        Assert.Equal(1800, b.WallClockSeconds);
+        Assert.Equal(TimeAttributionFlags.None, b.QualityFlags); // part1 anchored on the event
+
+        var totals = b.GetSegmentTotals();
+        Assert.Equal(120, totals[TimeAttributionSegments.DevicePrep]);     // W1: T0 → +2m
+        Assert.Equal(1080, totals[TimeAttributionSegments.EspApps]);       // W1: +2m → part1End
+        Assert.Equal(450, totals[TimeAttributionSegments.IdentityHello]);  // W2: +30s → +8m
+        Assert.Equal(120, totals[TimeAttributionSegments.DesktopHandoff]); // W2: +8m → +10m
+        // W2's 30 s resume gap has no phase context — unattributed, not guessed.
+        Assert.Equal(30, b.UnattributedSeconds);
+        // No span may live inside the pause.
+        Assert.DoesNotContain(b.Segments, s => s.StartUtc > part1End && s.EndUtc < resumedAt);
+    }
+
+    [Fact]
+    public void WhiteGlove_WithoutPart1CompleteEvent_FallsBackAndFlags()
+    {
+        var resumedAt = T0.AddDays(1);
+        var completedAt = resumedAt.AddMinutes(10);
+        var lastPart1Event = T0.AddMinutes(20);
+
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(lastPart1Event, "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(resumedAt.AddSeconds(10), "agent_started", EnrollmentPhase.AccountSetup),
+            Evt(completedAt, "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt, durationSeconds: 1800, wg: true, resumedAt: resumedAt))!;
+
+        AssertExactPartition(b);
+        Assert.True(b.QualityFlags.HasFlag(TimeAttributionFlags.WhiteGloveAnchorsIncomplete));
+        Assert.Equal(1800, b.WallClockSeconds);
+    }
+
+    [Fact]
+    public void WhiteGlove_Part2LongerThanStoredDuration_DegradesToSingleWindow_Flagged()
+    {
+        // Stored duration (600 s) contradicts the resume stamp (part 2 alone spans 900 s):
+        // no honest two-window split exists — degrade to the single derived window instead
+        // of inventing a negative part 1.
+        var resumedAt = T0.AddDays(1);
+        var completedAt = resumedAt.AddMinutes(15);
+
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(resumedAt.AddSeconds(5), "agent_started", EnrollmentPhase.AccountSetup),
+            Evt(completedAt, "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt, durationSeconds: 600, wg: true, resumedAt: resumedAt))!;
+
+        AssertExactPartition(b);
+        Assert.Equal(600, b.WallClockSeconds);
+        Assert.True(b.QualityFlags.HasFlag(TimeAttributionFlags.WhiteGloveAnchorsIncomplete));
+    }
+
+    // ── blocking list missing / truncated ───────────────────────────────────
+
+    [Fact]
+    public void NoBlockingLists_MeansUnknown_NotZero()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(2), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(T0.AddMinutes(3), "app_install_started", data: AppData(AppA, "App A")),
+            Evt(T0.AddMinutes(8), "app_install_completed", data: AppData(AppA, "App A", "Installed")),
+            Evt(T0.AddMinutes(10), "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddMinutes(10), durationSeconds: 600))!;
+
+        AssertExactPartition(b);
+        Assert.True(b.QualityFlags.HasFlag(TimeAttributionFlags.BlockingSetUnknown));
+        Assert.Empty(b.BlockingApps);
+        Assert.Equal(0, b.BlockingAppCount);
+        Assert.Null(b.EspAppsOccupancySeconds); // unknown — NOT 0 (rule 1)
+    }
+
+    [Fact]
+    public void EspConfigWithoutListKeys_IsNotEvidence_LaterEmissionNeverErasesEarlierLists()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(1), "esp_config_detected", data: EspLists(win32Ids: new[] { AppA })),
+            Evt(T0.AddMinutes(2), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(T0.AddMinutes(3), "app_install_started", data: AppData(AppA, "App A")),
+            Evt(T0.AddMinutes(8), "app_install_completed", data: AppData(AppA, "App A", "Installed")),
+            // Later emission whose probe found no Diagnostics key — no espTracked* keys at all.
+            Evt(T0.AddMinutes(9), "esp_config_detected",
+                data: new Dictionary<string, object> { ["source"] = "registry_firstsync" }),
+            Evt(T0.AddMinutes(10), "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddMinutes(10), durationSeconds: 600))!;
+
+        Assert.False(b.QualityFlags.HasFlag(TimeAttributionFlags.BlockingSetUnknown));
+        Assert.Equal(AppA, Assert.Single(b.BlockingApps).AppId);
+    }
+
+    [Fact]
+    public void TruncatedBlockingList_SetsFlag_AbsentAppsStayUnknown()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            // Uncapped total (60) exceeds the emitted list (1 id) → cap dropped entries.
+            Evt(T0.AddMinutes(1), "esp_config_detected", data: EspLists(win32Count: 60, AppA)),
+            Evt(T0.AddMinutes(2), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(T0.AddMinutes(3), "app_install_started", data: AppData(AppC, "Maybe Capped App")),
+            Evt(T0.AddMinutes(7), "app_install_completed", data: AppData(AppC, "Maybe Capped App", "Installed")),
+            Evt(T0.AddMinutes(10), "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddMinutes(10), durationSeconds: 600))!;
+
+        Assert.True(b.QualityFlags.HasFlag(TimeAttributionFlags.BlockingSetTruncated));
+        // App C is absent from the (capped) list → it stays UNKNOWN: no interval, no claim.
+        Assert.Empty(b.BlockingApps);
+        Assert.Equal(0, b.BlockingAppCount);
+    }
+
+    // ── retry: occupancy spans to the LAST terminal event (audit Q1) ────────
+
+    [Fact]
+    public void Retry_IntervalRunsFromFirstStart_ToLastTerminalEvent()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(1), "esp_config_detected", data: EspLists(win32Ids: new[] { AppA })),
+            Evt(T0.AddMinutes(2), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(T0.AddMinutes(6), "app_install_started", data: AppData(AppA, "App A")),
+            Evt(T0.AddMinutes(8), "app_install_failed", data: AppData(AppA, "App A")),
+            Evt(T0.AddMinutes(9), "app_install_started", data: AppData(AppA, "App A")),   // IME retry
+            Evt(T0.AddMinutes(12), "app_install_completed", data: AppData(AppA, "App A", "Installed")),
+            Evt(T0.AddMinutes(15), "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddMinutes(15), durationSeconds: 900))!;
+
+        AssertExactPartition(b);
+        var interval = Assert.Single(b.BlockingApps);
+        // First started (+6m) → LAST terminal (+12m) = 360 s. The payload timing would have
+        // frozen at the first failure (+8m) — event timestamps are the only valid source.
+        Assert.Equal(360, interval.Seconds);
+        Assert.Equal(360, b.EspAppsOccupancySeconds);
+    }
+
+    // ── reboots: spans from event gaps, never the detection event's stamp ───
+
+    [Fact]
+    public void RebootSpan_ComesFromEventGapAroundLastBootUtc_NotFromDetectionTimestamp()
+    {
+        var boot = T0.AddMinutes(12);
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(5), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(T0.AddMinutes(10), "app_install_started", data: AppData(AppA, "App A")), // last pre-reboot
+            Evt(T0.AddMinutes(14), "system_reboot_detected",                             // next run, detection-time
+                data: new Dictionary<string, object> { ["lastBootUtc"] = boot.ToString("o") }),
+            // Duplicate detection of the SAME boot (batch replay) — must not double-count.
+            Evt(T0.AddMinutes(14.5), "system_reboot_detected",
+                data: new Dictionary<string, object> { ["lastBootUtc"] = boot.ToString("o") }),
+            Evt(T0.AddMinutes(20), "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddMinutes(20), durationSeconds: 1200))!;
+
+        AssertExactPartition(b);
+        var span = Assert.Single(b.RebootSpans);
+        // Gap = last event before boot (+10m) → first observation at/after boot (+14m).
+        Assert.Equal(T0.AddMinutes(10), span.StartUtc);
+        Assert.Equal(T0.AddMinutes(14), span.EndUtc);
+        Assert.Equal(240, span.Seconds);
+        Assert.Equal(240, b.RebootSeconds);
+        // The reboot began inside the apps phase — cross-cutting annotation, segment unchanged.
+        Assert.Equal(TimeAttributionSegments.EspApps, span.SegmentKey);
+        Assert.Equal(1200 - 300, b.GetSegmentTotals()[TimeAttributionSegments.EspApps]);
+    }
+
+    // ── WhiteGlove pause vs. intervals/reboots (Codex review P1): the pause lies INSIDE
+    // the windows' hull, so hull-clamping alone would count it — a reboot bracketing the
+    // pause must contribute only its in-window flanks, never the pause itself ─────────────
+
+    [Fact]
+    public void WhiteGlove_RebootGapAcrossPause_CountsOnlyInWindowFlanks()
+    {
+        var part1End = T0.AddMinutes(20);
+        var resumedAt = T0.AddDays(2);                 // 2-day pause
+        var completedAt = resumedAt.AddMinutes(10);    // part 2 = 600 s → part 1 = 1200 s
+        var bootInsidePause = T0.AddDays(1);
+
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(2), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(part1End, "whiteglove_part1_complete"),
+            // — pause: device sealed, user boots it a day later —
+            Evt(resumedAt.AddSeconds(30), "agent_started", EnrollmentPhase.AccountSetup),
+            Evt(resumedAt.AddSeconds(40), "system_reboot_detected",
+                data: new Dictionary<string, object> { ["lastBootUtc"] = bootInsidePause.ToString("o") }),
+            Evt(completedAt, "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt, durationSeconds: 1800, wg: true, resumedAt: resumedAt))!;
+
+        AssertExactPartition(b);
+        var span = Assert.Single(b.RebootSpans);
+        // Gap = part1End → first post-boot event (+30 s into part 2). In-window seconds are
+        // ONLY the part-2 flank (30 s) — the ~2-day pause never counts (pre-fix: ~172 830 s
+        // of "reboot" in a 30-minute enrollment).
+        Assert.Equal(part1End, span.StartUtc);
+        Assert.Equal(resumedAt.AddSeconds(30), span.EndUtc);
+        Assert.Equal(30, span.Seconds);
+        Assert.Equal(30, b.RebootSeconds);
+    }
+
+    [Fact]
+    public void WhiteGlove_BlockingIntervalAcrossPause_CountsOnlyInWindowSeconds()
+    {
+        var part1End = T0.AddMinutes(20);
+        var resumedAt = T0.AddDays(2);
+        var completedAt = resumedAt.AddMinutes(10);
+
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(1), "esp_config_detected", data: EspLists(win32Ids: new[] { AppA })),
+            Evt(T0.AddMinutes(2), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(T0.AddMinutes(10), "app_install_started", data: AppData(AppA, "App A")),
+            Evt(part1End, "whiteglove_part1_complete"),
+            // — pause —
+            Evt(resumedAt.AddSeconds(30), "agent_started", EnrollmentPhase.AccountSetup),
+            // The app's final terminal lands in part 2 (user-scope finish after resume).
+            Evt(resumedAt.AddMinutes(2), "app_install_completed", data: AppData(AppA, "App A", "Installed")),
+            Evt(completedAt, "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt, durationSeconds: 1800, wg: true, resumedAt: resumedAt))!;
+
+        AssertExactPartition(b);
+        var interval = Assert.Single(b.BlockingApps);
+        // Chronological endpoints stay the real event times…
+        Assert.Equal(T0.AddMinutes(10), interval.StartUtc);
+        Assert.Equal(resumedAt.AddMinutes(2), interval.EndUtc);
+        // …but Seconds is the in-window sum: part 1 tail (10 min) + part 2 head (2 min).
+        Assert.Equal(720, interval.Seconds);
+        // Occupancy intersects with the esp_apps span (part 1 only) — pause never leaks in.
+        Assert.Equal(600, b.EspAppsOccupancySeconds);
+    }
+
+    [Fact]
+    public void WhiteGlove_IntervalWhollyInsidePause_MakesNoClaim_AndNoSkewFlag()
+    {
+        var part1End = T0.AddMinutes(20);
+        var resumedAt = T0.AddDays(2);
+        var completedAt = resumedAt.AddMinutes(10);
+
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0, "agent_started", EnrollmentPhase.DeviceSetup),
+            Evt(T0.AddMinutes(1), "esp_config_detected", data: EspLists(win32Ids: new[] { AppA })),
+            Evt(T0.AddMinutes(2), "esp_phase_changed", EnrollmentPhase.AppsDevice),
+            Evt(part1End, "whiteglove_part1_complete"),
+            // Both endpoints inside the pause (post-seal tail activity) — observed, but in no window.
+            Evt(part1End.AddHours(1), "app_install_started", data: AppData(AppA, "App A")),
+            Evt(part1End.AddHours(2), "app_install_completed", data: AppData(AppA, "App A", "Installed")),
+            Evt(resumedAt.AddSeconds(30), "agent_started", EnrollmentPhase.AccountSetup),
+            Evt(completedAt, "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt, durationSeconds: 1800, wg: true, resumedAt: resumedAt))!;
+
+        AssertExactPartition(b);
+        // No in-window observation → no interval claim; and nothing is wrong with the clocks,
+        // so the skew flag must NOT fire (it would exclude the session from fleet medians).
+        Assert.Empty(b.BlockingApps);
+        Assert.False(b.QualityFlags.HasFlag(TimeAttributionFlags.ClockSkewDropped));
+    }
+
+    // ── non-computable sessions ─────────────────────────────────────────────
+
+    [Theory]
+    [InlineData("Incomplete")]   // terminal but deliberately NO DurationSeconds
+    [InlineData("InProgress")]
+    [InlineData("Pending")]
+    public void NonComputableStatuses_ReturnNull(string status)
+    {
+        var input = Input(LinearSession(), completedAt: T0.AddMinutes(30), durationSeconds: 1800, status: status);
+        Assert.Null(TimeAttributionCalculator.Compute(input));
+    }
+
+    [Fact]
+    public void MissingDuration_ReturnsNull_NeverGuessesFromCompletedMinusStarted()
+    {
+        var input = Input(LinearSession(), completedAt: T0.AddMinutes(30), durationSeconds: 0);
+        Assert.Null(TimeAttributionCalculator.Compute(input));
+    }
+
+    // ── no phase evidence at all ────────────────────────────────────────────
+
+    [Fact]
+    public void NoPhaseDeclarations_LeaveEverythingUnattributed()
+    {
+        var events = new List<EnrollmentEvent>
+        {
+            Evt(T0.AddMinutes(1), "network_state_change"),
+            Evt(T0.AddMinutes(9), "enrollment_complete"),
+        };
+
+        var b = TimeAttributionCalculator.Compute(
+            Input(events, completedAt: T0.AddMinutes(10), durationSeconds: 600))!;
+
+        AssertExactPartition(b);
+        Assert.Empty(b.Segments);
+        Assert.Equal(600, b.UnattributedSeconds); // no evidence → no claim (rule 1)
+    }
+}

src/Backend/AutopilotMonitor.Functions.Tests/TimeAttributionPersistenceAndAggregationTests.cs

@@ -0,0 +1,458 @@
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// F1 PR2 (insights spec §F1 "Data &amp; compute changes"): persistence round-trips for the
+/// SessionTimeBreakdowns / TimeAttributionAggregates rows (table-storage-serialization rule —
+/// every property must survive Store→Map, tri-states included), the pure daily-aggregation
+/// core (<see cref="MaintenanceService.BuildTimeAttributionAggregates"/>: clean/flagged/missing
+/// disclosure, per-class bucketing, fixed segment stack, per-app gates) and the what-if bound.
+/// </summary>
+public class TimeAttributionPersistenceAndAggregationTests
+{
+    private static readonly DateTime T0 = new(2026, 7, 26, 10, 0, 0, DateTimeKind.Utc);
+    private const string TenantA = "aaaaaaaa-0000-0000-0000-000000000001";
+    private const string TenantB = "bbbbbbbb-0000-0000-0000-000000000002";
+    private const string AppX = "aaaaaaaa-1111-2222-3333-444444444444";
+    private const string AppY = "bbbbbbbb-1111-2222-3333-444444444444";
+
+    // ── breakdown row round-trip ────────────────────────────────────────────
+
+    [Fact]
+    public void BreakdownEntity_RoundTripsAllFields_IncludingJsonLists()
+    {
+        var breakdown = new SessionTimeBreakdown
+        {
+            TenantId = TenantA,
+            SessionId = "s-1",
+            AttributionVersion = 1,
+            EventCountAtCompute = 261,
+            WallClockSeconds = 1800,
+            UnattributedSeconds = 30,
+            RebootSeconds = 240,
+            BlockingAppCount = 3,
+            EspAppsOccupancySeconds = 600,
+            QualityFlags = TimeAttributionFlags.PartialObservation | TimeAttributionFlags.BlockingSetTruncated,
+            Segments = new List<TimeAttributionSpan>
+            {
+                new() { SegmentKey = TimeAttributionSegments.DevicePrep, StartUtc = T0, EndUtc = T0.AddMinutes(5), Seconds = 300 },
+                new() { SegmentKey = TimeAttributionSegments.EspApps, StartUtc = T0.AddMinutes(5), EndUtc = T0.AddMinutes(30), Seconds = 1500 },
+            },
+            RebootSpans = new List<RebootSpan>
+            {
+                new() { StartUtc = T0.AddMinutes(10), EndUtc = T0.AddMinutes(14), Seconds = 240, SegmentKey = TimeAttributionSegments.EspApps },
+            },
+            BlockingApps = new List<BlockingAppInterval>
+            {
+                new() { AppId = AppX, AppName = "App X", StartUtc = T0.AddMinutes(6), EndUtc = T0.AddMinutes(16), Seconds = 600 },
+            },
+        };
+
+        var mapped = TableStorageService.MapToSessionTimeBreakdown(
+            TableStorageService.BuildSessionTimeBreakdownEntity(breakdown));
+
+        Assert.Equal(TenantA, mapped.TenantId);
+        Assert.Equal("s-1", mapped.SessionId);
+        Assert.Equal(1, mapped.AttributionVersion);
+        // Sweep change signal (Codex review: late batches must trigger a recompute) — a lost
+        // column would read as 0 and recompute forever OR mask real drift.
+        Assert.Equal(261, mapped.EventCountAtCompute);
+        Assert.Equal(1800, mapped.WallClockSeconds);
+        Assert.Equal(30, mapped.UnattributedSeconds);
+        Assert.Equal(240, mapped.RebootSeconds);
+        Assert.Equal(3, mapped.BlockingAppCount);
+        Assert.Equal(600, mapped.EspAppsOccupancySeconds);
+        Assert.Equal(TimeAttributionFlags.PartialObservation | TimeAttributionFlags.BlockingSetTruncated, mapped.QualityFlags);
+
+        Assert.Equal(2, mapped.Segments.Count);
+        Assert.Equal(TimeAttributionSegments.DevicePrep, mapped.Segments[0].SegmentKey);
+        Assert.Equal(T0, mapped.Segments[0].StartUtc);
+        Assert.Equal(300, mapped.Segments[0].Seconds);
+
+        var reboot = Assert.Single(mapped.RebootSpans);
+        Assert.Equal(TimeAttributionSegments.EspApps, reboot.SegmentKey);
+        Assert.Equal(240, reboot.Seconds);
+
+        var app = Assert.Single(mapped.BlockingApps);
+        Assert.Equal(AppX, app.AppId);
+        Assert.Equal("App X", app.AppName);
+        Assert.Equal(600, app.Seconds);
+    }
+
+    [Fact]
+    public void BreakdownEntity_OccupancyTriState_AbsentColumnMapsToNull_NeverZero()
+    {
+        var unknown = new SessionTimeBreakdown
+        {
+            TenantId = TenantA, SessionId = "s-1", WallClockSeconds = 600,
+            EspAppsOccupancySeconds = null, QualityFlags = TimeAttributionFlags.BlockingSetUnknown,
+        };
+
+        var entity = TableStorageService.BuildSessionTimeBreakdownEntity(unknown);
+        Assert.False(entity.ContainsKey("EspAppsOccupancySeconds"));
+        Assert.Null(TableStorageService.MapToSessionTimeBreakdown(entity).EspAppsOccupancySeconds);
+
+        // Zero is a real measured value (blocking set known, nothing occupied) — must survive.
+        var zero = new SessionTimeBreakdown
+        {
+            TenantId = TenantA, SessionId = "s-2", WallClockSeconds = 600, EspAppsOccupancySeconds = 0,
+        };
+        Assert.Equal(0, TableStorageService.MapToSessionTimeBreakdown(
+            TableStorageService.BuildSessionTimeBreakdownEntity(zero)).EspAppsOccupancySeconds);
+    }
+
+    // ── aggregate row round-trip ────────────────────────────────────────────
+
+    [Fact]
+    public void AggregateEntity_RoundTripsAllFields()
+    {
+        var aggregate = new TimeAttributionDailyAggregate
+        {
+            TenantId = TenantA,
+            Date = "2026-07-26",
+            EnrollmentClass = "user_driven",
+            AttributionVersion = 1,
+            CleanSessionCount = 23,
+            FlaggedExcludedCount = 4,
+            MissingBreakdownCount = 1,
+            ComputedAt = T0,
+            SegmentStats = new List<TimeAttributionSegmentStat>
+            {
+                new() { SegmentKey = TimeAttributionSegments.EspApps, MedianSeconds = 600, P75Seconds = 700, P90Seconds = 900 },
+            },
+            TopBlockingApps = new List<TimeAttributionBlockingAppStat>
+            {
+                new()
+                {
+                    AppId = AppX, AppName = "App X", SessionCount = 12,
+                    MedianSeconds = 300, P75Seconds = 400, MedianSavingSeconds = 120, P75SavingSeconds = 200,
+                },
+            },
+        };
+
+        var entity = TableStorageService.BuildTimeAttributionAggregateEntity(aggregate);
+        Assert.Equal("2026-07-26|user_driven", entity.RowKey);
+
+        var mapped = TableStorageService.MapToTimeAttributionAggregate(entity);
+        Assert.Equal(TenantA, mapped.TenantId);
+        Assert.Equal("2026-07-26", mapped.Date);
+        Assert.Equal("user_driven", mapped.EnrollmentClass);
+        Assert.Equal(1, mapped.AttributionVersion);
+        Assert.Equal(23, mapped.CleanSessionCount);
+        Assert.Equal(4, mapped.FlaggedExcludedCount);
+        Assert.Equal(1, mapped.MissingBreakdownCount);
+
+        var segment = Assert.Single(mapped.SegmentStats);
+        Assert.Equal(TimeAttributionSegments.EspApps, segment.SegmentKey);
+        Assert.Equal(600, segment.MedianSeconds);
+        Assert.Equal(900, segment.P90Seconds);
+
+        var app = Assert.Single(mapped.TopBlockingApps);
+        Assert.Equal(AppX, app.AppId);
+        Assert.Equal(12, app.SessionCount);
+        Assert.Equal(120, app.MedianSavingSeconds);
+    }
+
+    // ── enrollment class ────────────────────────────────────────────────────
+
+    [Fact]
+    public void EnrollmentClass_Precedence_WhiteGlove_Wdp_SelfDeploying_UserDriven()
+    {
+        Assert.Equal("whiteglove", TimeAttributionCalculator.GetEnrollmentClass(
+            new SessionSummary { IsPreProvisioned = true, EnrollmentType = "v2", IsSelfDeployingProfile = true }));
+        Assert.Equal("device_preparation", TimeAttributionCalculator.GetEnrollmentClass(
+            new SessionSummary { EnrollmentType = "v2", IsSelfDeployingProfile = true }));
+        Assert.Equal("self_deploying", TimeAttributionCalculator.GetEnrollmentClass(
+            new SessionSummary { IsSelfDeployingProfile = true }));
+        Assert.Equal("user_driven", TimeAttributionCalculator.GetEnrollmentClass(new SessionSummary()));
+    }
+
+    // ── what-if bound ───────────────────────────────────────────────────────
+
+    private static BlockingAppInterval Interval(string appId, DateTime start, DateTime end)
+        => new() { AppId = appId, AppName = appId, StartUtc = start, EndUtc = end, Seconds = (int)(end - start).TotalSeconds };
+
+    [Fact]
+    public void WhatIf_LastEndingApp_SavesTailToPreviousEnd_OthersSaveNothing()
+    {
+        var intervals = new List<BlockingAppInterval>
+        {
+            Interval(AppX, T0, T0.AddMinutes(10)),                 // ends 10:10
+            Interval(AppY, T0.AddMinutes(5), T0.AddMinutes(20)),   // ends 10:20 — critical-path end
+        };
+
+        // Removing Y moves the path end 10:20 → 10:10.
+        Assert.Equal(600, TimeAttributionCalculator.WhatIfSavingSeconds(intervals, AppY));
+        // Removing X changes nothing — Y still ends at 10:20.
+        Assert.Equal(0, TimeAttributionCalculator.WhatIfSavingSeconds(intervals, AppX));
+        // An app without a measured interval yields no claim.
+        Assert.Equal(0, TimeAttributionCalculator.WhatIfSavingSeconds(intervals, "cccccccc-0000-0000-0000-000000000000"));
+    }
+
+    [Fact]
+    public void WhatIf_OnlyBlockingApp_FallsBackToOwnStart()
+    {
+        var intervals = new List<BlockingAppInterval> { Interval(AppX, T0.AddMinutes(5), T0.AddMinutes(20)) };
+        Assert.Equal(900, TimeAttributionCalculator.WhatIfSavingSeconds(intervals, AppX));
+    }
+
+    [Fact]
+    public void WhatIf_IdleGapBeforeLastApp_CountsIntoTheBound()
+    {
+        // A ends 10:00; X runs 10:05 → 10:20. Removing X exposes 10:00 as the path end —
+        // the ESP waited for X to START too, so the bound is 20 min, not 15 (spec formula).
+        var intervals = new List<BlockingAppInterval>
+        {
+            Interval(AppY, T0.AddMinutes(-30), T0),
+            Interval(AppX, T0.AddMinutes(5), T0.AddMinutes(20)),
+        };
+        Assert.Equal(1200, TimeAttributionCalculator.WhatIfSavingSeconds(intervals, AppX));
+    }
+
+    // ── daily aggregation core ──────────────────────────────────────────────
+
+    private static SessionSummary Session(string tenantId, DateTime startedAt, bool wg = false)
+        => new()
+        {
+            TenantId = tenantId,
+            SessionId = Guid.NewGuid().ToString(),
+            StartedAt = startedAt,
+            Status = SessionStatus.Succeeded,
+            IsPreProvisioned = wg,
+        };
+
+    private static SessionTimeBreakdown Breakdown(
+        TimeAttributionFlags flags = TimeAttributionFlags.None,
+        int espAppsSeconds = 600,
+        int unattributed = 0,
+        List<BlockingAppInterval>? apps = null)
+        => new()
+        {
+            AttributionVersion = TimeAttributionCalculator.CurrentVersion,
+            WallClockSeconds = espAppsSeconds + 300 + unattributed,
+            UnattributedSeconds = unattributed,
+            QualityFlags = flags,
+            Segments = new List<TimeAttributionSpan>
+            {
+                new() { SegmentKey = TimeAttributionSegments.DevicePrep, StartUtc = T0, EndUtc = T0.AddSeconds(300), Seconds = 300 },
+                new() { SegmentKey = TimeAttributionSegments.EspApps, StartUtc = T0.AddSeconds(300), EndUtc = T0.AddSeconds(300 + espAppsSeconds), Seconds = espAppsSeconds },
+            },
+            BlockingApps = apps ?? new List<BlockingAppInterval>(),
+        };
+
+    [Fact]
+    public void Aggregates_BucketPerTenantClassDate_AndMirrorGlobal()
+    {
+        var pairs = new List<(SessionSummary, SessionTimeBreakdown)>
+        {
+            (Session(TenantA, T0), Breakdown(espAppsSeconds: 100)),
+            (Session(TenantA, T0), Breakdown(espAppsSeconds: 300)),
+            (Session(TenantA, T0, wg: true), Breakdown(espAppsSeconds: 900)),   // separate class
+            (Session(TenantB, T0), Breakdown(espAppsSeconds: 500)),             // separate tenant
+        };
+
+        var aggregates = MaintenanceService.BuildTimeAttributionAggregates(
+            pairs, Array.Empty<SessionSummary>(), T0);
+
+        // Tenant A: user_driven + whiteglove; Tenant B: user_driven; global: user_driven + whiteglove.
+        Assert.Equal(5, aggregates.Count);
+
+        var tenantAUde = aggregates.Single(a => a.TenantId == TenantA && a.EnrollmentClass == "user_driven");
+        Assert.Equal("2026-07-26", tenantAUde.Date);
+        Assert.Equal(2, tenantAUde.CleanSessionCount);
+        Assert.Equal(TimeAttributionCalculator.CurrentVersion, tenantAUde.AttributionVersion);
+        // Median of {100, 300} = 100 (nearest-rank: ceil(0.5·2)−1 = index 0 — repo convention).
+        Assert.Equal(100, tenantAUde.SegmentStats.Single(s => s.SegmentKey == TimeAttributionSegments.EspApps).MedianSeconds);
+
+        var wg = aggregates.Single(a => a.TenantId == TenantA && a.EnrollmentClass == "whiteglove");
+        Assert.Equal(1, wg.CleanSessionCount); // classes never mixed
+
+        var globalUde = aggregates.Single(a => a.TenantId == "global" && a.EnrollmentClass == "user_driven");
+        Assert.Equal(3, globalUde.CleanSessionCount); // A(2) + B(1)
+    }
+
+    [Fact]
+    public void Aggregates_FlaggedSessions_AreExcludedFromStats_ButDisclosed()
+    {
+        var pairs = new List<(SessionSummary, SessionTimeBreakdown)>
+        {
+            (Session(TenantA, T0), Breakdown(espAppsSeconds: 100)),
+            (Session(TenantA, T0), Breakdown(flags: TimeAttributionFlags.PartialObservation, espAppsSeconds: 99999)),
+        };
+
+        var aggregate = MaintenanceService.BuildTimeAttributionAggregates(
+                pairs, Array.Empty<SessionSummary>(), T0)
+            .Single(a => a.TenantId == TenantA);
+
+        Assert.Equal(1, aggregate.CleanSessionCount);
+        Assert.Equal(1, aggregate.FlaggedExcludedCount);
+        // The flagged 99999s outlier must not shape the median.
+        Assert.Equal(100, aggregate.SegmentStats.Single(s => s.SegmentKey == TimeAttributionSegments.EspApps).MedianSeconds);
+    }
+
+    [Fact]
+    public void Aggregates_AllFlaggedDay_YieldsDisclosureRow_WithoutStats()
+    {
+        var pairs = new List<(SessionSummary, SessionTimeBreakdown)>
+        {
+            (Session(TenantA, T0), Breakdown(flags: TimeAttributionFlags.ClockSkewDropped)),
+        };
+
+        var aggregate = MaintenanceService.BuildTimeAttributionAggregates(
+                pairs, Array.Empty<SessionSummary>(), T0)
+            .Single(a => a.TenantId == TenantA);
+
+        Assert.Equal(0, aggregate.CleanSessionCount);
+        Assert.Equal(1, aggregate.FlaggedExcludedCount);
+        Assert.Empty(aggregate.SegmentStats);   // no clean sessions → no statistical claim
+        Assert.Empty(aggregate.TopBlockingApps);
+    }
+
+    [Fact]
+    public void Aggregates_BlockingOnlyFlags_StayInSegmentStats()
+    {
+        // BlockingSetUnknown/Truncated limit per-app blocking EVIDENCE, not the measured spans.
+        // Gating on any flag starved the fleet aggregates in production (903/1000 breakdowns
+        // carried BlockingSetUnknown, 2026-07-27) — blocking-only flagged sessions must count
+        // as clean; only duration-critical flags exclude.
+        var pairs = new List<(SessionSummary, SessionTimeBreakdown)>
+        {
+            (Session(TenantA, T0), Breakdown(flags: TimeAttributionFlags.BlockingSetUnknown, espAppsSeconds: 100)),
+            (Session(TenantA, T0), Breakdown(flags: TimeAttributionFlags.BlockingSetTruncated, espAppsSeconds: 300)),
+            (Session(TenantA, T0), Breakdown(
+                flags: TimeAttributionFlags.BlockingSetUnknown | TimeAttributionFlags.PartialObservation,
+                espAppsSeconds: 99999)), // duration-critical bit set → still excluded
+        };
+
+        var aggregate = MaintenanceService.BuildTimeAttributionAggregates(
+                pairs, Array.Empty<SessionSummary>(), T0)
+            .Single(a => a.TenantId == TenantA);
+
+        Assert.Equal(2, aggregate.CleanSessionCount);
+        Assert.Equal(1, aggregate.FlaggedExcludedCount);
+        // Median of {100, 300} = 100 (nearest-rank, lower value — repo convention).
+        Assert.Equal(100, aggregate.SegmentStats.Single(s => s.SegmentKey == TimeAttributionSegments.EspApps).MedianSeconds);
+    }
+
+    [Fact]
+    public void Aggregates_MissingBreakdowns_AreCounted_NeverGuessed()
+    {
+        var missing = new List<SessionSummary> { Session(TenantA, T0) };
+
+        var aggregate = MaintenanceService.BuildTimeAttributionAggregates(
+                Array.Empty<(SessionSummary, SessionTimeBreakdown)>(), missing, T0)
+            .Single(a => a.TenantId == TenantA);
+
+        Assert.Equal(0, aggregate.CleanSessionCount);
+        Assert.Equal(1, aggregate.MissingBreakdownCount);
+        Assert.Empty(aggregate.SegmentStats);
+    }
+
+    [Fact]
+    public void Aggregates_SegmentStack_AlwaysCarriesAllSegmentsPlusUnattributed_AbsentAsZero()
+    {
+        var pairs = new List<(SessionSummary, SessionTimeBreakdown)>
+        {
+            (Session(TenantA, T0), Breakdown(unattributed: 42)),
+        };
+
+        var aggregate = MaintenanceService.BuildTimeAttributionAggregates(
+                pairs, Array.Empty<SessionSummary>(), T0)
+            .Single(a => a.TenantId == TenantA);
+
+        Assert.Equal(6, aggregate.SegmentStats.Count); // 5 canonical + unattributed — the full stack
+        // The fixture has no user_esp span → honest 0, not absent.
+        Assert.Equal(0, aggregate.SegmentStats.Single(s => s.SegmentKey == TimeAttributionSegments.UserEsp).MedianSeconds);
+        Assert.Equal(42, aggregate.SegmentStats.Single(s => s.SegmentKey == TimeAttributionSegments.Unattributed).MedianSeconds);
+    }
+
+    [Fact]
+    public void Aggregates_RollingDateKey_MergesAllDatesIntoRangeStatistics()
+    {
+        // Two sessions on DIFFERENT days — the rolling row must merge them (a median of
+        // per-day medians would not be the range median; the rolling rows are the honest
+        // range statistics the fleet panel reads).
+        var pairs = new List<(SessionSummary, SessionTimeBreakdown)>
+        {
+            (Session(TenantA, T0), Breakdown(espAppsSeconds: 100)),
+            (Session(TenantA, T0.AddDays(-3)), Breakdown(espAppsSeconds: 300)),
+        };
+
+        var rolling = MaintenanceService.BuildTimeAttributionAggregates(
+            pairs, Array.Empty<SessionSummary>(), T0, MaintenanceService.RollingAggregateDateKey);
+
+        var row = rolling.Single(a => a.TenantId == TenantA);
+        Assert.Equal(MaintenanceService.RollingAggregateDateKey, row.Date);
+        Assert.Equal(2, row.CleanSessionCount);
+        // Rolling rows sort AFTER every "yyyy-MM-dd|…" key so date-range reads and the
+        // age-based retention filter never touch them.
+        Assert.True(string.CompareOrdinal($"{row.Date}|user_driven", "2026-12-31|zzz") > 0);
+    }
+
+    [Fact]
+    public void Aggregates_PerAppRows_GateAtFiveSessions_AndCarryWhatIfBounds()
+    {
+        var pairs = new List<(SessionSummary, SessionTimeBreakdown)>();
+        // App X in 5 sessions (ends last each time → saving = its full tail over device-prep-only baseline).
+        for (var i = 0; i < 5; i++)
+        {
+            pairs.Add((Session(TenantA, T0), Breakdown(apps: new List<BlockingAppInterval>
+            {
+                Interval(AppX, T0.AddMinutes(5), T0.AddMinutes(15)), // only measured blocking app → saving 600
+            })));
+        }
+        // App Y in only 4 sessions → below the per-app row gate.
+        for (var i = 0; i < 4; i++)
+        {
+            pairs.Add((Session(TenantA, T0), Breakdown(apps: new List<BlockingAppInterval>
+            {
+                Interval(AppY, T0.AddMinutes(5), T0.AddMinutes(6)),
+            })));
+        }
+
+        var aggregate = MaintenanceService.BuildTimeAttributionAggregates(
+                pairs, Array.Empty<SessionSummary>(), T0)
+            .Single(a => a.TenantId == TenantA);
+
+        var row = Assert.Single(aggregate.TopBlockingApps);
+        Assert.Equal(AppX, row.AppId);
+        Assert.Equal(5, row.SessionCount);
+        Assert.Equal(600, row.MedianSeconds);
+        Assert.Equal(600, row.MedianSavingSeconds); // sole blocking app → bound = full interval
+    }
+
+    // ── stale-bucket reconcile key consistency (Codex review) ───────────────
+
+    [Fact]
+    public void RollingAggregateEntity_RowKey_MatchesTargetedDeleteKey()
+    {
+        // The sweep's reconcile deletes by (Date, EnrollmentClass) — the entity builder and the
+        // delete path must agree on the RK shape for BOTH daily and rolling rows, or stale
+        // rolling rows would never be removed.
+        var rolling = new TimeAttributionDailyAggregate
+        {
+            TenantId = TenantA, Date = "rolling30", EnrollmentClass = "whiteglove",
+        };
+        Assert.Equal("rolling30|whiteglove", TableStorageService.BuildTimeAttributionAggregateEntity(rolling).RowKey);
+
+        var daily = new TimeAttributionDailyAggregate
+        {
+            TenantId = TenantA, Date = "2026-07-27", EnrollmentClass = "user_driven",
+        };
+        Assert.Equal("2026-07-27|user_driven", TableStorageService.BuildTimeAttributionAggregateEntity(daily).RowKey);
+    }
+
+    [Fact]
+    public void TimeAttribution_InclusiveWindowStart_YieldsExactly30CalendarDays()
+    {
+        // Codex review: both range ends are inclusive — subtracting the full WindowDays
+        // returned 31 day keys under a "windowDays: 30" label.
+        var today = new System.DateTime(2026, 7, 27);
+        Assert.Equal(today.AddDays(-29),
+            Functions.Metrics.TimeAttributionResponse.InclusiveWindowStart(today, Functions.Metrics.TimeAttributionResponse.WindowDays));
+    }
+}

src/Backend/AutopilotMonitor.Functions/DataAccess/TableStorage/TableConfigRepository.cs

@@ -413,6 +413,7 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
                 { "EnableTimezoneAutoSet", config.EnableTimezoneAutoSet },
                 { "NtpServer", config.NtpServer },
                 { "EnableImeMatchLog", config.EnableImeMatchLog },
+                { "EnableGatherRuleDebugLog", config.EnableGatherRuleDebugLog },
                 { "LogLevel", config.LogLevel },
                 { "MaxBatchSize", config.MaxBatchSize },
                 { "DiagnosticsBlobSasUrl", config.DiagnosticsBlobSasUrl },
@@ -514,6 +515,7 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
                 EnableTimezoneAutoSet = entity.GetBoolean("EnableTimezoneAutoSet"),
                 NtpServer = string.IsNullOrWhiteSpace(entity.GetString("NtpServer")) ? "time.windows.com" : entity.GetString("NtpServer"),
                 EnableImeMatchLog = entity.GetBoolean("EnableImeMatchLog"),
+                EnableGatherRuleDebugLog = entity.GetBoolean("EnableGatherRuleDebugLog"),
                 LogLevel = entity.GetString("LogLevel"),
                 MaxBatchSize = entity.GetInt32("MaxBatchSize"),
                 DiagnosticsBlobSasUrl = entity.GetString("DiagnosticsBlobSasUrl"),

src/Backend/AutopilotMonitor.Functions/DataAccess/TableStorage/TableHardwareRejectionNotificationTracker.cs

@@ -1,6 +1,8 @@
+using System.Text.Json;
 using AutopilotMonitor.Functions.Services;
 using AutopilotMonitor.Shared;
 using AutopilotMonitor.Shared.DataAccess;
+using AutopilotMonitor.Shared.Models;
 using Azure;
 using Azure.Data.Tables;
 using Microsoft.Extensions.Logging;
@@ -13,6 +15,8 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
     ///   - hardware rejection: "{manufacturer-lower}|{model-lower}" (trimmed)
     ///   - TPM PSS unsupported: "tpmpss|{serial-lower}" (trimmed; the literal "tpmpss" prefix
     ///     cannot collide with a hardware key because no real manufacturer is named "tpmpss")
+    ///   - F3 rule regression: "ruleregression|{ruleId-lower}" (trimmed; payload-carrying rows
+    ///     that are refreshed while the episode is active and deleted on re-arm)
     /// Race-safe via AddEntityAsync: Azure Table Storage returns 409 Conflict if the entity already exists.
     /// </summary>
     public class TableHardwareRejectionNotificationTracker : IHardwareRejectionNotificationTracker
@@ -109,16 +113,102 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
             }
         }
 
+        public async Task<bool> TryRegisterRuleRegressionAsync(string tenantId, RuleRegressionAlert alert)
+        {
+            if (string.IsNullOrWhiteSpace(tenantId) || string.IsNullOrWhiteSpace(alert?.RuleId))
+                return false;
+
+            try
+            {
+                await _table.AddEntityAsync(BuildRuleRegressionEntity(tenantId, alert!));
+                _logger.LogInformation(
+                    "RuleRegression tracker registered: tenant={TenantId} rule={RuleId}", tenantId, alert!.RuleId);
+                return true;
+            }
+            catch (RequestFailedException ex) when (ex.Status == 409)
+            {
+                // Episode already active — one bell per episode.
+                return false;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex,
+                    "RuleRegression tracker failed: tenant={TenantId} rule={RuleId}", tenantId, alert!.RuleId);
+                // Fail closed so we do not double-fire if the row was actually written.
+                return false;
+            }
+        }
+
+        public async Task RefreshRuleRegressionAsync(string tenantId, RuleRegressionAlert alert)
+        {
+            if (string.IsNullOrWhiteSpace(tenantId) || string.IsNullOrWhiteSpace(alert?.RuleId))
+                return;
+            try
+            {
+                // Replace-mode upsert with the FULL payload incl. the caller-carried
+                // FirstNotifiedAt — the retention sweep re-arms on the ORIGINAL age, so a
+                // refresh must never rejuvenate the row.
+                await _table.UpsertEntityAsync(BuildRuleRegressionEntity(tenantId, alert!), TableUpdateMode.Replace);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex,
+                    "RuleRegression tracker refresh failed: tenant={TenantId} rule={RuleId} (stale numbers remain)",
+                    tenantId, alert!.RuleId);
+            }
+        }
+
+        public async Task DeleteRuleRegressionAsync(string tenantId, string ruleId)
+        {
+            if (string.IsNullOrWhiteSpace(tenantId) || string.IsNullOrWhiteSpace(ruleId))
+                return;
+            try
+            {
+                await _table.DeleteEntityAsync(tenantId.ToLowerInvariant(), BuildRuleRegressionRowKey(ruleId));
+            }
+            catch (RequestFailedException ex) when (ex.Status == 404)
+            {
+                // Already gone (retention sweep or concurrent pass) — idempotent.
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex,
+                    "RuleRegression tracker delete failed: tenant={TenantId} rule={RuleId} (episode stays until retention)",
+                    tenantId, ruleId);
+            }
+        }
+
+        public async Task<List<RuleRegressionAlert>> GetRuleRegressionsAsync(string tenantId)
+        {
+            var results = new List<RuleRegressionAlert>();
+            if (string.IsNullOrWhiteSpace(tenantId)) return results;
+            try
+            {
+                var partitionKey = tenantId.ToLowerInvariant();
+                // '}' (0x7D) sorts directly after '|' (0x7C) — prefix range over "ruleregression|…".
+                var filter = $"PartitionKey eq '{partitionKey}' and RowKey ge '{RuleRegressionRowKeyPrefix}' and RowKey lt 'ruleregression}}'";
+                await foreach (var entity in _table.QueryAsync<TableEntity>(filter: filter))
+                {
+                    results.Add(MapToRuleRegressionAlert(entity));
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "RuleRegression tracker list failed for tenant {TenantId}", tenantId);
+            }
+            return results;
+        }
+
         public async Task<int> DeleteOlderThanAsync(DateTime cutoffUtc)
         {
             try
             {
-                // Rows are insert-once (AddEntityAsync, never updated), so FirstNotifiedAt == creation time.
-                // Pruning here resets the lifetime dedup for BOTH key spaces in this table: a hardware
-                // model rejected again after the cutoff rings once more, and so does a TPM-PSS device
-                // that reports again ("tpmpss|{serial}" rows are pruned by the same sweep). Acceptable
-                // in both cases — the portal only surfaces recent rejections anyway, and a device whose
-                // TPM was never fixed is worth surfacing again after a month of silence.
+                // FirstNotifiedAt == the row's first registration (rule-regression refreshes carry
+                // it forward unchanged). Pruning here resets the dedup for EVERY key space in this
+                // table: a hardware model rejected again after the cutoff rings once more, so does
+                // a TPM-PSS device that reports again ("tpmpss|{serial}" rows), and a rule
+                // regression still active after the window fires a fresh bell — a month-old
+                // still-burning regression is worth a reminder (spec §F3 retention re-arm).
                 var filter = $"FirstNotifiedAt lt datetime'{cutoffUtc:yyyy-MM-ddTHH:mm:ss}Z'";
                 var query = _table.QueryAsync<TableEntity>(filter: filter, select: new[] { "PartitionKey", "RowKey" });
 
@@ -160,5 +250,72 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
             var sn = (serialNumber ?? string.Empty).Trim().ToLowerInvariant();
             return $"tpmpss|{sn}";
         }
+
+        internal const string RuleRegressionRowKeyPrefix = "ruleregression|";
+
+        internal static string BuildRuleRegressionRowKey(string ruleId)
+        {
+            var id = (ruleId ?? string.Empty).Trim().ToLowerInvariant();
+            return $"{RuleRegressionRowKeyPrefix}{id}";
+        }
+
+        // internal static: entity builder + mapper are pinned by round-trip unit tests
+        // (table-storage-serialization rule — every property must survive Store→Map).
+        internal static TableEntity BuildRuleRegressionEntity(string tenantId, RuleRegressionAlert alert)
+        {
+            var entity = new TableEntity(tenantId.ToLowerInvariant(), BuildRuleRegressionRowKey(alert.RuleId))
+            {
+                ["TenantId"] = tenantId,
+                ["RuleId"] = alert.RuleId,
+                ["RuleTitle"] = alert.RuleTitle ?? string.Empty,
+                ["WindowFireCount"] = alert.WindowFireCount,
+                ["WindowSessionCount"] = alert.WindowSessionCount,
+                ["BaselineFireCount"] = alert.BaselineFireCount,
+                ["BaselineSessionCount"] = alert.BaselineSessionCount,
+                ["WindowRatePct"] = alert.WindowRatePct,
+                ["BaselineRatePct"] = alert.BaselineRatePct,
+                ["WindowStartDate"] = alert.WindowStartDate ?? string.Empty,
+                ["WindowEndDate"] = alert.WindowEndDate ?? string.Empty,
+                ["FirstNotifiedAt"] = alert.FirstNotifiedAt,
+                ["LastEvaluatedAt"] = alert.LastEvaluatedAt,
+            };
+            // Tri-states: absent column = "no claim" — a zero-baseline alert has no finite lift,
+            // and a missing dimension means "no clear concentration", never a guessed one.
+            if (alert.Lift.HasValue)
+                entity["Lift"] = alert.Lift.Value;
+            if (alert.Dimension != null)
+                entity["DimensionJson"] = JsonSerializer.Serialize(alert.Dimension);
+            return entity;
+        }
+
+        internal static RuleRegressionAlert MapToRuleRegressionAlert(TableEntity entity)
+        {
+            RuleRegressionDimension? dimension = null;
+            var dimensionJson = entity.GetString("DimensionJson");
+            if (!string.IsNullOrEmpty(dimensionJson))
+            {
+                try { dimension = JsonSerializer.Deserialize<RuleRegressionDimension>(dimensionJson!); }
+                catch (JsonException) { dimension = null; } // corrupt column — degrade to "no claim"
+            }
+
+            return new RuleRegressionAlert
+            {
+                TenantId = entity.GetString("TenantId") ?? entity.PartitionKey,
+                RuleId = entity.GetString("RuleId") ?? entity.RowKey.Substring(RuleRegressionRowKeyPrefix.Length),
+                RuleTitle = entity.GetString("RuleTitle") ?? string.Empty,
+                WindowFireCount = entity.GetInt32("WindowFireCount") ?? 0,
+                WindowSessionCount = entity.GetInt32("WindowSessionCount") ?? 0,
+                BaselineFireCount = entity.GetInt32("BaselineFireCount") ?? 0,
+                BaselineSessionCount = entity.GetInt32("BaselineSessionCount") ?? 0,
+                WindowRatePct = entity.GetDouble("WindowRatePct") ?? 0,
+                BaselineRatePct = entity.GetDouble("BaselineRatePct") ?? 0,
+                Lift = entity.GetDouble("Lift"),
+                WindowStartDate = entity.GetString("WindowStartDate") ?? string.Empty,
+                WindowEndDate = entity.GetString("WindowEndDate") ?? string.Empty,
+                Dimension = dimension,
+                FirstNotifiedAt = entity.GetDateTimeOffset("FirstNotifiedAt")?.UtcDateTime ?? DateTime.MinValue,
+                LastEvaluatedAt = entity.GetDateTimeOffset("LastEvaluatedAt")?.UtcDateTime ?? DateTime.MinValue,
+            };
+        }
     }
 }

src/Backend/AutopilotMonitor.Functions/DataAccess/TableStorage/TableMaintenanceRepository.cs

@@ -99,6 +99,9 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
         public Task DeleteEventSessionIndexEntryAsync(string tenantId, string sessionId)
             => _storage.DeleteEventSessionIndexEntryAsync(tenantId, sessionId);
 
+        public Task<List<(string TenantId, string SessionId)>> GetAllSessionTombstoneKeysAsync()
+            => _storage.GetAllSessionTombstoneKeysAsync();
+
         /// <summary>
         /// Tenant offboarding cascade-worker session enumerator. Yields one row per session
         /// belonging to <paramref name="tenantId"/>. Storage exceptions are intentionally

src/Backend/AutopilotMonitor.Functions/DataAccess/TableStorage/TableMetricsRepository.cs

@@ -111,5 +111,53 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
 
         public Task<int> DeleteRuleStatsOlderThanAsync(DateTime cutoffDate)
             => _storage.DeleteRuleStatsOlderThanAsync(cutoffDate);
+
+        public Task<SessionTimeBreakdown?> ComputeAndStoreSessionTimeBreakdownAsync(string tenantId, string sessionId)
+            => _storage.ComputeAndStoreSessionTimeBreakdownAsync(tenantId, sessionId);
+
+        public Task<SessionTimeBreakdown?> GetSessionTimeBreakdownAsync(string tenantId, string sessionId)
+            => _storage.GetSessionTimeBreakdownAsync(tenantId, sessionId);
+
+        public Task ResolveEspBlockingForSessionAsync(string tenantId, string sessionId)
+            => _storage.ResolveEspBlockingForSessionAsync(tenantId, sessionId);
+
+        public Task<bool> SaveTimeAttributionAggregateAsync(TimeAttributionDailyAggregate aggregate)
+            => _storage.SaveTimeAttributionAggregateAsync(aggregate);
+
+        public Task<List<TimeAttributionDailyAggregate>> GetTimeAttributionAggregatesAsync(string tenantId, DateTime startDate, DateTime endDate)
+            => _storage.GetTimeAttributionAggregatesAsync(tenantId, startDate, endDate);
+
+        public Task<List<TimeAttributionDailyAggregate>> GetRollingTimeAttributionAggregatesAsync(string tenantId)
+            => _storage.GetRollingTimeAttributionAggregatesAsync(tenantId);
+
+        public Task DeleteTimeAttributionAggregateAsync(string tenantId, string dateKey, string enrollmentClass)
+            => _storage.DeleteTimeAttributionAggregateAsync(tenantId, dateKey, enrollmentClass);
+
+        public Task<int> DeleteTimeAttributionAggregatesOlderThanAsync(DateTime cutoffDate)
+            => _storage.DeleteTimeAttributionAggregatesOlderThanAsync(cutoffDate);
+
+        public Task<DeviceHistory?> GetDeviceHistoryAsync(string tenantId, string serialKey)
+            => _storage.GetDeviceHistoryAsync(tenantId, serialKey);
+
+        public Task<List<DeviceHistory>> GetDeviceHistoriesByTenantAsync(string tenantId)
+            => _storage.GetDeviceHistoriesByTenantAsync(tenantId);
+
+        public Task<bool> UpsertDeviceHistoryAsync(DeviceHistory history)
+            => _storage.UpsertDeviceHistoryAsync(history);
+
+        public Task DeleteDeviceHistoryAsync(string tenantId, string serialKey)
+            => _storage.DeleteDeviceHistoryAsync(tenantId, serialKey);
+
+        public Task<bool> SaveDeviceJourneyAggregateAsync(DeviceJourneyDailyAggregate aggregate)
+            => _storage.SaveDeviceJourneyAggregateAsync(aggregate);
+
+        public Task<List<DeviceJourneyDailyAggregate>> GetDeviceJourneyAggregatesAsync(string tenantId, DateTime startDate, DateTime endDate)
+            => _storage.GetDeviceJourneyAggregatesAsync(tenantId, startDate, endDate);
+
+        public Task DeleteDeviceJourneyAggregateAsync(string tenantId, string dateKey)
+            => _storage.DeleteDeviceJourneyAggregateAsync(tenantId, dateKey);
+
+        public Task<int> DeleteDeviceJourneyAggregatesOlderThanAsync(DateTime cutoffDate)
+            => _storage.DeleteDeviceJourneyAggregatesOlderThanAsync(cutoffDate);
     }
 }

src/Backend/AutopilotMonitor.Functions/DataAccess/TableStorage/TableRuleRepository.cs

@@ -30,6 +30,9 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
         public Task<List<RuleResult>> GetRuleResultsAsync(string tenantId, string sessionId)
             => _storage.GetRuleResultsAsync(tenantId, sessionId);
 
+        public Task<List<string>> GetRuleHitSessionIdsAsync(string tenantId, string ruleId, DateTime sinceUtc, int maxResults = 2000)
+            => _storage.GetRuleHitSessionIdsAsync(tenantId, ruleId, sinceUtc, maxResults);
+
         public Task<bool> StoreGatherRuleAsync(GatherRule rule, string tenantId = "global")
             => _storage.StoreGatherRuleAsync(rule, tenantId);
 

src/Backend/AutopilotMonitor.Functions/DataAccess/TableStorage/TableSessionRepository.cs

@@ -84,7 +84,32 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
             // otherwise a swept-Incomplete session keeps whatever stale live count it had.
             // Idempotent + fail-soft, so the redundancy is cheap.
             if (transitioned && (status == SessionStatus.Succeeded || status == SessionStatus.Failed || status == SessionStatus.Incomplete))
+            {
                 await _storage.ReconcileSessionCountersAsync(tenantId, sessionId);
+                // F1 PR1: same single-writer seam — join the session's app rows against its
+                // latest esp_config_detected lists exactly once, when the event stream is
+                // complete. Positive evidence only (listed ⇒ EspBlocking=true, absent ⇒ stays
+                // unknown). Idempotent + fail-soft like the counter reconcile above.
+                await _storage.ResolveEspBlockingForSessionAsync(tenantId, sessionId);
+
+                // F1 PR2: compute + persist the time-attribution breakdown once, now that the
+                // terminal write stamped CompletedAt/DurationSeconds and the event stream is
+                // complete. Succeeded/Failed only — Incomplete deliberately stores no duration,
+                // so there is no wall clock to partition (the compute would no-op anyway; the
+                // gate just saves the point-reads). Fail-soft; the 30d maintenance sweep
+                // self-heals any miss.
+                if (status == SessionStatus.Succeeded || status == SessionStatus.Failed)
+                    await _storage.ComputeAndStoreSessionTimeBreakdownAsync(tenantId, sessionId);
+
+                // F2 PR4: upsert this terminal session into its device's history chain at the
+                // same seam, so the session-detail "Attempt N" banner is fresh rather than a
+                // sweep-cycle old. ALL three terminal statuses — Incomplete is a non-successful
+                // journey attempt, unlike the duration-gated breakdown above. Re-terminal
+                // reclassifications (admin mark, late completion) flow through here too and
+                // update the chain entry's status. Fail-soft + idempotent; the maintenance
+                // sweep self-heals any miss.
+                await _storage.UpdateDeviceHistoryForSessionAsync(tenantId, sessionId);
+            }
 
             return transitioned;
         }
@@ -123,6 +148,14 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
         public Task UpdateSessionImeAgentVersionAsync(string tenantId, string sessionId, string version)
             => _storage.UpdateSessionImeAgentVersionAsync(tenantId, sessionId, version);
 
+        public Task UpdateSessionNetworkLatencyAsync(string tenantId, string sessionId,
+            double avgLatencyMs, int requestCount)
+            => _storage.UpdateSessionNetworkLatencyAsync(tenantId, sessionId, avgLatencyMs, requestCount);
+
+        public Task UpdateSessionConnectionTypeAsync(string tenantId, string sessionId,
+            string connectionType)
+            => _storage.UpdateSessionConnectionTypeAsync(tenantId, sessionId, connectionType);
+
         public Task<List<SessionSummary>> GetSessionsWithEventCountAboveAsync(string tenantId, int threshold)
             => _storage.GetSessionsWithEventCountAboveAsync(tenantId, threshold);
 

src/Backend/AutopilotMonitor.Functions/Functions/Apps/AppsAnalyticsHelper.cs

@@ -141,13 +141,21 @@ namespace AutopilotMonitor.Functions.Functions.Apps
 
             var summaries = allSummaries.Where(s => s.StartedAt >= cutoff).ToList();
 
-            var apps = summaries.GroupBy(s => s.AppName).Select(g =>
+            // F1 PR1 (audit Q3): appId-collision rows merge two distinct apps under one name —
+            // they are excluded from every per-app group and disclosed via collisionExcluded.
+            var collisionExcluded = summaries.Count(s => s.AppIdCollision);
+
+            var apps = summaries.Where(s => !s.AppIdCollision).GroupBy(s => s.AppName).Select(g =>
             {
+                // PR0 classification (see MetricsMath.IsSkipTerminalState / HasMeasuredDuration):
+                // skips leave the rate + durations; duration stats read measured rows only.
                 var total = g.Count();
-                var succeeded = g.Count(s => s.Status == "Succeeded");
+                var succeededAll = g.Where(s => s.Status == "Succeeded").ToList();
+                var skipped = succeededAll.Count(MetricsMath.IsSkipTerminalState);
+                var installed = succeededAll.Where(s => !MetricsMath.IsSkipTerminalState(s)).ToList();
+                var measured = installed.Where(MetricsMath.HasMeasuredDuration).ToList();
                 var failed = g.Count(s => s.Status == "Failed");
-                var completed = g.Where(s => s.Status == "Succeeded").ToList();
-                var failureRate = MetricsMath.TerminalFailureRatePct(failed, succeeded);
+                var failureRate = MetricsMath.TerminalFailureRatePct(failed, installed.Count);
 
                 var firstHalf = g.Where(s => s.StartedAt < midpoint).ToList();
                 var secondHalf = g.Where(s => s.StartedAt >= midpoint).ToList();
@@ -158,12 +166,14 @@ namespace AutopilotMonitor.Functions.Functions.Apps
                     appName = g.Key,
                     appType = g.Select(s => s.AppType).FirstOrDefault(t => !string.IsNullOrEmpty(t)) ?? string.Empty,
                     totalInstalls = total,
-                    succeeded,
+                    succeeded = installed.Count,
+                    skipped,
+                    unmeasured = installed.Count - measured.Count,
                     failed,
                     failureRate,
-                    avgDurationSeconds = completed.Count > 0 ? Math.Round(completed.Average(s => s.DurationSeconds), 0) : 0,
-                    maxDurationSeconds = completed.Count > 0 ? completed.Max(s => s.DurationSeconds) : 0,
-                    avgDownloadBytes = completed.Count > 0 ? (long)completed.Average(s => s.DownloadBytes) : 0,
+                    avgDurationSeconds = measured.Count > 0 ? Math.Round(measured.Average(s => s.DurationSeconds), 0) : 0,
+                    maxDurationSeconds = measured.Count > 0 ? measured.Max(s => s.DurationSeconds) : 0,
+                    avgDownloadBytes = measured.Count > 0 ? (long)measured.Average(s => s.DownloadBytes) : 0,
                     trend,
                     trendDelta,
                     lastSeenAt = g.Max(s => s.CompletedAt ?? s.StartedAt)
@@ -182,6 +192,7 @@ namespace AutopilotMonitor.Functions.Functions.Apps
                     success = true,
                     totalApps = apps.Count,
                     totalInstalls = summaries.Count,
+                    collisionExcluded,
                     windowDays = days,
                     apps
                 };
@@ -198,6 +209,7 @@ namespace AutopilotMonitor.Functions.Functions.Apps
                 success = true,
                 totalApps = apps.Count,
                 totalInstalls = summaries.Count,
+                collisionExcluded,
                 windowDays = days,
                 count = page.Count,
                 offset,
@@ -223,11 +235,16 @@ namespace AutopilotMonitor.Functions.Functions.Apps
             var cutoff = now.AddDays(-days);
             var midpoint = now.AddDays(-days / 2.0);
 
-            var summaries = allSummaries
+            var inWindow = allSummaries
                 .Where(s => string.Equals(s.AppName, appName, StringComparison.OrdinalIgnoreCase)
                             && s.StartedAt >= cutoff)
                 .ToList();
 
+            // F1 PR1 (audit Q3): collision rows under this name mix in a second app's outcomes —
+            // excluded from every stat below, disclosed via collisionExcluded.
+            var collisionExcluded = inWindow.Count(s => s.AppIdCollision);
+            var summaries = inWindow.Where(s => !s.AppIdCollision).ToList();
+
             if (summaries.Count == 0)
             {
                 return new
@@ -236,11 +253,14 @@ namespace AutopilotMonitor.Functions.Functions.Apps
                     appName,
                     appType = string.Empty,
                     windowDays = days,
+                    collisionExcluded,
                     bucket = "day",
                     summary = new
                     {
                         totalInstalls = 0,
                         succeeded = 0,
+                        skipped = 0,
+                        unmeasured = 0,
                         failed = 0,
                         failureRate = 0,
                         avgDurationSeconds = 0,
@@ -260,13 +280,17 @@ namespace AutopilotMonitor.Functions.Functions.Apps
             }
 
             var total = summaries.Count;
-            var succeeded = summaries.Count(s => s.Status == "Succeeded");
+            // PR0 classification — skips leave rate + durations; durations read measured rows only.
+            var succeededAll = summaries.Where(s => s.Status == "Succeeded").ToList();
+            var skipped = succeededAll.Count(MetricsMath.IsSkipTerminalState);
+            var installed = succeededAll.Where(s => !MetricsMath.IsSkipTerminalState(s)).ToList();
+            var measured = installed.Where(MetricsMath.HasMeasuredDuration).ToList();
+            var succeeded = installed.Count;
             var failed = summaries.Count(s => s.Status == "Failed");
-            var completed = summaries.Where(s => s.Status == "Succeeded").ToList();
             var failureRate = MetricsMath.TerminalFailureRatePct(failed, succeeded);
-            var avgDurationSeconds = completed.Count > 0 ? Math.Round(completed.Average(s => s.DurationSeconds), 0) : 0;
-            var p95DurationSeconds = Percentile(completed.Select(s => s.DurationSeconds).ToList(), 0.95);
-            var avgDownloadBytes = completed.Count > 0 ? (long)completed.Average(s => s.DownloadBytes) : 0;
+            var avgDurationSeconds = measured.Count > 0 ? Math.Round(measured.Average(s => s.DurationSeconds), 0) : 0;
+            var p95DurationSeconds = Percentile(measured.Select(s => s.DurationSeconds).ToList(), 0.95);
+            var avgDownloadBytes = measured.Count > 0 ? (long)measured.Average(s => s.DownloadBytes) : 0;
 
             // Trend (same rule as list endpoint).
             var firstHalf = summaries.Where(s => s.StartedAt < midpoint).ToList();
@@ -287,7 +311,8 @@ namespace AutopilotMonitor.Functions.Functions.Apps
                 {
                     var vTotal = g.Count();
                     var vFailed = g.Count(s => s.Status == "Failed");
-                    var vSucceeded = g.Count(s => s.Status == "Succeeded");
+                    // Same PR0 convention as the top-level rate: skips are not attempts.
+                    var vSucceeded = g.Count(s => s.Status == "Succeeded" && !MetricsMath.IsSkipTerminalState(s));
                     return new
                     {
                         appVersion = g.Key,
@@ -347,7 +372,8 @@ namespace AutopilotMonitor.Functions.Functions.Apps
                 {
                     var modelTotal = g.Count();
                     var modelFailed = g.Count(x => x.Summary.Status == "Failed");
-                    var modelSucceeded = g.Count(x => x.Summary.Status == "Succeeded");
+                    // PR0 convention: skips are not attempts (same population as the headline rate).
+                    var modelSucceeded = g.Count(x => x.Summary.Status == "Succeeded" && !MetricsMath.IsSkipTerminalState(x.Summary));
                     var modelFailureRate = MetricsMath.TerminalFailureRatePct(modelFailed, modelSucceeded);
                     var lift = failureRate > 0
                         ? Math.Round(modelFailureRate / failureRate, 2)
@@ -373,11 +399,14 @@ namespace AutopilotMonitor.Functions.Functions.Apps
                 appName,
                 appType,
                 windowDays = days,
+                collisionExcluded,
                 bucket,
                 summary = new
                 {
                     totalInstalls = total,
                     succeeded,
+                    skipped,
+                    unmeasured = installed.Count - measured.Count,
                     failed,
                     failureRate,
                     avgDurationSeconds,
@@ -490,10 +519,13 @@ namespace AutopilotMonitor.Functions.Functions.Apps
         private static (string Trend, double? TrendDelta) ComputeFailureTrend(
             List<AppInstallSummary> firstHalf, List<AppInstallSummary> secondHalf)
         {
+            // PR0 convention: skips are not attempts — keep the trend on the same population
+            // as the headline failure rate, or a wave of not-applicable update policies would
+            // fake an "improving" trend.
             var fhFailed = firstHalf.Count(s => s.Status == "Failed");
-            var fhSucceeded = firstHalf.Count(s => s.Status == "Succeeded");
+            var fhSucceeded = firstHalf.Count(s => s.Status == "Succeeded" && !MetricsMath.IsSkipTerminalState(s));
             var shFailed = secondHalf.Count(s => s.Status == "Failed");
-            var shSucceeded = secondHalf.Count(s => s.Status == "Succeeded");
+            var shSucceeded = secondHalf.Count(s => s.Status == "Succeeded" && !MetricsMath.IsSkipTerminalState(s));
             if (fhFailed + fhSucceeded < 5 || shFailed + shSucceeded < 5)
                 return ("stable", null);
 
@@ -531,16 +563,17 @@ namespace AutopilotMonitor.Functions.Functions.Apps
                     var items = kv.Value;
                     var bTotal = items.Count;
                     var bFailed = items.Count(s => s.Status == "Failed");
-                    var bSucceeded = items.Count(s => s.Status == "Succeeded");
-                    var bCompleted = items.Where(s => s.Status == "Succeeded").ToList();
+                    // PR0 convention: skips are not attempts; durations read measured rows only.
+                    var bInstalled = items.Where(s => s.Status == "Succeeded" && !MetricsMath.IsSkipTerminalState(s)).ToList();
+                    var bMeasured = bInstalled.Where(MetricsMath.HasMeasuredDuration).ToList();
                     return (object)new
                     {
                         bucketStart = DateTime.SpecifyKind(kv.Key, DateTimeKind.Utc),
                         installs = bTotal,
-                        succeeded = bSucceeded,
+                        succeeded = bInstalled.Count,
                         failed = bFailed,
-                        failureRate = MetricsMath.TerminalFailureRatePct(bFailed, bSucceeded),
-                        avgDurationSeconds = bCompleted.Count > 0 ? Math.Round(bCompleted.Average(s => s.DurationSeconds), 0) : 0
+                        failureRate = MetricsMath.TerminalFailureRatePct(bFailed, bInstalled.Count),
+                        avgDurationSeconds = bMeasured.Count > 0 ? Math.Round(bMeasured.Average(s => s.DurationSeconds), 0) : 0
                     };
                 })
                 .ToList();

src/Backend/AutopilotMonitor.Functions/Functions/Config/GetAgentConfigFunction.cs

@@ -270,12 +270,13 @@ namespace AutopilotMonitor.Functions.Functions.Config
             var response = req.CreateResponse(HttpStatusCode.OK);
             await response.WriteAsJsonAsync(new AgentConfigResponse
             {
-                ConfigVersion = 35, // MDM reboot-policy watcher (mdm_policy_reboot_required / esp_reboot_coalescing)
+                ConfigVersion = 36, // EnableGatherRuleDebugLog (local gather-rule evaluation trace)
                 UploadIntervalSeconds = 10,
                 SelfDestructOnComplete = tenantConfig.SelfDestructOnComplete ?? true,
                 KeepLogFile = tenantConfig.KeepLogFile ?? false,
                 EnableGeoLocation = tenantConfig.EnableGeoLocation ?? true,
                 EnableImeMatchLog = tenantConfig.EnableImeMatchLog ?? false,
+                EnableGatherRuleDebugLog = tenantConfig.EnableGatherRuleDebugLog ?? false,
                 MaxAuthFailures = tenantConfig.MaxAuthFailures ?? 5,
                 AuthFailureTimeoutMinutes = tenantConfig.AuthFailureTimeoutMinutes ?? 0,
                 LogLevel = tenantConfig.LogLevel ?? "Info",

src/Backend/AutopilotMonitor.Functions/Functions/Infrastructure/AzureMonitorAlertWebhookFunction.cs

@@ -0,0 +1,216 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
+using System.Threading.Tasks;
+using AutopilotMonitor.Functions.Services;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Azure.Functions.Worker.Http;
+using Microsoft.Extensions.Logging;
+
+namespace AutopilotMonitor.Functions.Functions.Infrastructure
+{
+    /// <summary>
+    /// Receives Azure Monitor alert notifications (Common Alert Schema) from an Action Group
+    /// webhook receiver and re-emits them as ops events, so platform alerts flow through the
+    /// same OpsEventService → OpsAlertDispatchService fan-out (Telegram/Teams/Slack providers +
+    /// the portal ops-events list) as every internally raised operational event.
+    ///
+    /// The delivery path is deliberately independent of the portal: Azure Monitor → this
+    /// function → providers. A portal (SWA) outage cannot suppress these notifications — the
+    /// action group's e-mail receiver additionally stays as the backend-independent fallback,
+    /// because a self-hosted channel cannot alert on its own outage.
+    ///
+    /// Security: anonymous route (Action Group webhook receivers can only call a bare URI — no
+    /// custom headers), gated by a shared secret in the query string compared in constant time
+    /// against the OpsAlertWebhookSecret app setting. Fail-closed: while the setting is unset,
+    /// every request is rejected. Dispatch to providers only happens if an enabled ops alert
+    /// rule for EventType "AzureMonitorAlert" matches the mapped severity — the event itself is
+    /// always stored.
+    /// </summary>
+    public class AzureMonitorAlertWebhookFunction
+    {
+        internal const string SecretSettingName = "OpsAlertWebhookSecret";
+
+        // Common Alert Schema payloads for log-search alerts carry the search query, link URLs
+        // and dimension sets — a few KB in practice. 64 KB is a generous shape gate, not a throttle.
+        internal const int MaxContentLength = 64 * 1024;
+
+        private readonly OpsEventService _opsEventService;
+        private readonly ILogger<AzureMonitorAlertWebhookFunction> _logger;
+
+        public AzureMonitorAlertWebhookFunction(
+            OpsEventService opsEventService,
+            ILogger<AzureMonitorAlertWebhookFunction> logger)
+        {
+            _opsEventService = opsEventService;
+            _logger = logger;
+        }
+
+        [Function("AzureMonitorAlertWebhook")]
+        public async Task<HttpResponseData> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "ops/alert-webhook")] HttpRequestData req)
+        {
+            var configuredSecret = Environment.GetEnvironmentVariable(SecretSettingName);
+            var providedSecret = System.Web.HttpUtility.ParseQueryString(req.Url.Query ?? string.Empty)["secret"];
+
+            if (!SecretMatches(providedSecret, configuredSecret))
+            {
+                // Deliberately no detail in the response; the warning makes a misconfigured
+                // (unset) secret operator-visible in the logs.
+                _logger.LogWarning(
+                    "Azure Monitor alert webhook rejected: {Reason}",
+                    string.IsNullOrEmpty(configuredSecret) ? "secret not configured (fail-closed)" : "secret mismatch");
+                return req.CreateResponse(HttpStatusCode.Unauthorized);
+            }
+
+            // Bounded read instead of a Body.Length check: with ASP.NET Core integration the
+            // request body is a forward-only stream whose Length property throws
+            // NotSupportedException. Reading at most cap+1 chars detects oversize without ever
+            // needing to know the total size. (Char-based cap ≈ byte cap for a shape gate.)
+            string body;
+            using (var reader = new StreamReader(req.Body, Encoding.UTF8))
+            {
+                var buffer = new char[MaxContentLength + 1];
+                var read = await reader.ReadBlockAsync(buffer, 0, buffer.Length);
+                if (read > MaxContentLength)
+                {
+                    _logger.LogWarning("Azure Monitor alert webhook rejected: payload exceeds {Cap} char cap", MaxContentLength);
+                    return req.CreateResponse(HttpStatusCode.BadRequest);
+                }
+                body = new string(buffer, 0, read);
+            }
+
+            var alert = TryParse(body);
+            if (alert == null)
+            {
+                _logger.LogWarning("Azure Monitor alert webhook rejected: body is not a Common Alert Schema payload");
+                return req.CreateResponse(HttpStatusCode.BadRequest);
+            }
+
+            await _opsEventService.RecordAzureMonitorAlertAsync(
+                alert.AlertRule,
+                MapSeverity(alert.Severity),
+                alert.MonitorCondition,
+                alert.Description,
+                alert.Severity,
+                alert.MonitoringService,
+                alert.TargetResource,
+                alert.MetricValue);
+
+            _logger.LogInformation(
+                "Azure Monitor alert '{AlertRule}' {Condition} ({Severity}) recorded as ops event",
+                alert.AlertRule, alert.MonitorCondition, alert.Severity);
+
+            return req.CreateResponse(HttpStatusCode.OK);
+        }
+
+        /// <summary>
+        /// Constant-time secret comparison. Fail-closed: an unset/empty configured secret never
+        /// matches anything, so the endpoint stays dark until the app setting is provisioned.
+        /// </summary>
+        internal static bool SecretMatches(string? provided, string? configured)
+        {
+            if (string.IsNullOrEmpty(configured) || string.IsNullOrEmpty(provided))
+                return false;
+
+            return CryptographicOperations.FixedTimeEquals(
+                Encoding.UTF8.GetBytes(provided),
+                Encoding.UTF8.GetBytes(configured));
+        }
+
+        /// <summary>
+        /// Maps Azure Monitor severities (Sev0 = most severe … Sev4 = verbose) onto the ops event
+        /// severity scale. Unknown values fall back to Info so a schema drift can never escalate.
+        /// </summary>
+        internal static string MapSeverity(string? azureSeverity) => azureSeverity switch
+        {
+            "Sev0" => Shared.DataAccess.OpsEventSeverity.Critical,
+            "Sev1" => Shared.DataAccess.OpsEventSeverity.Error,
+            "Sev2" => Shared.DataAccess.OpsEventSeverity.Warning,
+            _ => Shared.DataAccess.OpsEventSeverity.Info,
+        };
+
+        /// <summary>
+        /// Parsed subset of the Common Alert Schema. Only <see cref="AlertRule"/> is mandatory;
+        /// everything else is best-effort so a partial payload still produces a usable ops event.
+        /// </summary>
+        internal sealed record ParsedAlert(
+            string AlertRule,
+            string? Severity,
+            string MonitorCondition,
+            string? Description,
+            string? MonitoringService,
+            string? TargetResource,
+            double? MetricValue);
+
+        /// <summary>
+        /// Defensively extracts data.essentials (+ the first condition's metricValue) from a
+        /// Common Alert Schema payload. Returns null when the body is not JSON or carries no
+        /// alert rule name — the two states in which no meaningful ops event can be formed.
+        /// </summary>
+        internal static ParsedAlert? TryParse(string body)
+        {
+            if (string.IsNullOrWhiteSpace(body))
+                return null;
+
+            try
+            {
+                using var doc = JsonDocument.Parse(body);
+                if (!doc.RootElement.TryGetProperty("data", out var data) ||
+                    !data.TryGetProperty("essentials", out var essentials))
+                    return null;
+
+                var alertRule = GetString(essentials, "alertRule");
+                if (string.IsNullOrWhiteSpace(alertRule))
+                    return null;
+
+                var targetResource = GetString(essentials, "targetResourceName");
+                if (string.IsNullOrEmpty(targetResource) &&
+                    essentials.TryGetProperty("alertTargetIDs", out var targets) &&
+                    targets.ValueKind == JsonValueKind.Array && targets.GetArrayLength() > 0 &&
+                    targets[0].ValueKind == JsonValueKind.String)
+                {
+                    // Fall back to the resource name segment of the first target resource ID.
+                    var id = targets[0].GetString() ?? string.Empty;
+                    targetResource = id[(id.LastIndexOf('/') + 1)..];
+                }
+
+                // Log-search alerts carry the observed value under alertContext.condition.allOf[0].
+                double? metricValue = null;
+                if (data.TryGetProperty("alertContext", out var ctx) &&
+                    ctx.ValueKind == JsonValueKind.Object &&
+                    ctx.TryGetProperty("condition", out var condition) &&
+                    condition.ValueKind == JsonValueKind.Object &&
+                    condition.TryGetProperty("allOf", out var allOf) &&
+                    allOf.ValueKind == JsonValueKind.Array && allOf.GetArrayLength() > 0 &&
+                    allOf[0].ValueKind == JsonValueKind.Object &&
+                    allOf[0].TryGetProperty("metricValue", out var mv) &&
+                    mv.ValueKind == JsonValueKind.Number)
+                {
+                    metricValue = mv.GetDouble();
+                }
+
+                return new ParsedAlert(
+                    alertRule!,
+                    GetString(essentials, "severity"),
+                    GetString(essentials, "monitorCondition") ?? "Fired",
+                    GetString(essentials, "description"),
+                    GetString(essentials, "monitoringService"),
+                    targetResource,
+                    metricValue);
+            }
+            catch (JsonException)
+            {
+                return null;
+            }
+        }
+
+        private static string? GetString(JsonElement element, string property)
+            => element.TryGetProperty(property, out var value) && value.ValueKind == JsonValueKind.String
+                ? value.GetString()
+                : null;
+    }
+}

src/Backend/AutopilotMonitor.Functions/Functions/Metrics/GetDeviceJourneyFunctions.cs

@@ -0,0 +1,358 @@
+using System.Net;
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Shared.DataAccess;
+using AutopilotMonitor.Shared.Models;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Azure.Functions.Worker.Http;
+using Microsoft.Extensions.Logging;
+
+namespace AutopilotMonitor.Functions.Functions.Metrics
+{
+    /// <summary>
+    /// F2 device-history / First-Time-Right read surfaces (insights spec §F2 "Surfaces", PR5).
+    /// All endpoints serve rows the terminal seam + maintenance sweep maintain — the journey
+    /// semantics live server-side (<see cref="DeviceJourneyCalculator"/>); no consumer re-derives
+    /// them. Durations in chain refs are the sessions' authoritative DurationSeconds verbatim.
+    /// </summary>
+    public class GetDeviceHistoryFunction
+    {
+        private readonly ILogger<GetDeviceHistoryFunction> _logger;
+        private readonly IMetricsRepository _metricsRepo;
+        private readonly ISessionRepository _sessionRepo;
+
+        public GetDeviceHistoryFunction(
+            ILogger<GetDeviceHistoryFunction> logger,
+            IMetricsRepository metricsRepo,
+            ISessionRepository sessionRepo)
+        {
+            _logger = logger;
+            _metricsRepo = metricsRepo;
+            _sessionRepo = sessionRepo;
+        }
+
+        /// <summary>
+        /// One device's enrollment history by serial number. history=null is a NORMAL outcome
+        /// (unknown device, junk/placeholder serial, or every ref pruned) — the banner simply
+        /// stays hidden. With ?sessionId= the response additionally carries that session's
+        /// attempt number within its journey (server-computed; works for live sessions too via
+        /// the virtual-attempt rule). Serves the session-detail banner and the MCP tool; a
+        /// Global Admin passes ?tenantId= for cross-tenant reads (TenantScoping.QueryParam),
+        /// with the sessionId-based owner fallback mirroring GetSessionTimeAttribution.
+        /// </summary>
+        [Function("GetDeviceHistory")]
+        public async Task<HttpResponseData> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "metrics/device-history")] HttpRequestData req)
+        {
+            try
+            {
+                // Authentication + MemberRead authorization enforced by PolicyEnforcementMiddleware;
+                // cross-tenant access via TargetTenantId (TenantScoping.QueryParam).
+                var requestCtx = req.GetRequestContext();
+                var query = System.Web.HttpUtility.ParseQueryString(req.Url.Query);
+                var rawSerial = query["serialNumber"];
+                var sessionId = query["sessionId"];
+
+                if (string.IsNullOrWhiteSpace(rawSerial))
+                {
+                    var badRequest = req.CreateResponse(HttpStatusCode.BadRequest);
+                    await badRequest.WriteAsJsonAsync(new { success = false, message = "serialNumber is required" });
+                    return badRequest;
+                }
+
+                // Junk/placeholder serials have no device identity — by design they never have a
+                // chain (disclosed in the fleet aggregate instead), so null here is honest.
+                var serialKey = DeviceJourneyCalculator.NormalizeSerial(rawSerial);
+                var effectiveTenantId = requestCtx.TargetTenantId;
+                var history = serialKey == null
+                    ? null
+                    : await _metricsRepo.GetDeviceHistoryAsync(effectiveTenantId, serialKey);
+
+                // Global-scope fallback (mirrors GetSessionTimeAttribution): a GA/operator opening
+                // a session without an explicit tenantId query param reads their home partition —
+                // resolve the owning tenant via the session and retry once.
+                if (history == null && serialKey != null && requestCtx.HasGlobalScope && !string.IsNullOrEmpty(sessionId))
+                {
+                    var resolvedTenantId = await _sessionRepo.FindSessionTenantIdAsync(sessionId!);
+                    if (resolvedTenantId != null &&
+                        !string.Equals(resolvedTenantId, effectiveTenantId, StringComparison.OrdinalIgnoreCase))
+                    {
+                        effectiveTenantId = resolvedTenantId;
+                        history = await _metricsRepo.GetDeviceHistoryAsync(effectiveTenantId, serialKey);
+                    }
+                }
+
+                // Attempt number for the requesting session — fail-soft: a missing session or an
+                // empty basis yields null, never a guessed position.
+                int? attemptNumber = null;
+                if (history != null && !string.IsNullOrEmpty(sessionId))
+                {
+                    var session = await _sessionRepo.GetSessionAsync(effectiveTenantId, sessionId!);
+                    if (session != null)
+                        attemptNumber = DeviceJourneyCalculator.ComputeAttemptNumber(history.Chain, sessionId!, session.StartedAt);
+                }
+
+                var response = req.CreateResponse(HttpStatusCode.OK);
+                await response.WriteAsJsonAsync(new { success = true, history, attemptNumber });
+                return response;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error fetching device history");
+                var errorResponse = req.CreateResponse(HttpStatusCode.InternalServerError);
+                await errorResponse.WriteAsJsonAsync(new { success = false, message = "Internal server error" });
+                return errorResponse;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Tenant fleet view: daily First-Time-Right rows of the requested window plus their sums,
+    /// the merged attempt histogram, and the "repeat devices" violator list. FTR counts are
+    /// additive, so unlike the median-based time-attribution panel this endpoint honors the
+    /// page's days selector honestly (window rate = sum over daily rows).
+    /// </summary>
+    public class GetDeviceJourneyMetricsFunction
+    {
+        private readonly ILogger<GetDeviceJourneyMetricsFunction> _logger;
+        private readonly IMetricsRepository _metricsRepo;
+        private readonly ISessionRepository _sessionRepo;
+
+        public GetDeviceJourneyMetricsFunction(
+            ILogger<GetDeviceJourneyMetricsFunction> logger,
+            IMetricsRepository metricsRepo,
+            ISessionRepository sessionRepo)
+        {
+            _logger = logger;
+            _metricsRepo = metricsRepo;
+            _sessionRepo = sessionRepo;
+        }
+
+        [Function("GetDeviceJourneyMetrics")]
+        public async Task<HttpResponseData> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "metrics/device-journeys")] HttpRequestData req)
+        {
+            try
+            {
+                // Authentication + MemberRead authorization enforced by PolicyEnforcementMiddleware
+                var tenantId = TenantHelper.GetTenantId(req);
+                var query = System.Web.HttpUtility.ParseQueryString(req.Url.Query);
+                var days = DeviceJourneyMetricsResponse.ClampDays(query["days"]);
+
+                var response = req.CreateResponse(HttpStatusCode.OK);
+                await response.WriteAsJsonAsync(await DeviceJourneyMetricsResponse.BuildAsync(
+                    _metricsRepo, _sessionRepo, tenantId, days, includeRepeatDevices: true));
+                return response;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error fetching device journey metrics");
+                var errorResponse = req.CreateResponse(HttpStatusCode.InternalServerError);
+                await errorResponse.WriteAsJsonAsync(new { success = false, message = "Internal server error" });
+                return errorResponse;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Global-admin variant: tenantId filters to one tenant (full response incl. repeat
+    /// devices); absent = the cross-tenant "global" aggregate rows, WITHOUT a repeat-devices
+    /// list — that would require scanning every tenant's DeviceHistories partition, and the
+    /// aggregated view has no per-device drill anyway. repeatDevices=null discloses the gap.
+    /// </summary>
+    public class GetGlobalDeviceJourneyMetricsFunction
+    {
+        private readonly ILogger<GetGlobalDeviceJourneyMetricsFunction> _logger;
+        private readonly IMetricsRepository _metricsRepo;
+        private readonly ISessionRepository _sessionRepo;
+
+        public GetGlobalDeviceJourneyMetricsFunction(
+            ILogger<GetGlobalDeviceJourneyMetricsFunction> logger,
+            IMetricsRepository metricsRepo,
+            ISessionRepository sessionRepo)
+        {
+            _logger = logger;
+            _metricsRepo = metricsRepo;
+            _sessionRepo = sessionRepo;
+        }
+
+        [Function("GetGlobalDeviceJourneyMetrics")]
+        public async Task<HttpResponseData> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "global/metrics/device-journeys")] HttpRequestData req)
+        {
+            try
+            {
+                // Authentication + GlobalReadOrAdmin authorization enforced by PolicyEnforcementMiddleware
+                var query = System.Web.HttpUtility.ParseQueryString(req.Url.Query);
+                var tenantIdFilter = query["tenantId"];
+                var days = DeviceJourneyMetricsResponse.ClampDays(query["days"]);
+                var partition = string.IsNullOrWhiteSpace(tenantIdFilter) ? "global" : tenantIdFilter!;
+
+                var response = req.CreateResponse(HttpStatusCode.OK);
+                await response.WriteAsJsonAsync(await DeviceJourneyMetricsResponse.BuildAsync(
+                    _metricsRepo, _sessionRepo, partition, days, includeRepeatDevices: partition != "global"));
+                return response;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error fetching global device journey metrics");
+                var errorResponse = req.CreateResponse(HttpStatusCode.InternalServerError);
+                await errorResponse.WriteAsJsonAsync(new { success = false, message = "Internal server error" });
+                return errorResponse;
+            }
+        }
+    }
+
+    /// <summary>Shared response shape for the tenant and global variants (mirrors TimeAttributionResponse).</summary>
+    internal static class DeviceJourneyMetricsResponse
+    {
+        internal const int DefaultWindowDays = 30;
+        internal const int MaxWindowDays = 180; // aggregate retention — older rows no longer exist
+        internal const int MaxRepeatDevices = 10;
+
+        internal static int ClampDays(string? raw)
+        {
+            if (!int.TryParse(raw, out var days)) return DefaultWindowDays;
+            return Math.Clamp(days, 1, MaxWindowDays);
+        }
+
+        /// <summary>
+        /// "Last N days" = exactly N calendar day keys including today — both range ends are
+        /// inclusive, so subtracting the full N would return N+1 days (Codex review: days=1
+        /// summed yesterday AND today).
+        /// </summary>
+        internal static DateTime InclusiveWindowStart(DateTime today, int days) => today.AddDays(-(days - 1));
+
+        internal static async Task<object> BuildAsync(
+            IMetricsRepository metricsRepo, ISessionRepository sessionRepo,
+            string partition, int days, bool includeRepeatDevices)
+        {
+            var today = DateTime.UtcNow.Date;
+            var daily = await metricsRepo.GetDeviceJourneyAggregatesAsync(partition, InclusiveWindowStart(today, days), today);
+            var totals = SumAggregates(daily);
+
+            List<object>? repeatDevices = null;
+            if (includeRepeatDevices)
+            {
+                var histories = await metricsRepo.GetDeviceHistoriesByTenantAsync(partition);
+                var candidates = SelectRepeatDevices(histories, today.AddDays(-days));
+                repeatDevices = new List<object>(candidates.Count);
+                foreach (var candidate in candidates)
+                {
+                    // Failure reason of the newest failed attempt — a bounded point-read per top
+                    // row (≤10), fail-soft: an unreadable/deleted session just leaves it empty.
+                    var lastFailureReason = string.Empty;
+                    if (candidate.NewestFailed != null)
+                    {
+                        try
+                        {
+                            var failedSession = await sessionRepo.GetSessionAsync(partition, candidate.NewestFailed.SessionId);
+                            lastFailureReason = failedSession?.FailureReason ?? string.Empty;
+                        }
+                        catch
+                        {
+                            // fail-soft — the row renders without a reason
+                        }
+                    }
+                    repeatDevices.Add(new
+                    {
+                        serialNumber = candidate.History.SerialNumber,
+                        manufacturer = candidate.History.Manufacturer,
+                        model = candidate.History.Model,
+                        attempts = candidate.History.CurrentJourneyAttempts,
+                        journeyCount = candidate.History.JourneyCount,
+                        lastStatus = candidate.Newest.Status,
+                        lastSessionId = candidate.Newest.SessionId,
+                        lastStartedAt = candidate.Newest.StartedAt,
+                        lastFailureReason,
+                    });
+                }
+            }
+
+            return new
+            {
+                success = true,
+                windowDays = days,
+                totals,
+                daily = daily.OrderBy(d => d.Date, StringComparer.Ordinal).ToList(),
+                repeatDevices,
+            };
+        }
+
+        /// <summary>Window totals (serialized camelCase by the worker's global serializer, like the model rows).</summary>
+        internal sealed class DeviceJourneyWindowTotals
+        {
+            public int CompletedJourneys { get; init; }
+            public int FirstTimeRight { get; init; }
+
+            /// <summary>Null with zero completed journeys — no rate claim, never 0 (truthfulness rule 1).</summary>
+            public double? FtrRatePct { get; init; }
+
+            public int ExcludedSessions { get; init; }
+            public List<DeviceJourneyAttemptBucket> AttemptHistogram { get; init; } = new();
+        }
+
+        /// <summary>
+        /// Window sums over the daily rows — honest because every field is an additive count
+        /// (rule: the FTR window rate IS the ratio of summed counts). internal static: pinned
+        /// by unit tests.
+        /// </summary>
+        internal static DeviceJourneyWindowTotals SumAggregates(IReadOnlyList<DeviceJourneyDailyAggregate> daily)
+        {
+            var completed = daily.Sum(d => d.CompletedJourneyCount);
+            var firstTimeRight = daily.Sum(d => d.FirstTimeRightCount);
+            return new DeviceJourneyWindowTotals
+            {
+                CompletedJourneys = completed,
+                FirstTimeRight = firstTimeRight,
+                FtrRatePct = completed > 0 ? Math.Round(firstTimeRight * 100.0 / completed, 1) : null,
+                ExcludedSessions = daily.Sum(d => d.ExcludedSessionCount),
+                AttemptHistogram = daily
+                    .SelectMany(d => d.AttemptHistogram)
+                    .GroupBy(b => b.Attempts)
+                    .Select(g => new DeviceJourneyAttemptBucket { Attempts = g.Key, JourneyCount = g.Sum(b => b.JourneyCount) })
+                    .OrderBy(b => b.Attempts)
+                    .ToList(),
+            };
+        }
+
+        internal sealed class RepeatDeviceCandidate
+        {
+            public DeviceHistory History { get; init; } = null!;
+            public DeviceSessionRef Newest { get; init; } = null!;
+            public DeviceSessionRef? NewestFailed { get; init; }
+        }
+
+        /// <summary>
+        /// Violator selection (spec: "repeat devices" table): devices whose LAST journey took
+        /// ≥2 attempts and whose newest terminal session falls inside the window — current pain,
+        /// not ancient history (a device that retried long ago but enrolls cleanly today does
+        /// not belong on a violator list). Ordered by attempts desc, then recency; capped at
+        /// <see cref="MaxRepeatDevices"/>. internal static: pinned by unit tests.
+        /// </summary>
+        internal static List<RepeatDeviceCandidate> SelectRepeatDevices(
+            IReadOnlyList<DeviceHistory> histories, DateTime windowStartUtc)
+        {
+            var candidates = new List<RepeatDeviceCandidate>();
+            foreach (var history in histories)
+            {
+                if (history.CurrentJourneyAttempts < 2 || history.Chain.Count == 0)
+                    continue;
+                var newest = history.Chain[history.Chain.Count - 1];
+                if (newest.StartedAt < windowStartUtc)
+                    continue;
+                candidates.Add(new RepeatDeviceCandidate
+                {
+                    History = history,
+                    Newest = newest,
+                    NewestFailed = history.Chain.LastOrDefault(r =>
+                        string.Equals(r.Status, nameof(SessionStatus.Failed), StringComparison.OrdinalIgnoreCase)),
+                });
+            }
+            return candidates
+                .OrderByDescending(c => c.History.CurrentJourneyAttempts)
+                .ThenByDescending(c => c.Newest.StartedAt)
+                .Take(MaxRepeatDevices)
+                .ToList();
+        }
+    }
+}

src/Backend/AutopilotMonitor.Functions/Functions/Metrics/GetGeographicMetricsFunction.cs

@@ -153,6 +153,18 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                     .Where(s => appsBySession.ContainsKey(s.SessionId))
                     .Count(s => appsBySession[s.SessionId].Any(a => a.DoDownloadMode >= 0));
 
+                // Agent→backend API latency: weight each session's stored average by its request
+                // count so the location figure equals Σ(latency·requests)/Σ(requests) — the exact
+                // whole-population average, not an average of session averages. Sessions from
+                // agents predating the feature carry no data and drop out.
+                var latencySessions = group
+                    .Where(s => s.AvgApiLatencyMs is > 0 && s.ApiRequestCount is > 0)
+                    .ToList();
+                var latencyRequestSum = latencySessions.Sum(s => (double)s.ApiRequestCount!.Value);
+                var avgApiLatency = latencyRequestSum > 0
+                    ? latencySessions.Sum(s => s.AvgApiLatencyMs!.Value * s.ApiRequestCount!.Value) / latencyRequestSum
+                    : 0;
+
                 locations.Add(new LocationMetrics
                 {
                     LocationKey = group.Key,
@@ -171,6 +183,8 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                     MinutesPerApp = Math.Round(minutesPerApp, 2),
                     AvgThroughputBytesPerSec = Math.Round(avgThroughput, 0),
                     TotalDownloadBytes = totalBytes,
+                    AvgApiLatencyMs = Math.Round(avgApiLatency, 0),
+                    ApiLatencySessionCount = latencySessions.Count,
                     // Delivery Optimization
                     DoSessionCount = doSessionCount,
                     AvgDoPercentPeerCaching = Math.Round(doAgg.PercentPeerCaching, 1),
@@ -202,6 +216,17 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                 .Select(l => l.AvgThroughputBytesPerSec).ToList();
             var globalAvgThroughput = allThroughputs.Count > 0 ? allThroughputs.Average() : 0;
 
+            // Global API latency: request-weighted over ALL geo sessions (not location averages),
+            // so big sites weigh in proportionally — same Σ(latency·requests)/Σ(requests) math as
+            // the per-location figure.
+            var globalLatencySessions = geoSessions
+                .Where(s => s.AvgApiLatencyMs is > 0 && s.ApiRequestCount is > 0)
+                .ToList();
+            var globalLatencyRequestSum = globalLatencySessions.Sum(s => (double)s.ApiRequestCount!.Value);
+            var globalAvgApiLatency = globalLatencyRequestSum > 0
+                ? globalLatencySessions.Sum(s => s.AvgApiLatencyMs!.Value * s.ApiRequestCount!.Value) / globalLatencyRequestSum
+                : 0;
+
             // Global DO metrics (weighted by bytes, not simple average)
             var globalDoPeers = locations.Sum(l => l.TotalDoBytesFromPeers);
             var globalDoHttp = locations.Sum(l => l.TotalDoBytesFromHttp);
@@ -219,6 +244,10 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                 loc.ThroughputVsGlobalPct = globalAvgThroughput > 0
                     ? Math.Round((loc.AvgThroughputBytesPerSec - globalAvgThroughput) / globalAvgThroughput * 100, 1) : 0;
 
+                // API latency vs global (positive = slower/farther from the backend region)
+                loc.ApiLatencyVsGlobalPct = globalAvgApiLatency > 0 && loc.AvgApiLatencyMs > 0
+                    ? Math.Round((loc.AvgApiLatencyMs - globalAvgApiLatency) / globalAvgApiLatency * 100, 1) : 0;
+
                 // AppLoadScore: normalize minutesPerApp to global median = 100
                 loc.AppLoadScore = globalMedianMinutesPerApp > 0
                     ? Math.Round(loc.MinutesPerApp / globalMedianMinutesPerApp * 100, 0) : 0;
@@ -243,6 +272,7 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                     AvgMinutesPerApp = Math.Round(globalAvgMinutesPerApp, 2),
                     AvgThroughputBytesPerSec = Math.Round(globalAvgThroughput, 0),
                     StdDevDurationMinutes = Math.Round(globalStdDev, 1),
+                    AvgApiLatencyMs = Math.Round(globalAvgApiLatency, 0),
                     AvgDoPercentPeerCaching = Math.Round(globalDoPct, 1),
                     TotalDoBytesFromPeers = globalDoPeers,
                     TotalDoBytesFromHttp = globalDoHttp

src/Backend/AutopilotMonitor.Functions/Functions/Metrics/GetImeVersionHistoryFunction.cs

@@ -1,6 +1,7 @@
 using System.Net;
 using AutopilotMonitor.Functions.Helpers;
 using AutopilotMonitor.Shared.DataAccess;
+using AutopilotMonitor.Shared.Models;
 using Microsoft.Azure.Functions.Worker;
 using Microsoft.Azure.Functions.Worker.Http;
 using Microsoft.Extensions.Logging;
@@ -34,24 +35,7 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                 var versions = await _sessionRepo.GetImeVersionHistoryAsync();
 
                 var response = req.CreateResponse(HttpStatusCode.OK);
-
-                if (requestCtx.HasGlobalScope)
-                {
-                    await response.WriteAsJsonAsync(versions);
-                }
-                else
-                {
-                    // Strip sensitive cross-tenant data for non-Global Admins
-                    var redacted = versions.Select(v => new
-                    {
-                        v.Version,
-                        v.FirstSeenAt,
-                        v.LastSeenAt,
-                        v.SessionCount
-                    });
-                    await response.WriteAsJsonAsync(redacted);
-                }
-
+                await response.WriteAsJsonAsync(BuildResponsePayload(versions, requestCtx.HasGlobalScope));
                 return response;
             }
             catch (Exception ex)
@@ -62,5 +46,35 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                 return errorResponse;
             }
         }
+
+        /// <summary>
+        /// Projects the archive for the caller's scope.
+        ///
+        /// Extracted from <see cref="Run"/> so the cross-tenant redaction boundary is
+        /// directly testable: this suite has no HTTP-level harness, so an inline projection
+        /// is unreachable from a test — and an unguarded redaction is exactly what a later
+        /// refactor opens silently.
+        ///
+        /// FirstSeenTenantId and FirstSeenSessionId name ANOTHER tenant's device and are
+        /// dropped for non-global callers. Version, dates and SessionCount deliberately stay:
+        /// the archive is a platform-wide view of Microsoft's IME rollout, and the route is
+        /// MemberRead precisely so any tenant member can read that view.
+        ///
+        /// Returned as <see cref="object"/> on purpose — System.Text.Json serializes an
+        /// `object` declared type using the RUNTIME type, so both branches keep the exact
+        /// wire format they had while the projection was inline.
+        /// </summary>
+        public static object BuildResponsePayload(
+            IEnumerable<ImeVersionHistoryEntry> versions, bool hasGlobalScope)
+        {
+            if (hasGlobalScope)
+            {
+                return versions.ToList();
+            }
+
+            return versions
+                .Select(v => new { v.Version, v.FirstSeenAt, v.LastSeenAt, v.SessionCount })
+                .ToList();
+        }
     }
 }

src/Backend/AutopilotMonitor.Functions/Functions/Metrics/GetTimeAttributionFunctions.cs

@@ -0,0 +1,196 @@
+using System.Net;
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Shared.DataAccess;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Azure.Functions.Worker.Http;
+using Microsoft.Extensions.Logging;
+
+namespace AutopilotMonitor.Functions.Functions.Metrics
+{
+    /// <summary>
+    /// F1 time-attribution read surfaces (insights spec §F1 "Surfaces", PR3). All three
+    /// endpoints serve PRE-COMPUTED rows — the per-session breakdown written at the terminal
+    /// transition and the aggregate rows the maintenance sweep maintains. No request-time
+    /// derivation: what the calculator computed is what every consumer (web, MCP) sees.
+    /// </summary>
+    public class GetSessionTimeAttributionFunction
+    {
+        private readonly ILogger<GetSessionTimeAttributionFunction> _logger;
+        private readonly IMetricsRepository _metricsRepo;
+        private readonly ISessionRepository _sessionRepo;
+
+        public GetSessionTimeAttributionFunction(
+            ILogger<GetSessionTimeAttributionFunction> logger,
+            IMetricsRepository metricsRepo,
+            ISessionRepository sessionRepo)
+        {
+            _logger = logger;
+            _metricsRepo = metricsRepo;
+            _sessionRepo = sessionRepo;
+        }
+
+        /// <summary>
+        /// Per-session breakdown for the session-detail attribution lane. A missing row is a
+        /// NORMAL outcome (pre-feature session, non-terminal, Incomplete — no wall clock) and
+        /// returns success with breakdown=null so the UI simply omits the lane.
+        /// </summary>
+        [Function("GetSessionTimeAttribution")]
+        public async Task<HttpResponseData> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "sessions/{sessionId}/time-attribution")] HttpRequestData req,
+            string sessionId)
+        {
+            try
+            {
+                // Authentication + MemberRead authorization enforced by PolicyEnforcementMiddleware;
+                // cross-tenant access via TargetTenantId (TenantScoping.QueryParam).
+                var requestCtx = req.GetRequestContext();
+
+                var breakdown = await _metricsRepo.GetSessionTimeBreakdownAsync(requestCtx.TargetTenantId, sessionId);
+
+                // Global-scope fallback (mirrors GetSessionEventsFunction): a GA/operator opening
+                // a session without an explicit tenantId query param reads their home partition —
+                // resolve the owning tenant and retry once.
+                if (breakdown == null && requestCtx.HasGlobalScope)
+                {
+                    var resolvedTenantId = await _sessionRepo.FindSessionTenantIdAsync(sessionId);
+                    if (resolvedTenantId != null &&
+                        !string.Equals(resolvedTenantId, requestCtx.TargetTenantId, StringComparison.OrdinalIgnoreCase))
+                    {
+                        breakdown = await _metricsRepo.GetSessionTimeBreakdownAsync(resolvedTenantId, sessionId);
+                    }
+                }
+
+                var response = req.CreateResponse(HttpStatusCode.OK);
+                await response.WriteAsJsonAsync(new { success = true, breakdown });
+                return response;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error fetching time attribution for session {SessionId}", sessionId);
+                var errorResponse = req.CreateResponse(HttpStatusCode.InternalServerError);
+                await errorResponse.WriteAsJsonAsync(new { success = false, message = "Internal server error" });
+                return errorResponse;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Tenant fleet view: the rolling 30-day range statistics per enrollment class (the panel's
+    /// stacked medians + top blocking apps) plus the daily rows for the per-day trend. The range
+    /// window is FIXED at the sweep's 30 days — daily medians cannot be merged into an arbitrary
+    /// range honestly, so no days parameter is offered.
+    /// </summary>
+    public class GetTimeAttributionMetricsFunction
+    {
+        private readonly ILogger<GetTimeAttributionMetricsFunction> _logger;
+        private readonly IMetricsRepository _metricsRepo;
+
+        public GetTimeAttributionMetricsFunction(
+            ILogger<GetTimeAttributionMetricsFunction> logger,
+            IMetricsRepository metricsRepo)
+        {
+            _logger = logger;
+            _metricsRepo = metricsRepo;
+        }
+
+        [Function("GetTimeAttributionMetrics")]
+        public async Task<HttpResponseData> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "metrics/time-attribution")] HttpRequestData req)
+        {
+            try
+            {
+                // Authentication + MemberRead authorization enforced by PolicyEnforcementMiddleware
+                var tenantId = TenantHelper.GetTenantId(req);
+                var response = req.CreateResponse(HttpStatusCode.OK);
+                await response.WriteAsJsonAsync(await TimeAttributionResponse.BuildAsync(_metricsRepo, tenantId));
+                return response;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error fetching time attribution metrics");
+                var errorResponse = req.CreateResponse(HttpStatusCode.InternalServerError);
+                await errorResponse.WriteAsJsonAsync(new { success = false, message = "Internal server error" });
+                return errorResponse;
+            }
+        }
+    }
+
+    /// <summary>Global-admin variant: tenantId filters to one tenant; absent = cross-tenant "global" rows.</summary>
+    public class GetGlobalTimeAttributionMetricsFunction
+    {
+        private readonly ILogger<GetGlobalTimeAttributionMetricsFunction> _logger;
+        private readonly IMetricsRepository _metricsRepo;
+
+        public GetGlobalTimeAttributionMetricsFunction(
+            ILogger<GetGlobalTimeAttributionMetricsFunction> logger,
+            IMetricsRepository metricsRepo)
+        {
+            _logger = logger;
+            _metricsRepo = metricsRepo;
+        }
+
+        [Function("GetGlobalTimeAttributionMetrics")]
+        public async Task<HttpResponseData> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "global/metrics/time-attribution")] HttpRequestData req)
+        {
+            try
+            {
+                // Authentication + GlobalReadOrAdmin authorization enforced by PolicyEnforcementMiddleware
+                var query = System.Web.HttpUtility.ParseQueryString(req.Url.Query);
+                var tenantIdFilter = query["tenantId"];
+                var partition = string.IsNullOrWhiteSpace(tenantIdFilter) ? "global" : tenantIdFilter!;
+
+                var response = req.CreateResponse(HttpStatusCode.OK);
+                await response.WriteAsJsonAsync(await TimeAttributionResponse.BuildAsync(_metricsRepo, partition));
+                return response;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error fetching global time attribution metrics");
+                var errorResponse = req.CreateResponse(HttpStatusCode.InternalServerError);
+                await errorResponse.WriteAsJsonAsync(new { success = false, message = "Internal server error" });
+                return errorResponse;
+            }
+        }
+    }
+
+    /// <summary>Shared response shape for the tenant and global variants (mirrors the MetricsMath single-source pattern).</summary>
+    internal static class TimeAttributionResponse
+    {
+        internal const int WindowDays = 30;
+
+        /// <summary>
+        /// Rolling rows are rewritten by every 2h sweep as long as the partition has window
+        /// sessions; a partition that went fully quiet stops being rewritten, so its rows would
+        /// otherwise serve arbitrarily old numbers as "last 30 days" (Codex review). 48h
+        /// tolerates a full day of sweep outage before the panel honestly goes empty.
+        /// </summary>
+        internal static readonly TimeSpan RollingMaxAge = TimeSpan.FromHours(48);
+
+        /// <summary>
+        /// "Last N days" = exactly N calendar day keys including today — both range ends are
+        /// inclusive, so subtracting the full N would return N+1 days (Codex review).
+        /// </summary>
+        internal static DateTime InclusiveWindowStart(DateTime today, int days) => today.AddDays(-(days - 1));
+
+        internal static async Task<object> BuildAsync(IMetricsRepository metricsRepo, string partition)
+        {
+            var freshCutoff = DateTime.UtcNow - RollingMaxAge;
+            var rolling = (await metricsRepo.GetRollingTimeAttributionAggregatesAsync(partition))
+                .Where(r => r.ComputedAt >= freshCutoff)
+                .ToList();
+            var today = DateTime.UtcNow.Date;
+            var daily = await metricsRepo.GetTimeAttributionAggregatesAsync(partition, InclusiveWindowStart(today, WindowDays), today);
+
+            return new
+            {
+                success = true,
+                windowDays = WindowDays,
+                // Range statistics per enrollment class (never mixed) — the UI gates rendering
+                // at cleanSessionCount >= 20 and shows "insufficient data (n=…)" below it.
+                classes = rolling.OrderBy(r => r.EnrollmentClass, StringComparer.Ordinal).ToList(),
+                daily = daily.OrderBy(d => d.Date, StringComparer.Ordinal).ToList(),
+            };
+        }
+    }
+}

src/Backend/AutopilotMonitor.Functions/Functions/Metrics/RuleStatsFunction.cs

@@ -16,13 +16,16 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
     {
         private readonly ILogger<RuleStatsFunction> _logger;
         private readonly IMetricsRepository _metricsRepo;
+        private readonly IHardwareRejectionNotificationTracker _notificationTracker;
 
         public RuleStatsFunction(
             ILogger<RuleStatsFunction> logger,
-            IMetricsRepository metricsRepo)
+            IMetricsRepository metricsRepo,
+            IHardwareRejectionNotificationTracker notificationTracker)
         {
             _logger = logger;
             _metricsRepo = metricsRepo;
+            _notificationTracker = notificationTracker;
         }
 
         /// <summary>
@@ -81,6 +84,9 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                 var result = new
                 {
                     rules = aggregated,
+                    // F3 PR6: active regression episodes (tracker rows) — the rules-page badge
+                    // and MCP get_rule_stats read them from here. Empty list = nothing regressed.
+                    regressions = await _notificationTracker.GetRuleRegressionsAsync(tenantId),
                     summary = new
                     {
                         totalEvaluations,
@@ -165,6 +171,11 @@ namespace AutopilotMonitor.Functions.Functions.Metrics
                 var result = new
                 {
                     rules = aggregated,
+                    // Regression episodes are tenant-scoped: present when drilling into one
+                    // tenant, empty for the cross-tenant "global" aggregate (no episode there).
+                    regressions = queryTenantId != "global"
+                        ? await _notificationTracker.GetRuleRegressionsAsync(queryTenantId)
+                        : new List<AutopilotMonitor.Shared.Models.RuleRegressionAlert>(),
                     summary = new
                     {
                         totalEvaluations,

src/Backend/AutopilotMonitor.Functions/Functions/Raw/QueryRawSessionsFunction.cs

@@ -130,6 +130,8 @@ namespace AutopilotMonitor.Functions.Functions.Raw
                 filter.IsSelfDeployingProfile = sdp;
             if (int.TryParse(query["rebootCountMin"], out var rcMin)) filter.RebootCountMin = rcMin;
             if (int.TryParse(query["rebootCountMax"], out var rcMax)) filter.RebootCountMax = rcMax;
+            var connectionType = query["connectionType"];
+            if (!string.IsNullOrEmpty(connectionType)) filter.ConnectionType = connectionType;
 
             var callerTenantId = TenantHelper.GetTenantId(req);
 

src/Backend/AutopilotMonitor.Functions/Functions/Sessions/SearchSessionsFunction.cs

@@ -140,6 +140,7 @@ public class SearchSessionsFunction
             ImeAgentVersion = query["imeAgentVersion"],
             AgentVersionPrefix = query["agentVersionPrefix"],
             ImeAgentVersionPrefix = query["imeAgentVersionPrefix"],
+            ConnectionType = query["connectionType"],
             // Limit field is a no-op in the paged path — pagination drives count.
         };
 
@@ -210,6 +211,9 @@ public class SearchSessionsFunction
             if (fields.Contains("imeAgentVersion")) dict["imeAgentVersion"] = s.ImeAgentVersion;
             if (fields.Contains("geoCountry")) dict["geoCountry"] = s.GeoCountry;
             if (fields.Contains("rebootCount")) dict["rebootCount"] = s.RebootCount;
+            if (fields.Contains("avgApiLatencyMs")) dict["avgApiLatencyMs"] = s.AvgApiLatencyMs;
+            if (fields.Contains("apiRequestCount")) dict["apiRequestCount"] = s.ApiRequestCount;
+            if (fields.Contains("connectionType")) dict["connectionType"] = s.ConnectionType;
 
             if (dict.Count == 0)
             {

src/Backend/AutopilotMonitor.Functions/Helpers/DeviceJourneyCalculator.cs

@@ -0,0 +1,244 @@
+using AutopilotMonitor.Shared.Models;
+
+namespace AutopilotMonitor.Functions.Helpers;
+
+/// <summary>
+/// One journey (a single deployment intent for one device): consecutive terminal attempts of a
+/// device key, ended by the first terminal success. Transient grouping result — never persisted.
+/// </summary>
+public sealed class DeviceJourney
+{
+    /// <summary>Terminal session refs of this journey, ordered by StartedAt ascending.</summary>
+    public List<DeviceSessionRef> Attempts { get; } = new();
+
+    /// <summary>True when the journey ended with a terminal success (its last attempt Succeeded).</summary>
+    public bool Completed { get; set; }
+
+    /// <summary>The success ref that completed the journey; null while open/abandoned.</summary>
+    public DeviceSessionRef? CompletingRef => Completed ? Attempts[Attempts.Count - 1] : null;
+}
+
+/// <summary>
+/// Deterministic, I/O-free core of the F2 device-history / First-Time-Right feature
+/// (insights spec §F2 — JourneyVersion 1). Owns the device-key normalization (trim +
+/// case-fold + junk-serial exclusion), the terminal-only chain maintenance (upsert by
+/// sessionId, cap 20 most recent) and the journey grouping:
+/// <list type="bullet">
+/// <item>Terminal set = Succeeded / Failed / Incomplete (production-verified status catalogue).
+/// A WhiteGlove <c>Pending</c> row is an OPEN session — WG part 1 + part 2 share ONE session
+/// row (second-sweep finding), so journeys never stitch WG parts and a WG device still waiting
+/// for its user session leaves the journey open, never failed.</item>
+/// <item>A journey ends with the first terminal SUCCESS; the next session starts a new journey
+/// (redeployment). A gap of &gt; 30 days since the previous terminal session also starts a new
+/// journey (device shelved/repurposed) — production gaps: median 4.9 h, 92 % &lt; 7 d.</item>
+/// <item>Attempt count = terminal sessions in the journey; Incomplete and Failed are
+/// non-successful attempts.</item>
+/// </list>
+/// </summary>
+public static class DeviceJourneyCalculator
+{
+    /// <summary>Bump on any grouping-semantics change so aggregates never mix definitions (truthfulness rule 8).</summary>
+    public const int CurrentVersion = 1;
+
+    /// <summary>Chain cap: the 20 most recent terminal sessions (spec §F2 — journey counts are chain-scoped).</summary>
+    internal const int MaxChainLength = 20;
+
+    /// <summary>New-journey boundary without a prior success. Constant in v1, not a setting (spec §F2).</summary>
+    internal const int JourneyGapDays = 30;
+
+    /// <summary>
+    /// Placeholder serials that are not device identities (spec §F2 + audit Q5: "Unknown" is the
+    /// agent's WMI-failure sentinel). Compared against the NORMALIZED (trimmed, lower-cased)
+    /// serial; anything shorter than 4 characters is junk regardless.
+    /// </summary>
+    private static readonly HashSet<string> JunkSerials = new(StringComparer.Ordinal)
+    {
+        "system serial number",
+        "to be filled by o.e.m.",
+        "default string",
+        "0",
+        "none",
+        "invalid",
+        "unknown",
+    };
+
+    /// <summary>
+    /// Normalizes a raw serial to the device-key form (trim + lower-case invariant) or returns
+    /// null for junk/placeholder serials — excluded devices never enter FTR and never get a
+    /// history chain (the exclusion is disclosed in the daily aggregate instead).
+    /// </summary>
+    public static string? NormalizeSerial(string? rawSerial)
+    {
+        if (string.IsNullOrWhiteSpace(rawSerial)) return null;
+        var normalized = rawSerial.Trim().ToLowerInvariant();
+        if (normalized.Length < 4) return null;
+        if (JunkSerials.Contains(normalized)) return null;
+        return normalized;
+    }
+
+    /// <summary>F2 terminal set — everything else (InProgress, Pending, Stalled, AwaitingUser, Unknown) is an open session.</summary>
+    public static bool IsTerminal(SessionStatus status)
+        => status == SessionStatus.Succeeded || status == SessionStatus.Failed || status == SessionStatus.Incomplete;
+
+    /// <summary>
+    /// Builds the chain ref for a terminal session; null for non-terminal statuses (defense in
+    /// depth — callers gate on <see cref="IsTerminal"/> already). Duration is the session's
+    /// authoritative <c>DurationSeconds</c> verbatim, never CompletedAt − StartedAt.
+    /// </summary>
+    public static DeviceSessionRef? BuildSessionRef(SessionSummary session)
+    {
+        if (!IsTerminal(session.Status)) return null;
+        return new DeviceSessionRef
+        {
+            SessionId = session.SessionId,
+            StartedAt = session.StartedAt,
+            CompletedAt = session.CompletedAt,
+            Status = session.Status.ToString(),
+            EnrollmentType = string.IsNullOrEmpty(session.EnrollmentType) ? "v1" : session.EnrollmentType,
+            IsPreProvisioned = session.IsPreProvisioned,
+            DurationSeconds = session.DurationSeconds,
+            AdminMarked = !string.IsNullOrEmpty(session.AdminMarkedAction),
+        };
+    }
+
+    /// <summary>
+    /// Merges refs into an existing chain: upsert by sessionId (a re-terminal reclassification,
+    /// e.g. Incomplete → Succeeded, replaces the entry), non-terminal refs dropped defensively,
+    /// ordered by StartedAt (tiebreak sessionId, ordinal) and capped to the
+    /// <see cref="MaxChainLength"/> MOST RECENT entries. Pure — inputs are not mutated.
+    /// </summary>
+    public static List<DeviceSessionRef> MergeChain(
+        IReadOnlyList<DeviceSessionRef>? existing, IEnumerable<DeviceSessionRef> updates)
+    {
+        var bySessionId = new Dictionary<string, DeviceSessionRef>(StringComparer.Ordinal);
+        if (existing != null)
+        {
+            foreach (var reference in existing)
+            {
+                if (!string.IsNullOrEmpty(reference.SessionId))
+                    bySessionId[reference.SessionId] = reference;
+            }
+        }
+        foreach (var update in updates)
+        {
+            if (update != null && !string.IsNullOrEmpty(update.SessionId))
+                bySessionId[update.SessionId] = update;
+        }
+
+        return SortAndCap(bySessionId.Values.Where(IsTerminalRef));
+    }
+
+    /// <summary>
+    /// Drops refs whose sessions were deleted (tombstoned or cascaded away) and re-normalizes
+    /// the chain. An empty result means the device has no observable history left — the caller
+    /// deletes the row rather than keeping an empty claim.
+    /// </summary>
+    public static List<DeviceSessionRef> RemoveSessionRefs(
+        IReadOnlyList<DeviceSessionRef> chain, ISet<string> deletedSessionIds)
+        => SortAndCap(chain.Where(r => IsTerminalRef(r) && !deletedSessionIds.Contains(r.SessionId)));
+
+    private static List<DeviceSessionRef> SortAndCap(IEnumerable<DeviceSessionRef> refs)
+    {
+        var sorted = refs
+            .OrderBy(r => r.StartedAt)
+            .ThenBy(r => r.SessionId, StringComparer.Ordinal)
+            .ToList();
+        if (sorted.Count > MaxChainLength)
+            sorted.RemoveRange(0, sorted.Count - MaxChainLength);
+        return sorted;
+    }
+
+    /// <summary>
+    /// A chain entry parses as terminal. Chains only ever receive terminal refs, but the JSON
+    /// column is data, not a proof — parse defensively (wire-type lesson: mirror the canonical
+    /// reader, never assume).
+    /// </summary>
+    private static bool IsTerminalRef(DeviceSessionRef reference)
+        => Enum.TryParse<SessionStatus>(reference.Status, ignoreCase: true, out var status) && IsTerminal(status);
+
+    /// <summary>
+    /// Groups an ordered terminal chain into journeys. The chain is re-sorted defensively;
+    /// non-terminal refs are ignored. See the class doc for the grouping rules.
+    /// </summary>
+    public static List<DeviceJourney> GroupJourneys(IReadOnlyList<DeviceSessionRef> chain)
+    {
+        var ordered = SortAndCap(chain.Where(IsTerminalRef));
+        var journeys = new List<DeviceJourney>();
+        DeviceJourney? current = null;
+        DeviceSessionRef? previous = null;
+
+        foreach (var reference in ordered)
+        {
+            var startNew =
+                current == null
+                || current.Completed
+                // Gap rule: > 30 days between the previous attempt's terminal moment and this
+                // start. CompletedAt is the honest "last seen terminal" timestamp; StartedAt is
+                // the defensive fallback (production: 0 terminal sessions without CompletedAt).
+                || (previous != null && reference.StartedAt - (previous.CompletedAt ?? previous.StartedAt) > TimeSpan.FromDays(JourneyGapDays));
+
+            if (startNew)
+            {
+                current = new DeviceJourney();
+                journeys.Add(current);
+            }
+
+            current!.Attempts.Add(reference);
+            if (string.Equals(reference.Status, nameof(SessionStatus.Succeeded), StringComparison.OrdinalIgnoreCase))
+                current.Completed = true;
+
+            previous = reference;
+        }
+
+        return journeys;
+    }
+
+    /// <summary>
+    /// Derived counts for the history row: journeys in the retained chain and the attempt count
+    /// of the LAST journey (open or completed) — the "Attempt N" the session banner renders.
+    /// </summary>
+    public static (int JourneyCount, int CurrentJourneyAttempts) Derive(IReadOnlyList<DeviceSessionRef> chain)
+    {
+        var journeys = GroupJourneys(chain);
+        if (journeys.Count == 0) return (0, 0);
+        return (journeys.Count, journeys[journeys.Count - 1].Attempts.Count);
+    }
+
+    /// <summary>
+    /// Attempt number of one session within its journey — the "Attempt N for this device" the
+    /// session-detail banner renders, computed server-side so no consumer re-derives journey
+    /// semantics. Terminal sessions sit in the chain and take their real position. A LIVE
+    /// (non-terminal) session is not a chain ref yet, so its position is computed by inserting
+    /// a virtual non-successful attempt at the session's StartedAt — the redeploy rule (a prior
+    /// completed journey starts a new one) and the 30-day gap rule then place it exactly like
+    /// the real ref would land once terminal. Null when the chain gives no basis (empty).
+    /// </summary>
+    public static int? ComputeAttemptNumber(
+        IReadOnlyList<DeviceSessionRef> chain, string sessionId, DateTime sessionStartedAt)
+    {
+        var effectiveChain = chain;
+        if (!chain.Any(r => string.Equals(r.SessionId, sessionId, StringComparison.Ordinal)))
+        {
+            if (chain.Count == 0) return null;
+            // Virtual ref: status is a NON-successful terminal placeholder purely for position
+            // math — it never persists and never marks the journey completed.
+            var virtualRef = new DeviceSessionRef
+            {
+                SessionId = sessionId,
+                StartedAt = sessionStartedAt,
+                Status = nameof(SessionStatus.Failed),
+            };
+            effectiveChain = MergeChain(chain, new[] { virtualRef });
+        }
+
+        foreach (var journey in GroupJourneys(effectiveChain))
+        {
+            for (var i = 0; i < journey.Attempts.Count; i++)
+            {
+                if (string.Equals(journey.Attempts[i].SessionId, sessionId, StringComparison.Ordinal))
+                    return i + 1;
+            }
+        }
+        return null; // session fell off the 20-cap when merged — no honest position claim
+    }
+}

src/Backend/AutopilotMonitor.Functions/Helpers/EspBlockingSets.cs

@@ -0,0 +1,115 @@
+using System.Collections;
+
+namespace AutopilotMonitor.Functions.Helpers;
+
+/// <summary>
+/// Parsed ESP blocking/tracking lists from an <c>esp_config_detected</c> event payload
+/// (agent emitter: <c>EspTrackingInfoProbe</c> → <c>DeviceInfoCollector.CollectEspConfiguration</c>).
+///
+/// Semantics (source-data audit Q2, insights spec §0.5): the lists are a POSITIVE-EVIDENCE set.
+/// An app id found in any list is proven ESP-blocking; an id that is absent is UNKNOWN — never
+/// "not blocking" — because the registry lists grow progressively (one timestamped subkey per
+/// CSP status write), the user-scope <c>S-&lt;SID&gt;</c> lists usually appear only after
+/// sign-in, each list is capped at 50 entries (uncapped totals ride in the <c>espTracked*Count</c>
+/// fields), and MSI ProductCodes / PFNs live in namespaces the IME <c>appId</c> may not match.
+/// Consumers must therefore always use the LATEST payload of a session that carries lists, and
+/// must map "absent" to null/unknown, never to false.
+/// </summary>
+public sealed class EspBlockingSets
+{
+    private readonly HashSet<string> _all;
+
+    private EspBlockingSets(
+        HashSet<string> all,
+        HashSet<string> userWin32AppIds,
+        int listedTotal,
+        bool isTruncated)
+    {
+        _all = all;
+        UserWin32AppIds = userWin32AppIds;
+        ListedCount = listedTotal;
+        IsTruncated = isTruncated;
+    }
+
+    /// <summary>Distinct ids across all four lists (Win32 device+user, MSI, PFN).</summary>
+    public int ListedCount { get; }
+
+    /// <summary>
+    /// True when any <c>espTracked*Count</c> exceeds its emitted list length — the 50-per-category
+    /// cap dropped entries, so even the positive evidence is incomplete for that category.
+    /// </summary>
+    public bool IsTruncated { get; }
+
+    /// <summary>
+    /// The user-scope Win32 subset (<c>espTrackedUserWin32AppIds</c>). Usually empty until the
+    /// agent-side re-emit fix ships (audit Q2) — exposed so callers can label user-ESP coverage
+    /// as unknown rather than inferring it from the merged list.
+    /// </summary>
+    public IReadOnlyCollection<string> UserWin32AppIds { get; }
+
+    /// <summary>Positive-evidence membership test (case-insensitive, all four lists).</summary>
+    public bool Contains(string? appId)
+        => !string.IsNullOrEmpty(appId) && _all.Contains(appId!);
+
+    /// <summary>
+    /// Parses the payload of one <c>esp_config_detected</c> event. Returns null when the payload
+    /// carries none of the <c>espTracked*</c> list keys (probe found no Diagnostics key — e.g.
+    /// non-Autopilot device or pre-list agent build): "no lists observed" must stay
+    /// distinguishable from "empty lists observed".
+    /// Handles both value shapes: live-ingest / storage-rehydrated data (<c>List&lt;object&gt;</c>
+    /// via EventDataNormalizer) and test fixtures (<c>string[]</c> / <c>List&lt;string&gt;</c>).
+    /// </summary>
+    public static EspBlockingSets? FromEventData(IReadOnlyDictionary<string, object>? data)
+    {
+        if (data == null) return null;
+
+        var win32 = ReadStringList(data, "espTrackedWin32AppIds");
+        var userWin32 = ReadStringList(data, "espTrackedUserWin32AppIds");
+        var msi = ReadStringList(data, "espTrackedMsiProductCodes");
+        var pfn = ReadStringList(data, "espTrackedModernAppPfns");
+
+        if (win32 == null && userWin32 == null && msi == null && pfn == null)
+            return null;
+
+        var all = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        foreach (var list in new[] { win32, userWin32, msi, pfn })
+            if (list != null)
+                foreach (var id in list)
+                    all.Add(id);
+
+        var userSet = new HashSet<string>(userWin32 ?? new List<string>(), StringComparer.OrdinalIgnoreCase);
+
+        // The agent emits uncapped distinct totals alongside the capped lists. The Win32 count
+        // covers the merged device+user list; user-Win32 has no own count field.
+        var truncated =
+            CountExceeds(data, "espTrackedWin32Count", win32) ||
+            CountExceeds(data, "espTrackedMsiCount", msi) ||
+            CountExceeds(data, "espTrackedModernCount", pfn);
+
+        return new EspBlockingSets(all, userSet, all.Count, truncated);
+    }
+
+    private static bool CountExceeds(IReadOnlyDictionary<string, object> data, string countKey, List<string>? list)
+    {
+        if (list == null) return false;
+        if (!data.TryGetValue(countKey, out var raw)) return false;
+        return long.TryParse(raw?.ToString(), out var count) && count > list.Count;
+    }
+
+    private static List<string>? ReadStringList(IReadOnlyDictionary<string, object> data, string key)
+    {
+        if (!data.TryGetValue(key, out var raw) || raw == null) return null;
+        // Strings enumerate as chars — exclude explicitly before the IEnumerable fallback.
+        if (raw is string) return null;
+        if (raw is not IEnumerable enumerable) return null;
+
+        var result = new List<string>();
+        foreach (var item in enumerable)
+        {
+            var s = item?.ToString()?.Trim();
+            if (!string.IsNullOrEmpty(s))
+                result.Add(s!);
+        }
+        return result;
+    }
+}

src/Backend/AutopilotMonitor.Functions/Helpers/MetricsMath.cs

@@ -20,6 +20,42 @@ public static class MetricsMath
         return finished > 0 ? Math.Round((double)failed / finished * 100, 1) : 0;
     }
 
+    /// <summary>
+    /// True when the row's terminal state says no real install attempt happened —
+    /// Skipped (not applicable, e.g. WinGet "Update for X" with the target app absent)
+    /// or Postponed. PR0 decision (2026-07-26): such rows are excluded from duration
+    /// statistics AND from the failure/success rate; they are reported as their own
+    /// category instead. Rows written before the TerminalState column existed return
+    /// false here (empty state) — they keep the legacy rate behavior because they
+    /// cannot be reclassified honestly.
+    /// </summary>
+    public static bool IsSkipTerminalState(AppInstallSummary s)
+        => s.TerminalState == "Skipped" || s.TerminalState == "Postponed";
+
+    /// <summary>
+    /// Upper plausibility bound for an observed install duration: 6 h, the agent's default
+    /// max observation lifetime (AgentMaxLifetimeMinutes = 360) — nothing longer can have
+    /// been continuously watched. Rows above it are emission artifacts, not slow installs:
+    /// a batch emission at session end pins CompletedAt far past the real finish (verified
+    /// in production 2026-07-27: app rows carrying 60 175 s in a session whose own wall
+    /// clock was 2 697 s; 490 rows &gt; 6 h overall, worst 117 days — dominating the
+    /// slowest-apps ranking with six-figure averages).
+    /// </summary>
+    public const int MaxPlausibleInstallDurationSeconds = 6 * 3600;
+
+    /// <summary>
+    /// True for a succeeded row whose install duration was actually observed. Zero /
+    /// absent duration on a non-skip succeeded row means the START was never observed
+    /// (agent attach window — audit finding, §0.5 of the insights spec); a duration above
+    /// <see cref="MaxPlausibleInstallDurationSeconds"/> means the END was never observed
+    /// (completion back-stamped at session end). Either way the duration is UNKNOWN —
+    /// averaging zeros understates (measured −18 % in production), averaging back-stamps
+    /// inflates. Duration statistics must only read rows where this is true; everything
+    /// else is reported as "unmeasured".
+    /// </summary>
+    public static bool HasMeasuredDuration(AppInstallSummary s)
+        => s.DurationSeconds > 0 && s.DurationSeconds <= MaxPlausibleInstallDurationSeconds;
+
     /// <summary>
     /// Builds the complete app-metrics response object from a (pre-time-filtered) set of app
     /// install summaries. Single source of truth for both the tenant (<c>metrics/app</c>) and
@@ -36,9 +72,24 @@ public static class MetricsMath
     {
         var summaryList = summaries as IList<AppInstallSummary> ?? summaries.ToList();
 
-        var appGroups = summaryList.GroupBy(s => s.AppName).Select(g =>
+        // F1 PR1 (audit Q3): a name-keyed row that merged two distinct appIds carries an
+        // unattributable status/duration mix — it must not shape any per-app group. Excluded
+        // here with a disclosed count (truthfulness rule 7); the fleet-wide DO rollup below
+        // keeps every row, since transferred bytes are real regardless of identity mixing.
+        var totalCollisionExcluded = summaryList.Count(s => s.AppIdCollision);
+
+        var appGroups = summaryList.Where(s => !s.AppIdCollision).GroupBy(s => s.AppName).Select(g =>
         {
-            var completed = g.Where(s => s.Status == "Succeeded").ToList();
+            // PR0 (2026-07-26) classification — see IsSkipTerminalState / HasMeasuredDuration:
+            //   skipped    = no real install attempt (TerminalState Skipped/Postponed)
+            //   installed  = succeeded rows that are not known skips (includes legacy rows
+            //                without TerminalState — they cannot be reclassified)
+            //   measured   = installed rows with an observed duration — the ONLY duration input
+            //   unmeasured = installed rows whose start was never observed (duration unknown)
+            var succeededAll = g.Where(s => s.Status == "Succeeded").ToList();
+            var skipped = succeededAll.Where(IsSkipTerminalState).ToList();
+            var installed = succeededAll.Where(s => !IsSkipTerminalState(s)).ToList();
+            var measured = installed.Where(HasMeasuredDuration).ToList();
             var failed = g.Where(s => s.Status == "Failed").ToList();
             var total = g.Count();
 
@@ -51,12 +102,16 @@ public static class MetricsMath
             {
                 appName = g.Key,
                 totalInstalls = total,
-                succeeded = completed.Count,
+                succeeded = installed.Count,
+                skipped = skipped.Count,
+                unmeasured = installed.Count - measured.Count,
                 failed = failed.Count,
-                failureRate = TerminalFailureRatePct(failed.Count, completed.Count),
-                avgDurationSeconds = completed.Count > 0 ? Math.Round(completed.Average(s => s.DurationSeconds), 0) : 0,
-                maxDurationSeconds = completed.Count > 0 ? completed.Max(s => s.DurationSeconds) : 0,
-                avgDownloadBytes = completed.Count > 0 ? (long)completed.Average(s => s.DownloadBytes) : 0,
+                // Skips leave the rate (they are not attempts); legacy rows stay in it.
+                failureRate = TerminalFailureRatePct(failed.Count, installed.Count),
+                avgDurationSeconds = measured.Count > 0 ? Math.Round(measured.Average(s => s.DurationSeconds), 0) : 0,
+                maxDurationSeconds = measured.Count > 0 ? measured.Max(s => s.DurationSeconds) : 0,
+                measuredInstalls = measured.Count,
+                avgDownloadBytes = measured.Count > 0 ? (long)measured.Average(s => s.DownloadBytes) : 0,
                 doTotalBytesDownloaded = doG.TotalBytesDownloaded,
                 doBytesFromPeers = doG.BytesFromPeers,
                 doBytesFromCacheServer = doG.BytesFromCacheServer,
@@ -71,8 +126,10 @@ public static class MetricsMath
             };
         }).ToList();
 
+        // Slowest ranking gates on MEASURED installs — an app whose durations were mostly
+        // unobserved must not rank as "fast" on a handful of zeros (audit §0.5).
         var slowestApps = SelectSlowestApps(
-            appGroups, a => a.succeeded, a => (double)a.avgDurationSeconds, minSamples: 3, take: 10);
+            appGroups, a => a.measuredInstalls, a => (double)a.avgDurationSeconds, minSamples: 3, take: 10);
 
         var topFailingApps = appGroups
             .Where(a => a.failed > 0)
@@ -88,6 +145,9 @@ public static class MetricsMath
             success = true,
             totalApps = appGroups.Count,
             totalInstalls = summaryList.Count,
+            totalSkipped = appGroups.Sum(a => a.skipped),
+            totalUnmeasured = appGroups.Sum(a => a.unmeasured),
+            totalCollisionExcluded,
             slowestApps,
             topFailingApps,
             deliveryOptimization = new
@@ -338,6 +398,38 @@ public static class MetricsMath
             .Take(take)
             .ToList();
     }
+
+    /// <summary>
+    /// Wilson score interval (95 % default) for a binomial proportion — the F3 regression
+    /// radar's statistical primitive (insights spec §F3: deterministic, unit-pinned). Bounds
+    /// are clamped to [0,1]; n = 0 yields the uninformative (0,1) so a zero-denominator
+    /// side can never claim separation.
+    /// </summary>
+    public static (double Lower, double Upper) WilsonInterval(int successes, int trials, double z = 1.96)
+    {
+        if (trials <= 0) return (0.0, 1.0);
+        var n = (double)trials;
+        var p = Math.Clamp((double)successes / n, 0.0, 1.0);
+        var z2 = z * z;
+        var denominator = 1.0 + z2 / n;
+        var center = (p + z2 / (2.0 * n)) / denominator;
+        var half = (z / denominator) * Math.Sqrt(p * (1.0 - p) / n + z2 / (4.0 * n * n));
+        return (Math.Max(0.0, center - half), Math.Min(1.0, center + half));
+    }
+
+    /// <summary>
+    /// One-sided two-proportion separation for a rate INCREASE: true when the current
+    /// window's Wilson lower bound lies strictly above the baseline's Wilson upper bound —
+    /// the intervals are disjoint in the regression direction, so the lift is statistically
+    /// real rather than small-n noise (insights spec §F3 detection gate 3).
+    /// </summary>
+    public static bool RateIncreaseSeparated(
+        int windowHits, int windowTrials, int baselineHits, int baselineTrials, double z = 1.96)
+    {
+        var window = WilsonInterval(windowHits, windowTrials, z);
+        var baseline = WilsonInterval(baselineHits, baselineTrials, z);
+        return window.Lower > baseline.Upper;
+    }
 }
 
 /// <summary>

src/Backend/AutopilotMonitor.Functions/Helpers/RuleRegressionRadar.cs

@@ -0,0 +1,255 @@
+using AutopilotMonitor.Shared.Models;
+
+namespace AutopilotMonitor.Functions.Helpers;
+
+/// <summary>One fired regression: a rule whose hit rate rose beyond every gate (see <see cref="RuleRegressionRadar"/>).</summary>
+public sealed class RuleRegressionFinding
+{
+    public string TenantId { get; init; } = string.Empty;
+    public string RuleId { get; init; } = string.Empty;
+    public string RuleTitle { get; init; } = string.Empty;
+    public string Severity { get; init; } = string.Empty;
+    public string Category { get; init; } = string.Empty;
+
+    public int WindowFireCount { get; init; }
+    public int WindowSessionCount { get; init; }
+    public int BaselineFireCount { get; init; }
+    public int BaselineSessionCount { get; init; }
+
+    public double WindowRatePct { get; init; }
+    public double BaselineRatePct { get; init; }
+
+    /// <summary>Window rate ÷ baseline rate, one decimal. Null when the baseline rate is 0 — a NEW signal has no finite lift, and we never invent one.</summary>
+    public double? Lift { get; init; }
+
+    public string WindowStartDate { get; init; } = string.Empty;
+    public string WindowEndDate { get; init; } = string.Empty;
+}
+
+/// <summary>
+/// Deterministic, I/O-free core of the F3 regression radar (insights spec §F3). Detects
+/// "this analyze rule suddenly fires much more often" from the daily <see cref="RuleStatsEntry"/>
+/// rows — RATES, not counts (absolute counts spike with every rollout wave): per (tenant, rule),
+/// hit rate = FireCount ÷ SessionsEvaluated, audit-verified to be session-deduplicated for
+/// analyze rules (gather rules are excluded until their per-batch dedup is fixed — Q6 follow-up,
+/// never silently included with bad math). A regression fires only when ALL hold:
+/// <list type="number">
+/// <item>trailing 7-day window has ≥ 5 hit sessions AND ≥ 20 evaluated sessions;</item>
+/// <item>window rate ≥ 2× the prior 28-day baseline rate;</item>
+/// <item>the Wilson 95 % intervals are disjoint in the increase direction
+/// (<see cref="MetricsMath.RateIncreaseSeparated"/>) — small-n noise never alerts.</item>
+/// </list>
+/// Suppressed (false positives are trust damage on a monitoring product): rules younger than
+/// baseline + window (grace period), rules edited inside the window (edits legitimately change
+/// hit rates), rules without an entity (deleted), and rules with an empty baseline denominator.
+/// </summary>
+public static class RuleRegressionRadar
+{
+    public const int WindowDays = 7;
+    public const int BaselineDays = 28;
+    public const int MinWindowHitSessions = 5;
+    public const int MinWindowSessions = 20;
+    public const double MinLift = 2.0;
+
+    /// <summary>An active alert re-arms once the window rate falls back under 1.5× baseline (spec §F3 suppression).</summary>
+    public const double ReArmLiftFactor = 1.5;
+
+    /// <summary>Dimension-concentration gates: a value must cover ≥5 hit sessions at ≥2× lift, or the alert says "no clear dimension concentration".</summary>
+    public const int MinDimensionSessions = 5;
+    public const double MinDimensionLift = 2.0;
+
+    /// <summary>Rule entity timestamps the suppression gates read (CreatedAt = grace period; UpdatedAt = edit-in-window).</summary>
+    public readonly record struct RuleTimestamps(DateTime CreatedAt, DateTime UpdatedAt);
+
+    /// <summary>
+    /// Evaluates one tenant's analyze-rule stats over the [target − 34d, target] horizon.
+    /// <paramref name="tenantEntries"/> must be the tenant's rows only (no "global" mirror);
+    /// gather rows are ignored defensively. <paramref name="ruleTimestamps"/> maps ruleId →
+    /// entity timestamps — a rule without an entry is suppressed (deleted rules never alert).
+    /// </summary>
+    public static List<RuleRegressionFinding> Evaluate(
+        IReadOnlyList<RuleStatsEntry> tenantEntries,
+        DateTime targetDateUtc,
+        IReadOnlyDictionary<string, RuleTimestamps> ruleTimestamps)
+    {
+        var findings = new List<RuleRegressionFinding>();
+        foreach (var group in AnalyzeRuleGroups(tenantEntries))
+        {
+            var sums = SumWindows(group.Value, targetDateUtc);
+
+            if (sums.WindowFire < MinWindowHitSessions) continue;
+            if (sums.WindowSessions < MinWindowSessions) continue;
+
+            // Entity gates: deleted rules never alert; new rules get the full baseline+window
+            // grace period; an edit inside the window legitimately changes the rate.
+            if (!ruleTimestamps.TryGetValue(group.Key, out var timestamps)) continue;
+            var windowStart = targetDateUtc.Date.AddDays(-(WindowDays - 1));
+            if (timestamps.CreatedAt > targetDateUtc.Date.AddDays(-(WindowDays - 1 + BaselineDays))) continue;
+            if (timestamps.UpdatedAt >= windowStart) continue;
+
+            // No observed baseline denominator (e.g. rule disabled throughout the baseline,
+            // re-enabled recently) — no honest comparison basis.
+            if (sums.BaselineSessions <= 0) continue;
+
+            var windowRate = (double)sums.WindowFire / sums.WindowSessions;
+            var baselineRate = (double)sums.BaselineFire / sums.BaselineSessions;
+            if (windowRate < MinLift * baselineRate) continue;
+            if (!MetricsMath.RateIncreaseSeparated(
+                    sums.WindowFire, sums.WindowSessions, sums.BaselineFire, sums.BaselineSessions))
+                continue;
+
+            var first = group.Value[0];
+            findings.Add(new RuleRegressionFinding
+            {
+                TenantId = first.TenantId,
+                RuleId = group.Key,
+                RuleTitle = first.RuleTitle,
+                Severity = first.Severity,
+                Category = first.Category,
+                WindowFireCount = sums.WindowFire,
+                WindowSessionCount = sums.WindowSessions,
+                BaselineFireCount = sums.BaselineFire,
+                BaselineSessionCount = sums.BaselineSessions,
+                WindowRatePct = Math.Round(windowRate * 100, 1),
+                BaselineRatePct = Math.Round(baselineRate * 100, 1),
+                Lift = baselineRate > 0 ? Math.Round(windowRate / baselineRate, 1) : null,
+                WindowStartDate = windowStart.ToString("yyyy-MM-dd"),
+                WindowEndDate = targetDateUtc.Date.ToString("yyyy-MM-dd"),
+            });
+        }
+        return findings
+            .OrderByDescending(f => f.WindowRatePct)
+            .ThenBy(f => f.RuleId, StringComparer.Ordinal)
+            .ToList();
+    }
+
+    /// <summary>
+    /// True when an ACTIVE alert for this rule may re-arm: nothing fired in the window anymore,
+    /// or the window rate fell back under <see cref="ReArmLiftFactor"/>× the baseline rate.
+    /// A zero-baseline alert ("new signal") re-arms only via the fires-stopped branch — there
+    /// is no rate threshold to fall under.
+    /// </summary>
+    public static bool ShouldReArm(IReadOnlyList<RuleStatsEntry> ruleEntries, DateTime targetDateUtc)
+    {
+        var sums = SumWindows(ruleEntries, targetDateUtc);
+        if (sums.WindowFire == 0) return true;
+        if (sums.BaselineFire <= 0 || sums.BaselineSessions <= 0 || sums.WindowSessions <= 0) return false;
+        var windowRate = (double)sums.WindowFire / sums.WindowSessions;
+        var baselineRate = (double)sums.BaselineFire / sums.BaselineSessions;
+        return windowRate < ReArmLiftFactor * baselineRate;
+    }
+
+    /// <summary>
+    /// The dominant dimension concentration among a regression's hit sessions, or null when no
+    /// dimension value reaches ≥<see cref="MinDimensionLift"/>× lift with
+    /// ≥<see cref="MinDimensionSessions"/> hit sessions — the alert then says
+    /// "no clear dimension concentration" instead of stretching for one (truthfulness rules 1/6).
+    /// Wording contract for consumers: "correlated — not necessarily causal".
+    /// </summary>
+    public static RuleRegressionDimension? ComputeDimensionConcentration(
+        IReadOnlyList<SessionSummary> hitSessions, IReadOnlyList<SessionSummary> allSessions)
+    {
+        if (hitSessions.Count == 0 || allSessions.Count == 0) return null;
+
+        var dimensions = new (string Name, Func<SessionSummary, string?> Selector)[]
+        {
+            ("osBuild", s => s.OsBuild),
+            ("model", s => $"{s.Manufacturer} {s.Model}".Trim()),
+            ("agentVersion", s => s.AgentVersion),
+            ("imeVersion", s => s.ImeAgentVersion),
+        };
+
+        RuleRegressionDimension? best = null;
+        foreach (var (name, selector) in dimensions)
+        {
+            var allCounts = CountValues(allSessions, selector);
+            foreach (var hit in CountValues(hitSessions, selector))
+            {
+                if (hit.Value < MinDimensionSessions) continue;
+                if (!allCounts.TryGetValue(hit.Key, out var allCount) || allCount <= 0) continue;
+
+                var hitShare = (double)hit.Value / hitSessions.Count;
+                var allShare = (double)allCount / allSessions.Count;
+                var lift = hitShare / allShare;
+                if (lift < MinDimensionLift) continue;
+
+                if (best == null || lift > best.Lift || (lift == best.Lift && hit.Value > best.HitCount))
+                {
+                    best = new RuleRegressionDimension
+                    {
+                        Dimension = name,
+                        Value = hit.Key,
+                        HitCount = hit.Value,
+                        HitSharePct = Math.Round(hitShare * 100, 1),
+                        AllSharePct = Math.Round(allShare * 100, 1),
+                        Lift = Math.Round(lift, 1),
+                    };
+                }
+            }
+        }
+        return best;
+    }
+
+    private static Dictionary<string, int> CountValues(
+        IReadOnlyList<SessionSummary> sessions, Func<SessionSummary, string?> selector)
+    {
+        var counts = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
+        foreach (var session in sessions)
+        {
+            var value = selector(session)?.Trim();
+            if (string.IsNullOrEmpty(value)) continue;
+            counts.TryGetValue(value!, out var current);
+            counts[value!] = current + 1;
+        }
+        return counts;
+    }
+
+    /// <summary>Groups a tenant's entries by ruleId, analyze rows only (defensive re-filter).</summary>
+    internal static Dictionary<string, List<RuleStatsEntry>> AnalyzeRuleGroups(IReadOnlyList<RuleStatsEntry> entries)
+    {
+        var groups = new Dictionary<string, List<RuleStatsEntry>>(StringComparer.OrdinalIgnoreCase);
+        foreach (var entry in entries)
+        {
+            if (!string.Equals(entry.RuleType, "analyze", StringComparison.OrdinalIgnoreCase)) continue;
+            if (string.IsNullOrEmpty(entry.RuleId)) continue;
+            if (!groups.TryGetValue(entry.RuleId, out var list))
+            {
+                list = new List<RuleStatsEntry>();
+                groups[entry.RuleId] = list;
+            }
+            list.Add(entry);
+        }
+        return groups;
+    }
+
+    internal readonly record struct WindowSums(int WindowFire, int WindowSessions, int BaselineFire, int BaselineSessions);
+
+    /// <summary>
+    /// Sums one rule's daily rows into the trailing window [target−6d, target] and the prior
+    /// baseline [target−34d, target−7d]. Dates are compared as ISO strings (the rows' own key
+    /// format); rows outside the horizon are ignored.
+    /// </summary>
+    internal static WindowSums SumWindows(IReadOnlyList<RuleStatsEntry> ruleEntries, DateTime targetDateUtc)
+    {
+        var windowStart = targetDateUtc.Date.AddDays(-(WindowDays - 1)).ToString("yyyy-MM-dd");
+        var baselineStart = targetDateUtc.Date.AddDays(-(WindowDays - 1 + BaselineDays)).ToString("yyyy-MM-dd");
+        var target = targetDateUtc.Date.ToString("yyyy-MM-dd");
+
+        int windowFire = 0, windowSessions = 0, baselineFire = 0, baselineSessions = 0;
+        foreach (var entry in ruleEntries)
+        {
+            if (string.CompareOrdinal(entry.Date, target) > 0) continue;
+            if (string.CompareOrdinal(entry.Date, windowStart) >= 0)
+            {
+                windowFire += entry.FireCount;
+                windowSessions += entry.SessionsEvaluated;
+            }
+            else if (string.CompareOrdinal(entry.Date, baselineStart) >= 0)
+            {
+                baselineFire += entry.FireCount;
+                baselineSessions += entry.SessionsEvaluated;
+            }
+        }
+        return new WindowSums(windowFire, windowSessions, baselineFire, baselineSessions);
+    }
+}

src/Backend/AutopilotMonitor.Functions/Helpers/TimeAttributionCalculator.cs

@@ -0,0 +1,666 @@
+using System.Globalization;
+using AutopilotMonitor.Shared;
+using AutopilotMonitor.Shared.Models;
+
+namespace AutopilotMonitor.Functions.Helpers;
+
+/// <summary>
+/// Inputs for <see cref="TimeAttributionCalculator.Compute"/> — the session facts the terminal
+/// writer persisted plus the session's full event stream in canonical order.
+/// </summary>
+public sealed class TimeAttributionInput
+{
+    public string TenantId { get; set; } = string.Empty;
+    public string SessionId { get; set; } = string.Empty;
+
+    /// <summary>Session status string. Only "Succeeded" and "Failed" are computable (Incomplete deliberately carries no DurationSeconds).</summary>
+    public string Status { get; set; } = string.Empty;
+
+    public DateTime StartedAt { get; set; }
+    public DateTime? CompletedAt { get; set; }
+
+    /// <summary>
+    /// The session's authoritative duration (second-sweep finding, insights spec §0.5): for
+    /// WhiteGlove it is part 1 + part 2 WITHOUT the pause, and re-terminal stamps move
+    /// CompletedAt — so this is the wall clock, never CompletedAt − StartedAt.
+    /// </summary>
+    public int? DurationSeconds { get; set; }
+
+    public bool IsPreProvisioned { get; set; }
+
+    /// <summary>WhiteGlove part-2 resume timestamp (session row), when present.</summary>
+    public DateTime? ResumedAt { get; set; }
+
+    /// <summary>Session events. Canonical order is Sequence ascending; the calculator re-sorts defensively.</summary>
+    public IReadOnlyList<EnrollmentEvent> Events { get; set; } = Array.Empty<EnrollmentEvent>();
+}
+
+/// <summary>
+/// Deterministic, I/O-free computation of a session's <see cref="SessionTimeBreakdown"/>
+/// (F1, insights spec — AttributionVersion 1). Every number is traceable to observed events;
+/// missing signals produce "unknown"/unattributed, never guesses (truthfulness rules 1/2).
+///
+/// Semantics pinned by the golden-fixture tests:
+/// <list type="bullet">
+/// <item><b>Wall clock = session DurationSeconds.</b> Observation windows are constructed to sum
+/// to it exactly: non-WhiteGlove = [CompletedAt − Duration, CompletedAt]; WhiteGlove = two windows
+/// in ONE session — [part1End − part1, part1End] and [ResumedAt, CompletedAt], where
+/// part1 = Duration − part2 and part1End is anchored on <c>whiteglove_part1_complete</c>.
+/// The pause between the windows is never attributed.</item>
+/// <item><b>Segments from phase-declaration events only</b> (phase strategy: only declaration
+/// events carry Phase != Unknown), bucketed Start/DevicePreparation/DeviceSetup → device_prep,
+/// AppsDevice → esp_apps, AccountSetup + FinalizingSetup → identity_hello, AppsUser → user_esp,
+/// Complete / <c>desktop_arrived</c> → desktop_handoff. A Failed-phase declaration ends
+/// attribution (the tail is unattributed, not relabeled). Anchors that go backward in canonical
+/// order are dropped (<see cref="TimeAttributionFlags.ClockSkewDropped"/>).</item>
+/// <item><b>Exact-partition invariant:</b> span seconds are floored, the remainder —
+/// unattributed holes plus sub-second dust — is reported as UnattributedSeconds, so
+/// sum(spans) + unattributed == wall clock holds exactly and is never normalized.</item>
+/// <item><b>Per-app intervals use event timestamps</b> (first started/download event → LAST
+/// terminal event, covering IME retries) — never the agent payload timing fields, which freeze
+/// at the first terminal transition (audit Q1).</item>
+/// <item><b>Blocking membership is positive evidence</b> from the LATEST
+/// <c>esp_config_detected</c> lists: listed ⇒ blocking; absent ⇒ unknown, never false (audit Q2).
+/// No lists ⇒ <see cref="TimeAttributionFlags.BlockingSetUnknown"/> and occupancy null.</item>
+/// <item><b>Reboot spans from event gaps</b> around the <c>lastBootUtc</c> payload — the
+/// <c>system_reboot_detected</c> event is detection-time-stamped by the next run and never used
+/// as the reboot moment (audit Q7). Reboots are a cross-cutting annotation, not a segment.</item>
+/// </list>
+/// </summary>
+public static class TimeAttributionCalculator
+{
+    /// <summary>Bump on any semantic change so aggregates never mix definitions (truthfulness rule 8).</summary>
+    public const int CurrentVersion = 1;
+
+    /// <summary>
+    /// Enrollment class for fleet aggregation — classes are NEVER mixed in one aggregate (a
+    /// WhiteGlove or WDP flow has a structurally different time profile than user-driven ESP).
+    /// Precedence: WhiteGlove (both parts live in one session row) → Windows Device Preparation
+    /// (EnrollmentType "v2" — different phase machinery) → self-deploying profile → user-driven.
+    /// </summary>
+    public static string GetEnrollmentClass(SessionSummary session)
+    {
+        if (session.IsPreProvisioned) return "whiteglove";
+        if (session.EnrollmentType == "v2") return "device_preparation";
+        if (session.IsSelfDeployingProfile) return "self_deploying";
+        return "user_driven";
+    }
+
+    /// <summary>Cap for the persisted per-app interval list (spec: top 20 by duration + uncapped count).</summary>
+    internal const int MaxBlockingAppIntervals = 20;
+
+    private readonly struct Window
+    {
+        public Window(DateTime start, DateTime end) { Start = start; End = end; }
+        public DateTime Start { get; }
+        public DateTime End { get; }
+    }
+
+    private sealed class Anchor
+    {
+        public DateTime Ts;
+        /// <summary>Segment key, or null = attribution ends here (Failed-phase declaration).</summary>
+        public string? Bucket;
+    }
+
+    private sealed class AppActivity
+    {
+        public string AppId = string.Empty;
+        public string AppName = string.Empty;
+        public DateTime? FirstStart;
+        public DateTime? LastTerminal;
+    }
+
+    /// <summary>
+    /// Returns the breakdown, or null when the session has no computable wall clock
+    /// (non-terminal, Incomplete — which deliberately stores no DurationSeconds — or a
+    /// missing/non-positive duration).
+    /// </summary>
+    public static SessionTimeBreakdown? Compute(TimeAttributionInput input)
+    {
+        if (input.Status != "Succeeded" && input.Status != "Failed") return null;
+        if (!input.CompletedAt.HasValue) return null;
+        if (!input.DurationSeconds.HasValue || input.DurationSeconds.Value <= 0) return null;
+
+        var completedAt = input.CompletedAt.Value;
+        var wallClock = input.DurationSeconds.Value;
+        var flags = TimeAttributionFlags.None;
+
+        // Canonical order (Sequence asc) — the authoritative event order per repo convention.
+        var events = input.Events.OrderBy(e => e.Sequence).ToList();
+
+        var windows = BuildWindows(input, completedAt, wallClock, events, ref flags);
+
+        var anchors = BuildAnchors(events, ref flags);
+        var spans = BuildSegmentSpans(windows, anchors);
+
+        var attributedSeconds = spans.Sum(s => s.Seconds);
+        var unattributed = wallClock - attributedSeconds;
+
+        // Blocking set: latest esp_config_detected emission that carries lists (positive
+        // evidence is never erased by a later probe failure; lists grow progressively).
+        EspBlockingSets? blockingSets = null;
+        for (var i = events.Count - 1; i >= 0 && blockingSets == null; i--)
+        {
+            if (events[i].EventType == Constants.EventTypes.EspConfigDetected)
+                blockingSets = EspBlockingSets.FromEventData(events[i].Data);
+        }
+        if (blockingSets == null || blockingSets.ListedCount == 0)
+            flags |= TimeAttributionFlags.BlockingSetUnknown;
+        else if (blockingSets.IsTruncated)
+            flags |= TimeAttributionFlags.BlockingSetTruncated;
+
+        var (blockingApps, blockingAppCount) = BuildBlockingAppIntervals(events, blockingSets, windows, ref flags);
+
+        int? occupancy = null;
+        if (blockingSets != null && blockingSets.ListedCount > 0)
+        {
+            var espAppsSpans = spans.Where(s => s.SegmentKey == TimeAttributionSegments.EspApps).ToList();
+            occupancy = ComputeOccupancySeconds(blockingApps, espAppsSpans);
+        }
+
+        var rebootSpans = BuildRebootSpans(events, windows, spans);
+
+        if (events.Any(e => e.EventType == Constants.EventTypes.AgentLateStart))
+            flags |= TimeAttributionFlags.PartialObservation;
+
+        return new SessionTimeBreakdown
+        {
+            TenantId = input.TenantId,
+            SessionId = input.SessionId,
+            AttributionVersion = CurrentVersion,
+            WallClockSeconds = wallClock,
+            Segments = spans,
+            UnattributedSeconds = unattributed,
+            RebootSeconds = rebootSpans.Sum(r => r.Seconds),
+            RebootSpans = rebootSpans,
+            BlockingApps = blockingApps
+                .OrderByDescending(a => a.Seconds)
+                .ThenBy(a => a.AppName, StringComparer.OrdinalIgnoreCase)
+                .Take(MaxBlockingAppIntervals)
+                .ToList(),
+            BlockingAppCount = blockingAppCount,
+            EspAppsOccupancySeconds = occupancy,
+            QualityFlags = flags,
+        };
+    }
+
+    // ── observation windows ─────────────────────────────────────────────────
+
+    /// <summary>
+    /// Windows are END-anchored on the authoritative timestamps (CompletedAt; part1End for WG
+    /// part 1) with the start derived so window lengths sum EXACTLY to DurationSeconds — the
+    /// invariant is against the stored duration, not against CompletedAt − StartedAt.
+    /// </summary>
+    private static List<Window> BuildWindows(
+        TimeAttributionInput input, DateTime completedAt, int wallClock,
+        List<EnrollmentEvent> events, ref TimeAttributionFlags flags)
+    {
+        if (input.IsPreProvisioned)
+        {
+            if (input.ResumedAt.HasValue && input.ResumedAt.Value < completedAt)
+            {
+                var resumedAt = input.ResumedAt.Value;
+                // Same truncation the terminal writer used for part2, so part1 comes out as the
+                // exact stored part-1 duration.
+                var part2 = (int)(completedAt - resumedAt).TotalSeconds;
+                var part1 = wallClock - part2;
+                if (part1 > 0)
+                {
+                    var part1End = ResolvePart1End(events, resumedAt, ref flags);
+                    if (part1End.HasValue)
+                    {
+                        var w1Start = part1End.Value.AddSeconds(-part1);
+                        return new List<Window>
+                        {
+                            new Window(w1Start, part1End.Value),
+                            new Window(resumedAt, completedAt),
+                        };
+                    }
+                }
+                // part1 <= 0 (stored duration contradicts the resume stamp) or no usable part-1
+                // anchor: fall through to a single derived window rather than inventing a split.
+            }
+            // WhiteGlove without a resolvable two-window split — the partition is still exact,
+            // but the WG semantics (pause exclusion boundaries) rest on no anchor.
+            flags |= TimeAttributionFlags.WhiteGloveAnchorsIncomplete;
+        }
+
+        return new List<Window> { new Window(completedAt.AddSeconds(-wallClock), completedAt) };
+    }
+
+    /// <summary>
+    /// Part-1 end anchor: the <c>whiteglove_part1_complete</c> event; fallback: the last event
+    /// at/before ResumedAt (flagged — the boundary is then observational, not declarative).
+    /// An anchor after ResumedAt is clamped to ResumedAt (windows must not overlap).
+    /// </summary>
+    private static DateTime? ResolvePart1End(
+        List<EnrollmentEvent> events, DateTime resumedAt, ref TimeAttributionFlags flags)
+    {
+        DateTime? part1End = null;
+        foreach (var evt in events)
+        {
+            if (evt.EventType == Constants.EventTypes.WhiteGlovePart1Complete)
+                part1End = evt.Timestamp;
+        }
+
+        if (!part1End.HasValue)
+        {
+            flags |= TimeAttributionFlags.WhiteGloveAnchorsIncomplete;
+            foreach (var evt in events)
+            {
+                if (evt.Timestamp <= resumedAt &&
+                    (!part1End.HasValue || evt.Timestamp > part1End.Value))
+                {
+                    part1End = evt.Timestamp;
+                }
+            }
+        }
+        else if (part1End.Value > resumedAt)
+        {
+            flags |= TimeAttributionFlags.WhiteGloveAnchorsIncomplete;
+            part1End = resumedAt;
+        }
+
+        return part1End;
+    }
+
+    // ── segment spans ───────────────────────────────────────────────────────
+
+    private static string? MapPhaseToSegment(EnrollmentPhase phase) => phase switch
+    {
+        EnrollmentPhase.Start => TimeAttributionSegments.DevicePrep,
+        EnrollmentPhase.DevicePreparation => TimeAttributionSegments.DevicePrep,
+        EnrollmentPhase.DeviceSetup => TimeAttributionSegments.DevicePrep,
+        EnrollmentPhase.AppsDevice => TimeAttributionSegments.EspApps,
+        EnrollmentPhase.AccountSetup => TimeAttributionSegments.IdentityHello,
+        EnrollmentPhase.AppsUser => TimeAttributionSegments.UserEsp,
+        EnrollmentPhase.FinalizingSetup => TimeAttributionSegments.IdentityHello,
+        EnrollmentPhase.Complete => TimeAttributionSegments.DesktopHandoff,
+        // Failed: attribution ends — the post-failure tail stays unattributed rather than
+        // being relabeled into a segment no phase ever declared.
+        EnrollmentPhase.Failed => null,
+        _ => null,
+    };
+
+    /// <summary>
+    /// Anchor list in canonical order: phase-declaration events (Phase != Unknown) plus
+    /// <c>desktop_arrived</c> (Phase=Unknown by convention, but the spec-designated handoff
+    /// anchor). Consecutive same-bucket anchors collapse; anchors whose timestamp goes
+    /// backward vs. the previously accepted anchor are dropped with ClockSkewDropped.
+    /// </summary>
+    private static List<Anchor> BuildAnchors(List<EnrollmentEvent> events, ref TimeAttributionFlags flags)
+    {
+        var anchors = new List<Anchor>();
+        foreach (var evt in events)
+        {
+            string? bucket;
+            var isDeclaration = false;
+            if (evt.EventType == Constants.EventTypes.DesktopArrived)
+            {
+                bucket = TimeAttributionSegments.DesktopHandoff;
+                isDeclaration = true;
+            }
+            else if (evt.Phase != EnrollmentPhase.Unknown)
+            {
+                bucket = MapPhaseToSegment(evt.Phase);
+                isDeclaration = true;
+            }
+            else
+            {
+                bucket = null;
+            }
+
+            if (!isDeclaration) continue;
+
+            if (anchors.Count > 0)
+            {
+                var prev = anchors[anchors.Count - 1];
+                if (evt.Timestamp < prev.Ts)
+                {
+                    flags |= TimeAttributionFlags.ClockSkewDropped;
+                    continue;
+                }
+                if (prev.Bucket == bucket)
+                    continue; // same-phase re-declaration (re-registration, replay) — no boundary
+            }
+
+            anchors.Add(new Anchor { Ts = evt.Timestamp, Bucket = bucket });
+        }
+        return anchors;
+    }
+
+    /// <summary>
+    /// Slices each window at the in-window anchors and buckets every slice by the phase context
+    /// active at its start. Context carries INTO window 0 from anchors at/before its start, but
+    /// never across the WhiteGlove pause into window 1+ (the resume gap makes no phase claim).
+    /// The leading gap of window 0 with no context is device_prep only when the first observed
+    /// anchor is still pre/at apps entry (the spec defines device_prep as session start → first
+    /// apps-phase entry); otherwise it stays unattributed.
+    /// </summary>
+    private static List<TimeAttributionSpan> BuildSegmentSpans(List<Window> windows, List<Anchor> anchors)
+    {
+        var spans = new List<TimeAttributionSpan>();
+
+        for (var w = 0; w < windows.Count; w++)
+        {
+            var window = windows[w];
+
+            string? context = null;
+            if (w == 0)
+            {
+                foreach (var a in anchors)
+                {
+                    if (a.Ts <= window.Start) context = a.Bucket;
+                    else break;
+                }
+            }
+
+            var inWindow = anchors.Where(a => a.Ts > window.Start && a.Ts < window.End).ToList();
+
+            if (w == 0 && context == null)
+            {
+                var first = inWindow.FirstOrDefault();
+                if (first != null &&
+                    (first.Bucket == TimeAttributionSegments.DevicePrep ||
+                     first.Bucket == TimeAttributionSegments.EspApps))
+                {
+                    context = TimeAttributionSegments.DevicePrep;
+                }
+            }
+
+            var cursor = window.Start;
+            foreach (var anchor in inWindow)
+            {
+                AddSpan(spans, context, cursor, anchor.Ts);
+                cursor = anchor.Ts;
+                context = anchor.Bucket;
+            }
+            AddSpan(spans, context, cursor, window.End);
+        }
+
+        return spans;
+    }
+
+    private static void AddSpan(List<TimeAttributionSpan> spans, string? bucket, DateTime start, DateTime end)
+    {
+        if (bucket == null || end <= start) return;
+        var seconds = (int)Math.Floor((end - start).TotalSeconds);
+        if (seconds <= 0) return; // sub-second slivers land in the unattributed remainder
+        spans.Add(new TimeAttributionSpan { SegmentKey = bucket, StartUtc = start, EndUtc = end, Seconds = seconds });
+    }
+
+    // ── blocking-app intervals + occupancy ──────────────────────────────────
+
+    private static (List<BlockingAppInterval> Intervals, int MatchedCount) BuildBlockingAppIntervals(
+        List<EnrollmentEvent> events, EspBlockingSets? sets, List<Window> windows, ref TimeAttributionFlags flags)
+    {
+        var intervals = new List<BlockingAppInterval>();
+        if (sets == null || sets.ListedCount == 0)
+            return (intervals, 0);
+
+        // Fold per-app activity from EVENT timestamps (never payload timing — audit Q1).
+        var apps = new Dictionary<string, AppActivity>(StringComparer.OrdinalIgnoreCase);
+        foreach (var evt in events)
+        {
+            var isStart = evt.EventType == Constants.EventTypes.AppInstallStart ||
+                          evt.EventType == Constants.EventTypes.AppDownloadStarted;
+            var isTerminal = evt.EventType == Constants.EventTypes.AppInstallComplete ||
+                             evt.EventType == Constants.EventTypes.AppInstallFailed ||
+                             evt.EventType == Constants.EventTypes.AppInstallSkipped;
+            if (!isStart && !isTerminal) continue;
+            if (evt.Data == null || !evt.Data.TryGetValue("appId", out var appIdObj)) continue;
+
+            var appId = appIdObj?.ToString()?.Trim();
+            if (string.IsNullOrEmpty(appId)) continue;
+
+            if (!apps.TryGetValue(appId!, out var activity))
+            {
+                activity = new AppActivity { AppId = appId! };
+                apps[appId!] = activity;
+            }
+            if (string.IsNullOrEmpty(activity.AppName) &&
+                evt.Data.TryGetValue("appName", out var nameObj))
+            {
+                activity.AppName = nameObj?.ToString()?.Trim() ?? string.Empty;
+            }
+
+            if (isStart && (!activity.FirstStart.HasValue || evt.Timestamp < activity.FirstStart.Value))
+                activity.FirstStart = evt.Timestamp;
+            // LAST terminal wins — an IME retry (Error → retry → Installed) extends the
+            // occupancy to the final outcome instead of freezing at the first failure.
+            if (isTerminal && (!activity.LastTerminal.HasValue || evt.Timestamp > activity.LastTerminal.Value))
+                activity.LastTerminal = evt.Timestamp;
+        }
+
+        var matched = 0;
+        foreach (var activity in apps.Values)
+        {
+            if (!sets.Contains(activity.AppId)) continue; // absent ⇒ unknown, never "not blocking"
+            matched++;
+
+            if (!activity.FirstStart.HasValue || !activity.LastTerminal.HasValue)
+                continue; // unobserved endpoint → no interval claim (attach window, audit §0.5)
+            if (activity.LastTerminal.Value < activity.FirstStart.Value)
+            {
+                flags |= TimeAttributionFlags.ClockSkewDropped;
+                continue;
+            }
+
+            var clamped = ClampToWindows(activity.FirstStart.Value, activity.LastTerminal.Value, windows);
+            if (!clamped.HasValue)
+            {
+                // Outside the hull entirely → pathological timestamps (flagged, as before).
+                // Inside the hull but touching no window (wholly inside the WhiteGlove pause):
+                // no in-window observation → no interval claim, and nothing wrong with clocks.
+                if (activity.LastTerminal.Value < windows[0].Start ||
+                    activity.FirstStart.Value > windows[windows.Count - 1].End)
+                {
+                    flags |= TimeAttributionFlags.ClockSkewDropped;
+                }
+                continue;
+            }
+
+            intervals.Add(new BlockingAppInterval
+            {
+                AppId = activity.AppId,
+                AppName = activity.AppName,
+                StartUtc = clamped.Value.Start,
+                EndUtc = clamped.Value.End,
+                // In-window seconds — a WG-pause-straddling interval never counts the pause.
+                Seconds = clamped.Value.Seconds,
+            });
+        }
+
+        return (intervals, matched);
+    }
+
+    /// <summary>
+    /// Clips [start, end] to the observation windows. Start/End are the clamped chronological
+    /// endpoints; <c>Seconds</c> counts ONLY time inside the windows — the WhiteGlove pause
+    /// between part 1 and part 2 lies inside the hull but is excluded, matching the session's
+    /// own <c>DurationSeconds</c> semantics (pause excluded by design). Null when the interval
+    /// overlaps no window at all: either it lies outside the hull entirely (pathological
+    /// timestamps) or wholly inside the pause (no in-window observation).
+    /// </summary>
+    private static (DateTime Start, DateTime End, int Seconds)? ClampToWindows(DateTime start, DateTime end, List<Window> windows)
+    {
+        DateTime? s = null, e = null;
+        double total = 0;
+        foreach (var window in windows)
+        {
+            var ws = start < window.Start ? window.Start : start;
+            var we = end > window.End ? window.End : end;
+            if (we < ws) continue;
+            if (s == null || ws < s.Value) s = ws;
+            if (e == null || we > e.Value) e = we;
+            total += (we - ws).TotalSeconds;
+        }
+        if (s == null || e == null) return null;
+        return (s.Value, e.Value, (int)Math.Floor(total));
+    }
+
+    /// <summary>
+    /// Critical-path occupancy: overlap-merged union of the blocking intervals, intersected
+    /// with the esp_apps spans. Whole-second floor on the total (consistent with span math).
+    /// </summary>
+    internal static int ComputeOccupancySeconds(
+        List<BlockingAppInterval> intervals, List<TimeAttributionSpan> espAppsSpans)
+    {
+        if (intervals.Count == 0 || espAppsSpans.Count == 0) return 0;
+
+        var merged = new List<(DateTime Start, DateTime End)>();
+        foreach (var iv in intervals.OrderBy(i => i.StartUtc))
+        {
+            if (merged.Count > 0 && iv.StartUtc <= merged[merged.Count - 1].End)
+            {
+                var last = merged[merged.Count - 1];
+                if (iv.EndUtc > last.End)
+                    merged[merged.Count - 1] = (last.Start, iv.EndUtc);
+            }
+            else
+            {
+                merged.Add((iv.StartUtc, iv.EndUtc));
+            }
+        }
+
+        double total = 0;
+        foreach (var span in espAppsSpans)
+        {
+            foreach (var (ms, me) in merged)
+            {
+                var s = ms > span.StartUtc ? ms : span.StartUtc;
+                var e = me < span.EndUtc ? me : span.EndUtc;
+                if (e > s) total += (e - s).TotalSeconds;
+            }
+        }
+        return (int)Math.Floor(total);
+    }
+
+    // ── what-if bound (fleet aggregation, F1 PR2) ───────────────────────────
+
+    /// <summary>
+    /// Upper-bound saving from removing app <paramref name="appId"/> from the ESP blocking set
+    /// of ONE session: the critical-path end (latest interval end) recomputed without the app's
+    /// interval — <c>max(0, cpEnd − cpEndWithoutX)</c> per the spec. When the app is the only
+    /// measured blocking interval, the fallback baseline is its own start (nothing else was
+    /// observed holding the path). An upper bound BY CONSTRUCTION — removing an app cannot slow
+    /// anything down, but hidden serialization may reduce real savings — so consumers must
+    /// phrase it as "up to", never as a promise (truthfulness rule 3). Returns 0 when the app
+    /// has no measured interval or does not end last.
+    /// </summary>
+    public static int WhatIfSavingSeconds(IReadOnlyList<BlockingAppInterval> intervals, string appId)
+    {
+        BlockingAppInterval? target = null;
+        DateTime? cpEnd = null, cpEndWithout = null;
+
+        foreach (var interval in intervals)
+        {
+            if (!cpEnd.HasValue || interval.EndUtc > cpEnd.Value)
+                cpEnd = interval.EndUtc;
+
+            if (string.Equals(interval.AppId, appId, StringComparison.OrdinalIgnoreCase))
+            {
+                target = interval; // one interval per app per session by construction
+            }
+            else if (!cpEndWithout.HasValue || interval.EndUtc > cpEndWithout.Value)
+            {
+                cpEndWithout = interval.EndUtc;
+            }
+        }
+
+        if (target == null || !cpEnd.HasValue) return 0;
+
+        // Spec formula verbatim: cpEnd − cpEndWithoutX. When X's removal exposes an earlier
+        // path end, the idle gap before X's start counts too — the ESP was waiting for X to
+        // START as much as to finish. Negative/zero → another app ends at or after X: no claim.
+        var baseline = cpEndWithout ?? target.StartUtc;
+        var saving = (cpEnd.Value - baseline).TotalSeconds;
+        return saving > 0 ? (int)Math.Floor(saving) : 0;
+    }
+
+    // ── reboot spans ────────────────────────────────────────────────────────
+
+    /// <summary>
+    /// One span per distinct observed boot: the event-stream gap bracketing <c>lastBootUtc</c>
+    /// (last event before the boot → first event at/after it). Fallback without a usable
+    /// payload: previous event → the detection event itself (which is genuinely post-boot —
+    /// usable as an observation bound, never as the boot moment). Spans are clipped to the
+    /// observation hull, so a WhiteGlove-pause reboot contributes nothing.
+    /// </summary>
+    private static List<RebootSpan> BuildRebootSpans(
+        List<EnrollmentEvent> events, List<Window> windows, List<TimeAttributionSpan> spans)
+    {
+        var result = new List<RebootSpan>();
+        var seenBoots = new HashSet<DateTime>();
+
+        for (var i = 0; i < events.Count; i++)
+        {
+            var evt = events[i];
+            if (evt.EventType != Constants.EventTypes.SystemRebootDetected) continue;
+
+            DateTime? lastBoot = null;
+            if (evt.Data != null && evt.Data.TryGetValue("lastBootUtc", out var lastBootObj))
+            {
+                var raw = lastBootObj?.ToString();
+                if (!string.IsNullOrEmpty(raw) &&
+                    DateTime.TryParse(raw, CultureInfo.InvariantCulture,
+                        DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal, out var parsed))
+                {
+                    lastBoot = parsed;
+                }
+            }
+
+            DateTime? gapStart = null, gapEnd = null;
+            if (lastBoot.HasValue)
+            {
+                if (!seenBoots.Add(lastBoot.Value)) continue; // duplicate detection of the same boot
+                foreach (var e in events)
+                {
+                    if (e.Timestamp < lastBoot.Value)
+                    {
+                        if (!gapStart.HasValue || e.Timestamp > gapStart.Value) gapStart = e.Timestamp;
+                    }
+                    else if (!gapEnd.HasValue || e.Timestamp < gapEnd.Value)
+                    {
+                        gapEnd = e.Timestamp;
+                    }
+                }
+            }
+            else if (i > 0)
+            {
+                gapStart = events[i - 1].Timestamp;
+                gapEnd = evt.Timestamp;
+            }
+
+            if (!gapStart.HasValue || !gapEnd.HasValue || gapEnd.Value <= gapStart.Value) continue;
+
+            var clamped = ClampToWindows(gapStart.Value, gapEnd.Value, windows);
+            if (!clamped.HasValue) continue;
+            // In-window seconds — a reboot gap bracketing the WhiteGlove pause contributes
+            // only its in-window flanks, never the pause itself.
+            var seconds = clamped.Value.Seconds;
+            if (seconds <= 0) continue;
+
+            result.Add(new RebootSpan
+            {
+                StartUtc = clamped.Value.Start,
+                EndUtc = clamped.Value.End,
+                Seconds = seconds,
+                SegmentKey = SegmentAt(spans, clamped.Value.Start),
+            });
+        }
+
+        return result;
+    }
+
+    private static string SegmentAt(List<TimeAttributionSpan> spans, DateTime ts)
+    {
+        foreach (var span in spans)
+        {
+            if (ts >= span.StartUtc && ts < span.EndUtc)
+                return span.SegmentKey;
+        }
+        return TimeAttributionSegments.Unattributed;
+    }
+}

src/Backend/AutopilotMonitor.Functions/Pagination/SearchSessionsPagination.cs

@@ -53,6 +53,7 @@ namespace AutopilotMonitor.Functions.Pagination
                 new KeyValuePair<string, string?>("startedBefore", filter.StartedBefore?.ToUniversalTime().ToString("o", CultureInfo.InvariantCulture)),
                 new KeyValuePair<string, string?>("rebootCountMin", filter.RebootCountMin?.ToString(CultureInfo.InvariantCulture)),
                 new KeyValuePair<string, string?>("rebootCountMax", filter.RebootCountMax?.ToString(CultureInfo.InvariantCulture)),
+                new KeyValuePair<string, string?>("connectionType", filter.ConnectionType),
             };
             if (filter.DeviceProperties != null)
             {

src/Backend/AutopilotMonitor.Functions/Security/EndpointAccessPolicyCatalog.cs

@@ -170,6 +170,11 @@ public static class EndpointAccessPolicyCatalog
         // ticket is the sole authority — authz happened at mint time (diagnostics/download-ticket,
         // MemberRead). See DiagnosticsTicketDownloadFunction.
         new("GET",    "diagnostics/download",       EndpointPolicy.PublicAnonymous),
+        // Azure Monitor action-group webhook (Common Alert Schema → ops event). Action groups
+        // cannot send custom headers, so the shared secret travels as ?secret= and is compared
+        // in constant time against the OpsAlertWebhookSecret app setting (fail-closed while
+        // unset). See AzureMonitorAlertWebhookFunction.
+        new("POST",   "ops/alert-webhook",          EndpointPolicy.PublicAnonymous),
 
         // ── DeviceOrBootstrapAuth ───────────────────────────────────────
         new("POST",   "agent/register-session",    EndpointPolicy.DeviceOrBootstrapAuth),
@@ -227,8 +232,14 @@ public static class EndpointAccessPolicyCatalog
         // (Inspector v1 — Plan §M6). Lift back to MemberRead+QueryParam at the v2 adminMode lift.
         new("GET",    "sessions/{sessionId}/analysis", EndpointPolicy.MemberRead, TenantScoping.QueryParam),
         new("GET",    "sessions/{sessionId}/vulnerability-report", EndpointPolicy.MemberRead, TenantScoping.QueryParam),
+        new("GET",    "sessions/{sessionId}/time-attribution", EndpointPolicy.MemberRead, TenantScoping.QueryParam),
         new("GET",    "metrics/app",               EndpointPolicy.MemberRead),
         new("GET",    "metrics/fleet-health",      EndpointPolicy.MemberRead),
+        new("GET",    "metrics/time-attribution",  EndpointPolicy.MemberRead),
+        // F2 device history: QueryParam scoping so the session-detail banner works cross-tenant
+        // (GA/delegated drill-in) over the SAME route MCP uses — no global duplicate needed.
+        new("GET",    "metrics/device-history",    EndpointPolicy.MemberRead, TenantScoping.QueryParam),
+        new("GET",    "metrics/device-journeys",   EndpointPolicy.MemberRead),
         new("GET",    "apps/list",                 EndpointPolicy.MemberRead),
         new("GET",    "apps/{appName}/analytics",  EndpointPolicy.MemberRead),
         new("GET",    "apps/{appName}/sessions",   EndpointPolicy.MemberRead),
@@ -394,6 +405,8 @@ public static class EndpointAccessPolicyCatalog
         new("GET",    "global/metrics/platform",    EndpointPolicy.GlobalReadOrAdmin),
         new("GET",    "global/metrics/app",         EndpointPolicy.GlobalReadOrAdmin, TenantScoping.QueryParam),
         new("GET",    "global/metrics/fleet-health", EndpointPolicy.GlobalReadOrAdmin, TenantScoping.QueryParam),
+        new("GET",    "global/metrics/time-attribution", EndpointPolicy.GlobalReadOrAdmin, TenantScoping.QueryParam),
+        new("GET",    "global/metrics/device-journeys", EndpointPolicy.GlobalReadOrAdmin, TenantScoping.QueryParam),
         new("GET",    "global/apps/list",           EndpointPolicy.GlobalReadOrAdmin, TenantScoping.QueryParam),
         new("GET",    "global/apps/{appName}/analytics", EndpointPolicy.GlobalReadOrAdmin, TenantScoping.QueryParam),
         new("GET",    "global/apps/{appName}/sessions",  EndpointPolicy.GlobalReadOrAdmin, TenantScoping.QueryParam),

src/Backend/AutopilotMonitor.Functions/Services/Deletion/DeletionManifestBuilder.cs

@@ -114,17 +114,20 @@ namespace AutopilotMonitor.Functions.Services.Deletion
             await AddDiscriminatorPkPropStepAsync(manifest, order: 14, table: Constants.TableNames.ClassifierVerdictsByIdLevel, tenantId, sessionId, safeTenantId, safeSessionId, cancellationToken);
             await AddDiscriminatorPkPropStepAsync(manifest, order: 15, table: Constants.TableNames.SignalsByKind, tenantId, sessionId, safeTenantId, safeSessionId, cancellationToken);
 
-            // ---- Steps 16 + 17: SoftwareInventory side-row (omit both for pre-side-row sessions). ----
+            // ---- Step 16: F1 time-attribution breakdown (PK=tenant, RK=sessionId; PR2). ----
+            await AddPkRkExactStepAsync(manifest, order: 16, table: Constants.TableNames.SessionTimeBreakdowns, partitionKey: tenantId, rowKey: sessionId, cancellationToken);
+
+            // ---- Steps 17 + 18: SoftwareInventory side-row (omit both for pre-side-row sessions). ----
             var contributionsRow = await _reader.GetEntityOrNullAsync(
                 Constants.TableNames.SessionInventoryContributions, tenantId, sessionId, cancellationToken);
             if (contributionsRow != null)
             {
-                AddSoftwareInventoryDecrementStep(manifest, order: 16, contributionsRow);
-                AddContributionsRowStep(manifest, order: 17, contributionsRow);
+                AddSoftwareInventoryDecrementStep(manifest, order: 17, contributionsRow);
+                AddContributionsRowStep(manifest, order: 18, contributionsRow);
             }
 
-            // ---- Step 18: Tombstone (SessionsIndex first, then Sessions). ----
-            AddTombstoneStep(manifest, order: 18, sessionsIndexRow, sessionRow);
+            // ---- Step 19: Tombstone (SessionsIndex first, then Sessions). ----
+            AddTombstoneStep(manifest, order: 19, sessionsIndexRow, sessionRow);
 
             // PreflightCounts derive from each step's RowCount, plus the AGGREGATE decrements length.
             manifest.PreflightCounts = ComputePreflightCounts(manifest);

src/Backend/AutopilotMonitor.Functions/Services/EventIngestProcessor.AppInstall.cs

@@ -9,7 +9,9 @@ namespace AutopilotMonitor.Functions.Services
     /// </summary>
     public sealed partial class EventIngestProcessor
     {
-        private void AggregateAppInstallEvent(EnrollmentEvent evt, string tenantId, string sessionId, Dictionary<string, AppInstallAggregationState> summaries)
+        // internal static (was private instance): pure function over its parameters — exposed as a
+        // test seam so the TerminalState / status-fold contract is pinned by unit tests (PR0).
+        internal static void AggregateAppInstallEvent(EnrollmentEvent evt, string tenantId, string sessionId, Dictionary<string, AppInstallAggregationState> summaries)
         {
             bool isRelevant =
                 evt.EventType == "app_install_started" || evt.EventType == "app_install_start" ||
@@ -51,6 +53,23 @@ namespace AutopilotMonitor.Functions.Services
 
             if (evt.Data != null)
             {
+                // F1 PR1 (audit Q3): the summaries dict — like the RowKey — is keyed by app NAME,
+                // but events carry the Intune app identity in `appId`. Adopt the first observed
+                // appId; if the same name later shows a DIFFERENT appId (device- + user-scope
+                // assignment, duplicate display names across rings), flag the row as a collision —
+                // its folded status/duration mixes two real apps and per-app fleet aggregates
+                // must exclude it. First-seen appId wins so the row stays deterministic.
+                if (evt.Data.TryGetValue("appId", out var appIdObj))
+                {
+                    var appId = appIdObj?.ToString()?.Trim();
+                    if (!string.IsNullOrEmpty(appId))
+                    {
+                        if (string.IsNullOrEmpty(summary.AppId))
+                            summary.AppId = appId!;
+                        else if (!string.Equals(summary.AppId, appId, StringComparison.OrdinalIgnoreCase))
+                            summary.AppIdCollision = true;
+                    }
+                }
                 if (evt.Data.TryGetValue("appVersion", out var appVersionObj))
                 {
                     var appVersion = appVersionObj?.ToString();
@@ -110,10 +129,21 @@ namespace AutopilotMonitor.Functions.Services
                     summary.CompletedAt = evt.Timestamp;
                     if (summary.StartedAt != DateTime.MinValue)
                         summary.DurationSeconds = Math.Max(1, EventTimestampValidator.SafeDurationSeconds(summary.StartedAt, evt.Timestamp));
+                    // PR0 (2026-07-26): the agent emits app_install_completed for EVERY terminal
+                    // transition — including Skipped/Postponed (V1 wire parity). The payload's
+                    // `state` field is the only way to tell a real install apart from a no-op
+                    // (e.g. WinGet "Update for X" policies that were not applicable). Persist it
+                    // so metrics can exclude skips from durations and rates. Unknown/absent state
+                    // leaves the sentinel empty — never guessed.
+                    var terminalStateRaw = evt.Data?.ContainsKey("state") == true
+                        ? evt.Data["state"]?.ToString() : null;
+                    if (terminalStateRaw == "Installed" || terminalStateRaw == "Skipped" || terminalStateRaw == "Postponed")
+                        summary.TerminalState = terminalStateRaw;
                     break;
 
                 case "app_install_failed":
                     summary.Status = "Failed";
+                    summary.TerminalState = "Error";
                     summary.CompletedAt = evt.Timestamp;
                     if (summary.StartedAt != DateTime.MinValue)
                         summary.DurationSeconds = Math.Max(1, EventTimestampValidator.SafeDurationSeconds(summary.StartedAt, evt.Timestamp));
@@ -143,6 +173,10 @@ namespace AutopilotMonitor.Functions.Services
                     // Empty (sentinel: no observation yet) and "InProgress" both flip to Succeeded.
                     if (summary.Status == "InProgress" || summary.Status == string.Empty)
                         summary.Status = "Succeeded";
+                    // Same guard for the terminal state: a dedicated skipped event never overrides
+                    // a stronger terminal (Installed/Error) already seen in this batch.
+                    if (string.IsNullOrEmpty(summary.TerminalState))
+                        summary.TerminalState = "Skipped";
                     break;
 
                 case "download_progress":

src/Backend/AutopilotMonitor.Functions/Services/EventIngestProcessor.cs

@@ -143,6 +143,22 @@ namespace AutopilotMonitor.Functions.Services
                 }
             }
 
+            if (TryComputeSessionApiLatency(request.Events, out var avgLatencyMs, out var apiRequestCount))
+            {
+                _ = _sessionRepo.UpdateSessionNetworkLatencyAsync(
+                        request.TenantId, request.SessionId, avgLatencyMs, apiRequestCount)
+                    .ContinueWith(t => _logger.LogWarning(t.Exception?.InnerException,
+                        "Fire-and-forget UpdateSessionNetworkLatencyAsync failed"), TaskContinuationOptions.OnlyOnFaulted);
+            }
+
+            if (TryExtractConnectionType(request.Events, out var connectionType))
+            {
+                _ = _sessionRepo.UpdateSessionConnectionTypeAsync(
+                        request.TenantId, request.SessionId, connectionType)
+                    .ContinueWith(t => _logger.LogWarning(t.Exception?.InnerException,
+                        "Fire-and-forget UpdateSessionConnectionTypeAsync failed"), TaskContinuationOptions.OnlyOnFaulted);
+            }
+
             var classification = ClassifyEvents(storedEvents);
 
             foreach (var summary in classification.AppInstallUpdates.Values)
@@ -395,6 +411,80 @@ namespace AutopilotMonitor.Functions.Services
             };
         }
 
+        /// <summary>
+        /// Session-wide API latency projection: the agent emits cumulative counters
+        /// (net_total_latency_ms / net_total_requests) in every agent_metrics_snapshot, so
+        /// the LAST snapshot of the batch carries the whole-session average up to now and a
+        /// plain overwrite is idempotent against replays. Agents predating the field simply
+        /// never match (net_total_latency_ms absent) — no fallback, fleet turns over
+        /// per-enrollment. Exposed as internal for unit testing.
+        /// </summary>
+        internal static bool TryComputeSessionApiLatency(
+            List<EnrollmentEvent> events, out double avgLatencyMs, out int requestCount)
+        {
+            avgLatencyMs = 0;
+            requestCount = 0;
+            var snapshot = events.LastOrDefault(e =>
+                e.EventType == Shared.Constants.EventTypes.AgentMetricsSnapshot &&
+                e.Data?.ContainsKey("net_total_latency_ms") == true);
+            if (snapshot?.Data == null ||
+                !TryGetDouble(snapshot.Data, "net_total_latency_ms", out var totalLatencyMs) ||
+                !TryGetDouble(snapshot.Data, "net_total_requests", out var totalRequests) ||
+                totalRequests <= 0)
+            {
+                return false;
+            }
+
+            avgLatencyMs = Math.Round(totalLatencyMs / totalRequests, 1);
+            requestCount = (int)totalRequests;
+            return true;
+        }
+
+        /// <summary>
+        /// Connection-type projection: the agent stamps connectionType ("WiFi"/"Ethernet")
+        /// into every network_interface_info emission (initial collect + re-collect), so the
+        /// LAST event of the batch carries the current media and a plain overwrite is
+        /// idempotent against replays. The no-NIC payload ({"status":"no_active_interface"})
+        /// carries no connectionType and never matches. Values outside WiFi/Ethernet are
+        /// dropped defensively. Exposed as internal for unit testing.
+        /// </summary>
+        internal static bool TryExtractConnectionType(
+            List<EnrollmentEvent> events, out string connectionType)
+        {
+            connectionType = string.Empty;
+            var nicEvent = events.LastOrDefault(e =>
+                e.EventType == Shared.Constants.EventTypes.NetworkInterfaceInfo &&
+                e.Data?.ContainsKey("connectionType") == true);
+            var raw = nicEvent?.Data?["connectionType"]?.ToString();
+            if (raw != "WiFi" && raw != "Ethernet")
+                return false;
+            connectionType = raw;
+            return true;
+        }
+
+        /// <summary>
+        /// Numeric reader for agent event Data values, which arrive as boxed Newtonsoft
+        /// primitives (integer → long, decimal → double) — same coercion ladder as
+        /// PlatformMetricsService.GetDouble (the proven parser for these snapshot fields),
+        /// plus invariant-culture string parsing. Exposed as internal for unit testing.
+        /// </summary>
+        internal static bool TryGetDouble(Dictionary<string, object> data, string key, out double value)
+        {
+            value = 0;
+            if (!data.TryGetValue(key, out var raw))
+                return false;
+            switch (raw)
+            {
+                case double d: value = d; return true;
+                case int i: value = i; return true;
+                case long l: value = l; return true;
+                case float f: value = f; return true;
+            }
+            return double.TryParse(raw?.ToString(),
+                System.Globalization.NumberStyles.Float,
+                System.Globalization.CultureInfo.InvariantCulture, out value);
+        }
+
         /// <summary>
         /// Stamps authoritative server-side fields onto all events before storage.
         /// TenantId and SessionId always come from the validated request metadata,

src/Backend/AutopilotMonitor.Functions/Services/MaintenanceService.Aggregation.cs

@@ -260,6 +260,298 @@ namespace AutopilotMonitor.Functions.Services
             }
         }
 
+        // ===== F1 TIME ATTRIBUTION (insights spec §F1, PR2) =====
+
+        /// <summary>Rolling sweep window: sessions started in the last 30 days (spec backfill horizon).</summary>
+        private const int TimeAttributionSweepDays = 30;
+
+        /// <summary>
+        /// RowKey date component of the rolling-window aggregate rows ("rolling30|{class}").
+        /// Sorts after every "yyyy-MM-dd|…" key, so date-range reads and the age-based retention
+        /// sweep never touch these perpetually-refreshed rows.
+        /// </summary>
+        internal const string RollingAggregateDateKey = "rolling30";
+
+        /// <summary>
+        /// Self-healing sweep for the F1 time attribution — deliberately NOT hooked into the
+        /// usage-snapshot catch-up (that pass skips dates whose snapshot already exists, and a
+        /// session that terminates days after it STARTED would then never reach its date's
+        /// aggregate). Owns both halves for the rolling window:
+        /// 1. Breakdown backfill: every terminal Succeeded/Failed session gets its breakdown
+        ///    computed if missing or written by an older AttributionVersion (rule 8: aggregates
+        ///    never mix algorithm versions — a stale row that cannot be recomputed, because its
+        ///    events aged out, counts as missing rather than polluting the stats). The inline
+        ///    terminal-transition compute is the primary writer; this converges to point-read
+        ///    existence checks.
+        /// 2. Daily aggregates: recomputed idempotently per (tenant × enrollment class × date)
+        ///    plus the "global" rows — late-terminating sessions and backfilled breakdowns are
+        ///    folded in on the next run by construction.
+        /// Sessions with a deletion cascade in flight are skipped so the sweep cannot write a
+        /// breakdown row after the session's deletion manifest was snapshotted.
+        /// </summary>
+        private async Task SweepTimeAttributionAsync()
+        {
+            try
+            {
+                var sw = Stopwatch.StartNew();
+                var today = DateTime.UtcNow.Date;
+                var sessions = await _maintenanceRepo.GetSessionsByDateRangeAsync(
+                    today.AddDays(-TimeAttributionSweepDays), today.AddDays(1));
+
+                var pairs = new List<(SessionSummary Session, SessionTimeBreakdown Breakdown)>();
+                var missing = new List<SessionSummary>();
+                var computed = 0;
+
+                foreach (var session in sessions)
+                {
+                    if (session.Status != SessionStatus.Succeeded && session.Status != SessionStatus.Failed)
+                        continue;
+                    if (!session.DurationSeconds.HasValue || session.DurationSeconds.Value <= 0)
+                        continue;
+                    if (!string.IsNullOrEmpty(session.DeletionState) && session.DeletionState != "None")
+                        continue;
+
+                    var breakdown = await _metricsRepo.GetSessionTimeBreakdownAsync(session.TenantId, session.SessionId);
+                    // Recompute when the row is missing, algorithm-stale, OR computed from an
+                    // incomplete event stream: the inline terminal compute is one-shot, but
+                    // batches can arrive AFTER the terminal transition (upload lag, replays,
+                    // the agent's async esp_config re-emits) — the session's EventCount is the
+                    // change signal (Codex review finding).
+                    var eventCountMoved = breakdown != null && breakdown.EventCountAtCompute != session.EventCount;
+                    if (breakdown == null || breakdown.AttributionVersion != TimeAttributionCalculator.CurrentVersion || eventCountMoved)
+                    {
+                        var hadNoRow = breakdown == null;
+                        breakdown = await _metricsRepo.ComputeAndStoreSessionTimeBreakdownAsync(session.TenantId, session.SessionId);
+                        if (breakdown != null) computed++;
+                        // Late batches can also carry esp_config_detected re-emits and app
+                        // events — re-join the blocking evidence from the fuller stream.
+                        // Idempotent, positive-evidence-only; also heals sessions that went
+                        // terminal before the resolution seam existed (hadNoRow backfill).
+                        if (eventCountMoved || hadNoRow)
+                            await _metricsRepo.ResolveEspBlockingForSessionAsync(session.TenantId, session.SessionId);
+                    }
+
+                    if (breakdown == null)
+                        missing.Add(session); // events aged out before backfill — disclosed, never guessed
+                    else
+                        pairs.Add((session, breakdown));
+                }
+
+                var now = DateTime.UtcNow;
+                var aggregates = BuildTimeAttributionAggregates(pairs, missing, now);
+                // Rolling window rows (RK "rolling30|{class}"): range statistics computed over the
+                // window's actual sessions. The daily rows can NOT be merged into a range claim
+                // (a median of per-day medians is not the range median), so the fleet panel reads
+                // these; the daily rows serve the per-day trend. Refreshed whole every sweep.
+                // "Last 30 days" means exactly 30 calendar days including today — the sweep's own
+                // query window is one day wider (backfill/late-heal coverage), so filter here.
+                var rollingWindowStart = today.AddDays(-(TimeAttributionSweepDays - 1));
+                aggregates.AddRange(BuildTimeAttributionAggregates(
+                    pairs.Where(p => p.Session.StartedAt >= rollingWindowStart).ToList(),
+                    missing.Where(s => s.StartedAt >= rollingWindowStart).ToList(),
+                    now, RollingAggregateDateKey));
+                var saved = 0;
+                foreach (var aggregate in aggregates)
+                {
+                    if (await _metricsRepo.SaveTimeAttributionAggregateAsync(aggregate))
+                        saved++;
+                }
+
+                // Stale-bucket reconcile (Codex review): a bucket that existed on a previous run
+                // but was NOT regenerated now (its sessions were deleted, or its class left the
+                // window) must not keep serving old numbers — a rolling row would otherwise stay
+                // stale forever. Scope: every partition this run wrote rows for; a partition that
+                // went FULLY quiet is not enumerable here — its rolling rows are neutralized
+                // read-side by the ComputedAt age filter in TimeAttributionResponse, and its
+                // daily rows age out of every queried window by construction.
+                var generatedKeys = new HashSet<(string TenantId, string Date, string Class)>(
+                    aggregates.Select(a => (a.TenantId, a.Date, a.EnrollmentClass)));
+                var removedStale = 0;
+                foreach (var partition in aggregates.Select(a => a.TenantId).Distinct().ToList())
+                {
+                    var existingRows = await _metricsRepo.GetRollingTimeAttributionAggregatesAsync(partition);
+                    existingRows.AddRange(await _metricsRepo.GetTimeAttributionAggregatesAsync(
+                        partition, today.AddDays(-TimeAttributionSweepDays), today));
+                    foreach (var row in existingRows)
+                    {
+                        if (generatedKeys.Contains((partition, row.Date, row.EnrollmentClass))) continue;
+                        await _metricsRepo.DeleteTimeAttributionAggregateAsync(partition, row.Date, row.EnrollmentClass);
+                        removedStale++;
+                    }
+                }
+
+                sw.Stop();
+                _logger.LogInformation(
+                    "Time-attribution sweep: {Sessions} terminal sessions in {Days}d window, {Computed} breakdowns computed, {Missing} missing, {Aggregates} aggregate rows written, {Removed} stale buckets removed in {Ms}ms",
+                    pairs.Count + missing.Count, TimeAttributionSweepDays, computed, missing.Count, saved, removedStale, sw.ElapsedMilliseconds);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "Time-attribution sweep failed (non-fatal)");
+            }
+        }
+
+        /// <summary>
+        /// Pure aggregation core behind <see cref="SweepTimeAttributionAsync"/> — internal static
+        /// so the bucketing/gating contract is pinned by unit tests. Per (tenant × class × date)
+        /// bucket plus mirrored "global" rows: only breakdowns without DURATION-critical flags
+        /// (<see cref="TimeAttributionFlagQuality.DurationCriticalFlags"/>) form the statistics —
+        /// blocking-set-only flags stay in (their spans are sound; unknown blocking simply
+        /// contributes no per-app intervals); excluded and missing ones are counted, never
+        /// silently dropped (rule 7).
+        /// Rows are written even below the ≥20 UI gate — the UI needs the n (rule 4). Segment
+        /// stats always carry the five canonical segments + unattributed (a session without a
+        /// span of a segment contributes 0 — the honest "per enrollment of this class" answer).
+        /// Per-app rows gate at ≥5 sessions, order by median interval, cap 20.
+        /// </summary>
+        internal static List<TimeAttributionDailyAggregate> BuildTimeAttributionAggregates(
+            IReadOnlyList<(SessionSummary Session, SessionTimeBreakdown Breakdown)> pairs,
+            IReadOnlyList<SessionSummary> missing,
+            DateTime computedAtUtc,
+            string? fixedDateKey = null)
+        {
+            const int minSessionsPerAppRow = 5;
+            const int maxAppRows = 20;
+
+            var buckets = new Dictionary<(string TenantId, string Date, string Class), List<SessionTimeBreakdown>>();
+            var flaggedCounts = new Dictionary<(string, string, string), int>();
+            var missingCounts = new Dictionary<(string, string, string), int>();
+
+            void Bump(Dictionary<(string, string, string), int> map, (string, string, string) key)
+            {
+                map.TryGetValue(key, out var current);
+                map[key] = current + 1;
+            }
+
+            foreach (var (session, breakdown) in pairs)
+            {
+                var date = fixedDateKey ?? session.StartedAt.ToString("yyyy-MM-dd");
+                var cls = TimeAttributionCalculator.GetEnrollmentClass(session);
+                foreach (var tenantKey in new[] { session.TenantId, "global" })
+                {
+                    var key = (tenantKey, date, cls);
+                    if (TimeAttributionFlagQuality.ExcludesFromFleetStats(breakdown.QualityFlags))
+                    {
+                        Bump(flaggedCounts, key);
+                        // Flagged sessions still materialize the bucket so a day whose sessions
+                        // were ALL flagged yields a row disclosing exactly that.
+                        if (!buckets.ContainsKey(key)) buckets[key] = new List<SessionTimeBreakdown>();
+                        continue;
+                    }
+                    if (!buckets.TryGetValue(key, out var list))
+                    {
+                        list = new List<SessionTimeBreakdown>();
+                        buckets[key] = list;
+                    }
+                    list.Add(breakdown);
+                }
+            }
+
+            foreach (var session in missing)
+            {
+                var date = fixedDateKey ?? session.StartedAt.ToString("yyyy-MM-dd");
+                var cls = TimeAttributionCalculator.GetEnrollmentClass(session);
+                foreach (var tenantKey in new[] { session.TenantId, "global" })
+                {
+                    var key = (tenantKey, date, cls);
+                    Bump(missingCounts, key);
+                    if (!buckets.ContainsKey(key)) buckets[key] = new List<SessionTimeBreakdown>();
+                }
+            }
+
+            var segmentKeys = new[]
+            {
+                TimeAttributionSegments.DevicePrep,
+                TimeAttributionSegments.EspApps,
+                TimeAttributionSegments.IdentityHello,
+                TimeAttributionSegments.UserEsp,
+                TimeAttributionSegments.DesktopHandoff,
+                TimeAttributionSegments.Unattributed,
+            };
+
+            var result = new List<TimeAttributionDailyAggregate>();
+            foreach (var entry in buckets)
+            {
+                var (tenantId, date, cls) = entry.Key;
+                var clean = entry.Value;
+
+                var aggregate = new TimeAttributionDailyAggregate
+                {
+                    TenantId = tenantId,
+                    Date = date,
+                    EnrollmentClass = cls,
+                    AttributionVersion = TimeAttributionCalculator.CurrentVersion,
+                    CleanSessionCount = clean.Count,
+                    FlaggedExcludedCount = flaggedCounts.TryGetValue(entry.Key, out var f) ? f : 0,
+                    MissingBreakdownCount = missingCounts.TryGetValue(entry.Key, out var m) ? m : 0,
+                    ComputedAt = computedAtUtc,
+                };
+
+                if (clean.Count > 0)
+                {
+                    var totalsPerSession = clean
+                        .Select(b =>
+                        {
+                            var totals = b.GetSegmentTotals();
+                            totals[TimeAttributionSegments.Unattributed] = b.UnattributedSeconds;
+                            return totals;
+                        })
+                        .ToList();
+
+                    foreach (var segmentKey in segmentKeys)
+                    {
+                        var values = totalsPerSession
+                            .Select(t => t.TryGetValue(segmentKey, out var v) ? (double)v : 0d)
+                            .OrderBy(v => v)
+                            .ToList();
+                        aggregate.SegmentStats.Add(new TimeAttributionSegmentStat
+                        {
+                            SegmentKey = segmentKey,
+                            MedianSeconds = (int)Math.Round(MetricsMath.Percentile(values, 50)),
+                            P75Seconds = (int)Math.Round(MetricsMath.Percentile(values, 75)),
+                            P90Seconds = (int)Math.Round(MetricsMath.Percentile(values, 90)),
+                        });
+                    }
+
+                    aggregate.TopBlockingApps = clean
+                        .SelectMany(b => b.BlockingApps.Select(interval => (Breakdown: b, Interval: interval)))
+                        .GroupBy(x => x.Interval.AppId, StringComparer.OrdinalIgnoreCase)
+                        .Where(g => g.Count() >= minSessionsPerAppRow)
+                        .Select(g =>
+                        {
+                            var seconds = g.Select(x => (double)x.Interval.Seconds).OrderBy(v => v).ToList();
+                            var savings = g
+                                // Cap at the session's wall clock: the what-if delta is computed
+                                // from raw interval endpoints, which can straddle the WhiteGlove
+                                // pause — no removal can save more than the enrollment took.
+                                .Select(x => (double)Math.Min(
+                                    TimeAttributionCalculator.WhatIfSavingSeconds(x.Breakdown.BlockingApps, g.Key),
+                                    x.Breakdown.WallClockSeconds))
+                                .OrderBy(v => v)
+                                .ToList();
+                            return new TimeAttributionBlockingAppStat
+                            {
+                                AppId = g.Key,
+                                AppName = g.Select(x => x.Interval.AppName).FirstOrDefault(n => !string.IsNullOrEmpty(n)) ?? string.Empty,
+                                SessionCount = g.Count(),
+                                MedianSeconds = (int)Math.Round(MetricsMath.Percentile(seconds, 50)),
+                                P75Seconds = (int)Math.Round(MetricsMath.Percentile(seconds, 75)),
+                                MedianSavingSeconds = (int)Math.Round(MetricsMath.Percentile(savings, 50)),
+                                P75SavingSeconds = (int)Math.Round(MetricsMath.Percentile(savings, 75)),
+                            };
+                        })
+                        .OrderByDescending(a => a.MedianSeconds)
+                        .ThenBy(a => a.AppName, StringComparer.OrdinalIgnoreCase)
+                        .Take(maxAppRows)
+                        .ToList();
+                }
+
+                result.Add(aggregate);
+            }
+
+            return result;
+        }
+
         /// <summary>
         /// Deletes usage tracking records older than 90 days from UserUsageLog.
         /// </summary>
@@ -782,6 +1074,34 @@ namespace AutopilotMonitor.Functions.Services
             {
                 _logger.LogWarning(ex, "Failed to cleanup old backup job records");
             }
+
+            // Time-attribution daily aggregates: same 180d window as the usage-metrics snapshots
+            // they sit beside. (SessionTimeBreakdowns needs no age sweep — breakdown rows are
+            // deleted with their session via the deletion-manifest cascade / offboarding wipe.)
+            try
+            {
+                var deleted = await _metricsRepo.DeleteTimeAttributionAggregatesOlderThanAsync(now.AddDays(-usageMetricsRetentionDays));
+                if (deleted > 0)
+                    _logger.LogInformation("Time-attribution aggregate cleanup: deleted {Count} rows older than {Days} days", deleted, usageMetricsRetentionDays);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "Failed to cleanup old time-attribution aggregates");
+            }
+
+            // Device-journey (FTR) daily aggregates: same 180d window. (DeviceHistories needs no
+            // age sweep — chain refs of deleted sessions are pruned tombstone-driven by
+            // SweepDeviceJourneysAsync and the rows die with tenant offboarding.)
+            try
+            {
+                var deleted = await _metricsRepo.DeleteDeviceJourneyAggregatesOlderThanAsync(now.AddDays(-usageMetricsRetentionDays));
+                if (deleted > 0)
+                    _logger.LogInformation("Device-journey aggregate cleanup: deleted {Count} rows older than {Days} days", deleted, usageMetricsRetentionDays);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "Failed to cleanup old device-journey aggregates");
+            }
         }
         /// <summary>
         /// Detects and cleans up orphaned events — events stored in the Events table

src/Backend/AutopilotMonitor.Functions/Services/MaintenanceService.DeviceJourneys.cs

@@ -0,0 +1,278 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Shared.Models;
+using Microsoft.Extensions.Logging;
+
+namespace AutopilotMonitor.Functions.Services
+{
+    /// <summary>
+    /// Partial: F2 device-history / First-Time-Right sweep (insights spec §F2, PR4).
+    /// </summary>
+    public partial class MaintenanceService
+    {
+        /// <summary>Rolling sweep window: sessions started in the last 30 days (mirrors the F1 attribution sweep).</summary>
+        private const int DeviceJourneySweepDays = 30;
+
+        /// <summary>
+        /// Self-healing sweep for the F2 device histories + daily FTR aggregates. The inline
+        /// terminal-transition update is the primary chain writer; this pass owns everything the
+        /// inline path cannot:
+        /// 1. Deleted-session cleanup: every session deletion (cascade + retention) leaves a
+        ///    SessionTombstones marker for ~7d — far longer than the sweep cadence — so dropping
+        ///    chain refs whose sessionId is tombstoned keeps chains truthful without per-ref
+        ///    existence point-reads. A chain left empty is deleted (a device with no observable
+        ///    sessions has no history claim).
+        /// 2. Chain backfill/heal: terminal sessions of the rolling window are merged into their
+        ///    device chains (pre-deploy sessions, inline misses, re-terminal reclassifications).
+        /// 3. Daily FTR aggregates: recomputed idempotently per (tenant × completion date) plus
+        ///    "global" mirror rows from the freshly merged chains — a journey buckets on the
+        ///    StartedAt date of its completing success session, so late-terminating sessions are
+        ///    folded into their date on the next pass by construction (F1 bucketing convention).
+        /// Cost: one tombstone-table scan, one window session scan, and ~1 point-read + 1 upsert
+        /// per window device per tick — same order as the F1 sweep; negligible at current fleet
+        /// size (the scaling lever is gating the per-device RMW on new terminal sessions).
+        /// </summary>
+        private async Task SweepDeviceJourneysAsync()
+        {
+            try
+            {
+                var sw = Stopwatch.StartNew();
+                var today = DateTime.UtcNow.Date;
+                var windowStart = today.AddDays(-DeviceJourneySweepDays);
+                var windowEnd = today.AddDays(1);
+
+                // ---- Phase 1: drop chain refs of deleted sessions (tombstone-driven). ----
+                var tombstones = await _maintenanceRepo.GetAllSessionTombstoneKeysAsync();
+                var deletedByTenant = tombstones
+                    .GroupBy(t => t.TenantId, StringComparer.OrdinalIgnoreCase)
+                    .ToDictionary(
+                        g => g.Key,
+                        g => (ISet<string>)new HashSet<string>(g.Select(x => x.SessionId), StringComparer.Ordinal),
+                        StringComparer.OrdinalIgnoreCase);
+
+                var refsCleaned = 0;
+                var rowsDeleted = 0;
+                foreach (var pair in deletedByTenant)
+                {
+                    var histories = await _metricsRepo.GetDeviceHistoriesByTenantAsync(pair.Key);
+                    foreach (var history in histories)
+                    {
+                        if (!history.Chain.Any(r => pair.Value.Contains(r.SessionId)))
+                            continue;
+
+                        var cleaned = DeviceJourneyCalculator.RemoveSessionRefs(history.Chain, pair.Value);
+                        if (cleaned.Count == 0)
+                        {
+                            await _metricsRepo.DeleteDeviceHistoryAsync(pair.Key, history.SerialKey);
+                            rowsDeleted++;
+                            continue;
+                        }
+
+                        var (journeyCount, currentAttempts) = DeviceJourneyCalculator.Derive(cleaned);
+                        history.Chain = cleaned;
+                        history.JourneyCount = journeyCount;
+                        history.CurrentJourneyAttempts = currentAttempts;
+                        history.JourneyVersion = DeviceJourneyCalculator.CurrentVersion;
+                        history.LastUpdated = DateTime.UtcNow;
+                        await _metricsRepo.UpsertDeviceHistoryAsync(history);
+                        refsCleaned++;
+                    }
+                }
+
+                // ---- Phase 2: merge the window's terminal sessions into their device chains. ----
+                var sessions = await _maintenanceRepo.GetSessionsByDateRangeAsync(windowStart, windowEnd);
+                var excludedSessions = new List<SessionSummary>();
+                var byDevice = new Dictionary<(string TenantId, string SerialKey), List<SessionSummary>>();
+
+                foreach (var session in sessions)
+                {
+                    if (!DeviceJourneyCalculator.IsTerminal(session.Status))
+                        continue;
+                    // Never (re-)add a ref for a session inside a deletion cascade — its
+                    // tombstone may already have been consumed by an earlier pass.
+                    if (!string.IsNullOrEmpty(session.DeletionState) && session.DeletionState != "None")
+                        continue;
+
+                    var serialKey = DeviceJourneyCalculator.NormalizeSerial(session.SerialNumber);
+                    if (serialKey == null)
+                    {
+                        excludedSessions.Add(session); // junk serial — disclosed, never silently dropped
+                        continue;
+                    }
+
+                    var key = (session.TenantId, serialKey);
+                    if (!byDevice.TryGetValue(key, out var list))
+                    {
+                        list = new List<SessionSummary>();
+                        byDevice[key] = list;
+                    }
+                    list.Add(session);
+                }
+
+                var mergedHistories = new List<DeviceHistory>(byDevice.Count);
+                foreach (var pair in byDevice)
+                {
+                    var (tenantId, serialKey) = pair.Key;
+                    var existing = await _metricsRepo.GetDeviceHistoryAsync(tenantId, serialKey);
+                    var refs = pair.Value
+                        .Select(DeviceJourneyCalculator.BuildSessionRef)
+                        .Where(r => r != null)
+                        .Select(r => r!);
+
+                    var chain = DeviceJourneyCalculator.MergeChain(existing?.Chain, refs);
+                    if (deletedByTenant.TryGetValue(tenantId, out var deletedIds))
+                        chain = DeviceJourneyCalculator.RemoveSessionRefs(chain, deletedIds);
+                    if (chain.Count == 0)
+                        continue;
+
+                    // Display fields follow the chain's newest entry (BuildDeviceHistoryRow rule);
+                    // pick the window session that IS that entry, falling back to any of the
+                    // device's window sessions (then the existing row's values win inside).
+                    var newestId = chain[chain.Count - 1].SessionId;
+                    var displaySource = pair.Value.FirstOrDefault(s => s.SessionId == newestId) ?? pair.Value[0];
+                    var history = TableStorageService.BuildDeviceHistoryRow(tenantId, serialKey, chain, existing, displaySource);
+                    await _metricsRepo.UpsertDeviceHistoryAsync(history);
+                    mergedHistories.Add(history);
+                }
+
+                // ---- Phase 3: daily FTR aggregates from the merged chains. ----
+                var aggregates = BuildDeviceJourneyAggregates(
+                    mergedHistories, excludedSessions, windowStart, windowEnd, DateTime.UtcNow);
+                var saved = 0;
+                foreach (var aggregate in aggregates)
+                {
+                    if (await _metricsRepo.SaveDeviceJourneyAggregateAsync(aggregate))
+                        saved++;
+                }
+
+                // Stale-bucket reconcile (Codex review): a date row that was not regenerated this
+                // run (its last completing journey was deleted or reclassified) must not keep
+                // serving old counts — FTR window rates are SUMS over these rows. Scope: every
+                // partition this run wrote rows for; fully-quiet partitions' rows age out of any
+                // queried window by construction (the FTR query is always today-anchored).
+                var generatedKeys = new HashSet<(string TenantId, string Date)>(
+                    aggregates.Select(a => (a.TenantId, a.Date)));
+                var removedStale = 0;
+                foreach (var partition in aggregates.Select(a => a.TenantId).Distinct().ToList())
+                {
+                    var existingRows = await _metricsRepo.GetDeviceJourneyAggregatesAsync(
+                        partition, windowStart, windowEnd.AddDays(-1));
+                    foreach (var row in existingRows)
+                    {
+                        if (generatedKeys.Contains((partition, row.Date))) continue;
+                        await _metricsRepo.DeleteDeviceJourneyAggregateAsync(partition, row.Date);
+                        removedStale++;
+                    }
+                }
+
+                sw.Stop();
+                _logger.LogInformation(
+                    "Device-journey sweep: {Devices} devices from {Sessions} terminal window sessions, {RefsCleaned} chains cleaned / {RowsDeleted} rows deleted (tombstones), {Excluded} junk-serial sessions excluded, {Aggregates} FTR rows written, {Removed} stale buckets removed in {Ms}ms",
+                    mergedHistories.Count, byDevice.Sum(d => d.Value.Count), refsCleaned, rowsDeleted, excludedSessions.Count, saved, removedStale, sw.ElapsedMilliseconds);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "Device-journey sweep failed (non-fatal)");
+            }
+        }
+
+        /// <summary>
+        /// Pure aggregation core behind <see cref="SweepDeviceJourneysAsync"/> — internal static
+        /// so the FTR contract is pinned by unit tests. A journey counts on the StartedAt date
+        /// (UTC) of its COMPLETING success session; only completed journeys enter numerator and
+        /// denominator (open and gap-abandoned journeys never count — spec §F2). Junk-serial
+        /// exclusions are disclosed per day (rule 7), producing disclosure-only rows when a day
+        /// has no completed journey. Rows are written even below the ≥20 UI gate (rule 4) and
+        /// mirrored into the "global" partition. Counts are additive across days — window rates
+        /// are sums over daily rows, so no rolling-window row exists (unlike the median-based F1
+        /// aggregates).
+        /// </summary>
+        internal static List<DeviceJourneyDailyAggregate> BuildDeviceJourneyAggregates(
+            IReadOnlyList<DeviceHistory> histories,
+            IReadOnlyList<SessionSummary> excludedSessions,
+            DateTime windowStartDate,
+            DateTime windowEndDateExclusive,
+            DateTime computedAtUtc)
+        {
+            var buckets = new Dictionary<(string TenantId, string Date), JourneyBucket>();
+
+            JourneyBucket Bucket((string, string) key)
+            {
+                if (!buckets.TryGetValue(key, out var bucket))
+                {
+                    bucket = new JourneyBucket();
+                    buckets[key] = bucket;
+                }
+                return bucket;
+            }
+
+            foreach (var history in histories)
+            {
+                foreach (var journey in DeviceJourneyCalculator.GroupJourneys(history.Chain))
+                {
+                    if (!journey.Completed)
+                        continue;
+                    var completedOn = journey.CompletingRef!.StartedAt.Date;
+                    if (completedOn < windowStartDate || completedOn >= windowEndDateExclusive)
+                        continue;
+
+                    var date = completedOn.ToString("yyyy-MM-dd");
+                    var attempts = journey.Attempts.Count;
+                    foreach (var tenantKey in new[] { history.TenantId, "global" })
+                    {
+                        var bucket = Bucket((tenantKey, date));
+                        bucket.CompletedJourneys++;
+                        if (attempts == 1) bucket.FirstTimeRight++;
+                        bucket.Histogram.TryGetValue(attempts, out var count);
+                        bucket.Histogram[attempts] = count + 1;
+                    }
+                }
+            }
+
+            foreach (var session in excludedSessions)
+            {
+                var date = session.StartedAt.Date;
+                if (date < windowStartDate || date >= windowEndDateExclusive)
+                    continue;
+                var dateStr = date.ToString("yyyy-MM-dd");
+                foreach (var tenantKey in new[] { session.TenantId, "global" })
+                {
+                    Bucket((tenantKey, dateStr)).ExcludedSessions++;
+                }
+            }
+
+            var result = new List<DeviceJourneyDailyAggregate>(buckets.Count);
+            foreach (var entry in buckets)
+            {
+                var (tenantId, date) = entry.Key;
+                result.Add(new DeviceJourneyDailyAggregate
+                {
+                    TenantId = tenantId,
+                    Date = date,
+                    JourneyVersion = DeviceJourneyCalculator.CurrentVersion,
+                    CompletedJourneyCount = entry.Value.CompletedJourneys,
+                    FirstTimeRightCount = entry.Value.FirstTimeRight,
+                    AttemptHistogram = entry.Value.Histogram
+                        .OrderBy(h => h.Key)
+                        .Select(h => new DeviceJourneyAttemptBucket { Attempts = h.Key, JourneyCount = h.Value })
+                        .ToList(),
+                    ExcludedSessionCount = entry.Value.ExcludedSessions,
+                    ComputedAt = computedAtUtc,
+                });
+            }
+            return result;
+        }
+
+        private sealed class JourneyBucket
+        {
+            public int CompletedJourneys;
+            public int FirstTimeRight;
+            public int ExcludedSessions;
+            public readonly Dictionary<int, int> Histogram = new Dictionary<int, int>();
+        }
+    }
+}