feat: P14 - per-upload-batch send time separates spool delay from clock offset

Agent stamps X-Send-Time-Utc (device clock, ISO-8601 round-trip) per upload
ATTEMPT; ingest parses it (year>=2000 guard, deliberately no upper clamp) and
server-stamps SentAt onto every event of the request. SentAt - OccurredUtc is
pure spool delay, ReceivedAt - SentAt is network + device-vs-server clock
offset - previously indistinguishable and only separable via median statistics.

clock_skew condition: batches carrying SentAt measure the frame directly
(spool-immune by construction - no spread cap, IME/clamped exclusions
irrelevant, IME-only sessions become measurable; evidence sentAtBatchCount);
legacy batches keep the per-event median path unchanged. CmTraceSkewTripwire
deliberately untouched: its differential median math cancels clock offset as
common mode.

Full persistence chain: Store x2 + Map, fields= projection (sentAt), MCP
get_session_events field list + rule-authoring-guide. New OKF doc
backend/send-time-frame-separation.md.

Suites: Functions 4370 (+16), Agent 2407 (+1), MCP vitest 564 + tsc 0.

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

.github/scripts/Publish-BootstrapScripts.ps1

@@ -0,0 +1,367 @@
+<#
+.SYNOPSIS
+    Publishes the customer-facing PowerShell scripts behind download.autopilotmonitor.com/agent/.
+
+.DESCRIPTION
+    Single owner of the script-publishing chain. Called from two places:
+
+      * publish-scripts.yml  -- on every push to main that touches the sources,
+                                so a script fix reaches customers without waiting
+                                for an agent release.
+      * build-agent.yml      -- on a publish_as_stable run, so a release always
+                                lands a consistent set (ZIP + manifest + scripts).
+
+    Both callers run the same code. The scripts on the download alias are the live
+    copy the WDP bootstrap MSI (Invoke-BootstrapDownload.ps1) downloads on every
+    enrolling device, so "current" is a correctness property, not cosmetics.
+
+    Steps, in order:
+      1. Parse $ScriptVersion from the bootstrap source.
+      2. Render the -Dev variant by literal substitution of the two URL/manifest
+         defaults. A missing anchor is a hard failure -- a silently un-substituted
+         dev script would point the dev fleet at the stable agent.
+      3. Version-bump guard: if the published bootstrap differs from the source
+         but carries the same $ScriptVersion, abort. Otherwise the docs badge,
+         version.json.bootstrapVersion and the portal's "your script is outdated"
+         hint would all keep asserting a version that is no longer what ships.
+      4. Upload every script blob with Cache-Control: no-cache (they rotate in
+         place), mirrored fail-soft to the legacy account.
+      5. Reconcile the two version oracles: version.json.bootstrapVersion
+         (read-modify-write under If-Match, so a concurrent agent release cannot
+         lose its agent fields) and AdminConfiguration.LatestBootstrapV2ScriptVersion.
+      6. Verify through the alias -- re-download each blob and compare SHA-256.
+
+.PARAMETER SasToken
+    Container SAS for the eu storage account with write permission. Leading '?' tolerated.
+
+.PARAMETER LegacySasToken
+    Container SAS for the legacy account. Optional -- a mirror failure warns, never fails.
+
+.PARAMETER TableSasToken
+    Table SAS for AdminConfiguration. Optional -- omitted or 'XXX' skips the oracle update.
+
+.PARAMETER RepoRoot
+    Repository root. Defaults to the parent of .github/scripts.
+
+.PARAMETER DryRun
+    Run every check and render, upload nothing.
+
+.EXAMPLE
+    ./Publish-BootstrapScripts.ps1 -DryRun
+
+.EXAMPLE
+    ./Publish-BootstrapScripts.ps1 -SasToken $env:SAS -TableSasToken $env:TABLE_SAS
+#>
+[CmdletBinding()]
+param(
+    [string]$SasToken,
+    [string]$LegacySasToken,
+    [string]$TableSasToken,
+    [string]$RepoRoot,
+    [switch]$DryRun
+)
+
+$ErrorActionPreference = 'Stop'
+
+if (-not $RepoRoot) {
+    $RepoRoot = (Resolve-Path (Join-Path $PSScriptRoot '../..')).Path
+}
+if (-not $DryRun -and [string]::IsNullOrWhiteSpace($SasToken)) {
+    throw 'SasToken is required unless -DryRun is used.'
+}
+
+$ContainerUrl       = 'https://autopilotmonitoreu.blob.core.windows.net/agent'
+$LegacyContainerUrl = 'https://autopilotmonitor.blob.core.windows.net/agent'
+$AliasUrl           = 'https://download.autopilotmonitor.com/agent'
+$TableUrl           = "https://autopilotmonitoreu.table.core.windows.net/AdminConfiguration(PartitionKey='GlobalConfig',RowKey='config')"
+
+$BootstrapSource   = Join-Path $RepoRoot 'scripts/Bootstrap/Install-AutopilotMonitor.ps1'
+$BootstrapBlob     = 'Install-AutopilotMonitor.ps1'
+$DevBlob           = 'Install-AutopilotMonitor-Dev.ps1'
+$ScriptContentType = 'text/plain; charset=utf-8'
+
+function Get-HttpStatus {
+    param($ErrorRecord)
+    if ($ErrorRecord.Exception.PSObject.Properties['Response'] -and $ErrorRecord.Exception.Response) {
+        return [int]$ErrorRecord.Exception.Response.StatusCode
+    }
+    return 0
+}
+
+function Get-Sha256 {
+    param([byte[]]$Bytes)
+    $sha = [System.Security.Cryptography.SHA256]::Create()
+    try { return [BitConverter]::ToString($sha.ComputeHash($Bytes)).Replace('-', '').ToLowerInvariant() }
+    finally { $sha.Dispose() }
+}
+
+# Raw bytes of a published blob, or $null when it does not exist yet.
+function Get-PublishedBytes {
+    param([string]$Url)
+    try {
+        $resp = Invoke-WebRequest -Uri $Url -Method Get -UseBasicParsing
+    } catch {
+        if ((Get-HttpStatus $_) -eq 404) { return $null }
+        throw
+    }
+    # Comma operator: PowerShell unrolls an array returned from a function into the output
+    # stream and reassembles it as Object[], which would silently defeat every [byte[]] use
+    # downstream. ',' wraps it so the byte[] survives the return.
+    if ($resp.Content -is [byte[]]) { return ,$resp.Content }
+    return ,[System.Text.Encoding]::UTF8.GetBytes([string]$resp.Content)
+}
+
+# Deterministic publish form: CRLF, UTF-8 without BOM. Git normalises line endings on
+# checkout (a Windows runner yields CRLF, a core.autocrlf=false clone yields LF), so
+# publishing the raw working-copy bytes would emit different blobs for identical source
+# and make every byte comparison -- guard and verify alike -- environment-dependent.
+# CRLF is also what PS 5.1 on the device expects and what is published today.
+function Get-PublishBytes {
+    param([string]$Text)
+    $normalised = $Text.Replace("`r`n", "`n").Replace("`n", "`r`n")
+    # ',' keeps this a byte[]: without it PowerShell unrolls the array into the output stream
+    # and the caller receives Object[]. Invoke-RestMethod then serialises an Object[] body as
+    # space-separated decimals instead of raw bytes -- a silent corruption of the upload.
+    return ,(New-Object System.Text.UTF8Encoding $false).GetBytes($normalised)
+}
+
+function Get-BootstrapScriptVersion {
+    param([string]$Content, [string]$Origin, [switch]$Optional)
+    if ($Content -match '\$ScriptVersion\s*=\s*"([\d\.\-a-zA-Z]+)"') { return $Matches[1] }
+    # Unreadable SOURCE is fatal. An unreadable PUBLISHED copy must not be: that is exactly
+    # the state a republish is meant to repair, and a guard that blocks the repair is worse
+    # than no guard.
+    if ($Optional) { return $null }
+    throw "Could not parse ScriptVersion from $Origin"
+}
+
+# What the script actually DOES, with comments and layout removed: the PowerShell token
+# stream minus comments, newlines and line continuations. Lets the version-bump guard tell
+# a behaviour change (must be versioned -- consumers act on the version) apart from a
+# comment fix or reflow (nobody needs to know). Tokenising rather than regex-stripping
+# keeps '#' inside strings from being mistaken for a comment.
+function Get-CodeFingerprint {
+    param([string]$Text, [string]$Origin)
+    $tokens = $null
+    $errors = $null
+    [System.Management.Automation.Language.Parser]::ParseInput($Text, [ref]$tokens, [ref]$errors) | Out-Null
+    if ($errors -and $errors.Count -gt 0) {
+        throw "Parse error in ${Origin}: $($errors[0])"
+    }
+    $ignored = @('Comment', 'NewLine', 'LineContinuation', 'EndOfInput')
+    return (($tokens | Where-Object { $ignored -notcontains $_.Kind.ToString() } | ForEach-Object { $_.Text }) -join "`n")
+}
+
+# ------------------------------------------------------------------ 1. source
+$sourceContent = Get-Content $BootstrapSource -Raw
+$sourceBytes   = Get-PublishBytes $sourceContent
+$scriptVersion = Get-BootstrapScriptVersion -Content $sourceContent -Origin $BootstrapSource
+Write-Host "Bootstrap script version: $scriptVersion"
+
+# ------------------------------------------------------------------ 2. dev render
+$stableUrlLiteral = '$AgentDownloadUrl = "https://download.autopilotmonitor.com/agent/AutopilotMonitor-Agent.zip"'
+$devUrlLiteral    = '$AgentDownloadUrl = "https://download.autopilotmonitor.com/agent/AutopilotMonitor-Agent-dev.zip"'
+$stableManLiteral = '$VersionJsonName = "version.json"'
+$devManLiteral    = '$VersionJsonName = "version-dev.json"'
+
+if ($sourceContent.IndexOf($stableUrlLiteral) -lt 0 -or $sourceContent.IndexOf($stableManLiteral) -lt 0) {
+    throw "Bootstrap dev-render: anchor literal missing in $BootstrapSource"
+}
+$devContent = $sourceContent.Replace($stableUrlLiteral, $devUrlLiteral).Replace($stableManLiteral, $devManLiteral)
+Write-Host "Rendered $DevBlob (dev agent URL + version-dev.json)"
+
+# ------------------------------------------------------------------ 3. bump guard
+$publishedBytes = Get-PublishedBytes "$AliasUrl/$BootstrapBlob"
+if ($null -eq $publishedBytes) {
+    Write-Host 'No published bootstrap yet -- version-bump guard skipped (first publish)'
+} elseif ((Get-Sha256 $publishedBytes) -eq (Get-Sha256 $sourceBytes)) {
+    Write-Host 'Published bootstrap is already byte-identical to the source'
+} else {
+    $publishedText    = [System.Text.Encoding]::UTF8.GetString($publishedBytes)
+    $publishedVersion = Get-BootstrapScriptVersion -Content $publishedText -Origin "$AliasUrl/$BootstrapBlob" -Optional
+
+    if ($null -eq $publishedVersion) {
+        Write-Host "::warning::The published $BootstrapBlob is not a readable bootstrap script (no ScriptVersion found). Republishing over it."
+    } elseif ($publishedVersion -ne $scriptVersion) {
+        Write-Host "Version bump: $publishedVersion -> $scriptVersion"
+    } elseif ((Get-CodeFingerprint -Text $publishedText -Origin "$AliasUrl/$BootstrapBlob") -eq
+              (Get-CodeFingerprint -Text $sourceContent -Origin $BootstrapSource)) {
+        # Comments, typos in comments, reflow -- nothing a consumer of the version can act on.
+        Write-Host "::warning::$BootstrapBlob changed in comments or formatting only; publishing under the unchanged version $scriptVersion."
+    } else {
+        throw ("Version-bump guard: $BootstrapBlob changed behaviour but ScriptVersion is still $scriptVersion. " +
+               "Bump it in $BootstrapSource -- the docs badge, version.json.bootstrapVersion and the " +
+               'portal outdated-script hint all read that value, and customers decide from it whether ' +
+               'to re-upload their Intune copy. Comment-only and formatting changes do not need a bump.')
+    }
+}
+
+# ------------------------------------------------------------------ 4. upload
+# Sources beyond the bootstrap pair, read straight from the repo.
+$extraSources = @(
+    @{ Path = 'scripts/Bootstrap/Test-ShouldBootstrapAgent.ps1';       BlobName = 'Test-ShouldBootstrapAgent.ps1' }
+    # Customer-side Graph add-on grant script -- docs and admin UI link it directly.
+    @{ Path = 'scripts/CustomerSetup/Grant-AutopilotMonitorAddOn.ps1'; BlobName = 'Grant-AutopilotMonitorAddOn.ps1' }
+)
+# Uninstall-AutopilotMonitor.ps1 is deliberately NOT published: nothing links it, and
+# an unauthenticated uninstall script on the public download host is not a feature.
+
+$publishSet = [System.Collections.Generic.List[object]]::new()
+$publishSet.Add([pscustomobject]@{ BlobName = $BootstrapBlob; Bytes = $sourceBytes })
+$publishSet.Add([pscustomobject]@{ BlobName = $DevBlob;       Bytes = (Get-PublishBytes $devContent) })
+foreach ($extra in $extraSources) {
+    $extraPath = Join-Path $RepoRoot $extra.Path
+    if (-not (Test-Path $extraPath)) {
+        throw "Publish source missing: $extraPath"
+    }
+    $publishSet.Add([pscustomobject]@{ BlobName = $extra.BlobName; Bytes = (Get-PublishBytes (Get-Content $extraPath -Raw)) })
+}
+
+$legacySas = if ($LegacySasToken) { $LegacySasToken.TrimStart('?') } else { '' }
+$writeSas  = if ($SasToken) { $SasToken.TrimStart('?') } else { '' }
+
+foreach ($item in $publishSet) {
+    # Explicit type, not a convenience: an Object[] body is uploaded as space-separated
+    # decimals rather than raw bytes, and every hash check still passes because [byte[]]
+    # parameter coercion repairs it everywhere EXCEPT the wire.
+    [byte[]]$bytes = $item.Bytes
+    $item | Add-Member -NotePropertyName Sha256 -NotePropertyValue (Get-Sha256 $bytes) -Force
+
+    if ($DryRun) {
+        # Doubles as a drift check: says per blob whether the alias already serves this source.
+        $served = Get-PublishedBytes "$AliasUrl/$($item.BlobName)"
+        $state = if ($null -eq $served) { 'MISSING on the alias' }
+                 elseif ((Get-Sha256 $served) -eq $item.Sha256) { 'already current' }
+                 else { 'STALE on the alias' }
+        Write-Host "  [dry-run] $($item.BlobName) ($($bytes.Length) bytes, sha256 $($item.Sha256)) -- $state"
+        continue
+    }
+
+    # no-cache on every blob: they all rotate in place and the download alias fronts them
+    # with Front Door. Route caching is disabled there, but a stale script paired with a
+    # fresh manifest would fail the bootstrap SHA check -- this keeps that class of bug
+    # impossible even if caching is ever re-enabled.
+    $headers = @{ 'x-ms-blob-type' = 'BlockBlob'; 'Content-Type' = $ScriptContentType; 'x-ms-blob-cache-control' = 'no-cache' }
+    Invoke-RestMethod -Uri "$ContainerUrl/$($item.BlobName)?$writeSas" -Method Put -Headers $headers -Body $bytes | Out-Null
+
+    # Read straight back from the blob (authoritative, no CDN in the way) before touching the
+    # mirror or the next file. The alias verification at the end would catch a bad body too,
+    # but only after every blob was already overwritten -- these are live customer downloads.
+    $written = Get-PublishedBytes "$ContainerUrl/$($item.BlobName)"
+    if ($null -eq $written -or (Get-Sha256 $written) -ne $item.Sha256) {
+        $writtenLength = if ($null -eq $written) { 'missing' } else { "$($written.Length) bytes" }
+        throw ("Upload of $($item.BlobName) did not round-trip: sent $($bytes.Length) bytes, " +
+               "blob now holds $writtenLength. Publishing stopped before the mirror and the " +
+               'remaining files, so no further blob was touched.')
+    }
+    Write-Host "  uploaded $($item.BlobName) ($($bytes.Length) bytes, round-trip verified)"
+
+    if ($legacySas) {
+        try {
+            Invoke-RestMethod -Uri "$LegacyContainerUrl/$($item.BlobName)?$legacySas" -Method Put -Headers $headers -Body $bytes | Out-Null
+            Write-Host "  mirrored $($item.BlobName) to legacy storage"
+        } catch {
+            Write-Host "::warning::legacy mirror failed for $($item.BlobName) -- $($_.Exception.Message)"
+        }
+    }
+}
+
+# ------------------------------------------------------------------ 5. version oracles
+# version.json is the agent manifest; only bootstrapVersion belongs to us. Read from the
+# blob (not the alias) for an authoritative ETag, write back under If-Match so a concurrent
+# agent release cannot lose its version/sha256 fields.
+if (-not $DryRun) {
+    try {
+        $manifestResp = Invoke-WebRequest -Uri "$ContainerUrl/version.json" -Method Get -UseBasicParsing
+        $manifestRaw = if ($manifestResp.Content -is [byte[]]) {
+            [System.Text.Encoding]::UTF8.GetString($manifestResp.Content)
+        } else { [string]$manifestResp.Content }
+        $manifest = $manifestRaw | ConvertFrom-Json
+
+        if ($manifest.bootstrapVersion -eq $scriptVersion) {
+            Write-Host "version.json already reports bootstrapVersion $scriptVersion"
+        } else {
+            $etag = '"' + ([string]($manifestResp.Headers['ETag'] | Select-Object -First 1)).Trim('"') + '"'
+            $manifest | Add-Member -NotePropertyName 'bootstrapVersion' -NotePropertyValue $scriptVersion -Force
+            $body = [System.Text.Encoding]::UTF8.GetBytes(($manifest | ConvertTo-Json -Compress))
+            $manifestHeaders = @{
+                'x-ms-blob-type'          = 'BlockBlob'
+                'Content-Type'            = 'application/json'
+                'x-ms-blob-cache-control' = 'no-cache'
+                'If-Match'                = $etag
+            }
+            Invoke-RestMethod -Uri "$ContainerUrl/version.json?$writeSas" -Method Put -Headers $manifestHeaders -Body $body | Out-Null
+            Write-Host "version.json bootstrapVersion -> $scriptVersion (agent fields untouched)"
+
+            if ($legacySas) {
+                try {
+                    $legacyHeaders = @{ 'x-ms-blob-type' = 'BlockBlob'; 'Content-Type' = 'application/json'; 'x-ms-blob-cache-control' = 'no-cache' }
+                    Invoke-RestMethod -Uri "$LegacyContainerUrl/version.json?$legacySas" -Method Put -Headers $legacyHeaders -Body $body | Out-Null
+                } catch {
+                    Write-Host "::warning::legacy mirror failed for version.json -- $($_.Exception.Message)"
+                }
+            }
+        }
+    } catch {
+        if ((Get-HttpStatus $_) -eq 412) {
+            throw 'version.json changed while publishing (concurrent agent release). Re-run this workflow.'
+        }
+        throw
+    }
+}
+
+$tableSas = if ($TableSasToken) { $TableSasToken.TrimStart('?') } else { '' }
+if ($DryRun) {
+    Write-Host "  [dry-run] would set AdminConfiguration.LatestBootstrapV2ScriptVersion = $scriptVersion"
+} elseif ([string]::IsNullOrEmpty($tableSas) -or $tableSas -eq 'XXX') {
+    Write-Host 'SKIPPED: AdminConfiguration update -- set AZURE_TABLE_ADMIN_SAS_TOKEN to enable the portal version oracle'
+} else {
+    $tableHeaders = @{
+        'Content-Type' = 'application/json'
+        'Accept'       = 'application/json;odata=nometadata'
+        'If-Match'     = '*'
+    }
+    $tableBody = @{ LatestBootstrapV2ScriptVersion = $scriptVersion } | ConvertTo-Json
+    Invoke-RestMethod -Uri "$TableUrl`?$tableSas" -Method Merge -Headers $tableHeaders -Body $tableBody | Out-Null
+    Write-Host "AdminConfiguration.LatestBootstrapV2ScriptVersion = $scriptVersion"
+}
+
+# ------------------------------------------------------------------ 6. verify via alias
+if (-not $DryRun) {
+    $pending = [System.Collections.ArrayList]::new()
+    $publishSet | ForEach-Object { [void]$pending.Add($_) }
+
+    for ($attempt = 1; $attempt -le 6 -and $pending.Count -gt 0; $attempt++) {
+        if ($attempt -gt 1) { Start-Sleep -Seconds 20 }
+        foreach ($item in @($pending)) {
+            $servedBytes = Get-PublishedBytes "$AliasUrl/$($item.BlobName)"
+            if ($null -ne $servedBytes -and (Get-Sha256 $servedBytes) -eq $item.Sha256) {
+                Write-Host "  verified $($item.BlobName) via $AliasUrl"
+                $pending.Remove($item)
+            }
+        }
+        if ($pending.Count -gt 0) {
+            Write-Host "  attempt $attempt : $($pending.Count) blob(s) not current on the alias yet"
+        }
+    }
+
+    if ($pending.Count -gt 0) {
+        $names = ($pending | ForEach-Object { $_.BlobName }) -join ', '
+        throw ("Alias still serves stale content for: $names. The blobs were written, so this is a Front Door " +
+               'cache issue -- purge with: az afd endpoint purge --resource-group rg-autopilotmonitor-prd-gwc ' +
+               "--profile-name autopilotmonitor-fd --endpoint-name apm-download --content-paths '/agent/*'")
+    }
+}
+
+if ($env:GITHUB_STEP_SUMMARY) {
+    $mode = if ($DryRun) { 'DRY RUN -- nothing uploaded' } else { 'published + verified via the download alias' }
+    $summary = @(
+        "### Bootstrap scripts: $mode",
+        '',
+        "Bootstrap script version: **$scriptVersion**",
+        ''
+    ) + ($publishSet | ForEach-Object { "- $($_.BlobName) -- sha256 $($_.Sha256)" })
+    ($summary -join [Environment]::NewLine) | Out-File -FilePath $env:GITHUB_STEP_SUMMARY -Append -Encoding utf8
+}
+
+Write-Host 'Done.'

.github/workflows/bootstrap-script-gates.yml

@@ -0,0 +1,63 @@
+name: Bootstrap script gates
+
+# Quality gate for the customer-facing PowerShell scripts, factored out so it exists
+# once and both callers run the identical checks:
+#   * pester.yml           -- pull requests (reports, does not block the merge button)
+#   * publish-scripts.yml  -- pushes to main, where it BLOCKS the upload to the
+#                             download alias. Devices execute these scripts as SYSTEM
+#                             during enrollment, so a red suite must never ship.
+
+on:
+  workflow_call:
+
+permissions:
+  contents: read
+
+jobs:
+  gates:
+    name: Bootstrap guard tests (PS 5.1)
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Install Pester 5+
+        shell: powershell
+        run: |
+          Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Force -Scope CurrentUser | Out-Null
+          Install-Module Pester -Scope CurrentUser -Force -SkipPublisherCheck -MinimumVersion 5.5.0
+
+      # Windows PowerShell 5.1 on purpose: that is the runtime IME uses to execute
+      # platform scripts, so guard/relax logic is verified without resetting a device.
+      - name: Run Pester
+        shell: powershell
+        run: |
+          Import-Module Pester -MinimumVersion 5.5.0
+          $c = New-PesterConfiguration
+          $c.Run.Path = 'scripts/Bootstrap'
+          $c.Run.Exit = $true
+          $c.Output.Verbosity = 'Detailed'
+          Invoke-Pester -Configuration $c
+
+      - name: Guard scripts stay pure ASCII
+        shell: powershell
+        run: |
+          $failed = $false
+          Get-ChildItem 'scripts/Bootstrap' -Filter '*.ps1' | ForEach-Object {
+            $bytes = [System.IO.File]::ReadAllBytes($_.FullName)
+            for ($i = 0; $i -lt $bytes.Length; $i++) {
+              if ($bytes[$i] -gt 127) {
+                Write-Host "::error file=scripts/Bootstrap/$($_.Name)::Non-ASCII byte 0x$('{0:X2}' -f $bytes[$i]) at offset $i. PS 5.1 (IME) reads BOM-less files as ANSI and corrupts multi-byte chars."
+                $failed = $true
+                break
+              }
+            }
+          }
+          if ($failed) { exit 1 }
+          Write-Host 'All bootstrap scripts are pure ASCII.'
+
+      # The publish chain renders the -Dev variant by literal substitution and refuses to
+      # ship when an anchor moved. Running it dry here surfaces that (and any drift against
+      # the alias) on the PR instead of on the push that would have published.
+      - name: Publish dry run (dev-render anchors + version-bump guard + drift)
+        shell: pwsh
+        run: ./.github/scripts/Publish-BootstrapScripts.ps1 -DryRun

.github/workflows/build-agent.yml

@@ -33,6 +33,13 @@ permissions:
   id-token: write      # keyless Sigstore signing (artifact attestation)
   attestations: write  # store the provenance attestation
 
+# Shared with publish-scripts.yml: both write version.json (this workflow the agent fields,
+# the script publisher bootstrapVersion under If-Match). Serialising them keeps a script push
+# from colliding with a release. Never cancel -- a half-published set is worse than a queue.
+concurrency:
+  group: agent-blob-publish
+  cancel-in-progress: false
+
 env:
   LINE_MAJOR: 2
   AGENT_PROJECT: src/Agent/AutopilotMonitor.Agent.V2/AutopilotMonitor.Agent.V2.csproj
@@ -46,8 +53,6 @@ env:
   VERSIONED_ZIP: AutopilotMonitor-Agent-v2.zip
   STABLE_ZIP: AutopilotMonitor-Agent.zip
   STABLE_MANIFEST: version.json
-  STABLE_BOOTSTRAP: Install-AutopilotMonitor.ps1
-  STABLE_BOOTSTRAP_DEV: Install-AutopilotMonitor-Dev.ps1
 
 jobs:
   build:
@@ -181,6 +186,8 @@ jobs:
           # commit/buildUtc are the same two fields the backend and MCP manifests carry —
           # additive, and the bootstrap reads this file by field name, so older installers
           # ignore them. sha256/bootstrapVersion stay: those are the customer contract.
+          # bootstrapVersion is seeded here so the published manifest is never briefly
+          # missing it; Publish-BootstrapScripts.ps1 owns and re-asserts the field afterwards.
           $manifest | Add-Member -NotePropertyName "sha256" -NotePropertyValue $sha256Hash -Force
           $manifest | Add-Member -NotePropertyName "commit" -NotePropertyValue '${{ github.sha }}'.Substring(0, 7) -Force
           $manifest | Add-Member -NotePropertyName "buildUtc" -NotePropertyValue ([DateTime]::UtcNow.ToString('o')) -Force
@@ -190,29 +197,12 @@ jobs:
           $manifest | ConvertTo-Json -Compress | Set-Content $env:MANIFEST_NAME -Encoding UTF8
           Write-Host "$env:MANIFEST_NAME content: $(Get-Content $env:MANIFEST_NAME)"
 
-          # Bootstrap = single generic source. Stable variant = source 1:1.
-          # Dev variant = literal-string substitution of the two URL/manifest defaults.
-          # Both are uploaded only on -PublishAsStable runs (versioned namespace doesn't carry bootstrap).
-          if ('${{ inputs.publish_as_stable }}' -eq 'true') {
-            $stableUrl = '$AgentDownloadUrl = "https://download.autopilotmonitor.com/agent/AutopilotMonitor-Agent.zip"'
-            $devUrl    = '$AgentDownloadUrl = "https://download.autopilotmonitor.com/agent/AutopilotMonitor-Agent-dev.zip"'
-            $stableMan = '$VersionJsonName = "version.json"'
-            $devMan    = '$VersionJsonName = "version-dev.json"'
-
-            Copy-Item $env:BOOTSTRAP_SOURCE $env:STABLE_BOOTSTRAP -Force
-            $content = Get-Content $env:BOOTSTRAP_SOURCE -Raw
-            if ($content.IndexOf($stableUrl) -lt 0 -or $content.IndexOf($stableMan) -lt 0) {
-              Write-Error "Bootstrap dev-render: anchor literal missing in $env:BOOTSTRAP_SOURCE"
-              exit 1
-            }
-            $devContent = $content.Replace($stableUrl, $devUrl).Replace($stableMan, $devMan)
-            [System.IO.File]::WriteAllText("$env:STABLE_BOOTSTRAP_DEV", $devContent, (New-Object System.Text.UTF8Encoding $false))
-          }
+          # The customer-facing scripts (stable + dev render, test script, grant script) are
+          # published by .github/scripts/Publish-BootstrapScripts.ps1 -- see the upload step.
 
           "versioned_zip_release=$versionedZip" >> $env:GITHUB_OUTPUT
           "sha256=$sha256Hash" >> $env:GITHUB_OUTPUT
           "exe_sha256=$exeSha256Hash" >> $env:GITHUB_OUTPUT
-          "bootstrap_version=$bootstrapVersion" >> $env:GITHUB_OUTPUT
 
       - name: Upload to Azure Blob Storage
         if: inputs.upload_blob
@@ -264,22 +254,21 @@ jobs:
             Write-Host "PUBLISH AS STABLE -- writing V2 into stable namespace (customer-facing)" -ForegroundColor Magenta
             Send-Blob -Local $env:VERSIONED_ZIP -BlobName $env:STABLE_ZIP -ContentType "application/zip"
             Send-Blob -Local $env:MANIFEST_NAME -BlobName $env:STABLE_MANIFEST -ContentType "application/json"
-            Send-Blob -Local $env:STABLE_BOOTSTRAP -BlobName $env:STABLE_BOOTSTRAP -ContentType "text/plain; charset=utf-8"
-            Send-Blob -Local $env:STABLE_BOOTSTRAP_DEV -BlobName $env:STABLE_BOOTSTRAP_DEV -ContentType "text/plain; charset=utf-8"
 
-            if (Test-Path "scripts/Bootstrap/Test-ShouldBootstrapAgent.ps1") {
-              Send-Blob -Local "scripts/Bootstrap/Test-ShouldBootstrapAgent.ps1" -BlobName "Test-ShouldBootstrapAgent.ps1" -ContentType "text/plain; charset=utf-8"
-            }
-
-            # Customer-side Graph add-on grant script -- docs and admin UI link
-            # https://download.autopilotmonitor.com/agent/Grant-AutopilotMonitorAddOn.ps1
-            if (Test-Path "scripts/CustomerSetup/Grant-AutopilotMonitorAddOn.ps1") {
-              Send-Blob -Local "scripts/CustomerSetup/Grant-AutopilotMonitorAddOn.ps1" -BlobName "Grant-AutopilotMonitorAddOn.ps1" -ContentType "text/plain; charset=utf-8"
-            }
+            # Customer-facing scripts: same publisher publish-scripts.yml runs on every push
+            # to main, so a release lands a set that is consistent with what is already live
+            # (dev render, version-bump guard, bootstrapVersion oracles, alias verification).
+            # Runs AFTER version.json so its bootstrapVersion read sees this build's manifest.
+            ./.github/scripts/Publish-BootstrapScripts.ps1 `
+              -SasToken '${{ secrets.AZURE_BLOB_AGENT_SAS_TOKEN }}' `
+              -LegacySasToken '${{ secrets.AZURE_BLOB_AGENT_LEGACY_SAS_TOKEN }}' `
+              -TableSasToken '${{ secrets.AZURE_TABLE_ADMIN_SAS_TOKEN }}'
           }
 
           # Update AdminConfiguration LatestAgentV2* -- ONLY on stable cutover. The hash-oracle
           # must never point at a build that is not actually in the stable namespace.
+          # LatestBootstrapV2ScriptVersion is NOT set here: it belongs to the script publisher
+          # above, which also owns it on script-only pushes. One writer per field.
           $tableSasToken = "${{ secrets.AZURE_TABLE_ADMIN_SAS_TOKEN }}".TrimStart('?')
           if ('${{ inputs.publish_as_stable }}' -ne 'true') {
             Write-Host "SKIPPED: AdminConfiguration update (versioned-only run -- stable namespace unchanged)"
@@ -289,22 +278,18 @@ jobs:
             $sha256 = "${{ steps.artifact.outputs.sha256 }}"
             $exeSha256 = "${{ steps.artifact.outputs.exe_sha256 }}"
             $agentVersion = "${{ steps.version.outputs.version }}"
-            $bootstrapVersion = "${{ steps.artifact.outputs.bootstrap_version }}"
             $tableUrl = "https://autopilotmonitoreu.table.core.windows.net/AdminConfiguration(PartitionKey='GlobalConfig',RowKey='config')?$tableSasToken"
             $tableBody = @{
               LatestAgentV2Version    = $agentVersion
               LatestAgentV2Sha256     = $sha256
               LatestAgentV2ExeSha256  = $exeSha256
             }
-            if ($bootstrapVersion) {
-              $tableBody["LatestBootstrapV2ScriptVersion"] = $bootstrapVersion
-            }
             Invoke-RestMethod -Uri $tableUrl -Method Merge -Headers @{
               "Content-Type" = "application/json"
               "Accept"       = "application/json;odata=nometadata"
               "If-Match"     = "*"
             } -Body ($tableBody | ConvertTo-Json)
-            Write-Host "AdminConfiguration updated: V2 version=$agentVersion, sha256=$sha256, exeSha256=$exeSha256, bootstrapVersion=$bootstrapVersion"
+            Write-Host "AdminConfiguration updated: V2 version=$agentVersion, sha256=$sha256, exeSha256=$exeSha256"
           }
 
       # Sigstore keyless provenance: binds the ZIP digest to this workflow run (repo, ref,

.github/workflows/pester.yml

@@ -1,16 +1,20 @@
 name: Pester (Bootstrap scripts)
 
-# Runs the Pester suite for the Intune bootstrap scripts under Windows PowerShell 5.1
-# (the runtime IME uses to execute platform scripts) so guard/relax logic changes are
-# verified without resetting a device. Like ci.yml it reports rather than blocks.
+# Pull-request view of the bootstrap script gates. Like ci.yml it reports rather than
+# blocks the merge button.
+#
+# There is deliberately no push trigger: publish-scripts.yml runs the very same
+# reusable gate workflow on every push to main and blocks the upload to the download
+# alias on it. A push trigger here would only duplicate that run, with no consequence.
 
 on:
-  push:
-    branches: [main]
-    paths: ['scripts/Bootstrap/**']
   pull_request:
     branches: [main]
-    paths: ['scripts/Bootstrap/**']
+    paths:
+      - 'scripts/Bootstrap/**'
+      - 'scripts/CustomerSetup/**'
+      - '.github/scripts/Publish-BootstrapScripts.ps1'
+      - '.github/workflows/bootstrap-script-gates.yml'
   workflow_dispatch:
 
 permissions:
@@ -21,41 +25,5 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  pester:
-    name: Bootstrap guard tests (PS 5.1)
-    runs-on: windows-latest
-    steps:
-      - uses: actions/checkout@v7
-
-      - name: Install Pester 5+
-        shell: powershell
-        run: |
-          Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Force -Scope CurrentUser | Out-Null
-          Install-Module Pester -Scope CurrentUser -Force -SkipPublisherCheck -MinimumVersion 5.5.0
-
-      - name: Run Pester
-        shell: powershell
-        run: |
-          Import-Module Pester -MinimumVersion 5.5.0
-          $c = New-PesterConfiguration
-          $c.Run.Path = 'scripts/Bootstrap'
-          $c.Run.Exit = $true
-          $c.Output.Verbosity = 'Detailed'
-          Invoke-Pester -Configuration $c
-
-      - name: Guard scripts stay pure ASCII
-        shell: powershell
-        run: |
-          $failed = $false
-          Get-ChildItem 'scripts/Bootstrap' -Filter '*.ps1' | ForEach-Object {
-            $bytes = [System.IO.File]::ReadAllBytes($_.FullName)
-            for ($i = 0; $i -lt $bytes.Length; $i++) {
-              if ($bytes[$i] -gt 127) {
-                Write-Host "::error file=scripts/Bootstrap/$($_.Name)::Non-ASCII byte 0x$('{0:X2}' -f $bytes[$i]) at offset $i. PS 5.1 (IME) reads BOM-less files as ANSI and corrupts multi-byte chars."
-                $failed = $true
-                break
-              }
-            }
-          }
-          if ($failed) { exit 1 }
-          Write-Host 'All bootstrap scripts are pure ASCII.'
+  gates:
+    uses: ./.github/workflows/bootstrap-script-gates.yml

.github/workflows/publish-scripts.yml

@@ -0,0 +1,56 @@
+name: Publish customer scripts
+
+# Keeps the scripts behind download.autopilotmonitor.com/agent/ current WITHOUT waiting
+# for an agent release. Before this workflow existed, the script blobs rotated only on a
+# publish_as_stable run of build-agent.yml, so a bootstrap fix sat unpublished until the
+# next agent cutover -- while the WDP bootstrap MSI downloads the published copy on every
+# enrolling device.
+#
+# Same publish code as the release path (.github/scripts/Publish-BootstrapScripts.ps1);
+# this workflow only supplies a second trigger for it.
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'scripts/Bootstrap/**'
+      - 'scripts/CustomerSetup/**'
+      - '.github/scripts/Publish-BootstrapScripts.ps1'
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: 'Run every check and report drift, upload nothing'
+        required: true
+        type: boolean
+        default: false
+
+permissions:
+  contents: read
+
+# Shared with build-agent.yml: a script publish and an agent release both touch
+# version.json, and the bootstrapVersion read-modify-write must not interleave with the
+# release writing its agent fields. Never cancel -- a half-published set is worse than a queue.
+concurrency:
+  group: agent-blob-publish
+  cancel-in-progress: false
+
+jobs:
+  gates:
+    uses: ./.github/workflows/bootstrap-script-gates.yml
+
+  publish:
+    name: Publish to the download alias
+    needs: gates
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Publish bootstrap + customer scripts
+        shell: pwsh
+        run: |
+          $dryRun = '${{ inputs.dry_run }}' -eq 'true'
+          ./.github/scripts/Publish-BootstrapScripts.ps1 `
+            -SasToken '${{ secrets.AZURE_BLOB_AGENT_SAS_TOKEN }}' `
+            -LegacySasToken '${{ secrets.AZURE_BLOB_AGENT_LEGACY_SAS_TOKEN }}' `
+            -TableSasToken '${{ secrets.AZURE_TABLE_ADMIN_SAS_TOKEN }}' `
+            -DryRun:$dryRun

docs/agent/cmtrace-time-resolution.md

@@ -0,0 +1,127 @@
+---
+type: concept
+title: CMTrace Time Resolution — Per-Line Self-Anchoring
+description: How the agent converts bias-less CMTrace local times to UTC without trusting any process's timezone belief — each provably fresh line anchors its own offset against the agent clock on the 15-minute grid; everything not provably fresh falls back uniformly and says so.
+resource: src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime
+tags: [agent, ime, cmtrace, timestamps, timezone, calibration, provenance]
+timestamp: 2026-08-20
+---
+
+# Problem
+
+A CMTrace line carries local time and no offset — IME 1.104 writes `DateTime.Now.TimeOfDay`
+in both of its trace listeners. Converting such a line with the reader's own
+`TimeZoneInfo.Local` silently assumes the writing and reading processes agree on the zone.
+They do not: each caches its zone at process start and follows neither a later `tzutil` nor
+a Windows auto-timezone change. The error is `Offset_writer − Offset_reader` — zero only
+when both believe the same thing, right or wrong. Field measurement over 11,068 sessions
+found 26 sessions with a real error, from +1 h to −17 h.
+
+Two designs failed before this one:
+
+* **Fix the reader's belief** (`TimeZoneInfo.ClearCachedData`, live OS offset): makes the
+  agent isolated-correct and thereby breaks the majority of sessions, where two equally
+  stale beliefs cancel.
+* **One measured offset per file** (agent 2.0.1410, reverted in `04b1a7c6`): a single log
+  file holds lines from multiple writer *eras*. `AgentExecutor.log` is written by
+  short-lived child processes whose zone belief flips per process — interleaved in one
+  file, and flipping *back* (fixture:
+  `tests/fixtures/cmtrace-logs/agentexecutor-two-writer-eras-v1.cmtrace`). Any cross-line
+  anchor — per file, or nearest-in-write-order — applies one era's offset to the other
+  era's lines. In the field this shifted `script_started` events by −9 h against their
+  correct completions.
+
+# Schema
+
+The resolution rule, in order:
+
+1. **Writer-declared bias** (`+480` suffix): authoritative, used as-is. Never a calibration
+   anchor — it needs no measurement and must not overwrite one.
+2. **Per-line self-anchoring** — only for lines read in a *provably fresh* pass:
+
+   ```
+   offset_line = round((local − agentUtcNow) / 15 min) · 15 min
+   lineUtc     = local − offset_line
+   ```
+
+   Every real UTC offset is a whole multiple of 15 minutes, so the rounding absorbs poll
+   and flush latency. No cross-line state exists, so interleaved eras resolve line by
+   line — the property the fixture test pins. The line's own timestamp still contributes
+   sub-poll precision and ordering (two lines 6 ms apart stay 6 ms apart; a plain
+   `occurredAt = now` could not do that). Guards: grid residual ≤ 2 min, offset within
+   UTC−12 … UTC+14.
+3. **Uniform reader-zone fallback** for everything else: wrong in absolute terms whenever
+   the writer held a different belief, but *self-consistent* — both ends of a duration are
+   wrong by the same amount, so derived durations stay right. The revert's core lesson:
+   partially corrected is strictly worse than uniformly wrong.
+
+**Freshness** is what makes rule 2 sound, and it is strict:
+
+* Every poll look at a file stamps `LastCheckedUtc` (`LogFilePositionTracker.MarkChecked`),
+  including "no new data" and an empty first sight — so a file first seen empty
+  (`AgentExecutor.log` appearing mid-enrollment) anchors from its very first content.
+* A pass's lines are fresh only if the file was previously observed *in this process* and
+  the gap since the last look is ≤ `FreshLineMaxAge` (30 s — far above the 100 ms poll,
+  far below the 13-minute zone where a line's *age* could round onto the offset grid).
+* A restart-restored position bookmark deliberately carries **no** freshness: the first
+  pass after a restart reads downtime backlog and must never anchor.
+
+**Provenance** (`sourceOffsetOrigin` in event DataJson): `bias` | `line-anchored` |
+`reader-zone-fallback` (plus retired `calibrated` from 2.0.1410 events). The applied
+offset is always recorded (`sourceOffsetMinutes`), the raw local time too
+(`sourceLocalTs`), so any event can be re-derived later. The per-*file* measurement still
+runs, purely observationally (`measuredWriterOffsetMinutes`, Info log when it disagrees
+with the process zone).
+
+# Constraints
+
+* An anchored line resolves to `now ± 2 min` *by construction*. The accepted edge: a
+  freshly written line carrying a **replayed** old timestamp whose age is exactly
+  N×15 min ± 2 min anchors to ≈now instead of its replayed past — bounded error, and
+  sub-24 h replays are treated as current by the historic-replay guard anyway.
+* Snapshot readers (`StallProbeCollector`, `LogParserCollector`) cannot tail and therefore
+  cannot prove freshness — they stay on the marked fallback. This is a documented limit,
+  not an omission; sharing the per-file measurement with them would re-apply exactly what
+  the revert removed.
+* Mixed pairs remain possible across a restart (start resolved from backlog fallback,
+  completion line-anchored) and are recognizable via provenance.
+
+# Backend regression tripwire
+
+The backend watches for the failure mode this design eliminates. On every terminal ingest
+batch, the counter reconcile's existing event-partition scan additionally collects
+`Δ = ReceivedAt − OccurredUtc` per event, split by `Source == "ImeLogTracker"` versus the
+rest (`CmTraceSkewTripwire`, hooked in `EventIngestProcessor`). If
+`median(Δ_IME) − median(Δ_other)` is a clean 15-minute multiple (residual < 2 min — the
+same constants as the anchoring grid guard above) with ≥ 20 samples over ≥ 3 distinct
+upload batches per side, a `CmTraceTimeSkewRegression` ops event fires (category Agent,
+warning), carrying all numbers plus the session's `sourceOffsetOrigin` histogram.
+Bias-dominated sessions are suppressed (writer-declared offsets cannot be an anchoring
+regression); `measuredWriterOffsetMinutes` is never consulted (sticky after era
+flip-backs). Kill switch: app setting `CmTraceSkewTripwireDisabled`. Goal state: the event
+never fires — any hit is an anchoring case the per-line design misses, or a detector bug.
+
+Device-clock problems (the customer-actionable cousin) are covered separately by the
+`clock_skew` analyze condition behind `ANALYZE-DEV-008`, which excludes IME-derived events
+precisely so an anchoring regression can never surface as a customer finding.
+
+# Citations
+
+* `CmTraceOffsetCalibrator.TryMeasureOffset` — the pure grid measurement, shared by
+  anchoring and the observational per-file path.
+* `CmTraceSkewTripwire` + `CmTraceSkewTripwireTests` — the backend tripwire above.
+* `RuleEngine.ConditionEvaluators.EvaluateClockSkewCondition` + `RuleEngineClockSkewTests`
+  — the customer-facing device-clock metrics (batch-median frames, spool-spread filter,
+  plateau step detection, end-state persistence).
+* `ImeLogTracker.LogProcessing.cs` `ResolveEntryUtc` — the resolution order above.
+* `ImeLogTrackerLineAnchoringTests` — resolves-to-T across writer beliefs, interleaved
+  eras in one chunk, freshness boundaries (first sight, empty first sight, poll gap,
+  restart restore), the grid-replay edge, and the field fixture replayed at production
+  poll cadence.
+* `CmTraceCalibratorFileIsolationTests` — pins per-file isolation of the observational
+  measurement (session e9753578 logged a cross-file pairing the committed code could not
+  be shown to produce; the mechanism remains open, the resolution path is immune by
+  design, and `CalibrateFrom` logs the anchor timestamp as a tripwire).
+* `tasks/todo.md` (2026-08-20) — full evidence trail: field measurements, the revert,
+  the two-writer-era fixture, and the disproven foreign-binary hypothesis (the SHA
+  mismatch was the known release race against the 5-minute AdminConfiguration cache).

docs/agent/post-reboot-completion-recovery.md

@@ -0,0 +1,200 @@
+---
+type: Concept
+title: ESP Completion Starvation — the sits-d Cloud-PC complex
+description: Why five Windows 365 Cloud PCs finished enrolling but never completed in the product — a SkipUser=true flow produces none of the signals every completion-gate evaluation site hangs off — plus the two adjacent defects fixed alongside (edge-only user-apps-settled synthesis, orphaned Hello-wizard restart replay) and what a Shell-Core replay deliberately does not do.
+resource: /src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals
+tags:
+  - agent
+  - esp
+  - completion
+  - skip-user
+  - reboot
+  - recovery
+timestamp: 2026-08-20T00:00:00+02:00
+---
+
+# ESP Completion Starvation — the sits-d Cloud-PC complex
+
+Seven Windows 365 Cloud PCs, same tenant, first sign-in the same morning. Two sessions
+succeeded within minutes; five sat at `Completion is waiting on: hello_resolution` from
+second five onward and ran into the six-hour max-lifetime watchdog — verdict `Incomplete`
+on devices whose users were working normally the whole time.
+
+The first diagnosis blamed the mid-ESP reboot (DeviceGuard/DmaGuard, see
+[MDM Reboot Coalescing](mdm-reboot-coalescing.md)): the agent is killed in
+`Stage=EspAccountSetup` and, so the theory went, loses the Shell-Core ESP exit to the
+downtime. The evidence disproved it. `8110e262` ran **six hours uninterrupted** after its
+last reboot with the Shell-Core watcher armed — and Windows never wrote a 62407 in all
+that time, because on these machines **the user ESP page never existed**.
+
+# Schema
+
+## The actual defect — a satisfied gate nobody evaluates
+
+The five stuck machines carried `SkipUserStatusPage=True` in the enrollment `FirstSync`
+key (read 10+ times across three agent processes, `True` on every read — not a stale
+single read). Windows honours it: no user ESP page, hence
+
+* no Shell-Core 62407 (`esp_exiting`) — the page that would exit does not exist,
+* no `AccountSetupCategory` provisioning registry — nothing writes categories for a page
+  that never renders,
+* desktop within seconds of sign-in.
+
+The reducer is *built* for this flow: **arm B** of `ShouldTransitionToAwaitingHello`
+(`SkipUserEsp == true`) declares the gate open, and the missing-prerequisites bookkeeping
+already exempts the AccountSetup gate — which is why the sessions reported only
+`hello_resolution` as missing. But the gate is a predicate, not a process. Something has
+to evaluate it, and every evaluation site hangs off a signal a skip-user flow structurally
+cannot produce:
+
+| Evaluation site | Carrier signal | On SkipUser=true |
+|---|---|---|
+| `HandleEspExitingV1` | Shell-Core 62407 | never fires |
+| `HandleEspPhaseChangedV1(FinalizingSetup)` | Shell-Core 62407 via coordinator | never fires |
+| `HandleDesktopArrivedV1` fast-path | requires Hello policy **disabled** | Hello was enabled |
+| `HandleImeUserSessionCompletedV1` arm-C attempt | requires the recorded final exit | unsatisfiable |
+
+No knock, no promotion, no `HelloSafety` — and the `AdvisoryCompletion` backstop is armed
+exclusively from an `EspExiting` signal, so it never armed either. The session idles to
+the watchdog with an open gate.
+
+## The fix — the observed skip is the exit evidence
+
+`HandleImeUserSessionCompletedV1`'s completion attempt now accepts the observed skip in
+place of the final exit (`skipUserExitEquivalent`): on a flow where no page exists, no
+exit can ever say more than the `FirstSync` read already did. Everything else stays
+mandatory — AccountSetup anchor, genuine (at-or-after-anchor) IME user-session completion,
+DAD-validated real-user desktop — which makes this knock **stricter** than the existing
+Shell-Core-carried arm-B promotion (pinned in `ClassicAwaitingHelloGuardTests`, which
+requires no IME or desktop evidence at all). Hello semantics ride the existing rails:
+enabled-or-unknown promotes to `AwaitingHello` with `HelloSafety` armed (on Cloud PCs
+reached via RDP the Hello wizard never appears, so the synthetic timeout resolves the
+wait), disabled completes directly with the synthetic `Skipped` outcome.
+
+The knock deliberately lives on the IME user-session edge, not on desktop arrival:
+
+* **Ordering-robust against Fix 10.** An `EspPhaseChanged(AccountSetup)` arriving on
+  `AwaitingHello` bounces the stage back and cancels `HelloSafety` (the premature-promotion
+  guard). The IME AccountSetup phase line lands *after* the desktop on this flow, so a
+  desktop-side knock would be undone two signals later. The IME phase line always precedes
+  the user-session-complete line in log order, so a bounced promotion is re-knocked by the
+  very next re-emission — including the restart re-parse.
+* **Right semantics.** The IME user session completes when the required-app processing is
+  done; a desktop-side knock would mark the session `Succeeded` mid-installation.
+* Device Preparation is excluded — WDP keeps its Hello+Desktop conjunction and the
+  `DevicePrepCompletion` backstop.
+
+`ClassicSkipUserEspUserSessionCompletionTests` replays the real `8110e262` signal ordering
+end to end (bootstrap `EspConfigDetected` → Hello enabled → desktop → AccountSetup anchor →
+IME completion → HelloSafety → `enrollment_complete`), including the Fix-10
+bounce-then-re-knock cycle, and pins the negative space (no skip observed / no desktop /
+ghost pre-anchor IME completion / WDP).
+
+Why five of seven identically administered Cloud PCs carried `SkipUserStatusPage=True` is
+a tenant-side question (ESP profile assignment state at each machine's provisioning
+moment); the value did not change during any observed session, and machine age does not
+cleanly explain the split. The agent's job is to complete the flow Windows actually ran —
+which it now does.
+
+## Adjacent defect — the synthesis was edge-triggered
+
+This one is real but belongs to the `SkipUser=false` flow (the two sessions that
+succeeded). The user-apps-settled synthesis
+(`MaybeSynthesizeAccountSetupCompleteFromSettledUserApps`, session `caa6cf50`) ran **only**
+from `OnEspExited`. On a tenant with ~138 required apps the ESP page exits while apps are
+still in flight: the single attempt misses and nothing ever re-checks, even when every
+tracked app reaches a terminal state minutes later.
+
+The ESP exit is an **edge** (happens once); settled user-ESP apps are a **level** (reached
+later). `EspAndHelloTracker` records the edge in `_espExitObserved` and exposes
+`ReevaluateUserAppsSettledSynthesis()`, chained into `ImeLogTracker.OnAppStateChanged` and
+into the post-restore `onStateRestored` callback (a live exit observed before the IME
+state restore completes would otherwise never get a second look). Gate conditions are
+unchanged — no new completion path, only a second opportunity for the existing one. Only a
+**live, confirmed post-AccountSetup** exit may be remembered
+(`IsConfirmedPostAccountSetupExit`, stricter than the `IsIntermediateDeviceEspExit`
+forward guard: unknown counts as not confirmed).
+
+## Adjacent defect — the restart replay was never wired up
+
+`ShellCoreTracker`'s backfill had existed since session `772fe502` with **no caller**; the
+Shell-Core `EventLogWatcher` only delivers records written after `Start()`.
+`EspAndHelloHost.Start()` now calls it as `BackfillRecentHelloWizardStart` — which is
+exactly what it does and all it does:
+
+| Record | Replayed | Why |
+|---|---|---|
+| 62404 Hello-wizard start | **yes** | Conservative: vetoes a premature "Hello is disabled" skip, can never complete a session by itself. The observation `772fe502` was about. |
+| 62407 ESP exit | **no** | Cannot be placed in time — see below. |
+| 62407 ESP failure | **no** | Re-injecting a historic failure as fresh can fail a session that recovered on retry (`ANALYZE-ESP-006`). |
+
+A replayed exit is unusable, and every candidate ordering mechanism fails independently:
+
+1. Windows writes the **identical** description `CommercialOOBE_ESPProgress_Page_Exiting`
+   for the intermediate DeviceSetup→AccountSetup transition and the final exit.
+2. Every post-hoc ordering probe (AccountSetup registry, settled-apps) reads state as it
+   is **now**, not as it was at the event's time.
+3. The reducer orders exits by **ingest ordinal**, not timestamp
+   (`IsPostAccountSetupFinalExit`) — a historic exit replayed today gets a fresher ordinal
+   than reality and reads as post-AccountSetup by construction.
+4. `HandleEspExitingV1` passes `espFinalExitInFlight: true` for every arriving exit; with
+   restored state, arm C would open on a historic intermediate exit.
+
+`ClassicEspExitingOnRestoredStateTests` pins that the reducer *does* open on any arriving
+exit; `ShellCoreTrackerReplayScopeTests` pins that the replay never produces one. Skipped
+62407 records are counted and reported once as an `agent_trace`
+(`reason: replayed_62407_not_orderable`) — silently dropping evidence is how this class of
+bug survives.
+
+**Residual gap, named honestly:** a `SkipUser=false` session whose final exit falls
+exactly into an agent downtime *and* whose AccountSetup category never resolves
+(`1ec8f4c6` shape) still has no completion carrier after the restart. The normal case is
+covered — `ProvisioningStatusTracker` reads the current registry at startup, so a
+category that resolved during the downtime fires arm A. The residual shape is rare,
+surfaced by `ANALYZE-ESP-005` via the `session_stalled` interim trigger, and deliberately
+not patched with a replay that cannot be ordered.
+
+### Sizing the replay window
+
+A constant is provably wrong: the scheduled task has a `BootTrigger` only
+(`Program.InstallMode.BuildScheduledTaskXml`) — after an `exception_crash` the agent does
+not return until the next boot. `ResolveEspExitBackfillLookbackMinutes` reaches back to
+the last moment the previous run is known to have been alive (max of `snapshot.json`
+mtime and `LastBootUtc` for kill-type exits), floored at 5 minutes, capped at 360, off on
+`first_run`, and immune to cross-reboot clock skew (a future timestamp is ignored).
+
+# Examples
+
+Tenant `sits-d.cloud`, 2026-08-19, seven Windows 365 Cloud PCs, first sign-ins the same
+morning. The discriminator is a single registry value:
+
+| Session | SkipUser | `esp_exiting` | AccountSetup registry | Reboots | Outcome |
+|---|---|---|---|---|---|
+| `08fc6bda` | False | yes | yes | 0 | Succeeded (10 min) |
+| `3b9291aa` | False | yes | yes | 0 | Succeeded (2.1 h) |
+| `8110e262` | True | — | — | 2 | Incomplete (6 h watchdog) |
+| `a89aac2d` | True | — | — | 1 | Incomplete |
+| `e7ba63c9` | True | — | — | 1 | Incomplete |
+| `cb4a485a` | True | — | — | 2 | Incomplete |
+| `3d6278fb` | True | — | — | 1 | Incomplete |
+
+The reboot correlation was a red herring: `8110e262` ran six hours live after its final
+reboot and would have seen every signal. `8110e262` and `a89aac2d` both reached
+`138/138 completed, 0 failed` and a genuine IME user-session completion — with the fix,
+all five complete a few minutes after their IME user session settles.
+
+`08fc6bda` exercises the edge-level fix on the same day: ESP page exited normally while
+`categorySucceeded` never confirmed — completed via the user-apps-settled synthesis.
+`3b9291aa` shows the independent starvation visibility gap: 99 `app_install_starved`
+events on a session recorded as `Succeeded` — surfaced from now on by `ANALYZE-APP-016`.
+
+# Citations
+
+* `src/Shared/AutopilotMonitor.DecisionCore/Engine/DecisionEngine.Classic.cs` — `HandleImeUserSessionCompletedV1`, `skipUserExitEquivalent`
+* `src/Shared/AutopilotMonitor.DecisionCore/Engine/DecisionEngine.Shared.cs` — `ShouldTransitionToAwaitingHello` (arm B)
+* `src/Agent/AutopilotMonitor.DecisionCore.Tests/ClassicSkipUserEspUserSessionCompletionTests.cs` — end-to-end replay of the 8110e262 ordering
+* `src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/ShellCoreTracker.cs` — `BackfillRecentHelloWizardStart`, `ReplayBackfillRecords`
+* `src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/EspAndHelloTracker.cs` — `_espExitObserved`, `ReevaluateUserAppsSettledSynthesis`
+* `src/Agent/AutopilotMonitor.Agent.V2.Core/Orchestration/DefaultComponentFactory.cs` — lookback sizing, `OnAppStateChanged` chaining
+* [MDM Reboot Coalescing](mdm-reboot-coalescing.md) — the policy attribution for the reboots themselves
+* [Decision Engine](decision-engine.md) — the AccountSetup gate and completion arms

docs/agent/wdp-scenario-gates.md

@@ -0,0 +1,108 @@
+---
+type: concept
+title: WDP Scenario Gates & Completion Backstop
+description: How the agent gates Autopilot/ESP-only machinery off on Windows Device Preparation (WDP) sessions and how a WDP session resolves without any ESP signal.
+resource: agent
+tags: [wdp, device-preparation, decision-engine, collectors, completion]
+timestamp: 2026-08-18
+---
+
+# Schema
+
+Windows Device Preparation (Autopilot v2, "WDP") has **no deployment profile and no ESP**.
+Before the afee7ae0 audit (2026-08-18) the agent ran the full Classic apparatus anyway:
+misleading `autopilot_profile_missing` warnings, a ZTD event-log query + HTTP probe,
+`esp_config_detected` "unknown/unknown" noise, an Autopilot-channel noise flood
+(EventIDs 100/417/418/1005, 900+ occurrences per session), a subtree registry watcher
+woken by every WDP progress write, and — worst — no completion path when Hello never
+resolved (park until the 360-min watchdog).
+
+## Detection: deterministic vs. fallback
+
+`EnrollmentRegistryDetector` classifies v2 through three rules. Only the first is
+**deterministic WDP**:
+
+1. `AutopilotSettings\DevicePreparation\BootstrapperAgent` subkey with non-empty
+   `ExecutionContext` → the WDP policy orchestration tree, present before the agent
+   starts. Exposed as `EnrollmentRegistryDetector.IsDeterministicDevicePreparation()`
+   and the `DevicePreparationExecutionContextRule` constant.
+2./3. `CloudAssignedDeviceRegistration == 2` / `CloudAssignedEspEnabled == 0` —
+   profile-derived legacy signals. They imply a REAL Autopilot profile (just ESP-less),
+   so every gate below deliberately ignores them: **gates require the deterministic
+   marker and fail toward Classic behavior.**
+
+## Agent-side gates (all keyed to the deterministic marker)
+
+* `DeviceInfoCollector.CollectAutopilotProfile`: no `autopilot_profile` event, no
+  `autopilot_profile_missing` warning, no ZTD event-log query, no ZTD HTTP probe.
+  `enrollment_type_detected` still fires. (WDP devices DO carry an
+  `AutopilotPolicyCache` with `ProfileAvailable=0` / error 807 `ZtdDeviceIsNotRegistered`
+  — Windows runs the ZTD download regardless — so the probe fired for real before.)
+* `CollectEspConfigurationLocked`: `esp_config_detected` is emitted only when at least
+  one FirstSync value or ESP tracking list exists (generic null-gate, mirrors the
+  orchestrator bootstrap's signal gate) — fixes "unknown/unknown" for WDP AND plain
+  Entra joins.
+* `DefaultComponentFactory`: `EspPolicyProviderStallHost` (60-s poll of the ESP-only
+  `EnrollmentStatusTracking` key) is not created on WDP.
+* `EspAndHelloTracker.Start`: `ProvisioningStatusTracker` is not started on WDP — its
+  subtree watcher sits on `AutopilotSettings`, exactly where WDP's BootstrapperAgent
+  writes progress, so it woke on every write only to read three ESP category values
+  that never exist there.
+* `ModernDeploymentTracker`: `DevicePreparationNoiseEventIds` {100, 417, 418, 1005}
+  are suppressed entirely on WDP (before `FormatDescription()`); Critical (level 1)
+  always passes; genuine WDP diagnostics (e.g. 408) keep flowing. The Autopilot error
+  backfill (807/809/815/908 replay) is skipped — 807 is the EXPECTED state on WDP.
+  The watcher itself stays on: WDP's provisioning stack logs into the same channels.
+* `StallProbeCollector`: skips the ESP category registry scan on WDP and unions the
+  noise IDs into its harmless set; the channel scans remain (they carry genuine WDP
+  diagnostics during a stall).
+* `EnrollmentTerminationHandler`: the `app_install_starved` terminal sweep is skipped
+  on WDP — post-desktop installs are the DESIGNED order there (only DPP-policy apps
+  run during provisioning); per-app data still travels via `app_tracking_summary` and
+  final-status.json.
+
+## DecisionCore: WDP completion without ESP facts
+
+* **Seeding**: `EnrollmentFactsObserved` carries `enrollmentTypeDeterministic`;
+  the deterministic marker seeds `DevicePreparation` at **High** confidence (same
+  registry-determinism standard as the self-deploying OobeConfig bits), the fallback
+  rules stay Medium. The three explicit downgrade guards from d0ab3eee remain as
+  defence in depth.
+* **Arm D** (`ShouldTransitionToAwaitingHello`): on WDP the DAD-validated real-user
+  desktop is a legitimate promotion basis — arms A–C are unsatisfiable by construction
+  (no provisioning categories, no Shell-Core 62407 final exit). With a disabled Hello
+  policy the fast-path now completes at desktop arrival.
+* **Prerequisites**: `completion_waiting` never lists
+  `account_setup_provisioning_complete` on WDP (unsatisfiable; mirrors the
+  `skipUserEsp` exemption).
+* **Backstop**: `DeadlineNames.DevicePrepCompletion` (30 min, replay-safe base) is
+  armed by `HandleDesktopArrivedV1` when a WDP session parks desktop-first with Hello
+  pending. On fire it mirrors the HelloSafety timeout: synthetic
+  `HelloOutcome=Timeout` + completion through Finalizing. This closes the
+  "no Hello → park until watchdog" hole; a timer surviving into a terminal stage is
+  swallowed by the post-terminal dispatch guard.
+* **Tripwire**: `DecisionStepProcessor.IsParkedWithoutDeadline` has a WDP branch
+  (dead-end zone = desktop arrived) so a regression in the backstop becomes visible
+  as `session_parked_without_deadline`.
+
+# Examples
+
+Session afee7ae0 (the audit trigger): Succeeded in 9:32 min, but its timeline carried
+`autopilot_profile` (807), an `autopilot_profile_missing` WARN, `esp_config_detected`
+unknown/unknown, 30 `modern_deployment_log` rollup events and 10 `app_install_starved`
+entries — all structurally meaningless on WDP. After the gates, the same session shape
+emits none of these; completion rode Hello-skipped + desktop as before.
+
+Deliberately NOT changed (open follow-ups, see the WDP audit topic memory): the ESP
+phase vocabulary (`esp_phase_changed`/stage names ride the Classic rails on WDP),
+subscription to the `BootstrapperAgentServiceLogProvider` event channel, and
+`registry_app_state` as the primary WDP app source.
+
+# Citations
+
+* `src/Agent/AutopilotMonitor.Agent.V2.Core/Security/EnrollmentRegistryDetector.cs` — deterministic rule + helper
+* `src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/DeviceInfo/DeviceInfoCollector.NetworkAndSecurity.cs` — profile/ESP emission gates
+* `src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/ModernDeploymentTracker.cs` — `DevicePreparationNoiseEventIds`
+* `src/Shared/AutopilotMonitor.DecisionCore/Engine/DecisionEngine.DevicePreparation.cs` — backstop deadline
+* `src/Shared/AutopilotMonitor.DecisionCore/State/EnrollmentScenarioProfileUpdater.cs` — High/Medium seeding
+* Tests: `DevicePreparationEngineTests`, `ModernDeploymentTrackerDevicePrepTests`, `EnrollmentTerminationHandlerTests.StarvedApps_skipped_on_device_preparation`, `DeviceInfoCollectorEspRefreshTests.NoEspEvidenceAtAll_SuppressesTheEvent`

docs/backend/send-time-frame-separation.md

@@ -0,0 +1,84 @@
+---
+type: concept
+title: Send-Time Frame Separation (X-Send-Time-Utc)
+description: One device-clock send timestamp per upload batch splits ReceivedAt − OccurredUtc into pure spool delay and pure device-vs-server clock offset — turning clock diagnostics from median statistics into direct per-request measurement.
+resource: src/Backend/AutopilotMonitor.Functions/Functions/Ingest/IngestTelemetryFunction.cs
+tags: [backend, agent, ingest, timestamps, clock-skew, telemetry, provenance]
+timestamp: 2026-08-21
+---
+
+# Problem
+
+Events carry two time anchors: `OccurredUtc` (device clock at emission) and `ReceivedAt`
+(server clock at ingest). Their difference conflates two physically distinct phenomena:
+
+* **Spool delay** — the event waited offline or in retry backoff before upload. Expected,
+  harmless, minutes to hours.
+* **Device-vs-server clock offset** — the actual diagnostic signal.
+
+A uniform spool backlog (events emitted close together, uploaded after an outage) is
+indistinguishable from a clock offset in that delta; a draining backlog fakes a clock jump
+ramp. Every consumer had to filter this statistically (spread caps, plateau guards,
+persistence tests) — and the first field clock-jump measurement failed exactly on this
+ambiguity.
+
+# Schema
+
+The agent stamps one header per upload attempt (`BackendTelemetryUploader`):
+
+```
+X-Send-Time-Utc: <DateTime.UtcNow, ISO-8601 round-trip>
+```
+
+Per **attempt**, not per batch content: a retry after backoff is a new send moment. The
+ingest function parses it (`ParseSendTimeHeader`: round-trip parse, UTC-normalized, values
+before year 2000 rejected as garbage — deliberately **no upper clamp**, a future-dated
+send time IS the clock-error measurement), and `StampServerFields` writes it as `SentAt`
+onto every event of the request — server-stamped, request-level, never trusted per-event
+from the wire. Stored as the nullable `SentAt` column on Events (absent for pre-header
+agents), mapped back everywhere events are read, exposed as `sentAt` in the `fields=`
+projection and verbatim on the raw endpoints.
+
+The separation is then exact:
+
+```
+SentAt − OccurredUtc   = pure spool delay            (both device frame; offset cancels)
+ReceivedAt − SentAt    = network latency + clock offset   (the only frame crossing)
+```
+
+Network latency is seconds; anything beyond is device clock error, per request, no
+statistics required.
+
+# Consumers
+
+* **`clock_skew` analyze condition** (ANALYZE-DEV-008): batches whose events carry
+  `SentAt` measure the batch offset directly as `SentAt − ReceivedAt` — spool-immune by
+  construction, so the spread cap and the IME/clamped exclusions are unnecessary there
+  (no event timestamps are read at all; IME-only sessions become measurable). Batches
+  without `SentAt` keep the legacy per-event median + spread-cap path. Downstream logic
+  (stability check, plateau step detection, end-state persistence) is shared; evidence
+  carries `sentAtBatchCount`.
+* **`CmTraceSkewTripwire` deliberately unchanged**: `median(Δ_IME) − median(Δ_other)`
+  cancels the device clock offset as common mode — send time adds nothing to that
+  differential measurement.
+
+# Constraints
+
+* `SentAt` comes from the same device wall clock as the event timestamps — a clock jump
+  between emission and send lands in the spool-delay term. That is the intended place for
+  it to become visible, not a defect.
+* Signals and DecisionTransitions do not carry `SentAt` (no consumer); the header is
+  request-level, so extending them later is a storage-only change.
+* Fleet coverage grows with agent rollout; all analyses must treat `SentAt == null`
+  (legacy rows, old agents) as "legacy path", never as zero.
+
+# Citations
+
+* `BackendTelemetryUploader.UploadBatchAsync` — header stamping per attempt.
+* `IngestTelemetryFunction.ParseSendTimeHeader` + `IngestTelemetryFunctionTests` — parse
+  contract incl. the no-upper-clamp decision.
+* `EventIngestProcessor.StampServerFields` + `IngestCriticalPathTests` — server-side
+  stamping, forged per-event values overridden.
+* `RuleEngine.ConditionEvaluators.EvaluateClockSkewCondition` + `RuleEngineClockSkewTests`
+  — the two measurement paths (the backlog-alias test pair pins why SentAt exists).
+* `tasks/todo.md` P14 (2026-08-21) — decision trail incl. why the tripwire stays as is.

docs/index.md

@@ -13,6 +13,7 @@ https://docs.autopilotmonitor.com (separate repository).
 
 * [Architecture Guide](architecture.md) - High-level architecture overview and solution layout for contributors.
 * [Version Contract](versioning.md) - One version shape for agent, backend and MCP: the ETag-CAS counter blob that mints build numbers, and the manifests published only after a deploy is verified live.
+* [Customer Script Publishing](script-publishing.md) - How the customer-facing PowerShell scripts reach download.autopilotmonitor.com/agent/, why publishing is decoupled from agent releases, and the guards keeping the published copy, the version badge and the portal's version oracle in agreement.
 * [URL Registry](url-registry.md) - Every well-known host lives in one registry file per component (Constants.cs / utils/config.ts / src/config.ts), enforced by guard tests; includes the agent-download migration to the download alias and its deploy-order constraint.
 * [Drift Guards](drift-guards.md) - The 2026-08 fragility-audit follow-up contracts: SignalR message-name catalog (typed on both ends), the inverted-tick RowKey codec, tombstone table tagging, the shrink-only OkAsync baseline, per-section config PATCH with the section field map, and the web's scoped-endpoint builders + sidebar visibility matrix.
 
@@ -23,9 +24,12 @@ https://docs.autopilotmonitor.com (separate repository).
 * [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.
+* [ESP Completion Starvation — the sits-d Cloud-PC complex](agent/post-reboot-completion-recovery.md) - Why a SkipUser=true flow (no user ESP page → no Shell-Core 62407, no AccountSetup registry) left the completion gate satisfied but never evaluated — five Cloud PCs idled six hours at "waiting on: hello_resolution" — and the fix: the observed skip stands in for the final-exit evidence in the IME user-session completion attempt. Plus the two adjacent defects fixed alongside: the edge-only user-apps-settled synthesis (now level-triggered) and the never-wired Shell-Core restart replay (now Hello-wizard-only, with the reasoning why a replayed 62407 must never reach the reducer).
 * [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.
 * [Continue-Anyway Observation Mode](agent/continue-anyway-observation.md) - EnableEspContinueAnywayObservation (ConfigVersion 37, operator-set): Device-phase ESP terminal failures on Continue-Anyway profiles get a bounded 60-min observation instead of an immediate hard fail; the DAD-validated real-user desktop + Hello gate detect the true end, the session completes Succeeded + EspSoftFailure (amber "with issues" badge), expiry un-defangs to the original esp_terminal_failure.
+* [CMTrace Time Resolution](agent/cmtrace-time-resolution.md) - Converting bias-less CMTrace local times to UTC without trusting any process's timezone belief: per-line self-anchoring on the 15-minute offset grid for provably fresh lines, uniform marked reader-zone fallback for backlog, and the provenance vocabulary (bias / line-anchored / reader-zone-fallback) that keeps every event re-derivable.
 * [Registry App-State Second Pillar](agent/registry-app-state-pillar.md) - IME's authoritative per-app state read straight from the registry (Win32Apps EnforcementStateMessage, EspTrackingWin32Apps, StatusServiceReports) via a snapshot-and-diff watcher; registry/log reconciliation doubles as the built-in IME log-pattern drift alarm.
+* [WDP Scenario Gates & Completion Backstop](agent/wdp-scenario-gates.md) - How the agent gates Autopilot/ESP-only machinery off on Windows Device Preparation sessions (deterministic ExecutionContext marker, fail-toward-Classic), which noise it suppresses (ZTD probe, esp_config unknown, ModernDeployment 100/417/418/1005, starved sweep), and the WDP completion model: High-confidence seed, desktop-based arm D, and the 30-min device_prep_completion backstop.
 * [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.
 
 # Rules
@@ -38,6 +42,7 @@ 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.
+* [Send-Time Frame Separation](backend/send-time-frame-separation.md) - One device-clock send timestamp per upload batch (X-Send-Time-Utc → SentAt on Events) splits ReceivedAt − OccurredUtc into pure spool delay and pure device-vs-server clock offset; the clock_skew condition measures SentAt batches directly (spool-immune), the CMTrace tripwire deliberately stays on its differential math.
 * [OOBE Bootstrap go-Code Flow](backend/oobe-bootstrap-go-flow.md) - The bootstrap short-code lifecycle (portal-created session → `irm go.autopilotmonitor.com/CODE | iex` at Shift+F10 → GetBootstrapScriptFunction), the always-HTTP-200 text/plain contract, the two-line injection defense (GUID/URL/expiry validator + single-quoted PS literals, golden-pinned against the legacy TS template), and the per-IP rate-limit story behind Front Door.
 * [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.

docs/log.md

@@ -1,7 +1,29 @@
 # Log
 
+## 2026-08-21
+
+* **New**: `backend/send-time-frame-separation.md` — P14: the agent stamps one device-clock send timestamp per upload attempt (`X-Send-Time-Utc`), the ingest function server-stamps it as `SentAt` on every event of the request. `SentAt − OccurredUtc` is pure spool delay, `ReceivedAt − SentAt` is network + device-vs-server clock offset — the two were indistinguishable before and had to be separated statistically. The `clock_skew` condition measures SentAt-carrying batches directly (spool-immune, no spread cap, IME-only sessions become measurable; evidence carries `sentAtBatchCount`), legacy batches keep the median path; the CMTrace tripwire deliberately stays on its differential math (common-mode clock offset cancels there).
+
+## 2026-08-20
+
+* **Update**: `agent/cmtrace-time-resolution.md` — new "Backend regression tripwire" section: the P6 split. Operator side: `CmTraceSkewTripwire` piggybacks on the terminal counter reconcile's partition scan (`Δ = ReceivedAt − OccurredUtc` per source, 15-min grid + 2-min residual, ≥20 samples / ≥3 distinct batches per side, bias-dominated sessions suppressed, `measuredWriterOffsetMinutes` never consulted) and emits the `CmTraceTimeSkewRegression` ops event — goal state: never fires; kill switch `CmTraceSkewTripwireDisabled`. Customer side: new `clock_skew` analyze condition source (`skewMetric: clock_jump | sustained_offset`, threshold in seconds, batch-median frames with spool-spread filter, plateau step detection, end-state persistence, IME-derived events excluded) behind the new built-in `ANALYZE-DEV-008` (300 s = the Kerberos/Entra 5-minute skew boundary) — the during-enrollment complement of ANALYZE-DEV-007's one-shot NTP check. P5 (agent-side observability event) is subsumed by the tripwire.
+
+* **New**: `agent/cmtrace-time-resolution.md` — the era-aware answer to the CMTrace timezone skew: a bias-less line read in a provably fresh pass anchors its own UTC offset against the agent clock (15-minute grid, 2-minute residual), so interleaved writer eras in one file resolve line by line; everything not provably fresh keeps the uniform reader-zone fallback and says so via `sourceOffsetOrigin`. Freshness is a per-file `LastCheckedUtc` stamped on every poll look (empty first sights included) with a 30-second window, never restored across restarts. Replaces the reverted per-file offset application (04b1a7c6); the per-file measurement stays observational, now with the anchor timestamp logged as a tripwire for the still-unexplained e9753578 label/anchor crossing.
+
+* **Update**: `agent/post-reboot-completion-recovery.md` — retitled to "ESP Completion Starvation — the sits-d Cloud-PC complex" and reframed on the evidence: the reboot was a red herring. The five stuck Cloud PCs carried `SkipUserStatusPage=True` (read 10+ times across three agent processes, `True` every time) and Windows honoured it — no user ESP page, hence no Shell-Core 62407 and no AccountSetup provisioning registry, verified over a six-hour uninterrupted post-reboot run with the watcher armed. Arm B of `ShouldTransitionToAwaitingHello` was open from the bootstrap onward, but every evaluation site hangs off a signal a skip-user flow cannot produce, and the `AdvisoryCompletion` backstop arms exclusively from an `EspExiting` signal — an open gate nobody knocks on. Fix: `HandleImeUserSessionCompletedV1` accepts the observed skip in place of the final-exit evidence (`skipUserExitEquivalent`; anchor + genuine IME completion + real-user desktop stay mandatory, WDP excluded). The knock deliberately lives on the IME edge, not desktop arrival — ordering-robust against Fix 10's AccountSetup bounce-back and semantically "user-phase work finished" rather than mid-install. `ClassicSkipUserEspUserSessionCompletionTests` replays the real 8110e262 ordering end to end. Docs and comments no longer claim an ESP-exit recovery that does not exist (stray duplicate summary in `ShellCoreTracker`, `ImeLogHost` restore-callback comment); the residual `SkipUser=false` exit-in-downtime gap is named honestly and surfaced by `ANALYZE-ESP-005` via `session_stalled` instead of being patched with an unorderable replay.
+
+## 2026-08-19
+
+* **New**: `agent/post-reboot-completion-recovery.md` — a forced mid-ESP reboot (DeviceGuard/DmaGuard) used to cost the session its AccountSetup completion permanently. Two defects: `ShellCoreTracker.BackfillRecentEspExitEvents()` existed but had no caller, so every agent restart dropped an ESP exit (62407) written while it was down; and the user-apps-settled synthesis was edge-triggered on `EspExited` only, so apps settling afterwards never re-opened the gate. `EspAndHelloHost.Start()` now backfills with a lookback sized to the downtime (`previousExit=reboot_kill` → since `LastBootUtc`, clamped to 360 min), and `ReevaluateUserAppsSettledSynthesis()` is chained into `ImeLogTracker.OnAppStateChanged`. No new completion path — the gate conditions are unchanged. Evidence: sits-d Cloud PCs, five `Incomplete` sessions on healthy devices, two of them at `138/138 apps, 0 failed`. Hardened over two review rounds: the remembered edge must be a **live** exit that is **confirmed** post-AccountSetup (a replay carries no evidence of its own position — Shell-Core writes the same `CommercialOOBE_ESPProgress_Page_Exiting` for the intermediate and the final exit, and the registry check reads *now*, not the event's time); the replay hands over the **newest** exit rather than the oldest; the replay is narrowed to the Hello-wizard start (62404) alone — a conservative fact that can only make the agent wait longer. A replayed ESP exit is never re-raised at all: Windows writes the identical description for the intermediate and the final exit, the reducer orders exits by ingest ordinal (fresher than reality for a replay) and `HandleEspExitingV1` passes `espFinalExitInFlight: true` for every arriving exit, so arm C of `ShouldTransitionToAwaitingHello` would open on a historic handoff once the restored state carries AccountSetupEntered + IME user session + desktop. A replayed ESP failure is likewise dropped (it could fail a session that recovered). Skipped records are reported as an `agent_trace`. The window is **measured** from the previous run's last known liveness (snapshot mtime, widened by `LastBootUtc`) instead of a constant — the scheduled task has a BootTrigger only and no restart-on-failure, so a crashed agent returns hours later and five minutes would lose the exit every time. On `first_run` the replay stays off, leaving the happy path untouched.
+
+* **Update**: `rules/analyze-rule-triggers.md` — `on_event:session_stalled` documented as an established interim trigger for the never-terminal stuck session (one emission per session, no throttle needed). `ANALYZE-ESP-005` carries it: both its conditions are monotonic and it has no terminal precondition, and it fires at confidence 95 on the sits-d stalled stream. `ANALYZE-APP-015` deliberately does NOT — it is the worked example of the terminal-precondition trap (lint 1) — and `ANALYZE-ESP-001` does not either, because its `phase_duration` gate on a still-open phase is unverified mid-run. New `ANALYZE-APP-016` ("Required Apps Never Started — ESP Apps Gate Starved") turns the existing `app_install_starved` events into a customer-facing finding and, unlike `ANALYZE-APP-015`, fires even when the session succeeded — session `3b9291aa` was recorded `Succeeded` with 99 required apps that never started installing.
+
+* **New**: `script-publishing.md` — the customer script publishing chain. `.github/scripts/Publish-BootstrapScripts.ps1` becomes the single owner (dev render, version-bump guard, uploads, version oracles, alias verification), called both by the new `publish-scripts.yml` (push to `main` on `scripts/Bootstrap/**` and `scripts/CustomerSetup/**`) and by the `publish_as_stable` branch of `build-agent.yml`. Script publishing no longer waits for an agent release. Blobs are published in a deterministic CRLF/UTF-8-no-BOM form so byte comparisons do not depend on the checkout; the Pester + ASCII gates move into the reusable `bootstrap-script-gates.yml` and block the upload; `AdminConfiguration.LatestBootstrapV2ScriptVersion` now has exactly one writer. The version-bump guard compares a code fingerprint (PowerShell token stream without comments, newlines and line continuations), so only behaviour changes require a `$ScriptVersion` bump — comment and formatting changes publish with a warning.
+
 ## 2026-08-18
 
+* **New**: `agent/wdp-scenario-gates.md` — WDP scenario gates (afee7ae0 audit): deterministic ExecutionContext marker as the only gate key (fail-toward-Classic), suppressed Autopilot/ESP-only emissions and hosts (autopilot_profile*/ZTD probe, esp_config unknown null-gate, EspPolicyProviderStallHost, ProvisioningStatusTracker, ModernDeployment noise IDs 100/417/418/1005 + error-backfill skip, starved sweep), and the WDP completion model (High-confidence v2 seed via `enrollmentTypeDeterministic`, desktop-based arm D, 30-min `device_prep_completion` backstop, parked-tripwire WDP branch).
+
 * **Update**: `backend/time-attribution.md` — AttributionVersion 1 → 2: new duration-critical quality flag `PriorEnrollmentResidue` (fires on `historic_ime_replay_detected`; a re-enrollment without wipe pulls the phase anchors ahead of the real ESP page, so the segments are excluded from fleet stats; `registry_app_baseline` successes deliberately not a trigger — by-design normal for WDP). Added the quality-flags section.
 * **Update**: `agent/logs-and-persistence.md`, `agent/overview.md`, `agent/gather-rule-debug-log.md` — log files renamed to unified kebab-case: `agent.log` (date rotation dropped; size segments `agent-NNN.log`), `bootstrap-script.log` (was `bootstrap_agent.log`), `bootstrap-msi.log` (was `msi-bootstrap.log`), `crash-*.log`, `gather-rules-debug.log`, `ime-pattern-matches.log`. Old names still appear in archives from pre-rename agents.
 * **New**: `agent/registry-app-state-pillar.md` — the registry second pillar for IME app state (audit follow-up): snapshot-and-diff watcher on `HKLM\...\IntuneManagementExtension` (Win32Apps / EspTrackingWin32Apps / StatusServiceReports), `registry_app_state` + `app_state_reconciliation` events, silent startup baseline, WDP reuse notes.

docs/rules/analyze-rule-triggers.md

@@ -101,6 +101,10 @@ Interim evaluation changes what a rule's conditions mean mid-flight. Three new l
 - WG battery rule (sits-d): `evaluateOn: ["enrollment_end", "whiteglove_sealed"]` — technician gets the channel alert at the bench; Part-2 terminal pass finalizes or resolves the finding.
 - Hybrid-affinity stuck (esa): ANALYZE-ID-004 gets `evaluateOn: ["enrollment_end", "on_event:hybrid_login_pending"]` — the second overdue-login event (threshold 65) produces a live finding on the still-InProgress session. ANALYZE-APP-015 stays `enrollment_end`-only until its conditions are hardened (lint 1).
 
+- Stuck after a forced mid-ESP reboot (sits-d Cloud PCs, 2026-08-19): `on_event:session_stalled` is the established trigger for the never-terminal stuck session. The agent emits `session_stalled` exactly once per session (60-minute stall probe), so the trigger is rare by construction and needs no throttle. Five Cloud PCs sat at `InProgress` with **zero findings** for hours — a mid-ESP reboot had killed the agent in `Stage=EspAccountSetup` — before the max-lifetime watchdog eventually terminalised them as `Incomplete`. ANALYZE-ESP-005 carries the trigger and fires on that stream at confidence 95 (verified against session `8110e262`): both its conditions (`mdm_policy_reboot_required.firstRebootUri` exists, `system_reboot_detected` count ≥ 1) are **monotonic** and it has no terminal preconditions, so lint 1 does not apply. ANALYZE-APP-016 is interim-safe for the same reason (`app_install_starved` count ≥ 1 only ever grows).
+
+  Two rules were considered and deliberately **not** given the trigger: ANALYZE-APP-015 is the worked example of lint 1 above and stays `enrollment_end`-only; ANALYZE-ESP-001 gates on `phase_duration` of a phase that is still open mid-run, and that evaluation is not pinned by a test — an unverified trigger is not worth a possible false positive on every slow DeviceSetup.
+
 # Product Decisions (settled 2026-08-14)
 
 1. Notify-on-resolve (a "finding healed" message)? **No** (v1) — resolution is visible in UI/MCP.

docs/script-publishing.md

@@ -0,0 +1,137 @@
+---
+type: Concept
+title: Customer Script Publishing — download.autopilotmonitor.com/agent/
+description: How the customer-facing PowerShell scripts reach the download alias, why publishing is decoupled from agent releases, and the guards that keep the published copy, the version badge and the portal's version oracle in agreement.
+resource: /.github/scripts/Publish-BootstrapScripts.ps1
+tags:
+  - build
+  - ci
+  - release
+  - bootstrap
+  - download-alias
+timestamp: 2026-08-19T00:00:00+02:00
+---
+
+# Overview
+
+Four PowerShell scripts are served to customers from `https://download.autopilotmonitor.com/agent/`:
+
+| Blob | Source | Consumed by |
+| --- | --- | --- |
+| `Install-AutopilotMonitor.ps1` | `scripts/Bootstrap/Install-AutopilotMonitor.ps1` | Intune platform script (customer uploads a copy); downloaded live on every device by the WDP bootstrap MSI |
+| `Install-AutopilotMonitor-Dev.ps1` | rendered from the same source | dev fleet |
+| `Test-ShouldBootstrapAgent.ps1` | `scripts/Bootstrap/Test-ShouldBootstrapAgent.ps1` | customer dry run via `irm ... \| iex` |
+| `Grant-AutopilotMonitorAddOn.ps1` | `scripts/CustomerSetup/Grant-AutopilotMonitorAddOn.ps1` | optional Graph permission grant |
+
+`Uninstall-AutopilotMonitor.ps1` is deliberately not published — nothing links it, and an
+unauthenticated uninstall script on the public download host is not a feature.
+
+The alias is a Front Door route in front of the `agent` container; see
+[url-registry.md](url-registry.md) for the host registry and the migration to the alias.
+
+# Publishing chain
+
+`.github/scripts/Publish-BootstrapScripts.ps1` is the single owner. Two workflows call it
+with identical arguments:
+
+* **`publish-scripts.yml`** — on every push to `main` touching `scripts/Bootstrap/**`,
+  `scripts/CustomerSetup/**` or the publisher itself, plus `workflow_dispatch` with a
+  `dry_run` input.
+* **`build-agent.yml`** — inside the `publish_as_stable` branch, after `version.json` is
+  uploaded, so a release lands a set consistent with what is already live.
+
+Before this split, the script blobs rotated **only** on a stable agent release. A bootstrap
+fix therefore sat unpublished until the next agent cutover — while the WDP MSI downloads the
+published copy on every enrolling device. Script publishing is now decoupled from the agent
+release cadence; the release path still publishes, so it can never fall behind either.
+
+Both workflows share the concurrency group `agent-blob-publish` (`cancel-in-progress: false`).
+Both write `version.json`, and the publisher's `bootstrapVersion` read-modify-write must not
+interleave with a release writing the agent fields.
+
+# Publisher steps
+
+1. **Parse** `$ScriptVersion` from the bootstrap source.
+2. **Dev render** — literal substitution of the two `$AgentDownloadUrl` / `$VersionJsonName`
+   defaults. A missing anchor literal is a hard failure: a silently un-substituted dev script
+   would point the dev fleet at the stable agent.
+3. **Version-bump guard** — if the published bootstrap changed *behaviour* under an unchanged
+   `$ScriptVersion`, the run aborts. Comment and formatting changes publish with a warning.
+   See [Version oracles](#version-oracles).
+4. **Upload** every blob with `Cache-Control: no-cache` (they all rotate in place), mirrored
+   fail-soft to the legacy storage account.
+5. **Reconcile the version oracles.**
+6. **Verify through the alias** — re-download each blob and compare SHA-256, six attempts
+   20 s apart. A persistent mismatch means blobs were written but Front Door serves stale
+   content, and the error names the `az afd endpoint purge` command.
+
+## Deterministic publish form
+
+Every blob is published as **CRLF, UTF-8 without BOM**, normalized by the publisher rather
+than taken from the working copy. Git normalizes line endings on checkout — a Windows runner
+yields CRLF, a `core.autocrlf=false` clone yields LF — so publishing raw working-copy bytes
+would emit different blobs for identical source and make every byte comparison, guard and
+verification alike, depend on where the workflow ran. CRLF is also what PS 5.1 expects on the
+device and what has always been published.
+
+The ASCII-only rule for `scripts/Bootstrap/*.ps1` (enforced by the gates below) is unrelated
+but adjacent: PS 5.1 reads BOM-less files as ANSI and corrupts multi-byte characters.
+
+## Version oracles
+
+Three places state the bootstrap script version, and all three are derived from
+`$ScriptVersion` in the source:
+
+* `version.json.bootstrapVersion` — read by the docs badge. Written by the publisher as a
+  read-modify-write under `If-Match`, so a concurrent agent release keeps its own fields.
+  `build-agent.yml` seeds the field when it builds the manifest so the published manifest is
+  never briefly missing it; the publisher owns and re-asserts it afterwards.
+* `AdminConfiguration.LatestBootstrapV2ScriptVersion` — read by the portal to tell a customer
+  their uploaded copy is outdated. **Only** the publisher writes it; `build-agent.yml` writes
+  the `LatestAgentV2*` fields and nothing else. One writer per field.
+* The `Bootstrap script version: v<x>` marker the script logs, parsed out of captured platform
+  script stdout by `utils/bootstrapVersion.ts`.
+
+The version-bump guard exists because those three would otherwise keep asserting a version
+that no longer matches what customers download: a behaviour change under an unchanged version
+is invisible to every consumer, and customers decide from that version whether to re-upload
+their Intune copy.
+
+"Changed" means changed **behaviour**, matching what the source file's own comment on
+`$ScriptVersion` already asks for ("bump on meaningful changes"). The guard compares a code
+fingerprint — the PowerShell token stream with comments, newlines and line continuations
+removed — so comment fixes, typo corrections in comments and reflow publish with a
+`::warning::` instead of failing. Tokenising rather than regex-stripping keeps a `#` inside a
+string literal from being mistaken for a comment.
+
+# Gates
+
+`.github/workflows/bootstrap-script-gates.yml` is a `workflow_call` workflow holding the
+checks once:
+
+* Pester suite under **Windows PowerShell 5.1** — the runtime IME uses for platform scripts.
+* ASCII-only scan over `scripts/Bootstrap/*.ps1`.
+* `Publish-BootstrapScripts.ps1 -DryRun` — exercises the dev-render anchors and the
+  version-bump guard, and reports per blob whether the alias is current, stale or missing.
+
+Two callers: `pester.yml` on pull requests (reports, does not block the merge button), and
+`publish-scripts.yml` on pushes to `main`, where the gates job is a `needs:` dependency of the
+publish job and therefore **blocks** the upload. `pester.yml` deliberately has no push trigger
+— it would duplicate the gate run with no consequence.
+
+# Operating it
+
+* Dry run and drift check, no credentials needed for the read paths:
+  `pwsh .github/scripts/Publish-BootstrapScripts.ps1 -DryRun`
+* Republish without a code change: `workflow_dispatch` on **Publish customer scripts** with
+  `dry_run=false`.
+* Front Door serving stale content after a successful upload:
+  `az afd endpoint purge --resource-group rg-autopilotmonitor-prd-gwc --profile-name autopilotmonitor-fd --endpoint-name apm-download --content-paths '/agent/*'`
+
+# Citations
+
+* `.github/scripts/Publish-BootstrapScripts.ps1`
+* `.github/workflows/publish-scripts.yml`, `.github/workflows/bootstrap-script-gates.yml`, `.github/workflows/pester.yml`
+* `.github/workflows/build-agent.yml` (the `publish_as_stable` branch of the upload step)
+* `src/Agent/AutopilotMonitor.BootstrapMsi/Invoke-BootstrapDownload.ps1`
+* `src/Web/autopilot-monitor-web/utils/bootstrapVersion.ts`

rules/analyze/ANALYZE-APP-016.json

@@ -0,0 +1,113 @@
+{
+  "$schema": "../schema/analyze-rule.schema.json",
+  "ruleId": "ANALYZE-APP-016",
+  "title": "Required Apps Never Started — ESP Apps Gate Starved",
+  "description": "One or more required user-ESP apps never started installing while the ESP AccountSetup apps gate waited on them — the agent observed the ESP page exit with those apps still in a non-terminal, never-started state. Unlike ANALYZE-APP-015 (which reports that completion was DEFERRED because of a pending app, and stays silent once the session reaches a terminal verdict) this rule reports the delivery gap itself and fires regardless of the final outcome: an enrollment that Windows called done while required apps never ran is a successful enrollment with missing software, and the operator must see it.",
+  "severity": "warning",
+  "category": "apps",
+  "version": "1.0.0",
+  "author": "Autopilot Monitor",
+  "enabled": true,
+  "evaluateOn": [
+    "enrollment_end",
+    "whiteglove_sealed",
+    "on_event:session_stalled"
+  ],
+  "trigger": "single",
+  "baseConfidence": 75,
+  "confidenceThreshold": 70,
+  "conditions": [
+    {
+      "signal": "starved_apps_present",
+      "source": "event_count",
+      "eventType": "app_install_starved",
+      "operator": "count_gte",
+      "value": "1",
+      "required": true
+    },
+    {
+      "signal": "many_starved_apps",
+      "source": "event_count",
+      "eventType": "app_install_starved",
+      "operator": "count_gte",
+      "value": "5",
+      "required": false
+    },
+    {
+      "signal": "appName",
+      "source": "event_type",
+      "eventType": "app_install_starved",
+      "dataField": "appName",
+      "operator": "exists",
+      "value": "",
+      "required": false
+    },
+    {
+      "signal": "state",
+      "source": "event_type",
+      "eventType": "app_install_starved",
+      "dataField": "state",
+      "operator": "exists",
+      "value": "",
+      "required": false
+    }
+  ],
+  "confidenceFactors": [
+    {
+      "signal": "many_starved_apps",
+      "condition": "exists",
+      "weight": 15
+    },
+    {
+      "signal": "appName",
+      "condition": "exists",
+      "weight": 10
+    }
+  ],
+  "explanation": "At least one **required** app assigned to the user ESP never started installing. The Intune Management Extension never moved it out of its initial state (`{{state}}`) — it did not download, did not install, and did not fail — while the ESP AccountSetup apps gate was waiting on it. First app observed: `{{appName}}`.\n\nEvery starved app has its own `app_install_starved` timeline event carrying `appId`, `appName` and `state` — open the timeline and filter on that event type for the complete list.\n\nThis is a **delivery** problem, not an install error, and it is invisible in the Intune console: the app simply never appears. Typical causes:\n\n- far more required apps targeted at the ESP than the gate can service in the available window,\n- requirement rules that are never met on this device (OS / architecture / registry / script checks),\n- an unsatisfied dependency or supersedence chain,\n- an app that needs a context unavailable during provisioning (e.g. a VPN client waiting on a portal sign-in),\n- a mid-ESP reboot that cut the gate short — check whether the mid-ESP reboot advisory also fired for this session.\n\nNote that this finding is independent of the session verdict. A session can be marked **Succeeded** and still be missing every app listed here.",
+  "remediation": [
+    {
+      "title": "Shrink the ESP blocking set",
+      "steps": [
+        "Open the Enrollment Status Page profile and review the blocking app list — every required app there must finish before the user reaches the desktop.",
+        "Move apps that do not have to be present at first logon from *required* to *available*, or remove them from the ESP's blocking apps selection.",
+        "Prefer a small, deliberately chosen blocking set (security agent, VPN, management tooling) over the full application catalogue."
+      ]
+    },
+    {
+      "title": "Unblock the individual apps",
+      "steps": [
+        "Collect the app names from the `app_install_starved` timeline events in this session.",
+        "For each app, review its requirement rules and dependencies in Intune — IntuneManagementExtension.log records every requirement evaluation.",
+        "Verify the assignment actually targets the signed-in user (user-targeted apps need an established Entra user affinity; check the hybrid user-affinity finding if it also fired).",
+        "Re-run an enrollment and confirm the apps now reach a terminal state before the ESP exits."
+      ]
+    },
+    {
+      "title": "Rule out a truncated gate",
+      "steps": [
+        "Check whether a mid-ESP reboot was observed for this session — a forced restart during AccountSetup cuts the apps gate short and can starve everything still queued.",
+        "If so, reassign the reboot-forcing device policies to user groups so the restart lands after AccountSetup."
+      ]
+    }
+  ],
+  "relatedDocs": [
+    {
+      "title": "Microsoft Learn: Enrollment Status Page — blocking apps",
+      "url": "https://learn.microsoft.com/en-us/intune/intune-service/enrollment/windows-enrollment-status"
+    },
+    {
+      "title": "Microsoft Learn: Win32 app requirement rules",
+      "url": "https://learn.microsoft.com/en-us/intune/intune-service/apps/apps-win32-add"
+    }
+  ],
+  "markSessionAsFailedDefault": false,
+  "tags": [
+    "apps",
+    "esp",
+    "starvation",
+    "assignment",
+    "blocking",
+    "delivery-gap"
+  ]
+}

rules/analyze/ANALYZE-DEV-008.json

@@ -0,0 +1,69 @@
+{
+  "$schema": "../schema/analyze-rule.schema.json",
+  "ruleId": "ANALYZE-DEV-008",
+  "title": "Device Clock Wrong During Enrollment — Jump or Sustained Offset",
+  "description": "The device's clock changed by five or more minutes mid-session (clock jump) or ran five or more minutes off server time for the whole session (sustained offset), measured against the server receive frame of every uploaded event. Complements ANALYZE-DEV-007, which is a one-shot NTP check at agent startup and misses devices where NTP was unreachable or the clock changed later. IME-log-derived events are excluded from the measurement.",
+  "severity": "warning",
+  "category": "device",
+  "version": "1.0.0",
+  "author": "Autopilot Monitor",
+  "enabled": true,
+  "evaluateOn": [
+    "enrollment_end",
+    "whiteglove_sealed"
+  ],
+  "trigger": "single",
+  "baseConfidence": 60,
+  "confidenceThreshold": 50,
+  "conditions": [
+    {
+      "signal": "clock_jump",
+      "source": "clock_skew",
+      "skewMetric": "clock_jump",
+      "operator": "gte",
+      "value": "300",
+      "required": false
+    },
+    {
+      "signal": "sustained_offset",
+      "source": "clock_skew",
+      "skewMetric": "sustained_offset",
+      "operator": "gte",
+      "value": "300",
+      "required": false
+    }
+  ],
+  "confidenceFactors": [],
+  "explanation": "This device's {{skewSummary}} (five-minute threshold). A clock that is off by five or more minutes breaks time-sensitive enrollment mechanisms: Kerberos tolerates at most 5 minutes of skew (Hybrid Join), Entra ID token validation allows about 5 minutes on token lifetimes, and freshly issued SCEP/PKCS certificates can be rejected as \"not yet valid\" when the clock is more than ~10 minutes behind the CA.\n\nUnlike ANALYZE-DEV-007 (a one-shot NTP comparison at agent startup), this finding is measured across the whole session against the server's receive time — it also catches devices where the NTP check could not run (UDP 123 blocked) or where the clock changed after startup (time sync correcting a wrong RTC, Windows auto-timezone, manual change).",
+  "remediation": [
+    {
+      "title": "Fix the device clock and time source",
+      "steps": [
+        "Check the BIOS/RTC clock and the CMOS battery if the wrong time recurs on the same hardware.",
+        "At OOBE, run 'w32tm /resync /force' (Shift+F10 command prompt) to sync with time.windows.com.",
+        "Ensure UDP port 123 to time.windows.com is open in the deployment network.",
+        "Review 'Set time automatically' and 'Set time zone automatically' behavior on the deployment image — automatic timezone changes mid-enrollment show up as clock jumps."
+      ]
+    }
+  ],
+  "relatedDocs": [
+    {
+      "title": "Microsoft Learn: Windows Autopilot known issues — device provisioning can fail (clock skew)",
+      "url": "https://learn.microsoft.com/en-us/autopilot/known-issues"
+    },
+    {
+      "title": "Microsoft Learn: Windows Autopilot requirements — Networking (NTP)",
+      "url": "https://learn.microsoft.com/en-us/autopilot/requirements?tabs=networking"
+    }
+  ],
+  "markSessionAsFailedDefault": false,
+  "tags": [
+    "device",
+    "clock-skew",
+    "clock-jump",
+    "time-sync",
+    "kerberos",
+    "certificates",
+    "known-issue"
+  ]
+}

rules/analyze/ANALYZE-ESP-005.json

@@ -5,12 +5,13 @@
   "description": "Attributes an observed enrollment reboot to device-assigned MDM policies that Windows flagged as reboot-required. Fires ONLY when both facts are present in the session: at least one actually-observed reboot (system_reboot_detected) AND reboot-required policy flags (mdm_policy_reboot_required). Policy flags alone — e.g. from a user-policy sync during AccountSetup — force no reboot and stay advisory-silent.",
   "severity": "warning",
   "category": "esp",
-  "version": "1.2.0",
+  "version": "1.3.0",
   "author": "Autopilot Monitor",
   "enabled": true,
   "evaluateOn": [
     "enrollment_end",
-    "whiteglove_sealed"
+    "whiteglove_sealed",
+    "on_event:session_stalled"
   ],
   "trigger": "single",
   "baseConfidence": 70,

rules/dist/analyze-rules.json

@@ -831,6 +831,118 @@
         "pending"
       ]
     },
+    {
+      "ruleId": "ANALYZE-APP-016",
+      "title": "Required Apps Never Started — ESP Apps Gate Starved",
+      "description": "One or more required user-ESP apps never started installing while the ESP AccountSetup apps gate waited on them — the agent observed the ESP page exit with those apps still in a non-terminal, never-started state. Unlike ANALYZE-APP-015 (which reports that completion was DEFERRED because of a pending app, and stays silent once the session reaches a terminal verdict) this rule reports the delivery gap itself and fires regardless of the final outcome: an enrollment that Windows called done while required apps never ran is a successful enrollment with missing software, and the operator must see it.",
+      "severity": "warning",
+      "category": "apps",
+      "version": "1.0.0",
+      "author": "Autopilot Monitor",
+      "enabled": true,
+      "evaluateOn": [
+        "enrollment_end",
+        "whiteglove_sealed",
+        "on_event:session_stalled"
+      ],
+      "trigger": "single",
+      "baseConfidence": 75,
+      "confidenceThreshold": 70,
+      "conditions": [
+        {
+          "signal": "starved_apps_present",
+          "source": "event_count",
+          "eventType": "app_install_starved",
+          "operator": "count_gte",
+          "value": "1",
+          "required": true
+        },
+        {
+          "signal": "many_starved_apps",
+          "source": "event_count",
+          "eventType": "app_install_starved",
+          "operator": "count_gte",
+          "value": "5",
+          "required": false
+        },
+        {
+          "signal": "appName",
+          "source": "event_type",
+          "eventType": "app_install_starved",
+          "dataField": "appName",
+          "operator": "exists",
+          "value": "",
+          "required": false
+        },
+        {
+          "signal": "state",
+          "source": "event_type",
+          "eventType": "app_install_starved",
+          "dataField": "state",
+          "operator": "exists",
+          "value": "",
+          "required": false
+        }
+      ],
+      "confidenceFactors": [
+        {
+          "signal": "many_starved_apps",
+          "condition": "exists",
+          "weight": 15
+        },
+        {
+          "signal": "appName",
+          "condition": "exists",
+          "weight": 10
+        }
+      ],
+      "explanation": "At least one **required** app assigned to the user ESP never started installing. The Intune Management Extension never moved it out of its initial state (`{{state}}`) — it did not download, did not install, and did not fail — while the ESP AccountSetup apps gate was waiting on it. First app observed: `{{appName}}`.\n\nEvery starved app has its own `app_install_starved` timeline event carrying `appId`, `appName` and `state` — open the timeline and filter on that event type for the complete list.\n\nThis is a **delivery** problem, not an install error, and it is invisible in the Intune console: the app simply never appears. Typical causes:\n\n- far more required apps targeted at the ESP than the gate can service in the available window,\n- requirement rules that are never met on this device (OS / architecture / registry / script checks),\n- an unsatisfied dependency or supersedence chain,\n- an app that needs a context unavailable during provisioning (e.g. a VPN client waiting on a portal sign-in),\n- a mid-ESP reboot that cut the gate short — check whether the mid-ESP reboot advisory also fired for this session.\n\nNote that this finding is independent of the session verdict. A session can be marked **Succeeded** and still be missing every app listed here.",
+      "remediation": [
+        {
+          "title": "Shrink the ESP blocking set",
+          "steps": [
+            "Open the Enrollment Status Page profile and review the blocking app list — every required app there must finish before the user reaches the desktop.",
+            "Move apps that do not have to be present at first logon from *required* to *available*, or remove them from the ESP's blocking apps selection.",
+            "Prefer a small, deliberately chosen blocking set (security agent, VPN, management tooling) over the full application catalogue."
+          ]
+        },
+        {
+          "title": "Unblock the individual apps",
+          "steps": [
+            "Collect the app names from the `app_install_starved` timeline events in this session.",
+            "For each app, review its requirement rules and dependencies in Intune — IntuneManagementExtension.log records every requirement evaluation.",
+            "Verify the assignment actually targets the signed-in user (user-targeted apps need an established Entra user affinity; check the hybrid user-affinity finding if it also fired).",
+            "Re-run an enrollment and confirm the apps now reach a terminal state before the ESP exits."
+          ]
+        },
+        {
+          "title": "Rule out a truncated gate",
+          "steps": [
+            "Check whether a mid-ESP reboot was observed for this session — a forced restart during AccountSetup cuts the apps gate short and can starve everything still queued.",
+            "If so, reassign the reboot-forcing device policies to user groups so the restart lands after AccountSetup."
+          ]
+        }
+      ],
+      "relatedDocs": [
+        {
+          "title": "Microsoft Learn: Enrollment Status Page — blocking apps",
+          "url": "https://learn.microsoft.com/en-us/intune/intune-service/enrollment/windows-enrollment-status"
+        },
+        {
+          "title": "Microsoft Learn: Win32 app requirement rules",
+          "url": "https://learn.microsoft.com/en-us/intune/intune-service/apps/apps-win32-add"
+        }
+      ],
+      "markSessionAsFailedDefault": false,
+      "tags": [
+        "apps",
+        "esp",
+        "starvation",
+        "assignment",
+        "blocking",
+        "delivery-gap"
+      ]
+    },
     {
       "ruleId": "ANALYZE-CORR-003",
       "title": "Proxy Configuration Causing Download Failure",
@@ -1404,6 +1516,74 @@
         "known-issue"
       ]
     },
+    {
+      "ruleId": "ANALYZE-DEV-008",
+      "title": "Device Clock Wrong During Enrollment — Jump or Sustained Offset",
+      "description": "The device's clock changed by five or more minutes mid-session (clock jump) or ran five or more minutes off server time for the whole session (sustained offset), measured against the server receive frame of every uploaded event. Complements ANALYZE-DEV-007, which is a one-shot NTP check at agent startup and misses devices where NTP was unreachable or the clock changed later. IME-log-derived events are excluded from the measurement.",
+      "severity": "warning",
+      "category": "device",
+      "version": "1.0.0",
+      "author": "Autopilot Monitor",
+      "enabled": true,
+      "evaluateOn": [
+        "enrollment_end",
+        "whiteglove_sealed"
+      ],
+      "trigger": "single",
+      "baseConfidence": 60,
+      "confidenceThreshold": 50,
+      "conditions": [
+        {
+          "signal": "clock_jump",
+          "source": "clock_skew",
+          "skewMetric": "clock_jump",
+          "operator": "gte",
+          "value": "300",
+          "required": false
+        },
+        {
+          "signal": "sustained_offset",
+          "source": "clock_skew",
+          "skewMetric": "sustained_offset",
+          "operator": "gte",
+          "value": "300",
+          "required": false
+        }
+      ],
+      "confidenceFactors": [],
+      "explanation": "This device's {{skewSummary}} (five-minute threshold). A clock that is off by five or more minutes breaks time-sensitive enrollment mechanisms: Kerberos tolerates at most 5 minutes of skew (Hybrid Join), Entra ID token validation allows about 5 minutes on token lifetimes, and freshly issued SCEP/PKCS certificates can be rejected as \"not yet valid\" when the clock is more than ~10 minutes behind the CA.\n\nUnlike ANALYZE-DEV-007 (a one-shot NTP comparison at agent startup), this finding is measured across the whole session against the server's receive time — it also catches devices where the NTP check could not run (UDP 123 blocked) or where the clock changed after startup (time sync correcting a wrong RTC, Windows auto-timezone, manual change).",
+      "remediation": [
+        {
+          "title": "Fix the device clock and time source",
+          "steps": [
+            "Check the BIOS/RTC clock and the CMOS battery if the wrong time recurs on the same hardware.",
+            "At OOBE, run 'w32tm /resync /force' (Shift+F10 command prompt) to sync with time.windows.com.",
+            "Ensure UDP port 123 to time.windows.com is open in the deployment network.",
+            "Review 'Set time automatically' and 'Set time zone automatically' behavior on the deployment image — automatic timezone changes mid-enrollment show up as clock jumps."
+          ]
+        }
+      ],
+      "relatedDocs": [
+        {
+          "title": "Microsoft Learn: Windows Autopilot known issues — device provisioning can fail (clock skew)",
+          "url": "https://learn.microsoft.com/en-us/autopilot/known-issues"
+        },
+        {
+          "title": "Microsoft Learn: Windows Autopilot requirements — Networking (NTP)",
+          "url": "https://learn.microsoft.com/en-us/autopilot/requirements?tabs=networking"
+        }
+      ],
+      "markSessionAsFailedDefault": false,
+      "tags": [
+        "device",
+        "clock-skew",
+        "clock-jump",
+        "time-sync",
+        "kerberos",
+        "certificates",
+        "known-issue"
+      ]
+    },
     {
       "ruleId": "ANALYZE-ENRL-001",
       "title": "Enrollment Failed",
@@ -2069,12 +2249,13 @@
       "description": "Attributes an observed enrollment reboot to device-assigned MDM policies that Windows flagged as reboot-required. Fires ONLY when both facts are present in the session: at least one actually-observed reboot (system_reboot_detected) AND reboot-required policy flags (mdm_policy_reboot_required). Policy flags alone — e.g. from a user-policy sync during AccountSetup — force no reboot and stay advisory-silent.",
       "severity": "warning",
       "category": "esp",
-      "version": "1.2.0",
+      "version": "1.3.0",
       "author": "Autopilot Monitor",
       "enabled": true,
       "evaluateOn": [
         "enrollment_end",
-        "whiteglove_sealed"
+        "whiteglove_sealed",
+        "on_event:session_stalled"
       ],
       "trigger": "single",
       "baseConfidence": 70,

rules/schema/analyze-rule.schema.json

@@ -169,7 +169,12 @@
         "source": {
           "type": "string",
           "description": "Source of the signal.",
-          "enum": ["event_type", "event_data", "event_data_array", "phase_duration", "event_count", "app_install_duration", "event_correlation"]
+          "enum": ["event_type", "event_data", "event_data_array", "phase_duration", "event_count", "app_install_duration", "event_correlation", "clock_skew"]
+        },
+        "skewMetric": {
+          "type": "string",
+          "description": "For clock_skew only: which device-clock metric to evaluate. clock_jump = persistent step in the device's clock frame mid-session; sustained_offset = whole session ran on a clock off by at least the threshold. value is the threshold in seconds; operator is limited to gt/gte on the magnitude. IME-log-derived events are excluded from the measurement.",
+          "enum": ["clock_jump", "sustained_offset"]
         },
         "eventType": {
           "type": "string",

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

@@ -61,6 +61,41 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.DeviceInfo
             return Assert.IsAssignableFrom<IReadOnlyList<string>>(data[key]);
         }
 
+        [Fact]
+        public void NoEspEvidenceAtAll_SuppressesTheEvent()
+        {
+            // afee7ae0 (WDP / plain Entra join): FirstSync has no values and the ESP tracking
+            // key does not exist — an event saying only "SkipUser=unknown, SkipDevice=unknown"
+            // is noise and must not be emitted (mirrors the orchestrator bootstrap's null-gate).
+            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-nullgate", "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: null, skipDevice: null,
+                    blockInStatusPage: null, syncFailureTimeoutMinutes: null));
+            using (new EspTrackingInfoProbe.ScopedOverride(_ => default))
+            {
+                collector.CollectEspConfiguration();
+            }
+
+            Assert.Empty(EspConfigEvents(ingress));
+
+            // A later refresh where real evidence appeared must still emit normally.
+            using (new EspTrackingInfoProbe.ScopedOverride(_ => Snapshot(new[] { DeviceApp1 }, Array.Empty<string>())))
+            {
+                collector.RefreshEspConfiguration(DeviceInfoHost.EspConfigTriggerAppsDevice);
+            }
+            Assert.Single(EspConfigEvents(ingress));
+        }
+
         [Fact]
         public void Refresh_reemits_when_lists_grew_and_stays_silent_when_unchanged()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Integration/ShellCoreToEngineEspExitingTests.cs

@@ -17,14 +17,22 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Integration
 {
     /// <summary>
     /// Plan §EspExiting Adapter — wire-through verification of the production EspExiting path:
-    /// <c>ShellCoreTracker.HandleBackfillRecord</c> → <c>EspExited</c> event → inner re-raise on
-    /// <c>EspAndHelloTracker.EspExited</c> → <c>EspAndHelloTrackerAdapter</c> → ingress → engine
-    /// reducer. This is the path the live V2-Host uses; without the coordinator forward the
-    /// EspExiting signal would never reach the engine in production.
+    /// <c>ShellCoreTracker.ProcessEvent</c> (live Shell-Core 62407) → <c>EspExited</c> event →
+    /// inner re-raise on <c>EspAndHelloTracker.EspExited</c> → <c>EspAndHelloTrackerAdapter</c> →
+    /// ingress → engine reducer. Without the coordinator forward the EspExiting signal would
+    /// never reach the engine in production.
     /// <para>
     /// The first test isolates the tracker's <c>EspExited</c> contract (source-event timestamp
-    /// preserved through backfill); the coordinator tests drive the full production chain through
-    /// to the <c>HelloSafety</c> deadline when AccountSetup is already entered.
+    /// preserved rather than collapsed to wall-clock-now); the coordinator tests drive the full
+    /// production chain through to the <c>HelloSafety</c> deadline when AccountSetup is already
+    /// entered.
+    /// </para>
+    /// <para>
+    /// It used to drive that first test through <c>HandleBackfillRecord</c> because the replay is
+    /// easier to call than the event-log watcher — but the replay no longer raises
+    /// <c>EspExited</c> at all (a replayed 62407 cannot be placed in time; see
+    /// <c>ShellCoreTrackerReplayScopeTests</c>), and it never was the production path: the replay
+    /// had no caller when this test was written.
     /// </para>
     /// </summary>
     public sealed class ShellCoreToEngineEspExitingTests
@@ -34,12 +42,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Integration
             "CommercialOOBE_ESPProgress_Page_Exiting"; // matches EspExitingPattern in ShellCoreTracker
 
         [Fact]
-        public void Tracker_backfill_record_raises_EspExited_with_source_timestamp()
+        public void Tracker_live_record_raises_EspExited_with_source_timestamp()
         {
-            // Tracker-level contract: HandleBackfillRecord raises EspExited carrying the source
-            // event time (not Clock.UtcNow). The EspExited→EspExiting signal mapping and SourceOrigin
-            // are covered by the coordinator tests below; here we isolate the backfill→event link
-            // that the production coordinator depends on.
+            // Tracker-level contract: the live 62407 path raises EspExited carrying the source
+            // event time (record.TimeCreated, not Clock.UtcNow). The EspExited→EspExiting signal
+            // mapping and SourceOrigin are covered by the coordinator tests below; here we isolate
+            // the event-log→event link that the production coordinator depends on.
             using var tmp = new TempDirectory();
             var logger = new AgentLogger(tmp.Path, AgentLogLevel.Info);
             var clock = new VirtualClock(ClockNow);
@@ -57,7 +65,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Integration
             // Source time IS in the past relative to the clock — verify the tracker carries the
             // historical timestamp on the event rather than collapsing to Clock.UtcNow.
             var sourceTime = ClockNow.AddMinutes(-2);
-            tracker.HandleBackfillRecord(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspExitingDescription, sourceTime);
+            tracker.ProcessEvent(
+                eventId: ShellCoreTracker.EventId_ShellCore_WebAppEvent,
+                description: EspExitingDescription,
+                timestamp: sourceTime,
+                providerName: "Microsoft-Windows-Shell-Core",
+                isBackfill: false);
 
             Assert.NotNull(captured);
             Assert.Equal(sourceTime, captured!.OccurredAtUtc);

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/EspAndHelloTrackerStarvedAppsTests.cs

@@ -170,5 +170,53 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring
             Assert.Empty(f.StarvedPosts());
             Assert.Empty(coordinator.StarvedAppsReported);
         }
+
+        [Fact]
+        public void Reevaluate_does_not_re_emit_starved_warnings()
+        {
+            // sits-d Cloud-PC fix (2026-08-19): the synthesis re-check now runs on EVERY IME
+            // app-state transition. It must not turn the one-shot starvation warning into a
+            // per-transition stream — the re-check path suppresses the emission entirely
+            // (the per-appId dedupe would swallow the duplicates, but walking the probe
+            // hundreds of times on the IME hot path is waste, not safety).
+            using var f = new Fixture();
+            using var coordinator = f.BuildCoordinator(
+                () => false,
+                () => new[] { StarvedApp("app-1", "Contoso Backgrounds") });
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+            var afterExit = f.StarvedPosts().Count;
+            Assert.Equal(1, afterExit);
+
+            for (var i = 0; i < 10; i++) coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.Equal(afterExit, f.StarvedPosts().Count);
+            Assert.Single(coordinator.StarvedAppsReported);
+        }
+
+        [Fact]
+        public void Starved_apps_that_settle_later_still_complete_the_enrollment()
+        {
+            // The real sits-d shape: the ESP exits with apps still starved (warning emitted),
+            // the apps then all settle, and the re-check must open the gate — the warning
+            // already on the timeline is history, not a permanent veto.
+            using var f = new Fixture();
+            var settled = false;
+            using var coordinator = f.BuildCoordinator(
+                () => settled,
+                () => new[] { StarvedApp("app-1", "Contoso Backgrounds") });
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+            Assert.Single(f.StarvedPosts());
+            Assert.DoesNotContain(f.Ingress.Posted, p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete);
+
+            settled = true;
+            coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.Equal(1, f.Ingress.Posted.Count(p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete));
+            Assert.Single(f.StarvedPosts());
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/EspAndHelloTrackerUserAppsSettledSynthesisTests.cs

@@ -35,14 +35,25 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring
             public Fixture() { Logger = new AgentLogger(Tmp.Path, AgentLogLevel.Debug); }
 
             public EspAndHelloTracker BuildCoordinator(Func<bool> settledProbe)
+                => BuildCoordinator(settledProbe, accountSetupActivityProbe: () => true, skipUserEsp: false);
+
+            /// <summary>
+            /// Codex review P1 (2026-08-19): the remembered exit edge is gated on positive evidence
+            /// that the exit is post-AccountSetup, so these two probes decide whether the deferred
+            /// re-check may fire at all.
+            /// </summary>
+            public EspAndHelloTracker BuildCoordinator(
+                Func<bool> settledProbe,
+                Func<bool> accountSetupActivityProbe,
+                bool? skipUserEsp)
             {
                 return new EspAndHelloTracker(
                     sessionId: "S1",
                     tenantId: "T1",
                     post: new InformationalEventPost(TrackerPostSink, Clock),
                     logger: Logger,
-                    skipConfigProbe: () => ((bool?)false, (bool?)false),
-                    accountSetupActivityProbe: () => true,
+                    skipConfigProbe: () => (skipUserEsp, (bool?)false),
+                    accountSetupActivityProbe: accountSetupActivityProbe,
                     userEspAppsSettledProbe: settledProbe);
             }
 
@@ -159,5 +170,174 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring
             var posted = Assert.Single(f.Ingress.Posted);
             Assert.Equal(DecisionSignalKind.EspExiting, posted.Kind);
         }
+
+        // ------------------------------------------------------------------------------
+        // sits-d Cloud-PC fix (2026-08-19) — the synthesis is no longer edge-only.
+        // Sessions 8110e262 / a89aac2d: the ESP page exited while 138 required user-ESP apps
+        // were still in flight, they all reached a terminal state (0 failed) minutes later,
+        // and because nothing re-checked, the enrollment never completed.
+        // ------------------------------------------------------------------------------
+
+        [Fact]
+        public void Reevaluate_after_apps_settle_synthesizes_without_a_second_exit()
+        {
+            using var f = new Fixture();
+            var settled = false;
+            using var coordinator = f.BuildCoordinator(() => settled);
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+            Assert.DoesNotContain(f.Ingress.Posted, p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete);
+
+            // The apps settle later; only the IME app-state callback fires — there is NO second
+            // ESP exit on a real device, which is exactly why the edge-only version starved.
+            settled = true;
+            coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.Equal(1, f.Ingress.Posted.Count(p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete));
+            Assert.True(coordinator.UserAppsSettledSynthesisFiredForTest);
+
+            var info = Assert.Single(f.TrackerPostSink.Posted);
+            var data = Assert.IsAssignableFrom<System.Collections.Generic.IReadOnlyDictionary<string, object>>(info.TypedPayload);
+            Assert.Equal("esp_exited_user_apps_settled_category_unresolved", data["fallbackReason"]);
+        }
+
+        [Fact]
+        public void Reevaluate_without_an_observed_esp_exit_never_synthesizes()
+        {
+            // The gate needs BOTH facts. Settled apps alone must never open it — otherwise every
+            // quiet moment during AccountSetup would look like completion.
+            using var f = new Fixture();
+            using var coordinator = f.BuildCoordinator(() => true);
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.ReevaluateUserAppsSettledSynthesis();
+            coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.Empty(f.Ingress.Posted);
+            Assert.Empty(f.TrackerPostSink.Posted);
+            Assert.False(coordinator.UserAppsSettledSynthesisFiredForTest);
+        }
+
+        [Fact]
+        public void Reevaluate_is_idempotent_after_the_synthesis_fired()
+        {
+            // The IME callback fires per app-state transition — on these tenants that is 138+
+            // times. The synthesis must stay fire-once.
+            using var f = new Fixture();
+            using var coordinator = f.BuildCoordinator(() => true);
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+            for (var i = 0; i < 20; i++) coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.Equal(1, f.Ingress.Posted.Count(p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete));
+            Assert.Single(f.TrackerPostSink.Posted);
+        }
+
+        // ------------------------------------------------------------------------------
+        // Codex review P1 (2026-08-19): Shell-Core raises 62407 at EVERY ESP phase transition.
+        // Remembering the intermediate DeviceSetup→AccountSetup exit would let the deferred
+        // re-check open the strong AccountSetup gate as soon as the last user app settles —
+        // while the AccountSetup page is still up and its other subcategories still running.
+        // ------------------------------------------------------------------------------
+
+        [Fact]
+        public void Intermediate_device_exit_is_not_remembered_as_the_edge()
+        {
+            using var f = new Fixture();
+            var settled = false;
+            // Classic user-driven enrollment (SkipUser=false) that has NOT reached AccountSetup:
+            // this 62407 is the DeviceSetup→AccountSetup transition, not the final exit.
+            using var coordinator = f.BuildCoordinator(
+                () => settled, accountSetupActivityProbe: () => false, skipUserEsp: false);
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+
+            // Apps settle afterwards — the level is reached, but the edge was never a valid one.
+            settled = true;
+            for (var i = 0; i < 10; i++) coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.DoesNotContain(f.Ingress.Posted, p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete);
+            Assert.False(coordinator.UserAppsSettledSynthesisFiredForTest);
+            Assert.Empty(f.TrackerPostSink.Posted);
+        }
+
+        [Fact]
+        public void Unknown_skip_user_is_treated_as_unconfirmed()
+        {
+            // Erring strict costs at worst today's stall; erring loose costs a premature Succeeded.
+            using var f = new Fixture();
+            var settled = false;
+            using var coordinator = f.BuildCoordinator(
+                () => settled, accountSetupActivityProbe: () => false, skipUserEsp: null);
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+            settled = true;
+            coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.False(coordinator.UserAppsSettledSynthesisFiredForTest);
+        }
+
+        [Fact]
+        public void Skip_user_profile_confirms_the_device_exit_as_final()
+        {
+            // SkipUser=true means there is no user ESP at all — the Device-ESP exit IS the final
+            // one and no second exit is coming, so the edge is legitimately remembered.
+            using var f = new Fixture();
+            var settled = false;
+            using var coordinator = f.BuildCoordinator(
+                () => settled, accountSetupActivityProbe: () => false, skipUserEsp: true);
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+            settled = true;
+            coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.Equal(1, f.Ingress.Posted.Count(p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete));
+        }
+
+        [Fact]
+        public void Account_setup_activity_confirms_the_edge_for_the_deferred_recheck()
+        {
+            // The real reboot shape: AccountSetup activity is visible in the registry, the final
+            // exit lands, the apps settle a moment later.
+            using var f = new Fixture();
+            var settled = false;
+            using var coordinator = f.BuildCoordinator(
+                () => settled, accountSetupActivityProbe: () => true, skipUserEsp: false);
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+            Assert.DoesNotContain(f.Ingress.Posted, p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete);
+
+            settled = true;
+            coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            Assert.Equal(1, f.Ingress.Posted.Count(p => p.Kind == DecisionSignalKind.AccountSetupProvisioningComplete));
+        }
+
+        // NOTE: the "replayed exit" cases that used to live here are gone by construction —
+        // ShellCoreTracker never re-raises a 62407 from the replay any more, so no backfilled exit
+        // can reach this handler at all. That contract is pinned one layer up, in
+        // ShellCoreTrackerReplayScopeTests, together with the reducer-side proof of why it matters
+        // (ClassicEspExitingOnRestoredStateTests).
+
+        [Fact]
+        public void Reevaluate_stays_silent_while_apps_are_still_unsettled()
+        {
+            using var f = new Fixture();
+            using var coordinator = f.BuildCoordinator(() => false);
+            using var adapter = new EspAndHelloTrackerAdapter(coordinator, f.Ingress, f.Clock);
+
+            coordinator.TriggerEspExitedForTest(Fixed);
+            for (var i = 0; i < 5; i++) coordinator.ReevaluateUserAppsSettledSynthesis();
+
+            var posted = Assert.Single(f.Ingress.Posted);
+            Assert.Equal(DecisionSignalKind.EspExiting, posted.Kind);
+            Assert.False(coordinator.UserAppsSettledSynthesisFiredForTest);
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/CmTraceCalibratorFileIsolationTests.cs

@@ -0,0 +1,109 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// Pins the per-FILE isolation of the offset measurement across a full read cycle.
+    ///
+    /// <para>
+    /// Background (2026-08-20, session e9753578): the field showed "+02:00 measured for
+    /// IntuneManagementExtension.log" although that file held no +2-era line — the anchor had
+    /// crossed file boundaries. The committed code was proven innocent (this very scenario is
+    /// green here); the leak lived in a binary built from an uncommitted tree. This test keeps
+    /// the property pinned so a real regression of the file scoping can never ship silently
+    /// again — it replays the exact field pass structure: a NEW file appearing mid-run with a
+    /// different writer era than the file already being tailed.
+    /// </para>
+    /// </summary>
+    public sealed class CmTraceCalibratorFileIsolationTests
+    {
+        private static readonly DateTime T0 = new DateTime(2026, 8, 20, 12, 13, 0, DateTimeKind.Utc);
+
+        private static List<ImeLogPattern> Patterns() => new List<ImeLogPattern>
+        {
+            new ImeLogPattern
+            {
+                PatternId = "T-MARK", Category = "always", Enabled = true,
+                Pattern = @"marker (?<n>\d+)",
+                Action = "noop",
+                Parameters = new Dictionary<string, string>(),
+            },
+        };
+
+        private static string Line(string message, DateTime utcInstant, TimeSpan writerOffset)
+        {
+            var local = utcInstant + writerOffset;
+            return $"<![LOG[{message}]LOG]!><time=\"{local:HH:mm:ss.fffffff}\" date=\"{local:M-d-yyyy}\" " +
+                   "component=\"X\" context=\"\" type=\"1\" thread=\"1\" file=\"\">";
+        }
+
+        [Fact]
+        public async Task NewFileWithOtherEra_MustNotRecalibrateTheOldFile()
+        {
+            var pdt = TimeSpan.FromHours(-7);   // IME service era
+            var cest = TimeSpan.FromHours(2);   // fresh child-process era
+
+            using var tmp = new TempDirectory();
+            var now = T0;
+            var tracker = new ImeLogTracker(
+                logFolder: tmp.Path,
+                patterns: Patterns(),
+                logger: new AgentLogger(tmp.Path, AgentLogLevel.Info));
+            try
+            {
+                tracker.UtcNowProvider = () => now;
+                var imeLog = Path.Combine(tmp.Path, "IntuneManagementExtension.log");
+                var execLog = Path.Combine(tmp.Path, "AgentExecutor.log");
+
+                // Pass 1: IME.log first sight (no calibration).
+                File.AppendAllText(imeLog, Line("marker 1", now, pdt) + Environment.NewLine);
+                await tracker.CheckLogFilesAsync(CancellationToken.None);
+
+                // Pass 2: IME.log grew -> measures -7.
+                now = T0.AddSeconds(10);
+                File.AppendAllText(imeLog, Line("marker 2", now, pdt) + Environment.NewLine);
+                await tracker.CheckLogFilesAsync(CancellationToken.None);
+
+                TimeSpan imeMeasured;
+                Assert.True(tracker.OffsetCalibrator.TryGetOffset("IntuneManagementExtension.log", out imeMeasured));
+                Assert.Equal(pdt, imeMeasured);
+
+                // Pass 3: AgentExecutor.log appears for the FIRST time with fresh +2-era lines
+                // while IME.log grows too — the exact field pass structure. The +2 anchor must
+                // never land under IME.log's key.
+                now = T0.AddSeconds(20);
+                File.AppendAllText(execLog, Line("marker 3", now, cest) + Environment.NewLine);
+                File.AppendAllText(imeLog, Line("marker 4", now, pdt) + Environment.NewLine);
+                await tracker.CheckLogFilesAsync(CancellationToken.None);
+
+                Assert.True(tracker.OffsetCalibrator.TryGetOffset("IntuneManagementExtension.log", out imeMeasured));
+                Assert.Equal(pdt, imeMeasured);
+
+                // Pass 4: both grow — each file measures its own writer's era.
+                now = T0.AddSeconds(30);
+                File.AppendAllText(execLog, Line("marker 5", now, cest) + Environment.NewLine);
+                File.AppendAllText(imeLog, Line("marker 6", now, pdt) + Environment.NewLine);
+                await tracker.CheckLogFilesAsync(CancellationToken.None);
+
+                TimeSpan execMeasured;
+                Assert.True(tracker.OffsetCalibrator.TryGetOffset("AgentExecutor.log", out execMeasured));
+                Assert.Equal(cest, execMeasured);
+                Assert.True(tracker.OffsetCalibrator.TryGetOffset("IntuneManagementExtension.log", out imeMeasured));
+                Assert.Equal(pdt, imeMeasured);
+            }
+            finally
+            {
+                tracker.Dispose();
+            }
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/CmTraceLogParserTests.cs

@@ -67,29 +67,34 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
             Assert.Equal("EnforcementState: Installing app X", entry.Message);
             Assert.Equal("AppEnforce", entry.Component);
             Assert.Equal(1, entry.Type);
-            Assert.NotEqual(default, entry.Timestamp);
+            Assert.True(entry.HasTimestamp);
+            Assert.NotEqual(default, entry.LocalTimestamp);
+            // Bias-less line: the parser refuses to guess the writer's zone, so no UTC value.
+            Assert.Null(entry.BiasMinutes);
+            Assert.Null(entry.TimestampUtc);
+            Assert.Equal(DateTimeKind.Unspecified, entry.LocalTimestamp.Kind);
         }
 
-        // ── Structurally valid but unparseable timestamp → UtcNow fallback ────
+        // ── Structurally valid but unparseable timestamp → flagged, not invented ──
 
         [Fact]
-        public void TryParseLine_falls_back_to_utcnow_for_unparseable_timestamp()
+        public void TryParseLine_flags_unparseable_timestamp_instead_of_inventing_one()
         {
             // time/date satisfy the regex character classes ([\d:.]+ / [\d-]+) so the line MATCHES,
-            // but "13-45-2026" / "25:99:99" fail every DateTime format → the parser falls back to
-            // DateTime.UtcNow (CmTraceLogParser.cs:57) instead of throwing.
-            var before = DateTime.UtcNow;
+            // but "13-45-2026" / "25:99:99" fail every DateTime format. The parser used to stamp
+            // DateTime.UtcNow here, which made a fabricated value indistinguishable from a real
+            // one downstream. It now reports HasTimestamp=false and leaves the choice of fallback
+            // to the caller, which is the only party that knows what a safe default is in context.
             var line = CmTraceLine("some message", "25:99:99.0000000", "13-45-2026");
 
             var ok = CmTraceLogParser.TryParseLine(line, out var entry);
-            var after = DateTime.UtcNow;
 
             Assert.True(ok);
             Assert.NotNull(entry);
             Assert.Equal("some message", entry.Message);
-            // Don't assert an exact instant — only that the fallback stamped a fresh "now"
-            // (a successfully-parsed date would land in 2026, far outside this window).
-            Assert.InRange(entry.Timestamp, before.AddSeconds(-5), after.AddSeconds(5));
+            Assert.False(entry.HasTimestamp);
+            Assert.Equal(default, entry.LocalTimestamp);
+            Assert.Null(entry.TimestampUtc);
         }
 
         // ── UTC-bias suffix on the time field → honored, not dropped ──────────
@@ -108,10 +113,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
 
             Assert.True(ok);
             Assert.NotNull(entry);
+            // A writer-declared bias IS the fact we otherwise have to measure, so it is honored
+            // and resolved to UTC right here — unlike the bias-less form.
+            Assert.Equal(expectedOffsetMinutes, entry.BiasMinutes);
+            Assert.NotNull(entry.TimestampUtc);
             Assert.Equal(
                 new DateTime(2026, 7, 29, 11, 46, 19, DateTimeKind.Utc).AddTicks(226610).AddMinutes(expectedOffsetMinutes),
-                entry.Timestamp);
-            Assert.Equal(DateTimeKind.Utc, entry.Timestamp.Kind);
+                entry.TimestampUtc!.Value);
+            Assert.Equal(DateTimeKind.Utc, entry.TimestampUtc!.Value.Kind);
         }
 
         // ── Oversized line → parses, no throw, no truncation of the message ───

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/CmTraceOffsetCalibratorTests.cs

@@ -0,0 +1,190 @@
+using System;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// Pins the measurement contract of <see cref="CmTraceOffsetCalibrator"/>.
+    ///
+    /// <para>
+    /// The cases are taken from real sessions: +1 h (GMT to W. Europe, session bfff9b1c) and
+    /// -17 h (a writer left on the Pacific OOBE default while the agent had moved to
+    /// E. Australia). The backlog case is the one the residual guard cannot catch on its own and
+    /// is the reason the freshness rule exists.
+    /// </para>
+    /// </summary>
+    public class CmTraceOffsetCalibratorTests
+    {
+        private const string Source = "IntuneManagementExtension.log";
+        private static readonly DateTime UtcNow = new DateTime(2026, 08, 20, 07, 31, 46, DateTimeKind.Utc);
+
+        /// <summary>A line written "now" by a writer that believes it is at <paramref name="offset"/>.</summary>
+        private static DateTime LineWrittenNow(TimeSpan offset, DateTime utcNow)
+            => DateTime.SpecifyKind(utcNow + offset, DateTimeKind.Unspecified);
+
+        [Theory]
+        [InlineData(2)]     // CEST — the bfff9b1c writer
+        [InlineData(1)]     // BST — what the agent wrongly assumed there
+        [InlineData(-7)]    // PDT — the OOBE default seen in the -17 h sessions
+        [InlineData(10)]    // E. Australia
+        [InlineData(14)]    // Line Islands, the upper bound
+        [InlineData(-12)]   // Dateline, the lower bound
+        public void MeasuresWholeHourOffsets(int hours)
+        {
+            var sut = new CmTraceOffsetCalibrator();
+            var offset = TimeSpan.FromHours(hours);
+
+            Assert.True(sut.TryCalibrate(Source, LineWrittenNow(offset, UtcNow), UtcNow));
+
+            TimeSpan measured;
+            Assert.True(sut.TryGetOffset(Source, out measured));
+            Assert.Equal(offset, measured);
+        }
+
+        [Theory]
+        [InlineData(330)]   // India, UTC+5:30
+        [InlineData(345)]   // Nepal, UTC+5:45
+        [InlineData(570)]   // Adelaide, UTC+9:30 — the +30 min sessions in the field data
+        public void MeasuresQuarterHourOffsets(int minutes)
+        {
+            var sut = new CmTraceOffsetCalibrator();
+            var offset = TimeSpan.FromMinutes(minutes);
+
+            Assert.True(sut.TryCalibrate(Source, LineWrittenNow(offset, UtcNow), UtcNow));
+
+            TimeSpan measured;
+            Assert.True(sut.TryGetOffset(Source, out measured));
+            Assert.Equal(offset, measured);
+        }
+
+        [Fact]
+        public void AbsorbsPollAndFlushLatency()
+        {
+            // The line was written a moment before we parsed it. That lag must vanish into the
+            // grid rather than shift the measured offset.
+            var sut = new CmTraceOffsetCalibrator();
+            var lineLocal = LineWrittenNow(TimeSpan.FromHours(2), UtcNow.AddMilliseconds(-450));
+
+            Assert.True(sut.TryCalibrate(Source, lineLocal, UtcNow));
+
+            TimeSpan measured;
+            Assert.True(sut.TryGetOffset(Source, out measured));
+            Assert.Equal(TimeSpan.FromHours(2), measured);
+        }
+
+        [Fact]
+        public void RejectsBacklogLine_EvenWhenItRoundsCleanly()
+        {
+            // THE case the residual guard cannot catch alone: a line exactly 30 minutes old is a
+            // clean multiple of the grid, so it rounds with zero residual — and would calibrate
+            // the offset half an hour wrong. Only the caller's freshness rule prevents this from
+            // ever being offered; this test pins that a 30-minute-old line does not silently
+            // produce the true offset.
+            var sut = new CmTraceOffsetCalibrator();
+            var thirtyMinutesOld = LineWrittenNow(TimeSpan.FromHours(2), UtcNow.AddMinutes(-30));
+
+            Assert.True(sut.TryCalibrate(Source, thirtyMinutesOld, UtcNow));
+
+            TimeSpan measured;
+            Assert.True(sut.TryGetOffset(Source, out measured));
+            Assert.Equal(TimeSpan.FromMinutes(90), measured);
+            Assert.NotEqual(TimeSpan.FromHours(2), measured);
+        }
+
+        [Fact]
+        public void RejectsOffGridCandidate()
+        {
+            // 7 minutes off the grid: not fresh, and not a timezone either.
+            var sut = new CmTraceOffsetCalibrator();
+            var offGrid = LineWrittenNow(TimeSpan.FromHours(2), UtcNow.AddMinutes(-7));
+
+            Assert.False(sut.TryCalibrate(Source, offGrid, UtcNow));
+
+            TimeSpan ignored;
+            Assert.False(sut.TryGetOffset(Source, out ignored));
+        }
+
+        [Fact]
+        public void RejectsOffsetOutsideAnyRealTimezone()
+        {
+            var sut = new CmTraceOffsetCalibrator();
+            var absurd = LineWrittenNow(TimeSpan.FromHours(20), UtcNow);
+
+            Assert.False(sut.TryCalibrate(Source, absurd, UtcNow));
+        }
+
+        [Fact]
+        public void SelfHeals_WhenTheWritingProcessPicksUpANewZone()
+        {
+            // The writer restarts mid-session and now believes CEST instead of the stale BST.
+            var sut = new CmTraceOffsetCalibrator();
+            Assert.True(sut.TryCalibrate(Source, LineWrittenNow(TimeSpan.FromHours(1), UtcNow), UtcNow));
+
+            var later = UtcNow.AddMinutes(5);
+            Assert.True(sut.TryCalibrate(Source, LineWrittenNow(TimeSpan.FromHours(2), later), later));
+
+            TimeSpan measured;
+            Assert.True(sut.TryGetOffset(Source, out measured));
+            Assert.Equal(TimeSpan.FromHours(2), measured);
+        }
+
+        [Fact]
+        public void IgnoresAnchorOlderThanTheCurrentOne()
+        {
+            var sut = new CmTraceOffsetCalibrator();
+            Assert.True(sut.TryCalibrate(Source, LineWrittenNow(TimeSpan.FromHours(2), UtcNow), UtcNow));
+
+            // An out-of-order line from before the current anchor must not move the offset back.
+            var earlier = UtcNow.AddMinutes(-10);
+            Assert.False(sut.TryCalibrate(Source, LineWrittenNow(TimeSpan.FromHours(1), earlier), earlier));
+
+            TimeSpan measured;
+            Assert.True(sut.TryGetOffset(Source, out measured));
+            Assert.Equal(TimeSpan.FromHours(2), measured);
+        }
+
+        [Fact]
+        public void KeepsSourcesIndependent()
+        {
+            // IntuneManagementExtension.log and AppWorkload.log are written by different
+            // processes and may hold different beliefs.
+            var sut = new CmTraceOffsetCalibrator();
+            Assert.True(sut.TryCalibrate("IntuneManagementExtension.log", LineWrittenNow(TimeSpan.FromHours(2), UtcNow), UtcNow));
+            Assert.True(sut.TryCalibrate("AppWorkload.log", LineWrittenNow(TimeSpan.FromHours(-7), UtcNow), UtcNow));
+
+            TimeSpan ime, appWorkload;
+            Assert.True(sut.TryGetOffset("IntuneManagementExtension.log", out ime));
+            Assert.True(sut.TryGetOffset("AppWorkload.log", out appWorkload));
+            Assert.Equal(TimeSpan.FromHours(2), ime);
+            Assert.Equal(TimeSpan.FromHours(-7), appWorkload);
+        }
+
+        [Fact]
+        public void ResolvesTheRealFieldLine_FromSessionBfff9b1c()
+        {
+            // Raw line: <![LOG[Agent version is: 1.104.102.0]LOG]!><time="09:31:46.5192284" ...>
+            // Server-side ReceivedAt puts the true UTC at 07:31:46.4. The old code produced
+            // 08:31:46.5192284 — local minus the agent's stale +1 h belief.
+            var sut = new CmTraceOffsetCalibrator();
+            var trueUtc = new DateTime(2026, 08, 20, 07, 31, 46, 400, DateTimeKind.Utc);
+            var lineLocal = new DateTime(2026, 08, 20, 09, 31, 46, 519, DateTimeKind.Unspecified);
+
+            Assert.True(sut.TryCalibrate(Source, lineLocal, trueUtc));
+
+            DateTime resolved;
+            Assert.True(sut.TryResolveUtc(Source, lineLocal, out resolved));
+            Assert.Equal(DateTimeKind.Utc, resolved.Kind);
+            Assert.Equal(new DateTime(2026, 08, 20, 07, 31, 46, 519, DateTimeKind.Utc), resolved);
+        }
+
+        [Fact]
+        public void ReportsUncalibratedSource_SoTheCallerCanFlagIt()
+        {
+            var sut = new CmTraceOffsetCalibrator();
+
+            DateTime resolved;
+            Assert.False(sut.TryResolveUtc(Source, UtcNow, out resolved));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerLineAnchoringTests.cs

@@ -0,0 +1,441 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Logging;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// Per-line self-anchoring — the era-aware successor to the reverted per-file offset
+    /// application (04b1a7c6).
+    ///
+    /// <para>
+    /// The property under test: a line read in a provably FRESH pass resolves to the instant it
+    /// was written, whatever timezone its writer believed — and neighbouring lines from writers
+    /// with DIFFERENT beliefs each resolve to their own era, because no cross-line state is
+    /// involved. That interleaving (fixture: AgentExecutor.log with PDT and CEST children in one
+    /// file, flipping both ways) is exactly what broke every cross-line anchor design.
+    /// </para>
+    ///
+    /// <para>
+    /// The freshness boundary is equally load-bearing: backlog (first sight, restart catch-up,
+    /// stalled polls) must NEVER anchor, because an old line's age can round onto the 15-minute
+    /// offset grid. Those paths keep the uniform reader-zone fallback.
+    /// </para>
+    /// </summary>
+    public sealed class ImeLogTrackerLineAnchoringTests
+    {
+        private static readonly DateTime T0 = new DateTime(2026, 8, 20, 12, 13, 0, DateTimeKind.Utc);
+
+        private static List<ImeLogPattern> Patterns() => new List<ImeLogPattern>
+        {
+            new ImeLogPattern
+            {
+                PatternId = "T-ALL", Category = "always", Enabled = true,
+                Pattern = @"marker (?<n>\d+)",
+                Action = "noop",
+                Parameters = new Dictionary<string, string>(),
+            },
+        };
+
+        /// <summary>A CMTrace line as a writer holding <paramref name="writerOffset"/> renders instant <paramref name="utcInstant"/>.</summary>
+        private static string Line(string message, DateTime utcInstant, TimeSpan writerOffset)
+        {
+            var local = utcInstant + writerOffset;
+            return $"<![LOG[{message}]LOG]!><time=\"{local:HH:mm:ss.fffffff}\" date=\"{local:M-d-yyyy}\" " +
+                   "component=\"X\" context=\"\" type=\"1\" thread=\"1\" file=\"\">";
+        }
+
+        private sealed class Harness : IDisposable
+        {
+            private readonly TempDirectory _tmp = new TempDirectory();
+            public ImeLogTracker Tracker { get; }
+            public DateTime Now { get; set; } = T0;
+
+            public Harness(string? stateDirectory = null)
+            {
+                Tracker = new ImeLogTracker(
+                    logFolder: _tmp.Path,
+                    patterns: Patterns(),
+                    logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                    stateDirectory: stateDirectory);
+                Tracker.UtcNowProvider = () => Now;
+            }
+
+            public string PathOf(string fileName) => Path.Combine(_tmp.Path, fileName);
+
+            public void Append(string fileName, string line)
+                => File.AppendAllText(PathOf(fileName), line + Environment.NewLine);
+
+            public Task Pass() => Tracker.CheckLogFilesAsync(CancellationToken.None);
+
+            public void Dispose()
+            {
+                Tracker.Dispose();
+                _tmp.Dispose();
+            }
+        }
+
+        [Theory]
+        // The writer's belief. A fresh line must resolve to the instant it was written,
+        // WHATEVER that belief is — including agreement with this process (the majority case,
+        // which a fix to the agent's own zone cache would have broken).
+        [InlineData(2)]     // CEST
+        [InlineData(1)]     // BST
+        [InlineData(0)]     // UTC
+        [InlineData(-7)]    // PDT — the OOBE default behind the -9 h and -17 h field cases
+        [InlineData(10)]    // E. Australia
+        public async Task FreshLine_ResolvesToItsTrueInstant_ForAnyWriterBelief(int writerOffsetHours)
+        {
+            var writerOffset = TimeSpan.FromHours(writerOffsetHours);
+            using var h = new Harness();
+
+            // First sight: backlog, must not anchor.
+            h.Append("IntuneManagementExtension.log", Line("marker 1", h.Now, writerOffset));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            var writtenAt = h.Now.AddMilliseconds(-80);   // written just before the poll sees it
+            h.Append("IntuneManagementExtension.log", Line("marker 2", writtenAt, writerOffset));
+            await h.Pass();
+
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, h.Tracker.LastMatchedSourceOffsetOrigin);
+            Assert.Equal(writtenAt, h.Tracker.LastMatchedLogTimestamp);
+            Assert.Equal(writerOffsetHours * 60, h.Tracker.LastMatchedSourceOffsetMinutes);
+        }
+
+        [Fact]
+        public async Task InterleavedEras_InOneGrowingPass_EachLineResolvesToItsOwnEra()
+        {
+            // The e9753578 file shape: two writer processes with different zone beliefs
+            // interleaved in ONE file. Any per-file offset gets one of them wrong by 9 h;
+            // per-line anchoring must get both right within the same chunk.
+            var pdt = TimeSpan.FromHours(-7);
+            var cest = TimeSpan.FromHours(2);
+            using var h = new Harness();
+
+            h.Append("AgentExecutor.log", Line("marker 1", h.Now, pdt));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            var wrotePdt = h.Now.AddMilliseconds(-90);
+            var wroteCest = h.Now.AddMilliseconds(-50);
+            h.Append("AgentExecutor.log", Line("marker 2", wrotePdt, pdt));
+            h.Append("AgentExecutor.log", Line("marker 3", wroteCest, cest));
+
+            var resolved = new List<(DateTime? Ts, CmTraceOffsetOrigin Origin, int? Offset)>();
+            Action<string> capture = _ => resolved.Add((
+                h.Tracker.LastMatchedLogTimestamp,
+                h.Tracker.LastMatchedSourceOffsetOrigin,
+                h.Tracker.LastMatchedSourceOffsetMinutes));
+            h.Tracker.OnPatternMatched += capture;
+            try
+            {
+                await h.Pass();
+            }
+            finally
+            {
+                h.Tracker.OnPatternMatched -= capture;
+            }
+
+            Assert.Equal(2, resolved.Count);
+            Assert.Equal(wrotePdt, resolved[0].Ts);
+            Assert.Equal(-420, resolved[0].Offset);
+            Assert.Equal(wroteCest, resolved[1].Ts);
+            Assert.Equal(120, resolved[1].Offset);
+            Assert.All(resolved, r => Assert.Equal(CmTraceOffsetOrigin.LineAnchored, r.Origin));
+        }
+
+        [Fact]
+        public async Task FirstSightBacklog_FallsBackToReaderZone()
+        {
+            using var h = new Harness();
+
+            h.Append("IntuneManagementExtension.log", Line("marker 1", h.Now.AddHours(-3), TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            Assert.Equal(CmTraceOffsetOrigin.None, h.Tracker.LastMatchedSourceOffsetOrigin);
+        }
+
+        [Fact]
+        public async Task FileFirstSeenEmpty_ItsFirstContentIsFresh()
+        {
+            // AgentExecutor.log in the field: the file APPEARS mid-enrollment. Seeing it empty
+            // (or not existing content-wise) counts as an observation, so its very first lines
+            // are provably written between passes and may anchor. This closes the warm-up gap
+            // for exactly the file whose eras flip the most.
+            using var h = new Harness();
+
+            File.WriteAllText(h.PathOf("AgentExecutor.log"), string.Empty);
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(5);
+            var writtenAt = h.Now.AddMilliseconds(-60);
+            h.Append("AgentExecutor.log", Line("marker 1", writtenAt, TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, h.Tracker.LastMatchedSourceOffsetOrigin);
+            Assert.Equal(writtenAt, h.Tracker.LastMatchedLogTimestamp);
+        }
+
+        [Fact]
+        public async Task PollGapBeyondFreshWindow_FallsBack()
+        {
+            // A stalled agent (GC, CPU starvation) re-polls after a long gap: the new bytes span
+            // the whole gap and their age is unbounded, so the pass must not anchor — even
+            // though most of its lines may in fact be recent. Conservative by design.
+            using var h = new Harness();
+
+            h.Append("IntuneManagementExtension.log", Line("marker 1", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+            h.Now = T0.AddSeconds(10);
+            h.Append("IntuneManagementExtension.log", Line("marker 2", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, h.Tracker.LastMatchedSourceOffsetOrigin);
+
+            // Gap far beyond FreshLineMaxAge.
+            h.Now = h.Now + ImeLogTracker.FreshLineMaxAge + TimeSpan.FromSeconds(10);
+            h.Append("IntuneManagementExtension.log", Line("marker 3", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            Assert.Equal(CmTraceOffsetOrigin.None, h.Tracker.LastMatchedSourceOffsetOrigin);
+
+            // And the very next tight poll is fresh again.
+            h.Now = h.Now.AddSeconds(1);
+            h.Append("IntuneManagementExtension.log", Line("marker 4", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, h.Tracker.LastMatchedSourceOffsetOrigin);
+        }
+
+        [Fact]
+        public async Task RestartWithRestoredBookmark_FirstPassIsBacklog_SecondPassAnchors()
+        {
+            // The persisted position bookmark survives a restart; the freshness guarantee must
+            // not — the first pass after a restart reads the downtime backlog, whose lines can
+            // be arbitrarily old.
+            using var stateDir = new TempDirectory();
+            using var h = new Harness(stateDirectory: stateDir.Path);
+
+            h.Append("IntuneManagementExtension.log", Line("marker 1", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+            h.Tracker.SaveStateForTest();
+
+            // "Restart": a second tracker over the same folder restores the bookmark.
+            using var h2 = new HarnessOver(h, stateDir.Path);
+            h2.Tracker.LoadStateForTest();
+
+            // Backlog written during the downtime — 30 min old, exactly on the offset grid,
+            // the nastiest possible backlog shape. Must NOT anchor.
+            h2.Now = T0.AddMinutes(30);
+            h2.Append(Line("marker 2", T0.AddSeconds(20), TimeSpan.FromHours(2)));
+            await h2.Pass();
+            Assert.Equal(CmTraceOffsetOrigin.None, h2.Tracker.LastMatchedSourceOffsetOrigin);
+
+            // The next tight poll is fresh again.
+            h2.Now = h2.Now.AddSeconds(1);
+            var writtenAt = h2.Now.AddMilliseconds(-70);
+            h2.Append(Line("marker 3", writtenAt, TimeSpan.FromHours(2)));
+            await h2.Pass();
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, h2.Tracker.LastMatchedSourceOffsetOrigin);
+            Assert.Equal(writtenAt, h2.Tracker.LastMatchedLogTimestamp);
+        }
+
+        /// <summary>Second tracker over the FIRST harness's log folder — the "restarted agent".</summary>
+        private sealed class HarnessOver : IDisposable
+        {
+            private readonly string _logFolder;
+            public ImeLogTracker Tracker { get; }
+            public DateTime Now { get; set; }
+
+            public HarnessOver(Harness original, string stateDirectory)
+            {
+                _logFolder = Path.GetDirectoryName(original.PathOf("x"));
+                Tracker = new ImeLogTracker(
+                    logFolder: _logFolder,
+                    patterns: Patterns(),
+                    logger: new AgentLogger(_logFolder, AgentLogLevel.Info),
+                    stateDirectory: stateDirectory);
+                Tracker.UtcNowProvider = () => Now;
+            }
+
+            public void Append(string line)
+                => File.AppendAllText(Path.Combine(_logFolder, "IntuneManagementExtension.log"), line + Environment.NewLine);
+
+            public Task Pass() => Tracker.CheckLogFilesAsync(CancellationToken.None);
+
+            public void Dispose() => Tracker.Dispose();
+        }
+
+        [Fact]
+        public async Task FreshlyWrittenReplayLine_OnExactGridAge_ResolvesToRoughlyNow()
+        {
+            // Characterization of the one accepted edge: a line freshly WRITTEN but carrying a
+            // REPLAYED timestamp whose age is exactly a grid multiple (here 30 min) measures
+            // that age as an "offset" and resolves to ~now instead of its replayed past. The
+            // error is bounded by construction (an anchored line always lands at now ± 2 min),
+            // and sub-24h replays are treated as current by the historic-replay guard anyway.
+            using var h = new Harness();
+
+            h.Append("IntuneManagementExtension.log", Line("marker 1", h.Now, TimeSpan.Zero));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            var replayedInstant = h.Now.AddMinutes(-30);
+            h.Append("IntuneManagementExtension.log", Line("marker 2", replayedInstant, TimeSpan.Zero));
+            await h.Pass();
+
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, h.Tracker.LastMatchedSourceOffsetOrigin);
+            Assert.NotNull(h.Tracker.LastMatchedLogTimestamp);
+            var error = (h.Tracker.LastMatchedLogTimestamp!.Value - h.Now).Duration();
+            Assert.True(error <= CmTraceOffsetCalibrator.MaxGridResidual,
+                $"anchored line must resolve to now ± residual, was off by {error}");
+        }
+
+        // =====================================================================
+        // The committed field fixture — session e9753578, ImeLogs/AgentExecutor.log.
+        // One file, two writer eras (PDT hour-05 / CEST hour-14), interleaved, flipping
+        // BOTH ways. Replayed here as the live tail the field agent saw: entry by entry,
+        // with the clock following the true write time.
+        // =====================================================================
+
+        private static string FixturePath()
+        {
+            var dir = AppContext.BaseDirectory;
+            for (int i = 0; i < 12; i++)
+            {
+                if (File.Exists(Path.Combine(dir, "AutopilotMonitor.sln")))
+                    return Path.Combine(dir, "tests", "fixtures", "cmtrace-logs",
+                        "agentexecutor-two-writer-eras-v1.cmtrace");
+                var parent = Directory.GetParent(dir)?.FullName;
+                if (parent == null || parent == dir) break;
+                dir = parent;
+            }
+            throw new DirectoryNotFoundException(
+                "Could not locate repo root (AutopilotMonitor.sln) walking up from " + AppContext.BaseDirectory);
+        }
+
+        /// <summary>Group the fixture's physical lines into complete CMTrace entries (multiline-safe).</summary>
+        private static List<string> FixtureEntries()
+        {
+            var entries = new List<string>();
+            string? pending = null;
+            foreach (var rawWithBom in File.ReadAllLines(FixturePath()))
+            {
+                // The fixture keeps the original file's BOM verbatim — it sat at the START of
+                // the real AgentExecutor.log, which is mid-file in this excerpt.
+                var raw = rawWithBom.TrimStart('');
+                if (pending == null)
+                {
+                    if (raw.Length == 0 || raw[0] == '#') continue;
+                    if (!raw.StartsWith("<![LOG[", StringComparison.Ordinal)) continue;
+                    if (raw.Contains("]LOG]!>")) { entries.Add(raw); continue; }
+                    pending = raw;
+                }
+                else
+                {
+                    pending += "\n" + raw;
+                    if (raw.Contains("]LOG]!>")) { entries.Add(pending!); pending = null; }
+                }
+            }
+            return entries;
+        }
+
+        [Fact]
+        public async Task TwoWriterEraFixture_EveryLineOfBothErasResolvesToItsTrueInstant()
+        {
+            // The committed fixture is a curated, verbatim excerpt of the transition window
+            // (commit policy: anonymized, versioned) — 20 entries covering both eras and the flip.
+            var entries = FixtureEntries();
+            Assert.True(entries.Count >= 15, $"fixture unexpectedly small: {entries.Count} entries");
+
+            using var h = new Harness();
+
+            // Match every fixture entry.
+            h.Tracker.CompilePatterns(new List<ImeLogPattern>
+            {
+                new ImeLogPattern
+                {
+                    PatternId = "T-ANY", Category = "always", Enabled = true,
+                    Pattern = ".+", Action = "noop",
+                    Parameters = new Dictionary<string, string>(),
+                },
+            });
+
+            // The file exists (empty) before its first content — first sight is the observation
+            // baseline, everything after is a fresh tail, exactly like the field.
+            File.WriteAllText(h.PathOf("AgentExecutor.log"), string.Empty);
+            h.Now = new DateTime(2026, 8, 20, 12, 13, 30, DateTimeKind.Utc);
+            await h.Pass();
+
+            var anchored = 0;
+            var resolvedList = new List<(DateTime Resolved, DateTime Expected)>();
+            Action<string> capture = _ =>
+            {
+                if (h.Tracker.LastMatchedSourceOffsetOrigin == CmTraceOffsetOrigin.LineAnchored)
+                    anchored++;
+                if (h.Tracker.LastMatchedLogTimestamp.HasValue && _expectedForCurrentEntry.HasValue)
+                    resolvedList.Add((h.Tracker.LastMatchedLogTimestamp.Value, _expectedForCurrentEntry.Value));
+            };
+            h.Tracker.OnPatternMatched += capture;
+            try
+            {
+                foreach (var entry in entries)
+                {
+                    CmTraceLogEntry? parsed;
+                    Assert.True(CmTraceLogParser.TryParseLine(entry, out parsed), "fixture entry did not parse");
+
+                    // Era by local hour: the fixture holds exactly two eras — PDT (UTC-7) lines
+                    // render at local hour 05, CEST (UTC+2) lines at hour 14 (fixture header).
+                    var eraOffset = parsed.LocalTimestamp.Hour == 14
+                        ? TimeSpan.FromHours(2)
+                        : TimeSpan.FromHours(-7);
+                    var trueUtc = DateTime.SpecifyKind(parsed.LocalTimestamp - eraOffset, DateTimeKind.Utc);
+
+                    // The clock follows the write; never move backwards (interleaved eras are
+                    // written in true-UTC order, but guard against sub-ms jitter).
+                    var readAt = trueUtc.AddMilliseconds(120);
+                    if (readAt > h.Now) h.Now = readAt;
+
+                    // In production the 100 ms poll keeps running through write silences — every
+                    // empty look refreshes the freshness window. The fixture's transition window
+                    // spans multi-minute write gaps, so replay that cadence with one empty poll
+                    // just before each append; without it the NEXT pass would (correctly!)
+                    // classify the gap as a stall and refuse to anchor.
+                    h.Now = h.Now.AddMilliseconds(-100);
+                    await h.Pass();
+                    h.Now = readAt;
+
+                    _expectedForCurrentEntry = trueUtc;
+                    File.AppendAllText(h.PathOf("AgentExecutor.log"), entry + Environment.NewLine);
+                    await h.Pass();
+                    _expectedForCurrentEntry = null;
+                }
+            }
+            finally
+            {
+                h.Tracker.OnPatternMatched -= capture;
+            }
+
+            // Every matched entry resolved to the instant its writer rendered — across BOTH
+            // eras, including the flips. This is the exact property whose absence produced the
+            // -9 h script durations.
+            Assert.Equal(entries.Count, resolvedList.Count);
+            Assert.All(resolvedList, r => Assert.Equal(r.Expected, r.Resolved));
+            Assert.True(anchored == resolvedList.Count,
+                $"expected every entry line-anchored, got {anchored}/{resolvedList.Count}");
+
+            // Both eras genuinely exercised: PDT entries render at local hour 05, CEST at 14.
+            Assert.Contains(resolvedList, r => (r.Expected + TimeSpan.FromHours(-7)).Hour == 5);
+            Assert.Contains(resolvedList, r => (r.Expected + TimeSpan.FromHours(2)).Hour == 14);
+        }
+
+        private DateTime? _expectedForCurrentEntry;
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerOffsetCalibrationTests.cs

@@ -0,0 +1,275 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// End-to-end offset calibration through a real read cycle.
+    ///
+    /// <para>
+    /// A CMTrace line states local time and nothing else, so its UTC value depends on which zone
+    /// the WRITING process believed it was in. The tracker used to substitute its own belief,
+    /// which is right only when the two happen to agree.
+    /// </para>
+    ///
+    /// <para>
+    /// These tests are deliberately independent of the machine they run on: the assertion is
+    /// always "a line written at instant T resolves to T", for every writer belief. That single
+    /// property covers both field cases at once — the writer disagreeing with us (the bug) and
+    /// the writer agreeing with us (the majority, which a naive fix would have broken).
+    /// </para>
+    /// </summary>
+    public sealed class ImeLogTrackerOffsetCalibrationTests
+    {
+        private const string LogFileName = "IntuneManagementExtension.log";
+        private static readonly DateTime T0 = new DateTime(2026, 8, 20, 7, 30, 0, DateTimeKind.Utc);
+
+        private static List<ImeLogPattern> Patterns() => new List<ImeLogPattern>
+        {
+            new ImeLogPattern
+            {
+                PatternId = "T-MARK", Category = "always", Enabled = true,
+                Pattern = @"marker (?<n>\d+)",
+                Action = "noop",
+                Parameters = new Dictionary<string, string>(),
+            },
+        };
+
+        /// <summary>A CMTrace line as a writer holding <paramref name="writerOffset"/> renders instant <paramref name="utcInstant"/>.</summary>
+        private static string Line(string message, DateTime utcInstant, TimeSpan writerOffset)
+        {
+            var local = utcInstant + writerOffset;
+            return $"<![LOG[{message}]LOG]!><time=\"{local:HH:mm:ss.fffffff}\" date=\"{local:M-d-yyyy}\" " +
+                   "component=\"IntuneManagementExtension\" context=\"\" type=\"1\" thread=\"1\" file=\"\">";
+        }
+
+        private sealed class Harness : IDisposable
+        {
+            private readonly TempDirectory _tmp = new TempDirectory();
+            public ImeLogTracker Tracker { get; }
+            public DateTime Now { get; set; } = T0;
+
+            public Harness()
+            {
+                Tracker = new ImeLogTracker(
+                    logFolder: _tmp.Path,
+                    patterns: Patterns(),
+                    logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info));
+                Tracker.UtcNowProvider = () => Now;
+            }
+
+            public string LogPath => Path.Combine(_tmp.Path, LogFileName);
+
+            public void Append(string line) => File.AppendAllText(LogPath, line + Environment.NewLine);
+
+            public Task Pass() => Tracker.CheckLogFilesAsync(CancellationToken.None);
+
+            public void Dispose()
+            {
+                Tracker.Dispose();
+                _tmp.Dispose();
+            }
+        }
+
+        [Theory]
+        // The writer's belief. The MEASUREMENT must recover it exactly, whatever it is.
+        [InlineData(2)]     // CEST
+        [InlineData(1)]     // BST
+        [InlineData(-7)]    // PDT — the OOBE default behind the -17 h and -9 h field cases
+        [InlineData(10)]    // E. Australia
+        [InlineData(0)]     // UTC
+        public async Task MeasuresTheWritersOffsetExactly_ForAnyBelief(int writerOffsetHours)
+        {
+            // NOTE: the per-FILE measurement asserted here is OBSERVATIONAL — its application was
+            // reverted on 2026-08-20 (04b1a7c6) because one offset per file is wrong when a file
+            // holds interleaved writer eras. Resolution now anchors per LINE instead (see
+            // ImeLogTrackerLineAnchoringTests, which restores the "a line written at T resolves
+            // to T" property era-safely). The per-file measurement stays for the Info log and
+            // measuredWriterOffsetMinutes provenance.
+            var writerOffset = TimeSpan.FromHours(writerOffsetHours);
+            using var h = new Harness();
+
+            h.Append(Line("marker 1", h.Now, writerOffset));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            h.Append(Line("marker 2", h.Now, writerOffset));
+            await h.Pass();
+
+            TimeSpan measured;
+            Assert.True(h.Tracker.OffsetCalibrator.TryGetOffset(LogFileName, out measured));
+            Assert.Equal(writerOffset, measured);
+        }
+
+        [Fact]
+        public async Task MeasuresTheWritersOffset_NotItsOwn()
+        {
+            using var h = new Harness();
+            var writerOffset = TimeSpan.FromHours(2);
+
+            h.Append(Line("marker 1", h.Now, writerOffset));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            h.Append(Line("marker 2", h.Now, writerOffset));
+            await h.Pass();
+
+            TimeSpan measured;
+            Assert.True(h.Tracker.OffsetCalibrator.TryGetOffset(LogFileName, out measured));
+            Assert.Equal(writerOffset, measured);
+        }
+
+        [Fact]
+        public async Task DoesNotCalibrateOnFirstSightOfAFile()
+        {
+            // The first pass reads from position 0, so the newest line in the file may be hours
+            // old. Anchoring on it would measure the line's age instead of the writer's offset.
+            using var h = new Harness();
+
+            h.Append(Line("marker 1", T0.AddHours(-3), TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            TimeSpan ignored;
+            Assert.False(h.Tracker.OffsetCalibrator.TryGetOffset(LogFileName, out ignored));
+        }
+
+        [Fact]
+        public async Task FollowsTheWriterAcrossARestartIntoANewZone()
+        {
+            // IME restarts mid-enrollment and picks up the timezone the OS moved to. The
+            // measurement has to follow, otherwise every later line is off by the difference.
+            using var h = new Harness();
+
+            h.Append(Line("marker 1", h.Now, TimeSpan.FromHours(1)));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            h.Append(Line("marker 2", h.Now, TimeSpan.FromHours(1)));
+            await h.Pass();
+
+            TimeSpan before;
+            Assert.True(h.Tracker.OffsetCalibrator.TryGetOffset(LogFileName, out before));
+            Assert.Equal(TimeSpan.FromHours(1), before);
+
+            // Writer restarts, now on +2.
+            h.Now = T0.AddSeconds(20);
+            h.Append(Line("marker 3", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(30);
+            var writtenAt = h.Now;
+            h.Append(Line("marker 4", writtenAt, TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            TimeSpan after;
+            Assert.True(h.Tracker.OffsetCalibrator.TryGetOffset(LogFileName, out after));
+            Assert.Equal(TimeSpan.FromHours(2), after);
+            // The measurement follows the restart. Applying it is what the 2026-08-20 revert
+            // removed — that is exactly the case a file with two writer eras breaks.
+            Assert.Equal(120, h.Tracker.LastMatchedMeasuredWriterOffsetMinutes);
+        }
+
+        [Fact]
+        public async Task HonorsAWriterDeclaredBiasWithoutMeasuring()
+        {
+            // A line carrying its own bias states the offset outright; it must be used as-is and
+            // must never become a calibration anchor.
+            using var h = new Harness();
+
+            h.Append(Line("marker 1", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            var writtenAt = h.Now;
+            var local = writtenAt + TimeSpan.FromHours(-8);        // a PST writer
+            h.Append($"<![LOG[marker 2]LOG]!><time=\"{local:HH:mm:ss.fffffff}+480\" date=\"{local:M-d-yyyy}\" " +
+                     "component=\"IntuneManagementExtension\" context=\"\" type=\"1\" thread=\"1\" file=\"\">");
+            await h.Pass();
+
+            Assert.True(h.Tracker.LastMatchedLogTimestamp.HasValue);
+            Assert.Equal(writtenAt, h.Tracker.LastMatchedLogTimestamp.Value);
+
+            TimeSpan ignored;
+            Assert.False(h.Tracker.OffsetCalibrator.TryGetOffset(LogFileName, out ignored));
+        }
+
+        [Fact]
+        public async Task RecordsMeasuredOffsetSeparatelyFromTheAppliedOne()
+        {
+            // The regression that forced the revert shipped an event tagged "calibrated" while
+            // carrying an offset that did not hold for that line. Measured and applied are now
+            // separate fields so a future reader cannot mistake one for the other.
+            using var h = new Harness();
+            var writerOffset = TimeSpan.FromHours(-7);   // PDT, the OOBE default
+
+            h.Append(Line("marker 1", h.Now, writerOffset));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            h.Append(Line("marker 2", h.Now, writerOffset));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(20);
+            h.Append(Line("marker 3", h.Now, writerOffset));
+            await h.Pass();
+
+            // Measured: the writer's actual belief, per file.
+            Assert.Equal(-420, h.Tracker.LastMatchedMeasuredWriterOffsetMinutes);
+
+            // Applied: the line's OWN anchor (fresh pass), never the per-file "calibrated" value —
+            // the two must stay distinguishable even when they agree numerically.
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, h.Tracker.LastMatchedSourceOffsetOrigin);
+            Assert.NotEqual(CmTraceOffsetOrigin.Calibrated, h.Tracker.LastMatchedSourceOffsetOrigin);
+        }
+
+        [Fact]
+        public async Task RecordsProvenance_AsFallback_BeforeAnyCalibration()
+        {
+            // The warm-up pass: the offset is not measured yet, so the reader zone is assumed and
+            // the event has to say so rather than look source-grounded.
+            using var h = new Harness();
+
+            h.Append(Line("marker 1", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            Assert.Equal(CmTraceOffsetOrigin.None, h.Tracker.LastMatchedSourceOffsetOrigin);
+            Assert.True(h.Tracker.LastMatchedSourceLocalTimestamp.HasValue);
+
+            // The APPLIED offset is reported even on the fallback path — an event that states no
+            // offset at all cannot be recomputed later, which defeats the purpose of recording
+            // provenance. Asserted against the running machine's zone so this stays portable.
+            var readerZone = (int)TimeZoneInfo.Local
+                .GetUtcOffset(h.Tracker.LastMatchedSourceLocalTimestamp!.Value).TotalMinutes;
+            Assert.Equal(readerZone, h.Tracker.LastMatchedSourceOffsetMinutes);
+        }
+
+        [Fact]
+        public async Task RecordsProvenance_ForADeclaredBias()
+        {
+            using var h = new Harness();
+
+            h.Append(Line("marker 1", h.Now, TimeSpan.FromHours(2)));
+            await h.Pass();
+
+            h.Now = T0.AddSeconds(10);
+            var local = h.Now + TimeSpan.FromHours(-8);
+            h.Append($"<![LOG[marker 2]LOG]!><time=\"{local:HH:mm:ss.fffffff}+480\" date=\"{local:M-d-yyyy}\" " +
+                     "component=\"IntuneManagementExtension\" context=\"\" type=\"1\" thread=\"1\" file=\"\">");
+            await h.Pass();
+
+            Assert.Equal(CmTraceOffsetOrigin.Bias, h.Tracker.LastMatchedSourceOffsetOrigin);
+            // Reported in the same sense as a measured offset (local = UTC + offset), so the two
+            // origins are directly comparable; the wire bias uses the opposite convention.
+            Assert.Equal(-480, h.Tracker.LastMatchedSourceOffsetMinutes);
+        }
+
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/ShellCoreTrackerReplayScopeTests.cs

@@ -0,0 +1,322 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Linq;
+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.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring
+{
+    /// <summary>
+    /// Scope of the Shell-Core replay: it recovers the Hello-wizard start and NOTHING else.
+    /// <para>
+    /// The replay had existed since session 772fe502 with no caller. Wiring it up (2026-08-19)
+    /// activated three rails at once, and only one of them is safe to replay:
+    /// </para>
+    /// <list type="bullet">
+    ///   <item><b>62404 Hello-wizard start — replayed.</b> A conservative fact: it vetoes a
+    ///     premature "Hello is disabled" skip and can never by itself complete a session, so
+    ///     replaying it can only make the agent wait longer, never finish early.</item>
+    ///   <item><b>62407 ESP exit — never replayed.</b> Windows writes the identical description
+    ///     for the intermediate DeviceSetup-to-AccountSetup transition and the final exit, so the
+    ///     record carries no evidence of its own position; the reducer orders exits by ingest
+    ///     ordinal, which for a replay is fresher than reality; and arm C of
+    ///     ShouldTransitionToAwaitingHello opens on any arriving exit once the restored state
+    ///     carries AccountSetupEntered + a genuine IME user session + desktop arrival. See
+    ///     ClassicEspExitingOnRestoredStateTests for the reducer half of that proof.</item>
+    ///   <item><b>62407 ESP failure — never replayed.</b> Re-injecting a historic failure as
+    ///     fresh can fail a session that recovered (ANALYZE-ESP-006).</item>
+    /// </list>
+    /// </summary>
+    public sealed class ShellCoreTrackerReplayScopeTests
+    {
+        private static readonly DateTime ClockNow = new DateTime(2026, 8, 19, 8, 43, 16, DateTimeKind.Utc);
+
+        // The REAL Shell-Core wording. Byte-identical for the intermediate DeviceSetup-to-
+        // AccountSetup transition and for the final post-AccountSetup exit — that identity is the
+        // whole reason a replayed exit cannot be classified.
+        private const string EspExitDescription = "CommercialOOBE_ESPProgress_Page_Exiting";
+        private const string EspFailureDescription = "CommercialOOBE_ESPProgress_Failure";
+        private const string AadHelloDescription = "CloudExperienceHost web app activity: AADHello";
+        private const string OtherWebAppDescription = "CloudExperienceHost web app activity: SomethingElse";
+
+        private sealed class Fixture : IDisposable
+        {
+            public TempDirectory Tmp { get; } = new TempDirectory();
+            public FakeSignalIngressSink PostSink { get; } = new FakeSignalIngressSink();
+            public VirtualClock Clock { get; } = new VirtualClock(ClockNow);
+
+            public ShellCoreTracker Build() => new ShellCoreTracker(
+                sessionId: "S1",
+                tenantId: "T1",
+                post: new InformationalEventPost(PostSink, Clock),
+                logger: new AgentLogger(Tmp.Path, AgentLogLevel.Info),
+                helloTracker: null);
+
+            public List<FakeSignalIngressSink.PostedSignal> AgentTraces() =>
+                PostSink.Posted.Where(p =>
+                    p.Payload != null
+                    && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                    && et == "agent_trace").ToList();
+
+            public void Dispose() => Tmp.Dispose();
+        }
+
+        private static (int, string, DateTime) Record(int id, string description, DateTime at)
+            => (id, description, at);
+
+        // ------------------------------------------------------------------ the wizard rail
+
+        [Fact]
+        public void The_hello_wizard_start_is_replayed_with_its_original_source_time()
+        {
+            // Session 772fe502: an agent restarted while the user sits inside the Hello wizard
+            // would otherwise never learn the wizard ran. This is the observation the replay
+            // exists for.
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var order = new List<string>();
+            HelloWizardStartedEventArgs? captured = null;
+            tracker.HelloWizardStarted += (_, args) => { order.Add("wizard"); captured = args; };
+            tracker.FinalizingSetupPhaseTriggered += (_, reason) => order.Add($"finalizing:{reason}");
+
+            var duringDowntime = ClockNow.AddMinutes(-37);
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, AadHelloDescription, duringDowntime),
+            });
+
+            Assert.Equal(new[] { "wizard", "finalizing:hello_wizard_started" }, order);
+            Assert.NotNull(captured);
+            // The historical time must survive the replay — collapsing to now would date the
+            // wizard after the restart and skew every duration derived from it.
+            Assert.Equal(duringDowntime, captured!.OccurredAtUtc);
+        }
+
+        [Fact]
+        public void The_wizard_replay_is_single_shot_across_repeated_records()
+        {
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var starts = 0;
+            tracker.HelloWizardStarted += (_, __) => starts++;
+
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, AadHelloDescription, ClockNow.AddMinutes(-30)),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, AadHelloDescription, ClockNow.AddMinutes(-20)),
+            });
+
+            Assert.Equal(1, starts);
+        }
+
+        [Fact]
+        public void A_non_hello_web_app_start_is_ignored()
+        {
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var starts = 0;
+            tracker.HelloWizardStarted += (_, __) => starts++;
+
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, OtherWebAppDescription, ClockNow.AddMinutes(-5)),
+            });
+
+            Assert.Equal(0, starts);
+            Assert.Empty(f.AgentTraces());
+        }
+
+        // ------------------------------------------------------------------ the exit rail
+
+        [Fact]
+        public void An_intermediate_only_window_raises_nothing_that_can_reach_the_reducer()
+        {
+            // THE regression this whole review chain is about: restart, and the only 62407 in the
+            // window is the historic DeviceSetup-to-AccountSetup handoff. Nothing may leave the
+            // tracker on a rail the decision engine listens to.
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var espExits = 0;
+            var finalizing = new List<string>();
+            var failures = 0;
+            tracker.EspExited += (_, __) => espExits++;
+            tracker.FinalizingSetupPhaseTriggered += (_, reason) => finalizing.Add(reason);
+            tracker.EspFailureDetected += (_, __) => failures++;
+
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspExitDescription, ClockNow.AddMinutes(-52)),
+            });
+
+            Assert.Equal(0, espExits);
+            Assert.Empty(finalizing);
+            Assert.Equal(0, failures);
+        }
+
+        [Fact]
+        public void Even_several_exits_in_the_window_stay_out_of_the_decision_stream()
+        {
+            // "Newest exit wins" was an earlier attempt at this problem. It does not help: if the
+            // final exit has not happened yet, the newest record in the window is still the
+            // intermediate one. Picking a record is the wrong lever — none of them is usable.
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var espExits = 0;
+            tracker.EspExited += (_, __) => espExits++;
+
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspExitDescription, ClockNow.AddMinutes(-52)),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspExitDescription, ClockNow.AddMinutes(-9)),
+            });
+
+            Assert.Equal(0, espExits);
+        }
+
+        [Fact]
+        public void A_historic_esp_failure_is_never_re_injected()
+        {
+            // A session that failed and then recovered on retry (ANALYZE-ESP-006) must not be
+            // failed again by its own history.
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var failures = new List<string>();
+            tracker.EspFailureDetected += (_, failureType) => failures.Add(failureType);
+
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspFailureDescription, ClockNow.AddMinutes(-40)),
+            });
+
+            Assert.Empty(failures);
+        }
+
+        // ------------------------------------------------------------------ visibility
+
+        [Fact]
+        public void Skipped_records_are_reported_once_as_an_agent_trace()
+        {
+            // Dropping evidence silently is how this class of bug survives. The gap has to stay
+            // visible to whoever debugs the session later — as an informational event, which is
+            // decision-neutral by construction.
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspExitDescription, ClockNow.AddMinutes(-52)),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspFailureDescription, ClockNow.AddMinutes(-40)),
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppEvent, EspExitDescription, ClockNow.AddMinutes(-9)),
+            });
+
+            var trace = Assert.Single(f.AgentTraces());
+            var data = Assert.IsAssignableFrom<IReadOnlyDictionary<string, object>>(trace.TypedPayload);
+            Assert.Equal(2, data["skippedEspExits"]);
+            Assert.Equal(1, data["skippedEspFailures"]);
+            Assert.Equal("replayed_62407_not_orderable", data["reason"]);
+            Assert.Equal(ClockNow.AddMinutes(-52).ToString("o"), data["oldestSkippedUtc"]);
+            Assert.Equal(ClockNow.AddMinutes(-9).ToString("o"), data["newestSkippedUtc"]);
+        }
+
+        [Fact]
+        public void A_wizard_only_window_reports_nothing_as_skipped()
+        {
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>
+            {
+                Record(ShellCoreTracker.EventId_ShellCore_WebAppStarted, AadHelloDescription, ClockNow.AddMinutes(-30)),
+            });
+
+            Assert.Empty(f.AgentTraces());
+        }
+
+        [Fact]
+        public void An_empty_batch_is_a_no_op()
+        {
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var raised = 0;
+            tracker.EspExited += (_, __) => raised++;
+            tracker.HelloWizardStarted += (_, __) => raised++;
+
+            tracker.ReplayBackfillRecords(new List<(int, string, DateTime)>());
+
+            Assert.Equal(0, raised);
+            Assert.Empty(f.AgentTraces());
+        }
+
+        // ------------------------------------------------------------------ live path untouched
+
+        [Fact]
+        public void The_live_path_still_raises_the_exit_normally()
+        {
+            // Narrowing the REPLAY must not narrow live observation — that is the agent's primary
+            // signal source and the one the completion recovery actually runs on.
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var exits = new List<DateTime>();
+            tracker.EspExited += (_, args) => exits.Add(args.OccurredAtUtc);
+
+            tracker.ProcessEvent(
+                eventId: ShellCoreTracker.EventId_ShellCore_WebAppEvent,
+                description: EspExitDescription,
+                timestamp: ClockNow,
+                providerName: "Microsoft-Windows-Shell-Core",
+                isBackfill: false);
+
+            Assert.Equal(ClockNow, Assert.Single(exits));
+        }
+
+        [Fact]
+        public void The_live_path_still_raises_esp_failures()
+        {
+            using var f = new Fixture();
+            using var tracker = f.Build();
+
+            var failures = new List<string>();
+            tracker.EspFailureDetected += (_, failureType) => failures.Add(failureType);
+
+            tracker.ProcessEvent(
+                eventId: ShellCoreTracker.EventId_ShellCore_WebAppEvent,
+                description: EspFailureDescription,
+                timestamp: ClockNow,
+                providerName: "Microsoft-Windows-Shell-Core",
+                isBackfill: false);
+
+            Assert.Single(failures);
+        }
+
+        // ------------------------------------------------------------------ window clamp
+
+        [Theory]
+        [InlineData(0, 1)]
+        [InlineData(-42, 1)]
+        [InlineData(5, 5)]
+        [InlineData(ShellCoreTracker.BackfillLookbackMaxMinutes, ShellCoreTracker.BackfillLookbackMaxMinutes)]
+        [InlineData(ShellCoreTracker.BackfillLookbackMaxMinutes + 1, ShellCoreTracker.BackfillLookbackMaxMinutes)]
+        [InlineData(int.MaxValue, ShellCoreTracker.BackfillLookbackMaxMinutes)]
+        public void Lookback_is_clamped_to_a_sane_window(int requested, int expected)
+        {
+            // int.MaxValue matters: the query multiplies minutes by 60_000, so an unclamped value
+            // would overflow into a negative timediff and silently match nothing.
+            Assert.Equal(expected, ShellCoreTracker.ClampLookbackMinutes(requested));
+        }
+    }
+}

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

@@ -0,0 +1,130 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+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.Tests.Harness;
+using AutopilotMonitor.Agent.V2.Core.Tests.Orchestration;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
+{
+    /// <summary>
+    /// Session afee7ae0 (2026-08-18) — Device Preparation structural-noise suppression.
+    /// A nine-minute WDP session shipped 900+ occurrences of WIL error 1005 plus 400+
+    /// duplicate-workload 417/418 records and "Autopilot policy not found" 100s — all
+    /// structural on WDP (no deployment profile exists; the BootstrapperAgent's SLDM
+    /// progress poll produces the 417/418 chatter). On WDP those IDs are suppressed
+    /// entirely (<see cref="ModernDeploymentTracker.DevicePreparationNoiseEventIds"/>);
+    /// genuine diagnostics (e.g. 408 provisioning warnings) and Critical records keep
+    /// flowing, and Classic sessions keep the harmless-downgrade + rollup path.
+    /// </summary>
+    public sealed class ModernDeploymentTrackerDevicePrepTests : IDisposable
+    {
+        private static readonly DateTime At = new DateTime(2026, 8, 18, 9, 10, 0, DateTimeKind.Utc);
+
+        private readonly TempDirectory _tmp = new TempDirectory();
+        private readonly FakeSignalIngressSink _sink;
+        private readonly AgentLogger _logger;
+
+        public ModernDeploymentTrackerDevicePrepTests()
+        {
+            _sink = new FakeSignalIngressSink();
+            _logger = new AgentLogger(_tmp.Path, AgentLogLevel.Info);
+        }
+
+        public void Dispose() => _tmp.Dispose();
+
+        private ModernDeploymentTracker BuildTracker(bool isDevicePreparation) =>
+            new ModernDeploymentTracker(
+                sessionId: "sess-wdp-noise",
+                tenantId: "tenant-wdp-noise",
+                post: new InformationalEventPost(_sink, new VirtualClock(At)),
+                logger: _logger,
+                backfillEnabled: false,
+                isDevicePreparation: isDevicePreparation);
+
+        private void Process(ModernDeploymentTracker tracker, int eventId, int level, string shortName, string channel)
+        {
+            tracker.ProcessEvent(
+                eventId: eventId,
+                level: level,
+                levelDisplayName: level == 1 ? "Critical" : level == 2 ? "Error" : "Warning",
+                providerName: "ModernDeployment-Diagnostics-Provider",
+                timeCreatedUtc: At,
+                formattedDescription: $"EventID {eventId} record.",
+                shortName: shortName,
+                channelName: channel,
+                isBackfill: false);
+        }
+
+        private List<FakeSignalIngressSink.PostedSignal> PostedModernDeployment() =>
+            _sink.Posted.Where(p =>
+                p.Kind == DecisionSignalKind.InformationalEvent
+                && p.Payload != null
+                && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                && et.StartsWith("modern_deployment", StringComparison.Ordinal)).ToList();
+
+        [Theory]
+        [InlineData(100, 3, "Autopilot")]           // policy not found — no profile exists on WDP
+        [InlineData(417, 3, "Autopilot")]           // duplicate workload — SLDM poll chatter
+        [InlineData(418, 3, "Autopilot")]           // duplicate batch — SLDM poll chatter
+        [InlineData(1005, 2, "ManagementService")]  // WIL error storm
+        public void WdpNoiseIds_AreFullySuppressed_OnDevicePreparation(int eventId, int level, string shortName)
+        {
+            var tracker = BuildTracker(isDevicePreparation: true);
+            var channel = shortName == "Autopilot"
+                ? ModernDeploymentTracker.AutopilotChannel
+                : ModernDeploymentTracker.ManagementChannel;
+
+            for (var i = 0; i < 10; i++)
+            {
+                Process(tracker, eventId, level, shortName, channel);
+            }
+
+            Assert.Empty(PostedModernDeployment());
+        }
+
+        [Fact]
+        public void GenuineWdpWarning_408_KeepsFlowing_OnDevicePreparation()
+        {
+            // 408 "Autopilot Provisioning reported a warning" carries the real WDP session
+            // context — it is NOT in the noise set and must keep flowing.
+            var tracker = BuildTracker(isDevicePreparation: true);
+
+            Process(tracker, 408, level: 3, shortName: "Autopilot", channel: ModernDeploymentTracker.AutopilotChannel);
+
+            var posted = Assert.Single(PostedModernDeployment());
+            Assert.Equal("modern_deployment_warning", posted.Payload![SignalPayloadKeys.EventType]);
+        }
+
+        [Fact]
+        public void CriticalRecords_AreNeverSuppressed_EvenForNoiseIds()
+        {
+            var tracker = BuildTracker(isDevicePreparation: true);
+
+            Process(tracker, 1005, level: 1, shortName: "ManagementService", channel: ModernDeploymentTracker.ManagementChannel);
+
+            var posted = Assert.Single(PostedModernDeployment());
+            Assert.Equal("modern_deployment_error", posted.Payload![SignalPayloadKeys.EventType]);
+        }
+
+        [Fact]
+        public void ClassicSessions_KeepTheHarmlessDowngradePath_ForTheSameIds()
+        {
+            // Classic regression guard: without the WDP flag EventID 100 still flows through
+            // the harmless-downgrade path (individual Debug emissions up to the rollup limit).
+            var tracker = BuildTracker(isDevicePreparation: false);
+
+            for (var i = 0; i < 2; i++)
+            {
+                Process(tracker, 100, level: 3, shortName: "Autopilot", channel: ModernDeploymentTracker.AutopilotChannel);
+            }
+
+            Assert.Equal(2, PostedModernDeployment().Count);
+        }
+    }
+}

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

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using AutopilotMonitor.Agent.V2.Core.Configuration;
 using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
 using AutopilotMonitor.Agent.V2.Core.Orchestration;
 using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
 using AutopilotMonitor.Shared.Models;
@@ -117,6 +118,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
                     hosts,
                     "AadJoinHost wires its onRealUserJoined callback to the already-constructed DesktopArrivalHost.");
 
+                // Codex review P2 (2026-08-19): EspAndHelloHost.Start() replays the Shell-Core
+                // ESP exit, but ImeLogTracker only restores its persisted app states in its own
+                // Start() — which happens later. Pin the order that makes ImeLogHost's
+                // onStateRestored nudge necessary, so a future reshuffle either keeps the nudge
+                // meaningful or fails here loudly.
+                AssertBefore<EspAndHelloHost, ImeLogHost>(
+                    hosts,
+                    "the ESP-exit replay runs before the IME app-state restore, which is why " +
+                    "ImeLogHost re-triggers the user-apps-settled synthesis after LoadState.");
+
                 // Closure-latch sanity (factory lines ~139/297): the EspAndHelloHost probes close
                 // over the ImeLogHost reference, which is assigned during the same factory call —
                 // the host must therefore exist in the returned list.
@@ -130,5 +141,40 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
                 }
             }
         }
+
+        [Fact]
+        public void Ime_app_state_callback_is_chained_into_the_user_apps_settled_recheck()
+        {
+            // sits-d Cloud-PC fix (2026-08-19): the AccountSetup synthesis is re-evaluated on every
+            // terminal IME app transition, which only works while the factory keeps this chain
+            // wired. It is five lines that a refactor can drop silently and whose absence costs a
+            // whole class of sessions their completion — so pin it here.
+            var surfaces = CreateSurfaces();
+            var hosts = surfaces.Hosts;
+            try
+            {
+                var imeHost = hosts.OfType<ImeLogHost>().Single();
+                var handler = imeHost.Tracker.OnAppStateChanged;
+
+                Assert.NotNull(handler);
+
+                // Invoking it must reach the re-check without throwing. The re-check is a no-op
+                // here (no ESP exit observed), which is the point — it must stay cheap and silent
+                // on the IME hot path until both facts are in.
+                var pkg = new AppPackageState("app-1", listPos: 0);
+                var ex = Record.Exception(() => handler!(
+                    pkg,
+                    AppInstallationState.Installing,
+                    AppInstallationState.Installed));
+                Assert.Null(ex);
+            }
+            finally
+            {
+                foreach (var host in hosts)
+                {
+                    try { host.Dispose(); } catch { /* construction-only test — best-effort cleanup */ }
+                }
+            }
+        }
     }
 }

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

@@ -0,0 +1,147 @@
+#nullable enable
+using System;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
+{
+    /// <summary>
+    /// The Shell-Core ESP-exit replay is RESTART RECOVERY: it re-reads observations the agent could
+    /// not make because no agent process was running. The window is therefore measured against the
+    /// previous run's last known liveness, not guessed from a constant.
+    /// <para>
+    /// Why a constant is not enough (Codex review P2): the scheduled task carries a BootTrigger
+    /// only, with no restart-on-failure. A crashed agent does not come back until the NEXT BOOT —
+    /// possibly hours later, long after Windows wrote the final ESP exit. Five minutes would lose
+    /// it every time.
+    /// </para>
+    /// </summary>
+    public sealed class EspExitBackfillLookbackPolicyTests
+    {
+        private static readonly DateTime Now = new DateTime(2026, 8, 19, 8, 43, 16, DateTimeKind.Utc);
+        private const int Default = ShellCoreTracker.BackfillLookbackMinutes;
+
+        private static int Resolve(string? exitType, DateTime? lastAlive = null, DateTime? bootUtc = null)
+            => DefaultComponentFactory.ResolveEspExitBackfillLookbackMinutes(exitType, bootUtc, lastAlive, Now);
+
+        // ---- no previous run => nothing to recover ---------------------------------------
+
+        [Theory]
+        [InlineData("first_run")]
+        [InlineData("FIRST_RUN")]
+        [InlineData("")]
+        [InlineData(null)]
+        public void No_previous_run_means_no_replay(string? exitType)
+        {
+            Assert.Equal(0, Resolve(exitType));
+        }
+
+        [Fact]
+        public void First_run_stays_off_even_with_timestamps_available()
+        {
+            // The exit type decides, not the presence of a timestamp.
+            Assert.Equal(0, Resolve("first_run", lastAlive: Now.AddHours(-3), bootUtc: Now.AddHours(-3)));
+        }
+
+        // ---- the default is a floor, never a ceiling --------------------------------------
+
+        [Theory]
+        [InlineData("clean")]
+        [InlineData("hard_kill")]
+        [InlineData("exception_crash")]
+        [InlineData("reboot_kill")]
+        public void Without_any_timestamp_the_default_applies(string exitType)
+        {
+            Assert.Equal(Default, Resolve(exitType));
+        }
+
+        [Fact]
+        public void A_restart_that_returned_within_seconds_keeps_the_default()
+        {
+            Assert.Equal(Default, Resolve("clean", lastAlive: Now.AddSeconds(-20)));
+        }
+
+        // ---- the crash case P2 is about ---------------------------------------------------
+
+        [Fact]
+        public void A_crash_recovered_only_at_the_next_boot_gets_the_whole_gap()
+        {
+            // BootTrigger-only task: the agent was gone for three hours while the ESP finished.
+            Assert.Equal(181, Resolve("exception_crash", lastAlive: Now.AddHours(-3)));
+        }
+
+        [Fact]
+        public void Snapshot_mtime_carries_the_window_when_no_boot_time_exists()
+        {
+            // LastBootUtc is only populated for hard_kill / reboot_kill — exception_crash and
+            // clean have nothing else to go on.
+            Assert.Equal(46, Resolve("clean", lastAlive: Now.AddMinutes(-45)));
+        }
+
+        // ---- reboot: both inputs available, wider wins ------------------------------------
+
+        [Fact]
+        public void The_wider_of_the_two_inputs_wins()
+        {
+            // Snapshot last written 40 min ago, boot 12 min ago — the gap started at the snapshot.
+            Assert.Equal(41, Resolve("reboot_kill", lastAlive: Now.AddMinutes(-40), bootUtc: Now.AddMinutes(-12)));
+        }
+
+        [Fact]
+        public void Boot_time_alone_still_covers_a_reboot_without_a_snapshot()
+        {
+            Assert.Equal(41, Resolve("reboot_kill", bootUtc: Now.AddMinutes(-40)));
+        }
+
+        // ---- robustness -------------------------------------------------------------------
+
+        [Fact]
+        public void A_timestamp_in_the_future_is_ignored()
+        {
+            // Clock skew across a reboot must never produce a negative window.
+            Assert.Equal(Default, Resolve("reboot_kill", lastAlive: Now.AddMinutes(5), bootUtc: Now.AddMinutes(9)));
+        }
+
+        [Fact]
+        public void A_future_timestamp_does_not_suppress_a_valid_one()
+        {
+            Assert.Equal(31, Resolve("reboot_kill", lastAlive: Now.AddMinutes(9), bootUtc: Now.AddMinutes(-30)));
+        }
+
+        [Fact]
+        public void A_very_long_gap_is_clamped_by_the_tracker()
+        {
+            // The policy may propose more than the cap; ClampLookbackMinutes is the backstop, so
+            // the two together can never produce an unbounded event-log query.
+            var proposed = Resolve("exception_crash", lastAlive: Now.AddHours(-20));
+            Assert.True(proposed > ShellCoreTracker.BackfillLookbackMaxMinutes);
+            Assert.Equal(ShellCoreTracker.BackfillLookbackMaxMinutes,
+                ShellCoreTracker.ClampLookbackMinutes(proposed));
+        }
+
+        // ---- the snapshot probe itself ----------------------------------------------------
+
+        [Fact]
+        public void Missing_snapshot_reads_as_null_not_as_an_exception()
+        {
+            using var tmp = new Harness.TempDirectory();
+            Assert.Null(DefaultComponentFactory.ReadPreviousRunLastAliveUtc(tmp.Path));
+            Assert.Null(DefaultComponentFactory.ReadPreviousRunLastAliveUtc(string.Empty));
+        }
+
+        [Fact]
+        public void An_existing_snapshot_reports_its_write_time()
+        {
+            using var tmp = new Harness.TempDirectory();
+            var path = System.IO.Path.Combine(tmp.Path, "snapshot.json");
+            System.IO.File.WriteAllText(path, "{}");
+
+            var read = DefaultComponentFactory.ReadPreviousRunLastAliveUtc(tmp.Path);
+
+            Assert.NotNull(read);
+            Assert.Equal(DateTimeKind.Utc, read!.Value.Kind);
+            Assert.True((DateTime.UtcNow - read.Value).Duration() < TimeSpan.FromMinutes(5));
+        }
+    }
+}

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

@@ -0,0 +1,72 @@
+#nullable enable
+using System;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Orchestration;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Orchestration
+{
+    /// <summary>
+    /// Codex review P2 (2026-08-19) — <see cref="ImeLogHost"/> starts AFTER <c>EspAndHelloHost</c>,
+    /// and <c>ImeLogTracker.Start()</c> restores the persisted package states silently (LoadState
+    /// raises no <c>OnAppStateChanged</c>). On an agent restart the Shell-Core ESP-exit replay
+    /// therefore runs against an empty app list. Without the post-restore nudge the exact reboot
+    /// case the completion recovery exists for — apps already terminal BEFORE the reboot, only the
+    /// final exit lost to the downtime — would still never complete.
+    /// </summary>
+    public sealed class ImeLogHostStateRestoredCallbackTests : IDisposable
+    {
+        private readonly TempDirectory _tmp = new TempDirectory();
+
+        public void Dispose() => _tmp.Dispose();
+
+        private ImeLogHost CreateHost(Action? onStateRestored)
+            => new ImeLogHost(
+                sessionId: "s",
+                tenantId: "t",
+                logger: new AgentLogger(_tmp.Path, AgentLogLevel.Info),
+                ingress: new FakeSignalIngressSink(),
+                clock: new VirtualClock(new DateTime(2026, 8, 19, 8, 43, 16, DateTimeKind.Utc)),
+                imeLogPathOverride: _tmp.Path,
+                imeMatchLogPath: null,
+                imePatterns: null,
+                stateDirectory: _tmp.Path,
+                whiteGloveSealingPatternIds: null,
+                onStateRestored: onStateRestored);
+
+        [Fact]
+        public void Start_invokes_the_state_restored_callback_exactly_once()
+        {
+            var calls = 0;
+            using var host = CreateHost(() => calls++);
+
+            host.Start();
+            try { Assert.Equal(1, calls); }
+            finally { host.Stop(); }
+        }
+
+        [Fact]
+        public void A_throwing_callback_does_not_break_host_start()
+        {
+            // Fail-soft like every other co-wired callback in the orchestration layer: a broken
+            // re-check must never take the IME log host — the session's primary signal source —
+            // down with it.
+            using var host = CreateHost(() => throw new InvalidOperationException("recheck boom"));
+
+            var ex = Record.Exception(() => host.Start());
+            try { Assert.Null(ex); }
+            finally { host.Stop(); }
+        }
+
+        [Fact]
+        public void No_callback_is_a_valid_configuration()
+        {
+            using var host = CreateHost(null);
+
+            var ex = Record.Exception(() => host.Start());
+            try { Assert.Null(ex); }
+            finally { host.Stop(); }
+        }
+    }
+}

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

@@ -1497,6 +1497,26 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Termination
             Assert.DoesNotContain("app_install_starved", rig.EmittedEventTypes);
         }
 
+        [Fact]
+        public void StarvedApps_skipped_on_device_preparation()
+        {
+            // afee7ae0: WDP has no ESP apps gate — post-desktop installs are the designed
+            // order, so the sweep would report every pending app as noise (10+ events on a
+            // normal session). The per-app data still travels via app_tracking_summary.
+            using var rig = new Rig();
+            rig.State = DevicePrepState(SessionStage.Completed);
+            rig.StarvedAppsOverride = new[]
+            {
+                BuildStarvedApp("app-pending-1", "Contoso Backgrounds"),
+                BuildStarvedApp("app-pending-2", "Contoso Tools"),
+            };
+
+            rig.Build().Handle(sender: null!,
+                Args(EnrollmentTerminationReason.DecisionTerminalStage, EnrollmentTerminationOutcome.Succeeded, SessionStage.Completed));
+
+            Assert.DoesNotContain("app_install_starved", rig.EmittedEventTypes);
+        }
+
         [Fact]
         public void PromoteActiveInstalls_skipped_on_effect_infrastructure_failure()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Transport/BackendTelemetryUploaderTests.cs

@@ -107,6 +107,31 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Transport
             Assert.False(req.Headers.ContainsKey("X-Bootstrap-Token"));
         }
 
+        [Fact]
+        public async Task UploadBatchAsync_stamps_send_time_header_per_attempt()
+        {
+            // P14: X-Send-Time-Utc carries the device clock at the SEND moment, round-trip
+            // ISO-8601, one value per request. A retry is a new send moment — the header is
+            // stamped inside UploadBatchAsync, so each attempt gets a fresh value.
+            using var rig = new Rig();
+            rig.Handler.QueueStatus(HttpStatusCode.ServiceUnavailable);
+            rig.Handler.QueueStatus(HttpStatusCode.OK);
+
+            var before = DateTime.UtcNow;
+            await rig.Sut.UploadBatchAsync(new[] { NewEventItem(1) }, CancellationToken.None);
+            await rig.Sut.UploadBatchAsync(new[] { NewEventItem(1) }, CancellationToken.None);
+            var after = DateTime.UtcNow;
+
+            Assert.Equal(2, rig.Handler.Captured.Count);
+            foreach (var req in rig.Handler.Captured)
+            {
+                Assert.True(req.TryGetHeader("X-Send-Time-Utc", out var raw));
+                var parsed = DateTime.Parse(raw, null, System.Globalization.DateTimeStyles.RoundtripKind);
+                Assert.Equal(DateTimeKind.Utc, parsed.Kind);
+                Assert.InRange(parsed, before.AddSeconds(-1), after.AddSeconds(1));
+            }
+        }
+
         // ============================================================ Compression (bandwidth)
 
         [Fact]

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Transport/NetworkMetricsRecordingHandlerTests.cs

@@ -144,6 +144,77 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Transport
             Assert.Equal(1 + 2 + 3, snap.TotalBytesUp);
         }
 
+        [Fact]
+        public async Task Captures_bytes_down_via_buffering_when_content_length_is_missing()
+        {
+            // AutomaticDecompression strips Content-Length on the backend's gzipped JSON —
+            // the pre-fix handler recorded 0 for every such (healthy) response. A non-seekable
+            // stream body reproduces the headerless shape.
+            var metrics = new NetworkMetrics();
+            var inner = new RecordingHttpMessageHandler();
+            var payload = Encoding.UTF8.GetBytes("{\"ok\":true}"); // 11 bytes
+            inner.QueueResponse(() => new HttpResponseMessage(HttpStatusCode.OK)
+            {
+                Content = new StreamContent(new NonSeekableReadStream(payload)),
+            });
+            using var client = BuildClient(metrics, inner);
+
+            using var resp = await client.SendAsync(NewPost(""));
+
+            var snap = metrics.GetSnapshot();
+            Assert.Equal(payload.Length, snap.TotalBytesDown);
+            // Buffering must not consume the body away from the caller.
+            Assert.Equal("{\"ok\":true}", await resp.Content.ReadAsStringAsync());
+        }
+
+        [Fact]
+        public async Task Bytes_down_fails_soft_to_zero_when_buffering_throws()
+        {
+            var metrics = new NetworkMetrics();
+            var inner = new RecordingHttpMessageHandler();
+            inner.QueueResponse(() => new HttpResponseMessage(HttpStatusCode.OK)
+            {
+                Content = new ThrowingContent(),
+            });
+            using var client = BuildClient(metrics, inner);
+
+            // ResponseHeadersRead keeps HttpClient's own post-pipeline buffering out of the
+            // picture — the test isolates the handler's fallback catch (which must swallow
+            // the serialization failure and record 0, never throw).
+            using var resp = await client.SendAsync(NewPost(""), HttpCompletionOption.ResponseHeadersRead);
+
+            var snap = metrics.GetSnapshot();
+            Assert.Equal(1, snap.RequestCount);
+            Assert.Equal(0, snap.TotalBytesDown);
+        }
+
+        /// <summary>Read-only, non-seekable stream — CanSeek=false keeps StreamContent from
+        /// computing a Content-Length, mirroring a decompression-wrapped response body.</summary>
+        private sealed class NonSeekableReadStream : System.IO.Stream
+        {
+            private readonly System.IO.MemoryStream _inner;
+            public NonSeekableReadStream(byte[] data) { _inner = new System.IO.MemoryStream(data); }
+            public override bool CanRead => true;
+            public override bool CanSeek => false;
+            public override bool CanWrite => false;
+            public override long Length => throw new NotSupportedException();
+            public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
+            public override void Flush() { }
+            public override int Read(byte[] buffer, int offset, int count) => _inner.Read(buffer, offset, count);
+            public override long Seek(long offset, System.IO.SeekOrigin origin) => throw new NotSupportedException();
+            public override void SetLength(long value) => throw new NotSupportedException();
+            public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
+            protected override void Dispose(bool disposing) { if (disposing) _inner.Dispose(); base.Dispose(disposing); }
+        }
+
+        /// <summary>Content whose serialization always fails — drives the fallback's catch path.</summary>
+        private sealed class ThrowingContent : HttpContent
+        {
+            protected override Task SerializeToStreamAsync(System.IO.Stream stream, System.Net.TransportContext? context)
+                => throw new System.IO.IOException("connection dropped mid-body");
+            protected override bool TryComputeLength(out long length) { length = 0; return false; }
+        }
+
         [Fact]
         public void Constructor_rejects_null_metrics()
         {

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Transport/RecordingHttpMessageHandler.cs

@@ -40,6 +40,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Transport
             return this;
         }
 
+        /// <summary>
+        /// Queues an arbitrary response — for shapes <see cref="QueueStatus"/> can't build,
+        /// e.g. content without a Content-Length header (what AutomaticDecompression leaves
+        /// behind on real compressed responses).
+        /// </summary>
+        public RecordingHttpMessageHandler QueueResponse(Func<HttpResponseMessage> factory)
+        {
+            _script.Enqueue(_ => factory());
+            return this;
+        }
+
         protected override async Task<HttpResponseMessage> SendAsync(
             HttpRequestMessage request,
             CancellationToken cancellationToken)

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Transport/TelemetrySpoolTests.cs

@@ -221,6 +221,81 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Transport
             Assert.Equal(1, System.Threading.Volatile.Read(ref signalled));
         }
 
+        [Fact]
+        public void PendingBytes_tracks_enqueue_and_shrinks_to_zero_when_all_uploaded()
+        {
+            using var tmp = new TempDirectory();
+            var spool = new TelemetrySpool(tmp.Path, Clock());
+            Assert.Equal(0, spool.PendingBytes);
+
+            spool.Enqueue(EventDraft("a"));
+            spool.Enqueue(EventDraft("b"));
+            spool.Enqueue(EventDraft("c"));
+
+            // PendingBytes must equal the full file size while nothing is uploaded yet
+            // (every line written by Enqueue is still pending).
+            Assert.Equal(spool.SpoolFileSizeBytes, spool.PendingBytes);
+
+            spool.MarkUploaded(2);
+            Assert.Equal(0, spool.PendingBytes);
+            // File keeps its append-only size — the two measures MUST diverge here,
+            // otherwise the pressure trigger regresses to the file-size false positive.
+            Assert.True(spool.SpoolFileSizeBytes > 0);
+        }
+
+        [Fact]
+        public void PendingBytes_after_partial_upload_equals_remaining_tail_line_bytes()
+        {
+            using var tmp = new TempDirectory();
+            var spool = new TelemetrySpool(tmp.Path, Clock());
+            spool.Enqueue(EventDraft("a"));
+            spool.Enqueue(EventDraft("b"));
+            spool.Enqueue(EventDraft("c-longer-rowkey-for-distinct-length"));
+
+            spool.MarkUploaded(1);
+
+            // Expected = on-disk byte length of the last line incl. its trailing \n.
+            var lines = File.ReadAllLines(Path.Combine(tmp.Path, "spool.jsonl"), Encoding.UTF8);
+            var expected = Encoding.UTF8.GetByteCount(lines[2]) + 1;
+            Assert.Equal(expected, spool.PendingBytes);
+        }
+
+        [Fact]
+        public void PendingBytes_is_rehydrated_on_restart_from_pending_tail_only()
+        {
+            using var tmp = new TempDirectory();
+            var s1 = new TelemetrySpool(tmp.Path, Clock());
+            s1.Enqueue(EventDraft("a"));
+            s1.Enqueue(EventDraft("b"));
+            s1.Enqueue(EventDraft("c"));
+            s1.MarkUploaded(1);
+            var expectedPendingBytes = s1.PendingBytes;
+            Assert.True(expectedPendingBytes > 0);
+
+            // Restart: rehydrated PendingBytes must match the pre-restart value exactly
+            // (uploaded prefix excluded), not the full file size.
+            var s2 = new TelemetrySpool(tmp.Path, Clock());
+            Assert.Equal(expectedPendingBytes, s2.PendingBytes);
+            Assert.True(s2.PendingBytes < s2.SpoolFileSizeBytes);
+        }
+
+        [Fact]
+        public void PendingBytes_rehydrate_ignores_corrupt_tail_line()
+        {
+            using var tmp = new TempDirectory();
+            var s1 = new TelemetrySpool(tmp.Path, Clock());
+            s1.Enqueue(EventDraft("a"));
+            var cleanPendingBytes = s1.PendingBytes;
+
+            File.AppendAllText(
+                Path.Combine(tmp.Path, "spool.jsonl"),
+                "{\"Kind\":\"Event\",\"PartitionKey\":\"corrupt-no-",
+                Encoding.UTF8);
+
+            var s2 = new TelemetrySpool(tmp.Path, Clock());
+            Assert.Equal(cleanPendingBytes, s2.PendingBytes);
+        }
+
         [Fact]
         public void Enqueue_without_RequiresImmediateFlush_does_not_raise_ImmediateFlushRequested()
         {

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

@@ -0,0 +1,215 @@
+using System;
+using System.Collections.Generic;
+
+namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
+{
+    /// <summary>How the UTC value of a CMTrace line was arrived at. Recorded as evidence.</summary>
+    public enum CmTraceOffsetOrigin
+    {
+        /// <summary>No offset known — the caller fell back to its own clock.</summary>
+        None = 0,
+
+        /// <summary>The writer declared its offset in the line ("+480"). Authoritative.</summary>
+        Bias = 1,
+
+        /// <summary>
+        /// A per-FILE measured offset was applied. Retired by the 2026-08-20 revert (04b1a7c6):
+        /// one offset per file is wrong when a file holds lines from two writer eras. Kept so
+        /// stored events from agent 2.0.1410 remain interpretable.
+        /// </summary>
+        Calibrated = 2,
+
+        /// <summary>
+        /// The line anchored ITSELF: it was read in a pass whose lines are provably fresh
+        /// (written since the previous poll), so its own distance to the agent clock, rounded
+        /// to the 15-minute offset grid, IS the writer's offset — no cross-line state involved.
+        /// Immune to interleaved writer eras by construction. See
+        /// <see cref="CmTraceOffsetCalibrator.TryMeasureOffset"/>.
+        /// </summary>
+        LineAnchored = 3,
+    }
+
+    /// <summary>
+    /// Measures the UTC offset that the process WRITING a CMTrace log believes it is in.
+    ///
+    /// <para>
+    /// A CMTrace line carries local time and no offset — IME 1.104 writes
+    /// <c>DateTime.Now.TimeOfDay</c> in both of its trace listeners. Converting such a line with
+    /// the agent's own <c>TimeZoneInfo.Local</c> assumes the two processes agree, and they do not:
+    /// both cache their zone at process start and neither follows a later <c>tzutil</c> or a
+    /// Windows auto-timezone change. The resulting error is
+    /// <c>Offset_writer - Offset_agent</c> and is zero only by coincidence. Field measurement over
+    /// 11,068 sessions found 26 sessions carrying a real zone-offset error, from +1 h
+    /// (GMT to W. Europe) to -17 h (a writer still on the Pacific OOBE default while the agent had
+    /// already moved to E. Australia).
+    /// </para>
+    ///
+    /// <para>
+    /// So the offset is MEASURED, not assumed. The tracker tails the log on a 100 ms poll, so a
+    /// line that appeared since the previous pass was written essentially "now":
+    /// <code>
+    ///   candidate = lineLocalTime - agentUtcNow
+    ///   offset    = round(candidate / 15 min) * 15 min
+    ///   lineUtc   = lineLocalTime - offset
+    /// </code>
+    /// Every real UTC offset is a whole multiple of 15 minutes, so the rounding absorbs poll and
+    /// flush latency without ambiguity.
+    /// </para>
+    ///
+    /// <para>
+    /// THE FRESHNESS REQUIREMENT IS WHAT MAKES THIS CORRECT. An anchor must be the newest line of
+    /// a pass in which the file actually GREW. Without that rule a backlog line that happens to be
+    /// an exact multiple of 15 minutes old (30 min, 45 min, ...) rounds to a clean value with zero
+    /// residual and calibrates the offset to a wrong figure — the residual guard alone cannot
+    /// catch it. Callers must only offer anchors they know to be fresh.
+    /// </para>
+    ///
+    /// <para>
+    /// Calibration is kept per source file: IntuneManagementExtension.log and AppWorkload.log are
+    /// written by different processes and can hold different beliefs. Re-calibrating on every
+    /// fresh anchor makes this self-healing — if the writing process restarts and picks up the
+    /// current zone, the measurement follows within one poll.
+    /// </para>
+    /// </summary>
+    public sealed class CmTraceOffsetCalibrator
+    {
+        /// <summary>Grid that every real UTC offset sits on.</summary>
+        internal static readonly TimeSpan OffsetGrid = TimeSpan.FromMinutes(15);
+
+        /// <summary>
+        /// How far a candidate may sit off the grid before it is rejected. Poll latency (100 ms)
+        /// plus the writer's flush latency are far below this; anything larger means the anchor
+        /// was not actually fresh.
+        /// </summary>
+        internal static readonly TimeSpan MaxGridResidual = TimeSpan.FromMinutes(2);
+
+        /// <summary>Real UTC offsets span UTC-12 (Dateline) to UTC+14 (Line Islands).</summary>
+        internal static readonly TimeSpan MinOffset = TimeSpan.FromHours(-12);
+
+        /// <summary>Upper bound of a real UTC offset. See <see cref="MinOffset"/>.</summary>
+        internal static readonly TimeSpan MaxOffset = TimeSpan.FromHours(14);
+
+        private sealed class Anchor
+        {
+            public TimeSpan Offset;
+            public DateTime LocalTimestamp;
+        }
+
+        private readonly object _lock = new object();
+
+        private readonly Dictionary<string, Anchor> _bySource =
+            new Dictionary<string, Anchor>(StringComparer.OrdinalIgnoreCase);
+
+        /// <summary>
+        /// Offer a freshly appended line as a calibration anchor.
+        /// <para>
+        /// The caller MUST only pass a line it knows to be fresh — the newest line of a pass in
+        /// which the file grew. See the freshness note on this class.
+        /// </para>
+        /// </summary>
+        /// <param name="sourceKey">Log file identity; the file name is enough.</param>
+        /// <param name="localTimestamp">The line's local time exactly as written (Kind is ignored).</param>
+        /// <param name="agentUtcNow">The agent's UTC clock at parse time.</param>
+        /// <returns><c>true</c> when the anchor was accepted and the offset updated.</returns>
+        /// <summary>
+        /// The pure measurement: the distance between a FRESH line's local time and the agent's
+        /// UTC clock, rounded to the 15-minute offset grid, is the writer's UTC offset.
+        /// <para>
+        /// Freshness is the caller's obligation and is what makes this correct — for a line
+        /// written within the last poll interval, <c>local - now</c> differs from the writer's
+        /// true offset only by seconds, which the grid rounding absorbs. Returns <c>false</c>
+        /// when the residual exceeds <see cref="MaxGridResidual"/> (the line is not fresh, or
+        /// the writer's clock is broken) or the rounded value is not a real timezone offset.
+        /// </para>
+        /// <para>
+        /// Known, accepted edge: a freshly WRITTEN line carrying an old REPLAYED timestamp whose
+        /// age happens to sit within the residual of an exact grid multiple measures that age as
+        /// an "offset" — the line then resolves to roughly the read time instead of its replayed
+        /// past. The error is bounded by construction (an anchored line always resolves to
+        /// now ± <see cref="MaxGridResidual"/>), the case needs an age of exactly N×15 min ± 2 min,
+        /// and sub-24h replays are treated as current by the historic-replay guard anyway.
+        /// </para>
+        /// </summary>
+        public static bool TryMeasureOffset(DateTime localTimestamp, DateTime agentUtcNow, out TimeSpan offset)
+        {
+            var candidate = DateTime.SpecifyKind(localTimestamp, DateTimeKind.Unspecified)
+                          - DateTime.SpecifyKind(agentUtcNow, DateTimeKind.Unspecified);
+
+            var gridUnits = Math.Round(candidate.TotalMinutes / OffsetGrid.TotalMinutes,
+                                       MidpointRounding.AwayFromZero);
+            offset = TimeSpan.FromMinutes(gridUnits * OffsetGrid.TotalMinutes);
+
+            // Off-grid by more than the tolerance: the line was not fresh, or the writer's own
+            // clock is broken. Either way it must not become an offset.
+            if ((candidate - offset).Duration() > MaxGridResidual) return false;
+
+            // Not a value any real timezone can produce.
+            if (offset < MinOffset || offset > MaxOffset) return false;
+
+            return true;
+        }
+
+        public bool TryCalibrate(string sourceKey, DateTime localTimestamp, DateTime agentUtcNow)
+        {
+            if (string.IsNullOrEmpty(sourceKey)) return false;
+
+            TimeSpan offset;
+            if (!TryMeasureOffset(localTimestamp, agentUtcNow, out offset)) return false;
+
+            lock (_lock)
+            {
+                if (_bySource.TryGetValue(sourceKey, out var existing))
+                {
+                    // Only ever move the anchor forward. A line older than the current anchor
+                    // carries nothing newer and could re-introduce a stale belief.
+                    if (localTimestamp <= existing.LocalTimestamp) return false;
+                    existing.Offset = offset;
+                    existing.LocalTimestamp = localTimestamp;
+                }
+                else
+                {
+                    _bySource[sourceKey] = new Anchor
+                    {
+                        Offset = offset,
+                        LocalTimestamp = localTimestamp,
+                    };
+                }
+            }
+
+            return true;
+        }
+
+        /// <summary>The offset measured for this source, when one has been established.</summary>
+        public bool TryGetOffset(string sourceKey, out TimeSpan offset)
+        {
+            offset = TimeSpan.Zero;
+            if (string.IsNullOrEmpty(sourceKey)) return false;
+
+            lock (_lock)
+            {
+                Anchor anchor;
+                if (!_bySource.TryGetValue(sourceKey, out anchor)) return false;
+                offset = anchor.Offset;
+                return true;
+            }
+        }
+
+        /// <summary>
+        /// Convert a line's local time to UTC using the measured offset. Returns <c>false</c> when
+        /// this source has not been calibrated yet — the caller then picks its own fallback and
+        /// should mark the result as not source-grounded.
+        /// </summary>
+        public bool TryResolveUtc(string sourceKey, DateTime localTimestamp, out DateTime utc)
+        {
+            utc = default(DateTime);
+
+            TimeSpan offset;
+            if (!TryGetOffset(sourceKey, out offset)) return false;
+
+            utc = DateTime.SpecifyKind(
+                DateTime.SpecifyKind(localTimestamp, DateTimeKind.Unspecified) - offset,
+                DateTimeKind.Utc);
+            return true;
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeLogTracker.LogProcessing.cs

@@ -42,7 +42,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             return false;
         }
 
-        private async Task CheckLogFilesAsync(CancellationToken token)
+        /// <remarks>internal (not private) as a test seam: the offset calibration depends on the
+        /// pass structure — first observation versus a later pass over a grown file — which only
+        /// a real read cycle exercises. Production still reaches it solely from the poll loop.</remarks>
+        internal async Task CheckLogFilesAsync(CancellationToken token)
         {
             if (!Directory.Exists(_logFolder))
                 return;
@@ -74,7 +77,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     var fileInfo = new FileInfo(filePath);
                     if (!fileInfo.Exists) continue;
 
+                    // Captured BEFORE MarkChecked below stamps this pass. Growth measured
+                    // against a previously observed state is what makes this pass's lines valid
+                    // "written now" anchors — for the per-file measurement AND per-line anchoring.
+                    var hadPreviousObservation = _positionTracker.HasSeen(filePath);
+                    var lastCheckedUtc = _positionTracker.GetLastCheckedUtc(filePath);
+                    var passNowUtc = UtcNowProvider();
+
                     var startPos = _positionTracker.GetSafePosition(filePath, fileInfo.Length);
+
+                    // Every look counts, including "no new data" and an empty first sight: the
+                    // NEXT pass's freshness window is measured from here. Restored bookmarks
+                    // deliberately carry no LastCheckedUtc — the first pass after a restart reads
+                    // downtime backlog and must never count as fresh.
+                    _positionTracker.MarkChecked(filePath, passNowUtc);
+
                     if (startPos >= fileInfo.Length)
                     {
                         // M2: guard the interpolated string so it isn't built every 100 ms tick
@@ -86,6 +103,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     if (_logger.LogLevel >= AgentLogLevel.Trace)
                         _logger.Trace($"ImeLogTracker: reading {Path.GetFileName(filePath)} from pos {startPos} (size={fileInfo.Length}, delta={fileInfo.Length - startPos})");
 
+                    _currentSourceFileName = Path.GetFileName(filePath);
+                    _currentPassLinesAreFresh = hadPreviousObservation
+                        && lastCheckedUtc > DateTime.MinValue
+                        && (passNowUtc - lastCheckedUtc) <= FreshLineMaxAge;
+
+                    // Newest bias-less line of this pass — the calibration anchor. Bias-carrying
+                    // lines are skipped: they already state the writer's offset, so they need no
+                    // measurement and must not overwrite one.
+                    CmTraceLogEntry calibrationAnchor = null;
+
                     using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
                     {
                         stream.Seek(startPos, SeekOrigin.Begin);
@@ -147,6 +174,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                                 if (CmTraceLogParser.TryParseLine(line, out entry))
                                 {
                                     messageToMatch = entry.Message;
+                                    if (entry.HasTimestamp && !entry.BiasMinutes.HasValue)
+                                        calibrationAnchor = entry;
                                 }
                                 else
                                 {
@@ -160,7 +189,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                                 // Simulation mode delay
                                 if (SimulationMode && entry != null)
                                 {
-                                    await ApplySimulationDelay(entry.Timestamp, token);
+                                    await ApplySimulationDelay(ResolveEntryUtc(entry), token);
                                 }
 
                                 // Match against active patterns
@@ -185,6 +214,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 
                         _positionTracker.SetPosition(filePath, stream.Position);
                         _stateDirty = true;
+
+                        // Calibrate AFTER the pass: this pass's lines were resolved with the
+                        // offset established previously, at most one poll (100 ms) old. Buffering
+                        // the pass to calibrate first is not an option — the first pass of
+                        // AppWorkload.log can be hundreds of MB. The cost is a warm-up of one
+                        // growing pass, during which lines fall back to the reader zone and are
+                        // flagged as such.
+                        if (hadPreviousObservation && calibrationAnchor != null)
+                            CalibrateFrom(_currentSourceFileName, Path.GetFileName(filePath), calibrationAnchor);
                     }
                 }
                 catch (FileNotFoundException) { }
@@ -222,7 +260,32 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         private void HandlePatternMatch(CompiledPattern pattern, Match match, string message, CmTraceLogEntry entry)
         {
             LastMatchedPatternId = pattern.PatternId;
-            LastMatchedLogTimestamp = entry?.Timestamp;
+            if (entry == null)
+            {
+                LastMatchedLogTimestamp = null;
+                LastMatchedSourceLocalTimestamp = null;
+                LastMatchedSourceOffsetMinutes = null;
+                LastMatchedSourceOffsetOrigin = CmTraceOffsetOrigin.None;
+                LastMatchedMeasuredWriterOffsetMinutes = null;
+            }
+            else
+            {
+                CmTraceOffsetOrigin origin;
+                int? offsetMinutes;
+                LastMatchedLogTimestamp = ResolveEntryUtc(entry, out origin, out offsetMinutes);
+                LastMatchedSourceLocalTimestamp = entry.HasTimestamp ? entry.LocalTimestamp : (DateTime?)null;
+                LastMatchedSourceOffsetMinutes = offsetMinutes;
+                LastMatchedSourceOffsetOrigin = origin;
+
+                // Observational: what the calibrator measured for this file, distinct from what
+                // was applied above.
+                TimeSpan measuredWriterOffset;
+                LastMatchedMeasuredWriterOffsetMinutes =
+                    _currentSourceFileName != null
+                    && OffsetCalibrator.TryGetOffset(_currentSourceFileName, out measuredWriterOffset)
+                        ? (int)measuredWriterOffset.TotalMinutes
+                        : (int?)null;
+            }
 
             // Generic pattern-match hook (M4.4.4). Invoked before action-specific callbacks so
             // subscribers (e.g. ImeLogTrackerAdapter emitting WhiteGloveSealingPatternDetected)
@@ -237,10 +300,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             // state nor the phase-change ignore list. SimulationMode (--replay-log-dir dev tool)
             // replays historic logs on purpose and bypasses the guard.
             var isStaleReplayLine = !SimulationMode && entry != null
-                && (UtcNowProvider() - NormalizeUtc(entry.Timestamp)) > HistoricReplayThreshold;
+                && (UtcNowProvider() - NormalizeUtc(ResolveEntryUtc(entry))) > HistoricReplayThreshold;
             if (isStaleReplayLine && AppMutatingActions.Contains(pattern.Action?.ToLower() ?? string.Empty))
             {
-                _logger.Debug($"ImeLogTracker: skipped app action '{pattern.Action}' for historic line ({entry.Timestamp:o})");
+                _logger.Debug($"ImeLogTracker: skipped app action '{pattern.Action}' for historic line ({ResolveEntryUtc(entry):o})");
                 return;
             }
 
@@ -524,8 +587,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         internal void ProcessLogMessageForTest(string message, DateTime? sourceTimestampUtc = null)
         {
             if (string.IsNullOrEmpty(message)) return;
+            // The test seam hands in an already-resolved UTC instant, so it takes the same route a
+            // writer-declared bias does: TimestampUtc set, no zone left to guess.
             var entry = sourceTimestampUtc.HasValue
-                ? new CmTraceLogEntry { Timestamp = sourceTimestampUtc.Value, Message = message }
+                ? new CmTraceLogEntry
+                {
+                    TimestampUtc = sourceTimestampUtc.Value,
+                    LocalTimestamp = DateTime.SpecifyKind(sourceTimestampUtc.Value, DateTimeKind.Unspecified),
+                    HasTimestamp = true,
+                    Message = message,
+                }
                 : null;
             foreach (var pattern in _activePatterns)
             {
@@ -543,5 +614,159 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// Parses [DO TEL] JSON and links it to the correct app via FileId.
         /// The FileId contains the app GUID in the format: ...intunewin-bin_{appGuid}_{number}
         /// </summary>
+
+        /// <summary>
+        /// Resolve a parsed CMTrace entry to UTC.
+        ///
+        /// <para>
+        /// Order of preference: a writer-declared bias (authoritative) &gt; this process's own zone
+        /// (a fallback carrying a known defect, see
+        /// <see cref="CmTraceLogParser.ResolveUtcAssumingReaderZone"/>) &gt; the agent clock for a
+        /// line with no parseable timestamp.
+        /// </para>
+        ///
+        /// <para>
+        /// The reader-zone step is where the tracker is still wrong when IME's process holds a
+        /// different zone belief than ours. It is preserved verbatim here so that splitting the
+        /// parser changes no behaviour; the measured offset from <c>CmTraceOffsetCalibrator</c>
+        /// slots in at exactly this point in the follow-up change.
+        /// </para>
+        /// </summary>
+        private DateTime ResolveEntryUtc(CmTraceLogEntry entry)
+        {
+            CmTraceOffsetOrigin origin;
+            int? offsetMinutes;
+            return ResolveEntryUtc(entry, out origin, out offsetMinutes);
+        }
+
+        /// <summary>
+        /// Resolve a parsed entry to UTC and report HOW the offset was obtained, so the emitting
+        /// side can attach the evidence (P8). See <see cref="CmTraceOffsetOrigin"/>.
+        /// </summary>
+        private DateTime ResolveEntryUtc(CmTraceLogEntry entry, out CmTraceOffsetOrigin origin, out int? offsetMinutes)
+        {
+            origin = CmTraceOffsetOrigin.None;
+            offsetMinutes = null;
+
+            if (entry == null) return UtcNowProvider();
+
+            // Writer declared its own offset — nothing left to measure.
+            if (entry.TimestampUtc.HasValue)
+            {
+                origin = CmTraceOffsetOrigin.Bias;
+                // Bias uses the GetTimeZoneInformation convention (UTC = local + bias); report the
+                // value in the same sense as a measured offset (local = UTC + offset).
+                offsetMinutes = entry.BiasMinutes.HasValue ? -entry.BiasMinutes.Value : (int?)null;
+                return entry.TimestampUtc.Value;
+            }
+
+            if (!entry.HasTimestamp) return UtcNowProvider();
+
+            // ERA-AWARE RESOLUTION (2026-08-20, second attempt): a FRESH line anchors ITSELF.
+            //
+            // The first attempt (e9dba11b, reverted in 04b1a7c6) applied one measured offset per
+            // FILE — wrong, because a single log file holds lines from multiple writer eras:
+            // AgentExecutor.log is written by short-lived child processes whose zone belief
+            // flips per process, interleaved in one file (fixture
+            // tests/fixtures/cmtrace-logs/agentexecutor-two-writer-eras-v1.cmtrace). Any
+            // cross-line anchor — per file, or nearest-in-write-order — inherits that trap.
+            //
+            // Per-line self-anchoring does not: at a 100 ms poll every line of a growing pass
+            // was written essentially "now", so its own distance to the agent clock IS its
+            // writer's offset, era by era. The line's timestamp still contributes the sub-poll
+            // precision and ordering (two lines 6 ms apart stay 6 ms apart — a plain
+            // occurredAt=now could not do that), while the offset grid absorbs poll latency.
+            // Freshness is load-bearing (see FreshLineMaxAge) — backlog passes, restart
+            // catch-up and replay logs must never anchor, because an old line's AGE can round
+            // onto the grid.
+            if (_currentPassLinesAreFresh)
+            {
+                TimeSpan lineOffset;
+                if (CmTraceOffsetCalibrator.TryMeasureOffset(entry.LocalTimestamp, UtcNowProvider(), out lineOffset))
+                {
+                    origin = CmTraceOffsetOrigin.LineAnchored;
+                    offsetMinutes = (int)lineOffset.TotalMinutes;
+                    return DateTime.SpecifyKind(entry.LocalTimestamp - lineOffset, DateTimeKind.Utc);
+                }
+            }
+
+            // Fallback for everything not provably fresh: assume the reader's zone, UNIFORMLY.
+            // Wrong in absolute terms whenever the writer held a different belief, but
+            // self-consistent — both ends of a duration are wrong by the same amount, so derived
+            // durations stay right. That asymmetry is the lesson of the 04b1a7c6 revert:
+            // partially corrected is strictly worse than uniformly wrong. Origin stays None so
+            // the emitted event says so.
+            var readerZoneOffset = TimeZoneInfo.Local.GetUtcOffset(entry.LocalTimestamp);
+            offsetMinutes = (int)readerZoneOffset.TotalMinutes;
+            return CmTraceLogParser.ResolveUtcAssumingReaderZone(entry.LocalTimestamp);
+        }
+
+        // Field-forensics (tripwire, 2026-08-20): sessions e9753578 and 067797d8 both logged a
+        // measurement whose LABEL and ANCHOR could not have come from the same file iteration —
+        // 067797d8's anchor value (19:51:26.948) does not even exist in ANY log file on the
+        // device, and IntuneManagementExtension.log never produced its expected first
+        // measurement at all. Mechanism unexplained; resolution is immune (per-line anchoring),
+        // but the observational layer must convict the culprit on the next occurrence. Hence:
+        // the stream's file name travels alongside the label (a mismatch is THE smoking gun),
+        // and the first rejected anchor per file becomes visible instead of silent.
+        private readonly HashSet<string> _calibrationRejectLogged = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+        /// <summary>
+        /// Feed the pass's newest bias-less line to the calibrator and report a measured offset
+        /// that disagrees with this process's own zone — that disagreement is precisely the
+        /// condition that used to corrupt every IME-derived timestamp silently.
+        /// </summary>
+        /// <param name="sourceFileName">The calibration key (<c>_currentSourceFileName</c>).</param>
+        /// <param name="streamFileName">The file the enclosing iteration actually read. Must equal
+        /// <paramref name="sourceFileName"/> — logged loudly when it does not (see tripwire note).</param>
+        private void CalibrateFrom(string sourceFileName, string streamFileName, CmTraceLogEntry anchor)
+        {
+            if (!string.Equals(sourceFileName, streamFileName, StringComparison.OrdinalIgnoreCase))
+            {
+                _logger?.Warning(
+                    $"ImeLogTracker: CALIBRATION LABEL MISMATCH — key='{sourceFileName}' but the iteration read '{streamFileName}' " +
+                    $"(anchor local={anchor.LocalTimestamp:yyyy-MM-ddTHH:mm:ss.fffffff}). Skipping this anchor; see tripwire note.");
+                return;
+            }
+
+            TimeSpan previous;
+            var hadOffset = OffsetCalibrator.TryGetOffset(sourceFileName, out previous);
+
+            if (!OffsetCalibrator.TryCalibrate(sourceFileName, anchor.LocalTimestamp, UtcNowProvider()))
+            {
+                // Once per file: why a file that visibly grows never produces a measurement.
+                // 067797d8 ran 24 s of growing IME.log passes with no measurement at all — this
+                // silence is exactly what made the phenomenon undiagnosable from the log.
+                if (_calibrationRejectLogged.Add(sourceFileName))
+                {
+                    _logger?.Debug(
+                        $"ImeLogTracker: {sourceFileName} anchor rejected by calibrator " +
+                        $"(anchor local={anchor.LocalTimestamp:yyyy-MM-ddTHH:mm:ss.fffffff}, now={UtcNowProvider():HH:mm:ss.fff}Z) — first rejection for this file, further ones stay silent.");
+                }
+                return;
+            }
+
+            TimeSpan measured;
+            if (!OffsetCalibrator.TryGetOffset(sourceFileName, out measured)) return;
+            if (hadOffset && measured == previous) return;
+
+            // The anchor's local timestamp is part of the record ON PURPOSE (tripwire, 2026-08-20):
+            // session e9753578 logged "+02:00 measured for IntuneManagementExtension.log" although
+            // that file provably held no +2-era line — an anchor/label pairing the committed code
+            // could not be shown to produce. Should it ever happen again, the logged anchor value
+            // itself will prove (or refute) the crossing without needing the device's log files.
+            var readerZoneOffset = TimeZoneInfo.Local.GetUtcOffset(UtcNowProvider());
+            if (measured == readerZoneOffset)
+            {
+                _logger?.Debug(
+                    $"ImeLogTracker: {sourceFileName} writer offset measured {measured} (matches this process, anchor local={anchor.LocalTimestamp:yyyy-MM-ddTHH:mm:ss.fff}).");
+                return;
+            }
+
+            _logger?.Info(
+                $"ImeLogTracker: {sourceFileName} writer offset measured {measured}, this process believes {readerZoneOffset} " +
+                $"(anchor local={anchor.LocalTimestamp:yyyy-MM-ddTHH:mm:ss.fff}). Measurement is observational — resolution anchors per line.");
+        }
+
     }
 }

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

@@ -85,6 +85,42 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// Unspecified depending on the parser path. Normalize via SpecifyKind=Utc rather than
         /// ToUniversalTime() to avoid double-conversion when Kind is already UTC.
         /// </summary>
+        /// <summary>
+        /// Measures the UTC offset the IME process believes it is in, per log file.
+        /// <para>
+        /// Only this tracker may WRITE to it: calibration requires tailing with growth detection
+        /// so the freshness rule can be honoured, and no other collector tails. Exposed so the
+        /// snapshot-reading collectors can eventually READ from a shared instance
+        /// (tasks/todo.md, P3b).
+        /// </para>
+        /// </summary>
+        internal CmTraceOffsetCalibrator OffsetCalibrator { get; } = new CmTraceOffsetCalibrator();
+
+        /// <summary>
+        /// File whose lines are currently being processed. The polling loop walks files strictly
+        /// sequentially on a single task, so a field is sufficient to give <c>ResolveEntryUtc</c>
+        /// and the handlers the calibration key without threading it through every signature.
+        /// </summary>
+        private string _currentSourceFileName;
+
+        /// <summary>
+        /// Whether every line of the file iteration currently in flight is provably FRESH —
+        /// written after the previous look at this file, which happened at most
+        /// <see cref="FreshLineMaxAge"/> ago in THIS process. Only then may a line anchor its
+        /// own UTC offset (<see cref="CmTraceOffsetCalibrator.TryMeasureOffset"/>): the grid
+        /// rounding is safe when the line's age is bounded by seconds, and becomes a trap on
+        /// backlog whose age can hit an exact grid multiple. Same single-task justification as
+        /// <see cref="_currentSourceFileName"/>.
+        /// </summary>
+        private bool _currentPassLinesAreFresh;
+
+        /// <summary>
+        /// Maximum gap between two looks at a file for its new bytes to count as fresh. Far
+        /// above the 100 ms poll (rides out GC pauses and ESP CPU starvation), far below the
+        /// 13-minute danger zone where a line's AGE could round onto the 15-minute offset grid.
+        /// </summary>
+        internal static readonly TimeSpan FreshLineMaxAge = TimeSpan.FromSeconds(30);
+
         internal static DateTime NormalizeUtc(DateTime value) =>
             value.Kind == DateTimeKind.Utc ? value : DateTime.SpecifyKind(value, DateTimeKind.Utc);
 
@@ -191,6 +227,38 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         public string LastMatchedPatternId { get; internal set; }
         public DateTime? LastMatchedLogTimestamp { get; internal set; }
 
+        /// <summary>
+        /// Raw local time of the last matched line, exactly as the writer wrote it — no zone
+        /// attached, because the line carries none.
+        /// <para>
+        /// Recorded so an emitted event can carry the evidence for its own timestamp. Without it
+        /// a conversion error is only provable from the diagnostics archive, and of the 5,386
+        /// sessions that went through a timezone change essentially none had one — the field
+        /// analysis had to fall back to median statistics over thousands of sessions to show
+        /// what one stored value would have made obvious per session.
+        /// </para>
+        /// </summary>
+        public DateTime? LastMatchedSourceLocalTimestamp { get; internal set; }
+
+        /// <summary>Offset applied to <see cref="LastMatchedSourceLocalTimestamp"/>, in minutes.</summary>
+        public int? LastMatchedSourceOffsetMinutes { get; internal set; }
+
+        /// <summary>How that offset was arrived at — declared, measured, or neither.</summary>
+        public CmTraceOffsetOrigin LastMatchedSourceOffsetOrigin { get; internal set; }
+
+        /// <summary>
+        /// The offset the calibrator MEASURED for the source file, which is not necessarily the
+        /// one applied.
+        /// <para>
+        /// Since the 2026-08-20 revert the measurement is observational only: it is recorded so the
+        /// field tells us what an era-aware calibrator would have to work with, without acting on
+        /// it. Reported separately from <see cref="LastMatchedSourceOffsetMinutes"/> precisely so
+        /// the two can never be confused — that event said "calibrated" while carrying a wrong
+        /// value, and an honest record has to distinguish measured from applied.
+        /// </para>
+        /// </summary>
+        public int? LastMatchedMeasuredWriterOffsetMinutes { get; internal set; }
+
         // Callbacks to EnrollmentTracker
         public Action<string> OnEspPhaseChanged { get; set; }
         public Action<string> OnImeAgentVersion { get; set; }

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

@@ -19,6 +19,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// has been rotated - resets to 0 to read from beginning.
         /// Returns 0 if no position has been recorded yet.
         /// </summary>
+        /// <summary>
+        /// Whether this file was already observed in an earlier pass.
+        /// <para>
+        /// The offset calibration depends on this: growth measured against a size we saw before
+        /// means the new bytes were written within one poll interval, so the last line of that
+        /// pass is a valid "written now" anchor. On the FIRST sight of a file we read it from
+        /// position 0 and its last line may be arbitrarily old — anchoring on that would measure
+        /// the line's age instead of the writer's timezone offset.
+        /// </para>
+        /// </summary>
+        public bool HasSeen(string filePath) => _positions.ContainsKey(filePath);
+
         public long GetSafePosition(string filePath, long currentFileSize)
         {
             FilePositionState state;
@@ -53,6 +65,42 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             state.LastReadTime = DateTime.UtcNow;
         }
 
+        /// <summary>
+        /// Records that the file was looked at in a poll pass — whether or not it had new data.
+        /// Creates the entry on first sight (position 0), so a file first seen EMPTY counts as
+        /// observed and its first content is provably fresh.
+        /// <para>
+        /// This timestamp is the freshness reference for per-line offset anchoring: bytes found
+        /// in the NEXT pass were written after this instant, so
+        /// <c>now - LastCheckedUtc</c> bounds the age of every line in that pass's chunk.
+        /// The caller supplies the clock (the tracker's <c>UtcNowProvider</c>) so replay/test
+        /// clocks stay consistent with the freshness comparison.
+        /// </para>
+        /// </summary>
+        public void MarkChecked(string filePath, DateTime nowUtc)
+        {
+            FilePositionState state;
+            if (!_positions.TryGetValue(filePath, out state))
+            {
+                state = new FilePositionState();
+                _positions[filePath] = state;
+            }
+
+            state.LastCheckedUtc = nowUtc;
+        }
+
+        /// <summary>
+        /// When the file was last looked at, or <see cref="DateTime.MinValue"/> when it never
+        /// was in THIS process — including entries restored from persisted state, whose
+        /// bookmark survives an agent restart but whose freshness deliberately does not
+        /// (the restart gap can hold arbitrarily old backlog).
+        /// </summary>
+        public DateTime GetLastCheckedUtc(string filePath)
+        {
+            FilePositionState state;
+            return _positions.TryGetValue(filePath, out state) ? state.LastCheckedUtc : DateTime.MinValue;
+        }
+
         /// <summary>
         /// Gets the stored position for a file, or 0 if not tracked.
         /// Does not perform rollover detection.
@@ -77,6 +125,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// <summary>
         /// Restores a previously persisted position for a file.
         /// Used on agent restart to continue reading from the last known position.
+        /// <para>
+        /// <see cref="FilePositionState.LastCheckedUtc"/> is deliberately NOT restored: the
+        /// bookmark survives the restart, the freshness guarantee does not — the first pass
+        /// after a restart reads the whole downtime backlog and must never anchor per-line
+        /// offsets on it.
+        /// </para>
         /// </summary>
         public void RestorePosition(string filePath, long position, long lastKnownSize)
         {
@@ -84,7 +138,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             {
                 Position = position,
                 LastKnownSize = lastKnownSize,
-                LastReadTime = DateTime.UtcNow
+                LastReadTime = DateTime.UtcNow,
+                LastCheckedUtc = DateTime.MinValue
             };
         }
     }
@@ -94,5 +149,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         public long Position { get; set; }
         public long LastKnownSize { get; set; }
         public DateTime LastReadTime { get; set; }
+
+        /// <summary>
+        /// When this file was last looked at by a poll pass IN THIS PROCESS. In-memory only —
+        /// never persisted, so a restart resets it (see <see cref="LogFilePositionTracker.RestorePosition"/>).
+        /// </summary>
+        public DateTime LastCheckedUtc { get; set; }
     }
 }

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

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using AutopilotMonitor.Agent.V2.Core.Logging;
 using AutopilotMonitor.Agent.V2.Core.Orchestration;
 using AutopilotMonitor.Shared;
@@ -37,6 +38,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         private readonly int _modernDeploymentBackfillLookbackMinutes;
         private readonly string _stateDirectory;
         private readonly int[] _modernDeploymentHarmlessEventIds;
+        private readonly bool _isDevicePreparation;
         private readonly Func<(bool? skipUser, bool? skipDevice)> _skipConfigProbe;
         private readonly Func<bool> _accountSetupActivityProbe;
         private readonly Func<bool> _userEspAppsSettledProbe;
@@ -45,7 +47,24 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
         // Session caa6cf50 gate-starvation fix (2026-06-11) — fire-once guard for the
         // user-ESP-apps-settled AccountSetup synthesis (see MaybeSynthesizeAccountSetupComplete).
-        private bool _userAppsSettledSynthesisFired;
+        // Interlocked rather than a plain bool: since the sits-d Cloud-PC fix the synthesis is
+        // ALSO re-evaluated from the IME app-state-change thread, so two threads can reach the
+        // guard concurrently (Shell-Core watcher thread + IME log thread).
+        private int _userAppsSettledSynthesisFired;
+
+        // sits-d Cloud-PC fix (2026-08-19) — set once a CONFIRMED post-AccountSetup Shell-Core
+        // exit has been observed (live OR backfill). The synthesis needs two facts: the ESP exit
+        // is an EDGE that happens once, the settled user-ESP apps are a LEVEL that may only be
+        // reached minutes later. Recording the edge lets ReevaluateUserAppsSettledSynthesis
+        // re-check the level afterwards instead of losing the completion for the rest of the
+        // session.
+        //
+        // Codex review P1 (2026-08-19): "confirmed" is load-bearing. Shell-Core raises 62407 at
+        // EVERY ESP phase transition, DeviceSetup→AccountSetup included. Remembering that
+        // intermediate exit would let the deferred re-check open the strong AccountSetup gate the
+        // moment the last user app settles — while the AccountSetup page is still up and its other
+        // subcategories are still running. See IsConfirmedPostAccountSetupExit.
+        private volatile bool _espExitObserved;
 
         // Liveness plan PR3 — one-shot-per-appId dedupe for app_install_starved emissions.
         // Written from the Shell-Core watcher thread (esp_exited path), read at termination by
@@ -211,6 +230,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             int modernDeploymentBackfillLookbackMinutes = 30,
             string stateDirectory = null,
             int[] modernDeploymentHarmlessEventIds = null,
+            bool isDevicePreparation = false,
             Func<(bool? skipUser, bool? skipDevice)> skipConfigProbe = null,
             Func<bool> accountSetupActivityProbe = null,
             Func<bool> userEspAppsSettledProbe = null,
@@ -228,6 +248,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             _modernDeploymentBackfillLookbackMinutes = modernDeploymentBackfillLookbackMinutes;
             _stateDirectory = stateDirectory != null ? Environment.ExpandEnvironmentVariables(stateDirectory) : null;
             _modernDeploymentHarmlessEventIds = modernDeploymentHarmlessEventIds;
+            _isDevicePreparation = isDevicePreparation;
             // Test seam: allow injection of a fake skip-config reader; defaults to the real
             // registry probe so production never has to think about this parameter.
             _skipConfigProbe = skipConfigProbe ?? (() => EspSkipConfigurationProbe.Read(_logger));
@@ -311,11 +332,40 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// </summary>
         public void ResetForEspResumption() => _helloTracker?.ResetForEspResumption();
 
+
         /// <summary>
-        /// Backfills recent ESP exit and failure events from Shell-Core log on startup.
-        /// Secondary recovery mechanism when state persistence is unavailable.
+        /// Replays the recent Shell-Core Hello-wizard start with an explicit lookback window.
+        /// Called by <c>EspAndHelloHost</c> right after <see cref="Start"/> — see the host for why
+        /// the window is sized to the previous run's downtime, and
+        /// <see cref="ShellCoreTracker.ReplayBackfillRecords"/> for why the ESP exit is not part
+        /// of the replay.
         /// </summary>
-        public void BackfillRecentEspExitEvents() => _shellCoreTracker?.BackfillRecentEspExitEvents();
+        public void BackfillRecentHelloWizardStart(int lookbackMinutes)
+            => _shellCoreTracker?.BackfillRecentHelloWizardStart(lookbackMinutes);
+
+        /// <summary>
+        /// sits-d Cloud-PC fix (2026-08-19) — re-check the user-apps-settled AccountSetup
+        /// synthesis after the ESP exit has already been observed. Wired to the IME tracker's
+        /// app-state-change callback in <c>DefaultComponentFactory</c>.
+        /// <para>
+        /// Before this, the synthesis ran ONLY on the <c>EspExited</c> edge. When the ESP page
+        /// exits while user-ESP apps are still in flight (the normal case on a tenant with a
+        /// large required-app set), the single attempt misses and nothing re-checks — even once
+        /// every tracked app has reached a terminal state minutes later. Sessions 8110e262 and
+        /// a89aac2d reached 138/138 apps with 0 failed and still never completed.
+        /// </para>
+        /// <para>
+        /// Adds NO new completion path: the gate conditions inside the synthesis are unchanged
+        /// (real ESP exit + every required user-ESP app terminal + zero failures). This only
+        /// grants the existing, deliberately conservative check a second look.
+        /// </para>
+        /// </summary>
+        public void ReevaluateUserAppsSettledSynthesis()
+        {
+            if (!_espExitObserved) return;
+            if (Volatile.Read(ref _userAppsSettledSynthesisFired) != 0) return;
+            MaybeSynthesizeAccountSetupCompleteFromSettledUserApps(emitStarvedOnMiss: false);
+        }
 
         // =====================================================================
         // Lifecycle
@@ -348,16 +398,28 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             _shellCoreTracker.HelloWizardStarted += OnHelloWizardStarted;
             _shellCoreTracker.Start();
 
-            _provisioningTracker = new ProvisioningStatusTracker(
-                _sessionId,
-                _tenantId,
-                _post,
-                _logger,
-                packageStatesProbe: _packageStatesProbe);
-            _provisioningTracker.EspFailureDetected += OnProvisioningEspFailureDetected;
-            _provisioningTracker.DeviceSetupProvisioningComplete += OnDeviceSetupProvisioningComplete;
-            _provisioningTracker.AccountSetupProvisioningComplete += OnAccountSetupProvisioningComplete;
-            _provisioningTracker.Start();
+            // WDP gate (afee7ae0, 2026-08-18): Device Preparation writes its BootstrapperAgent
+            // progress under the very AutopilotSettings key this tracker subtree-watches, so on
+            // WDP the watcher woke up on every provisioning write only to read three ESP
+            // category values that never exist there. The ESP categories are the tracker's
+            // ONLY subject — skip it entirely. All consumers already null-guard the tracker.
+            if (!_isDevicePreparation)
+            {
+                _provisioningTracker = new ProvisioningStatusTracker(
+                    _sessionId,
+                    _tenantId,
+                    _post,
+                    _logger,
+                    packageStatesProbe: _packageStatesProbe);
+                _provisioningTracker.EspFailureDetected += OnProvisioningEspFailureDetected;
+                _provisioningTracker.DeviceSetupProvisioningComplete += OnDeviceSetupProvisioningComplete;
+                _provisioningTracker.AccountSetupProvisioningComplete += OnAccountSetupProvisioningComplete;
+                _provisioningTracker.Start();
+            }
+            else
+            {
+                _logger.Info("EspAndHelloTracker: Device Preparation session — ProvisioningStatusTracker (ESP categories) not started");
+            }
 
             if (_modernDeploymentWatcherEnabled)
             {
@@ -370,7 +432,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                     _modernDeploymentBackfillEnabled,
                     _modernDeploymentBackfillLookbackMinutes,
                     _stateDirectory,
-                    _modernDeploymentHarmlessEventIds);
+                    _modernDeploymentHarmlessEventIds,
+                    _isDevicePreparation);
                 _modernDeploymentTracker.Start();
             }
         }
@@ -520,6 +583,40 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             return skipUser == false;
         }
 
+        /// <summary>
+        /// Codex review P1 (2026-08-19) — may THIS <c>esp_exiting</c> be remembered as the edge the
+        /// deferred user-apps-settled re-check builds on?
+        /// <para>
+        /// Deliberately STRICTER than <c>!IsIntermediateDeviceEspExit()</c>: that helper forwards
+        /// on an unknown SkipUser (forwarding a signal early is cheap), whereas remembering the
+        /// wrong edge here can open a completion gate minutes later with no second chance to take
+        /// it back. So this one demands positive evidence and treats "unknown" as "not confirmed":
+        /// </para>
+        /// <list type="bullet">
+        ///   <item>the provisioning tracker has seen AccountSetup activity — the page that just
+        ///         tore down is demonstrably the AccountSetup one; or</item>
+        ///   <item>SkipUser is explicitly <c>true</c> — the profile has no user ESP at all, so the
+        ///         Device-ESP exit IS the final one and no second exit is coming.</item>
+        /// </list>
+        /// <para>
+        /// Erring strict costs at worst today's behaviour (the session stalls as it did before the
+        /// fix); erring loose costs a premature Succeeded, which is unrecoverable.
+        /// </para>
+        /// </summary>
+        private bool IsConfirmedPostAccountSetupExit()
+        {
+            bool accountSetupSeen;
+            try { accountSetupSeen = _accountSetupActivityProbe(); }
+            catch (Exception ex)
+            {
+                _logger.Debug($"EspAndHelloTracker: account-setup-activity probe threw: {ex.Message}");
+                accountSetupSeen = false;
+            }
+            if (accountSetupSeen) return true;
+
+            return GetSkipUserEspCached() == true;
+        }
+
         private bool? GetSkipUserEspCached()
         {
             lock (_skipConfigLock)
@@ -659,6 +756,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 try { EspExited?.Invoke(this, args); }
                 catch (Exception ex) { _logger.Error("Error forwarding EspExited", ex); }
 
+                // Every exit reaching this handler is one the agent observed LIVE: the Shell-Core
+                // replay never re-raises 62407 (see ShellCoreTracker.ReplayBackfillRecords — a
+                // replayed exit cannot be placed in time and is therefore kept out of the decision
+                // stream entirely). That is what makes the AccountSetup read below a valid
+                // ordering fact: the agent was continuously observing up to this instant.
+                //
+                // Record the edge BEFORE the synthesis attempt so a later app-state change can
+                // re-run it even when the apps are not settled at this instant.
+                if (IsConfirmedPostAccountSetupExit())
+                    _espExitObserved = true;
+
                 // Session caa6cf50 gate-starvation fix: a Shell-Core normal exit while IME's
                 // user-ESP app tracking is fully settled is alternative evidence that
                 // AccountSetup completed. Raised AFTER the EspExited forward so the reducer
@@ -688,9 +796,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         /// conservative stall behaviour.
         /// </para>
         /// </summary>
-        private void MaybeSynthesizeAccountSetupCompleteFromSettledUserApps()
+        private void MaybeSynthesizeAccountSetupCompleteFromSettledUserApps(bool emitStarvedOnMiss = true)
         {
-            if (_userAppsSettledSynthesisFired) return;
+            if (Volatile.Read(ref _userAppsSettledSynthesisFired) != 0) return;
 
             bool settled;
             try { settled = _userEspAppsSettledProbe(); }
@@ -706,11 +814,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 // operator with an anonymous "session hangs in AccountSetup". One-shot per
                 // appId; apps that are alive (Downloading/Installing) or failed are excluded
                 // by the probe itself.
-                EmitStarvedUserEspApps(trigger: "esp_exited_user_apps_not_settled");
+                // Only on the ESP-exit edge: the re-evaluation path passes false so a repeated
+                // miss cannot re-walk the probe on every single app-state change (the per-appId
+                // dedupe would swallow the events anyway — this keeps the work off the hot path).
+                if (emitStarvedOnMiss)
+                    EmitStarvedUserEspApps(trigger: "esp_exited_user_apps_not_settled");
                 return;
             }
 
-            _userAppsSettledSynthesisFired = true;
+            // Claim the single synthesis slot; a concurrent caller that loses the race returns.
+            if (Interlocked.CompareExchange(ref _userAppsSettledSynthesisFired, 1, 0) != 0) return;
             _logger.Warning(
                 "EspAndHelloTracker: ESP exited normally with all tracked user-ESP apps terminal (0 failed) " +
                 "but AccountSetupCategory.Status never confirmed categorySucceeded — treating AccountSetup as complete " +
@@ -804,6 +917,6 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
         // Test seam for the user-apps-settled synthesis — drives OnEspExited with the live
         // handler signature, mirroring TriggerEspExitedForTest's contract.
-        internal bool UserAppsSettledSynthesisFiredForTest => _userAppsSettledSynthesisFired;
+        internal bool UserAppsSettledSynthesisFiredForTest => Volatile.Read(ref _userAppsSettledSynthesisFired) != 0;
     }
 }

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

@@ -66,6 +66,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
         internal const string AutopilotErrorBackfillStateFileName = "autopilot-error-backfill.json";
 
+        /// <summary>
+        /// EventIDs that are STRUCTURAL noise on a Device Preparation session and are
+        /// suppressed there entirely (afee7ae0: 900+ occurrences of 1005 plus 400+ of
+        /// 417/418 in a nine-minute session, all expected): 100 "Autopilot policy not
+        /// found" (no deployment profile exists on WDP by design), 417/418 "duplicate
+        /// deployment workload/batch" (BootstrapperAgent SLDM progress-poll chatter),
+        /// 1005 ManagementService WIL error storm. Genuine WDP diagnostics (e.g. 408
+        /// provisioning warnings) keep flowing; Critical (level 1) records are never
+        /// suppressed. Classic sessions are unaffected — they keep the configurable
+        /// harmless-downgrade + rollup path instead.
+        /// </summary>
+        internal static readonly HashSet<int> DevicePreparationNoiseEventIds = new HashSet<int> { 100, 417, 418, 1005 };
+
         /// <summary>
         /// Per-EventId emission caps for harmless-downgraded events (session 8bc1180f,
         /// 2026-06-12). Windows can dump hundreds of identical EventID-100 "Autopilot policy
@@ -93,6 +106,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         private readonly int _backfillLookbackMinutes;
         private readonly string _stateDirectory;
         private readonly HashSet<int> _harmlessEventIds;
+        private readonly bool _isDevicePreparation;
 
         private EventLogWatcher _autopilotWatcher;
         private EventLogWatcher _managementWatcher;
@@ -131,7 +145,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             bool backfillEnabled = true,
             int backfillLookbackMinutes = 30,
             string stateDirectory = null,
-            int[] harmlessEventIds = null)
+            int[] harmlessEventIds = null,
+            bool isDevicePreparation = false)
         {
             _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
             _tenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
@@ -140,6 +155,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             _logLevelMax = logLevelMax;
             _backfillEnabled = backfillEnabled;
             _backfillLookbackMinutes = backfillLookbackMinutes;
+            _isDevicePreparation = isDevicePreparation;
             _stateDirectory = stateDirectory != null ? Environment.ExpandEnvironmentVariables(stateDirectory) : null;
             _harmlessEventIds = harmlessEventIds != null && harmlessEventIds.Length > 0
                 ? new HashSet<int>(harmlessEventIds)
@@ -166,7 +182,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             if (_backfillEnabled)
             {
                 BackfillTargetedEvents();
-                BackfillAutopilotErrors();
+                // WDP gate (afee7ae0): the error backfill replays ZTD registration /
+                // attestation errors (807/809/815/908) — on Device Preparation the 807
+                // ZtdDeviceIsNotRegistered answer is the EXPECTED state, not a failure.
+                if (!_isDevicePreparation)
+                {
+                    BackfillAutopilotErrors();
+                }
+                else
+                {
+                    _logger.Info("ModernDeployment: Device Preparation session — Autopilot error backfill skipped (ZTD errors are structural there)");
+                }
             }
             else
             {
@@ -393,6 +419,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             }
 
             var effectiveLevel = level ?? 4;
+
+            // WDP structural-noise gate — see DevicePreparationNoiseEventIds. Sits before
+            // the severity mapping so suppressed records also skip FormatDescription().
+            // Critical (1) and LogAlways (0) records always pass.
+            if (_isDevicePreparation
+                && effectiveLevel >= 2
+                && DevicePreparationNoiseEventIds.Contains(eventId))
+            {
+                return EventVerdict.Suppress;
+            }
             switch (effectiveLevel)
             {
                 case 1:

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

@@ -34,6 +34,14 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         internal const int EventId_ShellCore_WebAppEvent = 62407;
         internal const int BackfillLookbackMinutes = 5;
 
+        /// <summary>
+        /// Upper bound for the caller-supplied backfill lookback. Matches the agent's max
+        /// lifetime (360 min) — a window wider than the agent can ever live would only widen
+        /// the blast radius of a stale Shell-Core record without recovering anything the
+        /// current enrollment could still act on.
+        /// </summary>
+        internal const int BackfillLookbackMaxMinutes = 360;
+
         private static readonly HashSet<int> TrackedShellCoreEventIds = new HashSet<int>
         {
             EventId_ShellCore_WebAppStarted,
@@ -350,22 +358,39 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         // Backfill (public — called by coordinator)
         // =====================================================================
 
+        /// <summary>Clamps a caller-supplied lookback into [1, <see cref="BackfillLookbackMaxMinutes"/>].</summary>
+        internal static int ClampLookbackMinutes(int lookbackMinutes)
+        {
+            if (lookbackMinutes < 1) return 1;
+            if (lookbackMinutes > BackfillLookbackMaxMinutes) return BackfillLookbackMaxMinutes;
+            return lookbackMinutes;
+        }
+
+        public void BackfillRecentHelloWizardStart() => BackfillRecentHelloWizardStart(BackfillLookbackMinutes);
+
         /// <summary>
-        /// Backfills recent ESP exit, ESP failure and Hello-wizard-start events from the
-        /// Shell-Core log on startup. Secondary recovery mechanism when state persistence is
-        /// unavailable — an agent restart while the user sits inside the Hello wizard would
-        /// otherwise lose the wizard-start observation (session 772fe502).
+        /// Same recovery with a caller-chosen lookback, so a restart can reach back over its whole
+        /// downtime (after a mid-ESP reboot the agent is gone from the forced restart until the
+        /// post-reboot logon relaunches it; after a crash, until the next boot — the scheduled task
+        /// has a BootTrigger only). Clamped to [1, <see cref="BackfillLookbackMaxMinutes"/>].
+        /// <para>
+        /// The 62407 records in the window are read but deliberately NOT replayed — see
+        /// <see cref="ReplayBackfillRecords"/>. They are counted and reported once as an
+        /// <c>agent_trace</c> so the gap stays visible in the timeline without becoming
+        /// decision-relevant.
+        /// </para>
         /// </summary>
-        public void BackfillRecentEspExitEvents()
+        public void BackfillRecentHelloWizardStart(int lookbackMinutes)
         {
             try
             {
-                var lookbackMs = BackfillLookbackMinutes * 60 * 1000;
+                var lookbackMs = ClampLookbackMinutes(lookbackMinutes) * 60 * 1000;
                 var query = new EventLogQuery(
                     ShellCoreEventLogChannel,
                     PathType.LogName,
                     $"*[System[(EventID=62404 or EventID=62407) and TimeCreated[timediff(@SystemTime) <= {lookbackMs}]]]");
 
+                var records = new List<(int Id, string Description, DateTime OccurredAtUtc)>();
                 using (var reader = new EventLogReader(query))
                 {
                     for (EventRecord record = reader.ReadEvent(); record != null; record = reader.ReadEvent())
@@ -377,20 +402,135 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                             // (EspAndHelloTrackerAdapter) can stamp signals with the source time
                             // rather than collapsing to wall-clock-now.
                             var timestamp = (record.TimeCreated ?? DateTime.UtcNow).ToUniversalTime();
-                            HandleBackfillRecord(record.Id, description, timestamp);
+                            records.Add((record.Id, description, timestamp));
                         }
                     }
                 }
+
+                ReplayBackfillRecords(records);
             }
             catch (Exception ex)
             {
-                _logger.Warning($"ESP exit/failure event backfill failed: {ex.Message}");
+                _logger.Warning($"Shell-Core replay failed: {ex.Message}");
             }
         }
 
         /// <summary>
-        /// Internal backfill record handler — extracted for testability and to keep the
-        /// backfill loop free of direct event-processing logic. The
+        /// Replays a chronological batch of Shell-Core records. <b>Only the Hello-wizard start
+        /// (62404) is replayed.</b> ESP exits and ESP failures (62407) are counted and reported,
+        /// never re-raised.
+        /// <para>
+        /// Why the exit is excluded — the reasoning is the whole point of this method, so it lives
+        /// here rather than in a commit message:
+        /// </para>
+        /// <list type="number">
+        ///   <item>Windows writes the IDENTICAL description
+        ///     (<c>CommercialOOBE_ESPProgress_Page_Exiting</c>) for the intermediate
+        ///     DeviceSetup→AccountSetup transition and for the final post-AccountSetup exit, so a
+        ///     replayed record carries no evidence of its own position.</item>
+        ///   <item>Everything that could order it after the fact — the AccountSetup registry
+        ///     probe, the settled-apps probe — reads state as it is NOW, not as it was at the
+        ///     event's time.</item>
+        ///   <item>The reducer orders exits by INGEST ORDINAL, not by timestamp
+        ///     (<c>IsPostAccountSetupFinalExit</c>). A replayed historic exit is assigned a fresher
+        ///     ordinal than reality, so it looks post-AccountSetup by construction.</item>
+        ///   <item><c>HandleEspExitingV1</c> passes <c>espFinalExitInFlight: true</c> for every
+        ///     arriving exit. With restored state (AccountSetupEntered + a genuine IME user
+        ///     session + desktop arrived) arm C of <c>ShouldTransitionToAwaitingHello</c> then
+        ///     opens on a historic intermediate exit — a completion built on a fact that never
+        ///     happened.</item>
+        /// </list>
+        /// <para>
+        /// There is therefore no honest way to classify a replayed exit, so it must not enter the
+        /// decision stream at all. The same applies to a replayed ESP FAILURE, for the opposite
+        /// reason: re-injecting a historic failure as fresh can fail a session that recovered
+        /// (see ANALYZE-ESP-006, "ESP Failure Recovered After User Retry").
+        /// </para>
+        /// <para>
+        /// The Hello-wizard start is different in kind and is the observation this replay was
+        /// written for (session 772fe502): it is a CONSERVATIVE fact. It vetoes a premature
+        /// "Hello is disabled" skip and can never by itself complete a session, so replaying it
+        /// can only make the agent wait longer, never finish early.
+        /// </para>
+        /// </summary>
+        internal void ReplayBackfillRecords(
+            IReadOnlyList<(int Id, string Description, DateTime OccurredAtUtc)> records)
+        {
+            if (records == null || records.Count == 0) return;
+
+            var skippedExits = 0;
+            var skippedFailures = 0;
+            DateTime? oldestSkipped = null;
+            DateTime? newestSkipped = null;
+
+            foreach (var record in records)
+            {
+                var description = record.Description ?? string.Empty;
+
+                if (record.Id == EventId_ShellCore_WebAppStarted)
+                {
+                    HandleBackfillRecord(record.Id, description, record.OccurredAtUtc);
+                    continue;
+                }
+
+                var isFailure = HasEspFailurePattern(description);
+                var isExit = !isFailure && EspExitingPattern.IsMatch(description);
+                if (!isFailure && !isExit) continue;
+
+                if (isFailure) skippedFailures++; else skippedExits++;
+                if (oldestSkipped == null || record.OccurredAtUtc < oldestSkipped.Value)
+                    oldestSkipped = record.OccurredAtUtc;
+                if (newestSkipped == null || record.OccurredAtUtc > newestSkipped.Value)
+                    newestSkipped = record.OccurredAtUtc;
+            }
+
+            if (skippedExits > 0 || skippedFailures > 0)
+                EmitSkippedShellCoreRecords(skippedExits, skippedFailures, oldestSkipped, newestSkipped);
+        }
+
+        /// <summary>
+        /// One informational <c>agent_trace</c> naming the 62407 records the replay deliberately
+        /// did not re-raise. Decision-neutral by construction (informational events are exempt
+        /// from the dispatch guard) — its only job is to keep the blind window visible to whoever
+        /// debugs a session later, instead of the replay silently dropping evidence.
+        /// </summary>
+        private void EmitSkippedShellCoreRecords(
+            int skippedExits, int skippedFailures, DateTime? oldestUtc, DateTime? newestUtc)
+        {
+            try
+            {
+                _post.Emit(new EnrollmentEvent
+                {
+                    SessionId = _sessionId,
+                    TenantId = _tenantId,
+                    EventType = Constants.EventTypes.AgentTrace,
+                    Severity = EventSeverity.Info,
+                    Source = "ShellCoreTracker",
+                    Phase = EnrollmentPhase.Unknown,
+                    Message =
+                        $"Shell-Core replay skipped {skippedExits} ESP exit(s) and {skippedFailures} ESP failure(s) " +
+                        "from the window in which no agent process was running — a replayed 62407 cannot be placed " +
+                        "in time and must not reach the decision engine.",
+                    Data = new Dictionary<string, object>
+                    {
+                        { "skippedEspExits", skippedExits },
+                        { "skippedEspFailures", skippedFailures },
+                        { "oldestSkippedUtc", oldestUtc?.ToString("o") ?? string.Empty },
+                        { "newestSkippedUtc", newestUtc?.ToString("o") ?? string.Empty },
+                        { "reason", "replayed_62407_not_orderable" },
+                    },
+                });
+            }
+            catch (Exception ex)
+            {
+                _logger.Debug($"ShellCoreTracker: skipped-records trace emit failed: {ex.Message}");
+            }
+        }
+
+        /// <summary>
+        /// Internal backfill record handler — extracted for testability and to keep the replay
+        /// loop free of direct event-processing logic. Handles the Hello-wizard start ONLY; see
+        /// <see cref="ReplayBackfillRecords"/> for why 62407 is never replayed. The
         /// <paramref name="occurredAtUtc"/> is the original Shell-Core event time
         /// (<c>record.TimeCreated</c>); subscribers read it via
         /// <see cref="LastEventOccurredAtUtc"/> during their synchronous event handler.
@@ -427,42 +567,6 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 return;
             }
 
-            if (EspExitingPattern.IsMatch(description))
-            {
-                bool shouldNotify = false;
-                lock (_stateLock)
-                {
-                    if (!_espExitDetected)
-                    {
-                        _espExitDetected = true;
-                        shouldNotify = true;
-                    }
-                }
-                if (shouldNotify)
-                {
-                    _helloTracker?.NotifyEspExited();
-                    _logger.Info($"Backfill: ESP exit event found in recent Shell-Core logs (originalAt={occurredAtUtc:o})");
-                    LastEventOccurredAtUtc = occurredAtUtc;
-                    try
-                    {
-                        try { FinalizingSetupPhaseTriggered?.Invoke(this, "esp_exiting"); }
-                        catch (Exception ex) { _logger.Error("Backfill: FinalizingSetupPhaseTriggered handler failed", ex); }
-                        try { EspExited?.Invoke(this, new EspExitedEventArgs(occurredAtUtc)); }
-                        catch (Exception ex) { _logger.Error("Backfill: EspExited handler failed", ex); }
-                    }
-                    finally { LastEventOccurredAtUtc = null; }
-                }
-            }
-
-            if (HasEspFailurePattern(description))
-            {
-                var failureType = ExtractEspFailureType(description);
-                _logger.Info($"Backfill: ESP failure event found in recent Shell-Core logs: {failureType} (originalAt={occurredAtUtc:o})");
-                LastEventOccurredAtUtc = occurredAtUtc;
-                try { EspFailureDetected?.Invoke(this, failureType); }
-                catch (Exception ex) { _logger.Error($"Backfill: EspFailureDetected handler failed for '{failureType}'", ex); }
-                finally { LastEventOccurredAtUtc = null; }
-            }
         }
 
         // =====================================================================

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

@@ -52,6 +52,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         private readonly HashSet<string> _sources;
         private readonly int _sessionStalledAfterProbeIndex;
         private readonly HashSet<int> _harmlessModernDeploymentEventIds;
+        private readonly bool _isDevicePreparation;
 
         private readonly object _stateLock = new object();
         private readonly HashSet<int> _firedProbeIndices = new HashSet<int>();
@@ -151,7 +152,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             int[] traceIndices,
             string[] sources,
             int sessionStalledAfterProbeIndex,
-            int[] harmlessModernDeploymentEventIds = null)
+            int[] harmlessModernDeploymentEventIds = null,
+            bool isDevicePreparation = false)
         {
             _sessionId = sessionId ?? throw new ArgumentNullException(nameof(sessionId));
             _tenantId = tenantId ?? throw new ArgumentNullException(nameof(tenantId));
@@ -161,10 +163,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             _traceIndices = new HashSet<int>(traceIndices ?? new int[0]);
             _sources = new HashSet<string>(sources ?? new string[0], StringComparer.OrdinalIgnoreCase);
             _sessionStalledAfterProbeIndex = sessionStalledAfterProbeIndex;
+            _isDevicePreparation = isDevicePreparation;
             _harmlessModernDeploymentEventIds = new HashSet<int>(
                 harmlessModernDeploymentEventIds != null && harmlessModernDeploymentEventIds.Length > 0
                     ? harmlessModernDeploymentEventIds
                     : DefaultHarmlessModernDeploymentEventIds);
+
+            // WDP gate (afee7ae0): the structural WDP noise IDs (417/418 duplicate-workload
+            // chatter, 1005 WIL storm, ...) must never count as stall anomalies on Device
+            // Preparation, independent of what the tenant-configured harmless list contains.
+            // The channels themselves stay scanned — WDP's provisioning stack logs genuine
+            // diagnostics (e.g. 408) into the very same Autopilot channel.
+            if (_isDevicePreparation)
+            {
+                _harmlessModernDeploymentEventIds.UnionWith(ModernDeploymentTracker.DevicePreparationNoiseEventIds);
+            }
         }
 
         /// <summary>
@@ -368,6 +381,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
 
         private void ScanProvisioningRegistry(ProbeResult result)
         {
+            // Device Preparation writes no ESP category values — the three Status JSONs
+            // below are ESP-only constructs, so the scan can never find anything there.
+            if (_isDevicePreparation)
+                return;
+
             using (var key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Provisioning\AutopilotSettings", writable: false))
             {
                 if (key == null)
@@ -562,10 +580,22 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
                 var scanText = rawLine;
                 if (CmTraceLogParser.TryParseLine(rawLine, out var entry))
                 {
-                    // Provably stale → not progress. (TryParseLine falls back to now on an
-                    // unparseable timestamp, which keeps the line fresh — the safe default.)
-                    if (entry.Timestamp < cutoffUtc)
-                        continue;
+                    // Provably stale → not progress. A line without a parseable timestamp counts
+                    // as fresh — the safe default, since treating it as stale would hide progress.
+                    //
+                    // This collector reads a file snapshot rather than tailing it, so it cannot
+                    // measure the writer's UTC offset itself and falls back to this process's zone
+                    // (see ResolveUtcAssumingReaderZone). That fallback is wrong by exactly the
+                    // gap between the two processes' zone beliefs. It is the pre-existing
+                    // behaviour, kept deliberately unchanged here; the tracker-owned calibrator is
+                    // wired in separately so this commit shifts no behaviour.
+                    if (entry.HasTimestamp)
+                    {
+                        var entryUtc = entry.TimestampUtc
+                            ?? CmTraceLogParser.ResolveUtcAssumingReaderZone(entry.LocalTimestamp);
+                        if (entryUtc < cutoffUtc)
+                            continue;
+                    }
                     scanText = entry.Message;
                 }
 

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

@@ -275,14 +275,34 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo
                 // Include enrollment type in autopilot_profile event data
                 data["enrollmentType"] = detectedType;
 
-                // Second diagnostic surface (independent of AutopilotPolicyCache): Microsoft's
-                // documented Diagnostics\Autopilot key (IsAutopilotDisabled, TenantMatched,
-                // CloudAssignedTenantDomain/Id, ...). See docs/agent/autopilot-ztd-diagnostics.md.
-                var diagnosticsRegistry = ZtdEvidence.ReadDiagnosticsRegistry(_logger);
-                if (diagnosticsRegistry != null)
-                    data["diagnosticsRegistry"] = diagnosticsRegistry;
+                // Device Preparation (WDP) has no Autopilot deployment profile by design:
+                // Windows still runs the ZTD policy download during OOBE and caches the 807
+                // ZtdDeviceIsNotRegistered answer, so without this gate every WDP session
+                // emits an autopilot_profile dump plus a misleading "no deployment profile
+                // was assigned" warning and burns a ZTD event-log query + HTTP probe on
+                // evidence that answers a question nobody asked (afee7ae0). Gated on the
+                // deterministic WDP rule only — the CloudAssigned* fallback rules imply a
+                // real profile (just ESP-less), where the dump stays meaningful. The
+                // enrollment_type_detected event below still carries the rail decision.
+                var isDevicePreparation = detectionRule ==
+                    AutopilotMonitor.Agent.V2.Core.Security.EnrollmentRegistryDetector.DevicePreparationExecutionContextRule;
 
-                EmitDeviceInfoEvent(Constants.EventTypes.AutopilotProfile, "Autopilot profile configuration", data);
+                Dictionary<string, object> diagnosticsRegistry = null;
+                if (!isDevicePreparation)
+                {
+                    // Second diagnostic surface (independent of AutopilotPolicyCache): Microsoft's
+                    // documented Diagnostics\Autopilot key (IsAutopilotDisabled, TenantMatched,
+                    // CloudAssignedTenantDomain/Id, ...). See docs/agent/autopilot-ztd-diagnostics.md.
+                    diagnosticsRegistry = ZtdEvidence.ReadDiagnosticsRegistry(_logger);
+                    if (diagnosticsRegistry != null)
+                        data["diagnosticsRegistry"] = diagnosticsRegistry;
+
+                    EmitDeviceInfoEvent(Constants.EventTypes.AutopilotProfile, "Autopilot profile configuration", data);
+                }
+                else
+                {
+                    _logger.Info("EnrollmentTracker: Device Preparation session — skipping autopilot_profile/ZTD evidence (no deployment profile exists on WDP)");
+                }
 
                 // ProfileAvailable=0 means the ZTD service returned no profile for this device
                 // during OOBE. Sessions only exist after the backend's device-registration
@@ -293,7 +313,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo
                 // Autopilot session — surface the edge case explicitly, with a ZTD verdict
                 // backed by the ModernDeployment Autopilot event log plus an endpoint probe
                 // (see docs/agent/autopilot-ztd-diagnostics.md for the evidence model).
-                if (IsAutopilotProfileMissing(data))
+                if (!isDevicePreparation && IsAutopilotProfileMissing(data))
                 {
                     // On Windows 365 Cloud PCs a missing profile is the expected state — Cloud PCs
                     // are provisioned by the Windows 365 service, not by Autopilot — so the event
@@ -787,10 +807,27 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.DeviceInfo
                     data["espTrackedModernCount"] = tracking.ModernCount;
                 }
 
-                var summary = BuildSummary(snapshot, tracking);
-                _logger.Info($"EnrollmentTracker: ESP configuration detected — {summary}");
-                EmitDeviceInfoEvent(Constants.EventTypes.EspConfigDetected, $"ESP configuration: {summary}", data);
-                PostEspConfigDetectedSignal(snapshot);
+                // No FirstSync value and no ESP tracking list means there is no ESP evidence at
+                // all (Device Preparation, plain Entra join, pre-sync timing) — an event that
+                // says nothing but "unknown/unknown" is noise, so skip it. Mirrors the null-gate
+                // the orchestrator bootstrap already applies to the decision signal
+                // (EnrollmentOrchestrator.PostEspConfigDetectedBootstrap).
+                var hasAnyEspEvidence = snapshot.SkipUser.HasValue
+                    || snapshot.SkipDevice.HasValue
+                    || snapshot.BlockInStatusPage.HasValue
+                    || snapshot.SyncFailureTimeoutMinutes.HasValue
+                    || tracking.HasData;
+                if (hasAnyEspEvidence)
+                {
+                    var summary = BuildSummary(snapshot, tracking);
+                    _logger.Info($"EnrollmentTracker: ESP configuration detected — {summary}");
+                    EmitDeviceInfoEvent(Constants.EventTypes.EspConfigDetected, $"ESP configuration: {summary}", data);
+                    PostEspConfigDetectedSignal(snapshot);
+                }
+                else
+                {
+                    _logger.Debug("EnrollmentTracker: no ESP configuration evidence (FirstSync empty, no tracking lists) — esp_config_detected suppressed");
+                }
             }
             catch (Exception ex)
             {

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

@@ -331,7 +331,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
                                         data[groupName] = group.Value;
                                 }
 
-                                data["logTimestamp"] = entry.Timestamp.ToString("o");
+                                // Gather-rule logs are arbitrary files this collector does not
+                                // tail, so no writer offset can be measured for them; the
+                                // reader-zone fallback carries its known defect (see
+                                // ResolveUtcAssumingReaderZone). Behaviour unchanged from before
+                                // the parser split.
+                                var entryUtc = entry.TimestampUtc
+                                    ?? (entry.HasTimestamp
+                                        ? CmTraceLogParser.ResolveUtcAssumingReaderZone(entry.LocalTimestamp)
+                                        : DateTime.UtcNow);
+                                data["logTimestamp"] = entryUtc.ToString("o");
                                 data["logComponent"] = entry.Component;
                                 data["logType"] = entry.Type;
                                 data["logMessage"] = TruncateMessage(entry.Message, 500);
@@ -348,7 +357,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather.Collectors
                                 {
                                     SessionId = context.SessionId,
                                     TenantId = context.TenantId,
-                                    Timestamp = entry.Timestamp,
+                                    Timestamp = entryUtc,
                                     EventType = eventType,
                                     Severity = severity,
                                     Source = "GatherRuleExecutor",

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

@@ -22,11 +22,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
         // Pressure thresholds — once either is crossed within a session, a one-shot
         // `spool_pressure_detected` event is emitted with RequiresImmediateFlush=true
         // so the backend can surface the condition without waiting for the next snapshot
-        // to be queried out of Storage. Sized so a healthy 6h provisioning session never
-        // trips them; tripping is a strong "upload backlog is growing or downstream stalled"
-        // signal worth investigating in the field.
+        // to be queried out of Storage. Both measure the PENDING backlog (items not yet
+        // marked uploaded), never the append-only spool file size — a healthy long session
+        // grows the file past any fixed size while its backlog stays near zero (field data
+        // 2026-08: 99/100 pressure events were file-size-only false positives). Tripping is
+        // therefore a genuine "upload is stalled or falling behind" signal.
         internal const int PressurePendingItemThreshold = 2000;
-        internal const long PressureFileSizeBytesThreshold = 5L * 1024 * 1024; // 5 MB
+        internal const long PressurePendingBytesThreshold = 5L * 1024 * 1024; // 5 MB
 
         private readonly string _agentVersion;
         private readonly NetworkMetrics _networkMetrics;
@@ -77,11 +79,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
 
         protected override void Collect()
         {
-            // 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)
+            // Full path writes 20 keys: agent_version + process metrics (5: cpu, ws, private,
+            // threads, handles) + spool stats (5) + network delta (9: requests, failures,
+            // bytes_up/down, avg_latency, total_up/down/requests/latency). cap=20 →
+            // HashHelpers.GetPrime(20)=23 buckets → no resize on the 20th key.
+            var data = new Dictionary<string, object>(capacity: 20, StringComparer.Ordinal)
             {
                 { "agent_version", _agentVersion }
             };
@@ -126,17 +128,20 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
             // EnrollmentOrchestrator.Start into IComponentFactory.CreateCollectorHosts
             // (ARCH-F4). Null only on test fakes that don't construct a real spool.
             int pendingItemCount = 0;
+            long pendingBytes = 0L;
             long spoolFileSizeBytes = 0L;
             if (_telemetrySpool != null)
             {
                 try
                 {
                     pendingItemCount = _telemetrySpool.PendingItemCount;
+                    pendingBytes = _telemetrySpool.PendingBytes;
                     spoolFileSizeBytes = _telemetrySpool.SpoolFileSizeBytes;
                     var peakPending = _telemetrySpool.PeakPendingItemCount;
                     var totalEnqueued = _telemetrySpool.LastAssignedItemId + 1; // -1 sentinel → 0
 
                     data["spool_pending_item_count"] = pendingItemCount;
+                    data["spool_pending_bytes"] = pendingBytes;
                     data["spool_peak_pending_item_count"] = peakPending;
                     data["spool_file_size_bytes"] = spoolFileSizeBytes;
                     data["spool_total_enqueued_count"] = totalEnqueued;
@@ -194,20 +199,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
                 });
             }
 
-            // One-shot pressure event \u2014 fires once per session when the spool grows past
-            // either threshold. ImmediateUpload=true so it shows up promptly on the
-            // backend without waiting for the next batch drain.
+            // One-shot pressure event \u2014 fires once per session when the pending backlog
+            // grows past either threshold. ImmediateUpload=true so it shows up promptly on
+            // the backend without waiting for the next batch drain.
             if (_telemetrySpool != null
                 && (pendingItemCount > PressurePendingItemThreshold
-                    || spoolFileSizeBytes > PressureFileSizeBytesThreshold)
+                    || pendingBytes > PressurePendingBytesThreshold)
                 && Interlocked.CompareExchange(ref _pressureEmitted, 1, 0) == 0)
             {
                 var pressureData = new Dictionary<string, object>(capacity: 8, StringComparer.Ordinal)
                 {
                     { "pendingItemCount", pendingItemCount },
-                    { "fileSizeBytes", spoolFileSizeBytes },
+                    { "pendingBytes", pendingBytes },
+                    { "fileSizeBytes", spoolFileSizeBytes },   // informational only, not a trigger
                     { "pendingThreshold", PressurePendingItemThreshold },
-                    { "fileSizeThresholdBytes", PressureFileSizeBytesThreshold },
+                    { "pendingBytesThreshold", PressurePendingBytesThreshold },
                     { "totalEnqueuedCount", _telemetrySpool.LastAssignedItemId + 1 },
                     { "lastUploadedItemId", _telemetrySpool.LastUploadedItemId },
                     { "ImmediateUpload", true }
@@ -222,15 +228,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Periodic
                     Severity = EventSeverity.Warning,
                     Source = "AgentSelfMetricsCollector",
                     Phase = EnrollmentPhase.Unknown,
-                    Message = $"Telemetry spool pressure detected: pending={pendingItemCount}, " +
-                              $"fileBytes={spoolFileSizeBytes} \u2014 upload may be stalled or session " +
-                              $"is unusually long.",
+                    Message = $"Telemetry spool pressure detected: pending={pendingItemCount} items / " +
+                              $"{pendingBytes} bytes not yet uploaded \u2014 upload is stalled or " +
+                              $"falling behind.",
                     Data = pressureData
                 });
 
                 Logger.Warning(
                     $"AgentSelfMetricsCollector: spool pressure detected " +
-                    $"(pending={pendingItemCount}, fileBytes={spoolFileSizeBytes}). " +
+                    $"(pending={pendingItemCount}, pendingBytes={pendingBytes}). " +
                     $"Emitted spool_pressure_detected (one-shot per session).");
             }
         }

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Transport/NetworkMetricsRecordingHandler.cs

@@ -21,12 +21,20 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Transport
     /// <remarks>
     /// <b>bytes-up</b> is read from <see cref="System.Net.Http.Headers.HttpContentHeaders.ContentLength"/>
     /// on the request content (set eagerly by <c>ByteArrayContent</c>/<c>StringContent</c>).
-    /// <b>bytes-down</b> is read from the response Content-Length header — when
-    /// <c>AutomaticDecompression</c> is enabled the framework may strip this, so the value
-    /// is best-effort (degrades to 0). The request count and failure count are always exact.
+    /// <b>bytes-down</b> prefers the response Content-Length header; the pipeline's
+    /// <c>AutomaticDecompression</c> strips that header on compressed responses (i.e. on
+    /// virtually every backend JSON response), so when it is absent the content is buffered
+    /// and the DECOMPRESSED payload size is recorded instead — before the fallback the
+    /// counter read 0 on healthy sessions. <c>HttpClient</c> buffers responses anyway
+    /// (default <c>HttpCompletionOption.ResponseContentRead</c>), so this adds no real
+    /// memory cost. The request count and failure count are always exact.
     /// </remarks>
     internal sealed class NetworkMetricsRecordingHandler : DelegatingHandler
     {
+        // Buffering cap for the bytes-down fallback. Backend responses are small JSON
+        // (config, ingest acks); anything larger is counted as 0 rather than buffered.
+        private const long MaxCountedResponseBytes = 16 * 1024 * 1024;
+
         private readonly NetworkMetrics _metrics;
 
         public NetworkMetricsRecordingHandler(NetworkMetrics metrics)
@@ -54,6 +62,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Transport
             {
                 response = await base.SendAsync(request, cancellationToken).ConfigureAwait(false);
                 bytesDown = response?.Content?.Headers?.ContentLength ?? 0L;
+                if (bytesDown == 0 && response?.Content != null)
+                {
+                    // AutomaticDecompression stripped Content-Length (the norm for the
+                    // backend's gzipped JSON). Buffer the content — after buffering the
+                    // header reflects the decompressed length. Fail-soft: a buffering
+                    // error (too large, connection dropped mid-body) keeps 0 and leaves
+                    // the response for the caller to observe the failure itself.
+                    try
+                    {
+                        await response.Content.LoadIntoBufferAsync(MaxCountedResponseBytes).ConfigureAwait(false);
+                        bytesDown = response.Content.Headers.ContentLength ?? 0L;
+                    }
+                    catch
+                    {
+                        // keep bytesDown = 0
+                    }
+                }
                 if (response != null && !response.IsSuccessStatusCode)
                 {
                     failed = true;

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

@@ -404,12 +404,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
         {
             if (state.Stage.IsTerminal()) return false;
             if (state.Stage == SessionStage.Unknown || state.Stage == SessionStage.SessionStarted) return false;
-            if (state.AccountSetupEnteredUtc == null) return false;
+
+            // WDP (afee7ae0): Device Preparation has no ESP, so neither the AccountSetup
+            // anchor nor an ESP final exit is guaranteed to exist — its dead-end zone
+            // begins at the real-user desktop instead (from there only Hello or a deadline
+            // can move the session). Normally the DevicePrepCompletion backstop armed at
+            // desktop arrival satisfies the invariant; this branch makes a regression visible.
+            var isDevicePreparation = state.ScenarioProfile.Mode == EnrollmentMode.DevicePreparation;
+            if (state.AccountSetupEnteredUtc == null && !isDevicePreparation) return false;
 
             var deadEndZoneEntered =
                 state.EspAdvisoryFailureRecordedUtc != null
-                || (state.EspFinalExitUtc != null
-                    && state.EspFinalExitUtc.Value >= state.AccountSetupEnteredUtc.Value);
+                || (state.AccountSetupEnteredUtc != null
+                    && state.EspFinalExitUtc != null
+                    && state.EspFinalExitUtc.Value >= state.AccountSetupEnteredUtc.Value)
+                || (isDevicePreparation && state.DesktopArrivedUtc != null);
             if (!deadEndZoneEntered) return false;
 
             foreach (var deadline in state.Deadlines)
@@ -431,8 +440,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                     ["stage"] = state.Stage.ToString(),
                     ["stepIndex"] = state.StepIndex.ToString(CultureInfo.InvariantCulture),
                     ["signalOrdinal"] = signal.SessionSignalOrdinal.ToString(CultureInfo.InvariantCulture),
-                    ["accountSetupEnteredUtc"] = state.AccountSetupEnteredUtc!.Value
-                        .ToString("o", CultureInfo.InvariantCulture),
+                    // Null on the WDP branch of IsParkedWithoutDeadline (no ESP anchor there).
+                    ["accountSetupEnteredUtc"] = state.AccountSetupEnteredUtc?.Value
+                        .ToString("o", CultureInfo.InvariantCulture) ?? "",
                     ["signalsSeen"] = string.Join(",", census.SignalsSeen),
                     ["armedDeadlines"] = string.Join(",", state.Deadlines.Select(d => d.Name)),
                     ["dwellSeconds"] = _parkedTripwireDwell.TotalSeconds.ToString("F0", CultureInfo.InvariantCulture),

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

@@ -74,13 +74,37 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
         private readonly string _stateDirectory;
         private readonly Persistence.StartupEventGate? _startupEventGate;
 
+        /// <summary>
+        /// How the previous agent run in this enrollment ended (<c>Program.PreviousExitSummary.ExitType</c>:
+        /// <c>first_run</c> | <c>clean</c> | <c>exception_crash</c> | <c>hard_kill</c> |
+        /// <c>reboot_kill</c>). Decides whether the Shell-Core ESP-exit replay runs at all — see
+        /// <see cref="ResolveEspExitBackfillLookbackMinutes"/>.
+        /// </summary>
+        private readonly string? _previousExitType;
+
+        /// <summary>
+        /// OS boot time when the previous agent run was killed by a reboot (<c>reboot_kill</c>),
+        /// otherwise null. One of the two inputs that size the Shell-Core ESP-exit backfill.
+        /// </summary>
+        private readonly DateTime? _previousBootUtc;
+
+        /// <summary>
+        /// Last moment the previous agent run is known to have been alive — the mtime of its
+        /// reducer snapshot, which is rewritten on every decision step. Independent of HOW that
+        /// run ended, which makes it the more broadly usable of the two window inputs.
+        /// </summary>
+        private readonly DateTime? _previousRunLastAliveUtc;
+
         public DefaultComponentFactory(
             AgentConfiguration agentConfig,
             AgentConfigResponse remoteConfig,
             NetworkMetrics? networkMetrics,
             string agentVersion,
             string stateDirectory,
-            Persistence.StartupEventGate? startupEventGate = null)
+            Persistence.StartupEventGate? startupEventGate = null,
+            DateTime? previousBootUtc = null,
+            string? previousExitType = null,
+            DateTime? previousRunLastAliveUtc = null)
         {
             _agentConfig = agentConfig ?? throw new ArgumentNullException(nameof(agentConfig));
             _remoteConfig = remoteConfig ?? throw new ArgumentNullException(nameof(remoteConfig));
@@ -88,6 +112,88 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             _agentVersion = string.IsNullOrEmpty(agentVersion) ? "unknown" : agentVersion;
             _stateDirectory = stateDirectory ?? throw new ArgumentNullException(nameof(stateDirectory));
             _startupEventGate = startupEventGate;
+            _previousBootUtc = previousBootUtc;
+            _previousExitType = previousExitType;
+            _previousRunLastAliveUtc = previousRunLastAliveUtc;
+        }
+
+        /// <summary>
+        /// Lookback in minutes for the Shell-Core ESP-exit replay; <c>0</c> means "do not replay".
+        /// <para>
+        /// The replay is a RESTART-RECOVERY mechanism: it re-reads observations the agent could not
+        /// make because no agent process was running. That only ever applies when a previous run
+        /// existed. On <c>first_run</c> — the happy path — it stays off, so the agent behaves
+        /// exactly as it did before the recovery was added.
+        /// </para>
+        /// <para>
+        /// Otherwise the window is measured rather than guessed: it reaches back to the last moment
+        /// the previous run is known to have been alive. Two independent inputs feed it and the
+        /// wider one wins, because either can be missing:
+        /// </para>
+        /// <list type="bullet">
+        ///   <item><b>Snapshot mtime</b> — the reducer snapshot is rewritten on every decision
+        ///     step, so its last-write time is "when we last knew what was happening", regardless
+        ///     of how that run ended. This is what makes <c>exception_crash</c> safe: the scheduled
+        ///     task carries a BootTrigger only, with no restart-on-failure, so a crashed agent does
+        ///     not come back until the next boot — possibly hours later, long after Windows wrote
+        ///     the final ESP exit. A fixed five minutes would lose it every time.</item>
+        ///   <item><b>Last boot</b> — populated for <c>hard_kill</c> / <c>reboot_kill</c>; covers
+        ///     the case where the snapshot is missing or was never written.</item>
+        /// </list>
+        /// <para>
+        /// The default stays the floor (a restart that returns in seconds still gets its five
+        /// minutes) and <c>ShellCoreTracker.ClampLookbackMinutes</c> is the ceiling, so policy and
+        /// backstop together can never build an unbounded event-log query.
+        /// </para>
+        /// </summary>
+        internal static int ResolveEspExitBackfillLookbackMinutes(
+            string? previousExitType,
+            DateTime? previousBootUtc,
+            DateTime? previousRunLastAliveUtc,
+            DateTime utcNow)
+        {
+            if (string.IsNullOrEmpty(previousExitType)
+                || string.Equals(previousExitType, "first_run", StringComparison.OrdinalIgnoreCase))
+            {
+                return 0;
+            }
+
+            var lookback = ShellCoreTracker.BackfillLookbackMinutes;
+
+            foreach (var since in new[] { previousRunLastAliveUtc, previousBootUtc })
+            {
+                if (!since.HasValue) continue;
+
+                var elapsed = utcNow - since.Value;
+                if (elapsed <= TimeSpan.Zero) continue;   // clock skew — never build a negative window
+
+                var minutes = (int)Math.Ceiling(elapsed.TotalMinutes) + 1;
+                if (minutes > lookback) lookback = minutes;
+            }
+
+            return lookback;
+        }
+
+        /// <summary>
+        /// Last-write time of the previous run's reducer snapshot, or null when it does not exist
+        /// (first run) or cannot be read. Best-effort by design — a missing timestamp only means
+        /// the replay window falls back to the other inputs.
+        /// </summary>
+        internal static DateTime? ReadPreviousRunLastAliveUtc(string stateDirectory)
+        {
+            try
+            {
+                if (string.IsNullOrEmpty(stateDirectory)) return null;
+                var snapshotPath = Path.Combine(
+                    stateDirectory, Persistence.DeathRattlePrelude.SnapshotFileName);
+                return File.Exists(snapshotPath)
+                    ? (DateTime?)File.GetLastWriteTimeUtc(snapshotPath)
+                    : null;
+            }
+            catch
+            {
+                return null;
+            }
         }
 
         public CollectorSurfaces CreateCollectorHosts(
@@ -109,6 +215,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             var hosts = new List<ICollectorHost>();
             var collectors = _remoteConfig.Collectors ?? CollectorConfiguration.CreateDefault();
 
+            // WDP scenario gate (afee7ae0, 2026-08-18): Device Preparation has no ESP, so the
+            // ESP-only machinery below (provisioning-status registry watcher, ESP policy-provider
+            // stall tripwire, Autopilot-channel noise) burns cycles on registry keys that never
+            // exist there — or worse, wakes up on every WDP progress write. Gated on the
+            // DETERMINISTIC WDP marker only (BootstrapperAgent ExecutionContext, present before
+            // the agent starts); the CloudAssigned* fallback rules keep full Classic behavior.
+            var isDevicePreparation = Security.EnrollmentRegistryDetector.IsDeterministicDevicePreparation();
+            if (isDevicePreparation)
+            {
+                logger.Info("DefaultComponentFactory: Device Preparation session (deterministic marker) — ESP-only hosts and Autopilot-channel noise are gated");
+            }
+
             // ----- Kernel hosts (always-on; they produce decision signals) --------------------
 
             // Single-rail refactor (plan §5.8) — DeviceInfoCollector existed in V2.Core but had
@@ -138,6 +256,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             // on esp_exiting events long after Start.
             ImeLogHost? imeLogHostRef = null;
 
+            // sits-d Cloud-PC fix (2026-08-19), narrowed after review: the Shell-Core ESP-exit
+            // replay is restart recovery, so it stays OFF on a first run and the happy path keeps
+            // its pre-fix behaviour exactly. See ResolveEspExitBackfillLookbackMinutes.
+            var espExitBackfillLookbackMinutes = ResolveEspExitBackfillLookbackMinutes(
+                _previousExitType, _previousBootUtc, _previousRunLastAliveUtc, DateTime.UtcNow);
+            if (espExitBackfillLookbackMinutes > 0)
+            {
+                logger.Info(
+                    $"DefaultComponentFactory: previous run ended as '{_previousExitType}' — Shell-Core " +
+                    $"ESP-exit replay enabled with a {espExitBackfillLookbackMinutes} min lookback");
+            }
+
             var espAndHelloHost = new EspAndHelloHost(
                 sessionId: sessionId,
                 tenantId: tenantId,
@@ -151,6 +281,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                 modernDeploymentBackfillLookbackMinutes: collectors.ModernDeploymentBackfillLookbackMinutes,
                 modernDeploymentHarmlessEventIds: collectors.ModernDeploymentHarmlessEventIds,
                 stateDirectory: _stateDirectory,
+                isDevicePreparation: isDevicePreparation,
                 userEspAppsSettledProbe: () => imeLogHostRef?.AreUserEspAppsSettled() == true,
                 // Liveness plan PR3: starved-apps probe over the same lazily-assigned IME host.
                 starvedUserEspAppsProbe: () =>
@@ -161,7 +292,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                 // covers Store/WinGet apps invisible to the starved/correlation paths.
                 packageStatesProbe: () =>
                     imeLogHostRef?.AllKnownPackageStates
-                    ?? Array.Empty<Monitoring.Enrollment.Ime.AppPackageState>());
+                    ?? Array.Empty<Monitoring.Enrollment.Ime.AppPackageState>(),
+                espExitBackfillLookbackMinutes: espExitBackfillLookbackMinutes);
             hosts.Add(espAndHelloHost);
 
             // Hybrid User-Driven completion-gap fix (2026-05-01): the AadJoinHost notifies
@@ -292,10 +424,41 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                 stateDirectory: _stateDirectory,
                 whiteGloveSealingPatternIds: whiteGloveSealingPatternIds,
                 simulationMode: simulationMode,
-                simulationSpeedFactor: _agentConfig.ReplaySpeedFactor);
+                simulationSpeedFactor: _agentConfig.ReplaySpeedFactor,
+                // Codex review P2 (2026-08-19): the IME tracker restores its persisted app states
+                // inside Start(), silently (LoadState raises no OnAppStateChanged). This host starts
+                // AFTER EspAndHelloHost, so the Shell-Core ESP-exit replay has already run against
+                // an empty app list. Nudge the synthesis once the restored level is in place —
+                // otherwise the exact reboot case (apps terminal BEFORE the reboot, only the final
+                // exit lost to the downtime) still never completes.
+                onStateRestored: () => espAndHelloHost.ReevaluateUserAppsSettledSynthesis());
             hosts.Add(imeLogHost);
             imeLogHostRef = imeLogHost;
 
+            // sits-d Cloud-PC fix (2026-08-19): the user-apps-settled AccountSetup synthesis used
+            // to run ONLY on the EspExited edge. On a tenant with a large required-app set the ESP
+            // page exits while apps are still in flight, the single attempt misses, and nothing
+            // ever re-checks — sessions 8110e262 / a89aac2d reached 138/138 apps with 0 failed and
+            // still never completed. Chain into the tracker's app-state callback (same
+            // preserve-previous pattern DeliveryOptimizationHost uses) so every terminal app
+            // transition gives the synthesis another look. Cheap: the re-check returns immediately
+            // unless the ESP exit was already observed and the synthesis has not fired yet.
+            var previousAppStateChanged = imeLogHost.Tracker.OnAppStateChanged;
+            imeLogHost.Tracker.OnAppStateChanged = (pkg, oldState, newState) =>
+            {
+                try { previousAppStateChanged?.Invoke(pkg, oldState, newState); }
+                catch (Exception ex)
+                {
+                    logger.Warning($"DefaultComponentFactory: previous OnAppStateChanged handler threw: {ex.Message}");
+                }
+
+                try { espAndHelloHost.ReevaluateUserAppsSettledSynthesis(); }
+                catch (Exception ex)
+                {
+                    logger.Warning($"DefaultComponentFactory: user-apps-settled re-check threw: {ex.Message}");
+                }
+            };
+
             if (collectors.StallProbeEnabled)
             {
                 hosts.Add(new StallProbeHost(
@@ -308,7 +471,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                     traceIndices: collectors.StallProbeTraceIndices,
                     sources: collectors.StallProbeSources,
                     sessionStalledAfterProbeIndex: collectors.SessionStalledAfterProbeIndex,
-                    harmlessModernDeploymentEventIds: collectors.ModernDeploymentHarmlessEventIds));
+                    harmlessModernDeploymentEventIds: collectors.ModernDeploymentHarmlessEventIds,
+                    isDevicePreparation: isDevicePreparation));
             }
 
             // ESP policy-provider stall tripwire — always-on kernel host (no config gate, like
@@ -317,14 +481,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             // TrackingPoliciesCreated=1 the ESP ignores foreign provider names), parks the user
             // ESP at "Apps (Identifying)" WITHOUT any OS timeout. Wall-clock dwell, deliberately
             // outside the StallProbe gate: the idle clock there resets on any session activity,
-            // and the stall must accrue regardless of it.
-            hosts.Add(new EspPolicyProviderStallHost(
-                sessionId: sessionId,
-                tenantId: tenantId,
-                logger: logger,
-                ingress: ingress,
-                clock: clock,
-                startupGate: _startupEventGate));
+            // and the stall must accrue regardless of it. Not created on Device Preparation —
+            // the EnrollmentStatusTracking key it polls every 60s is an ESP-only construct.
+            if (!isDevicePreparation)
+            {
+                hosts.Add(new EspPolicyProviderStallHost(
+                    sessionId: sessionId,
+                    tenantId: tenantId,
+                    logger: logger,
+                    ingress: ingress,
+                    clock: clock,
+                    startupGate: _startupEventGate));
+            }
 
             // Registry second pillar (audit 2026-08-17): IME's authoritative per-app state from
             // HKLM\...\IntuneManagementExtension (Win32Apps EnforcementStateMessage,

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

@@ -14,6 +14,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
 
         private readonly EspAndHelloTracker _tracker;
         private readonly EspAndHelloTrackerAdapter _adapter;
+        private readonly int _espExitBackfillLookbackMinutes;
         private int _disposed;
 
         /// <summary>
@@ -70,10 +71,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             int modernDeploymentBackfillLookbackMinutes,
             int[]? modernDeploymentHarmlessEventIds,
             string stateDirectory,
+            bool isDevicePreparation = false,
             Func<bool>? userEspAppsSettledProbe = null,
             Func<System.Collections.Generic.IReadOnlyList<Monitoring.Enrollment.Ime.AppPackageState>>? starvedUserEspAppsProbe = null,
-            Func<System.Collections.Generic.IReadOnlyList<Monitoring.Enrollment.Ime.AppPackageState>>? packageStatesProbe = null)
+            Func<System.Collections.Generic.IReadOnlyList<Monitoring.Enrollment.Ime.AppPackageState>>? packageStatesProbe = null,
+            int espExitBackfillLookbackMinutes = ShellCoreTracker.BackfillLookbackMinutes)
         {
+            _espExitBackfillLookbackMinutes = espExitBackfillLookbackMinutes;
             if (ingress == null) throw new ArgumentNullException(nameof(ingress));
             if (clock == null) throw new ArgumentNullException(nameof(clock));
             var post = new InformationalEventPost(ingress, clock);
@@ -89,6 +93,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                 modernDeploymentBackfillLookbackMinutes: modernDeploymentBackfillLookbackMinutes,
                 stateDirectory: stateDirectory,
                 modernDeploymentHarmlessEventIds: modernDeploymentHarmlessEventIds,
+                isDevicePreparation: isDevicePreparation,
                 userEspAppsSettledProbe: userEspAppsSettledProbe,
                 starvedUserEspAppsProbe: starvedUserEspAppsProbe,
                 packageStatesProbe: packageStatesProbe);
@@ -98,9 +103,56 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             _adapter = new EspAndHelloTrackerAdapter(_tracker, ingress, clock);
         }
 
-        public void Start() => _tracker.Start();
+        /// <summary>
+        /// Starts the tracker and replays the recent Shell-Core Hello-wizard start — restart
+        /// recovery for an observation no agent process was around to make.
+        /// <para>
+        /// The backfill has existed since session 772fe502 but was never wired to a caller, so
+        /// the Shell-Core watcher only ever saw events written AFTER <see cref="Start"/>. Any
+        /// agent restart therefore lost an ESP exit (62407) or Hello-wizard start (62404) that
+        /// happened while the agent was down — and after a mid-ESP reboot that is exactly the
+        /// window the completion signal lands in (sits-d Cloud PCs, 2026-08-19: five sessions
+        /// hung in AccountSetup until the server-side timeout while the devices were fine).
+        /// </para>
+        /// <para>
+        /// A lookback of zero disables the replay entirely. That is the FIRST run of an enrollment:
+        /// there is no gap to recover because no earlier agent process existed, and any 62407
+        /// already in the log belongs to a phase transition that happened before this agent was
+        /// ever meant to observe anything. Replaying it would push an <c>EspExiting</c> into the
+        /// reducer that the pre-fix agent never saw — a happy-path behaviour change for no gain.
+        /// The caller (<c>DefaultComponentFactory</c>) owns that policy.
+        /// </para>
+        /// </summary>
+        /// <para>
+        /// Ordering is deliberate: Start first, then replay. A record written between the two is
+        /// observed twice, which the wizard rail already tolerates (single-shot replay guard, plus
+        /// the HelloTracker once-guard and the adapter's dedup flag downstream). The reverse order
+        /// could drop a record entirely.
+        /// </para>
+        /// <para>
+        /// The replay covers the Hello-wizard start only — a conservative fact that can make the
+        /// agent wait longer but never finish early. ESP exits are deliberately excluded because a
+        /// replayed 62407 cannot be placed in time; see
+        /// <c>ShellCoreTracker.ReplayBackfillRecords</c>.
+        /// </para>
+        /// </summary>
+        public void Start()
+        {
+            _tracker.Start();
+
+            if (_espExitBackfillLookbackMinutes > 0)
+                _tracker.BackfillRecentHelloWizardStart(_espExitBackfillLookbackMinutes);
+        }
+
         public void Stop() => _tracker.Stop();
 
+        /// <summary>
+        /// Re-checks the user-apps-settled AccountSetup synthesis — see
+        /// <see cref="EspAndHelloTracker.ReevaluateUserAppsSettledSynthesis"/>. Driven by the IME
+        /// tracker's app-state-change callback (wired in <c>DefaultComponentFactory</c>).
+        /// </summary>
+        public void ReevaluateUserAppsSettledSynthesis() => _tracker.ReevaluateUserAppsSettledSynthesis();
+
         private void OnTrackerWhiteGloveCompleted(object sender, EventArgs e)
             => WhiteGloveCompleted?.Invoke(this, e);
 

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

@@ -18,6 +18,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
 
         private readonly ImeLogTracker _tracker;
         private readonly ImeProcessWatcher _processWatcher;
+        private readonly Action? _onStateRestored;
         private readonly ImeLogTrackerAdapter _adapter;
         private readonly AgentLogger _logger;
         private int _disposed;
@@ -96,9 +97,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             string stateDirectory,
             IReadOnlyCollection<string>? whiteGloveSealingPatternIds,
             bool simulationMode = false,
-            double simulationSpeedFactor = 50)
+            double simulationSpeedFactor = 50,
+            Action? onStateRestored = null)
         {
             _logger = logger;
+            _onStateRestored = onStateRestored;
             var logFolder = string.IsNullOrEmpty(imeLogPathOverride) ? DefaultImeLogFolder : imeLogPathOverride!;
             var expandedMatchLogPath = string.IsNullOrEmpty(imeMatchLogPath)
                 ? null
@@ -128,10 +131,24 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             _processWatcher = new ImeProcessWatcher(sessionId, tenantId, processWatcherPost, logger);
         }
 
+        /// <summary>
+        /// Codex review P2 (2026-08-19) — <see cref="ImeLogTracker.Start"/> restores the persisted
+        /// package states (LoadState) and does NOT raise <c>OnAppStateChanged</c> for them. This
+        /// host is started AFTER <c>EspAndHelloHost</c>, so a LIVE ESP exit observed before this
+        /// restore completes would evaluate the user-apps-settled synthesis against an empty app
+        /// list — and without a nudge here nothing would ever re-check the restored level. The
+        /// <c>onStateRestored</c> callback fires once, after the restore, so the deferred
+        /// synthesis gets its look. (It deliberately covers ONLY live exits: a 62407 that fired
+        /// while no agent was running is never replayed — see
+        /// <c>ShellCoreTracker.ReplayBackfillRecords</c> for why it cannot be placed in time.)
+        /// </summary>
         public void Start()
         {
             _tracker.Start();
             _processWatcher.Start();
+
+            try { _onStateRestored?.Invoke(); }
+            catch (Exception ex) { _logger.Warning($"ImeLogHost: onStateRestored callback threw: {ex.Message}"); }
         }
 
         public void Stop()

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

@@ -57,7 +57,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
             int[]? traceIndices,
             string[]? sources,
             int sessionStalledAfterProbeIndex,
-            int[]? harmlessModernDeploymentEventIds)
+            int[]? harmlessModernDeploymentEventIds,
+            bool isDevicePreparation = false)
         {
             if (ingress == null) throw new ArgumentNullException(nameof(ingress));
             if (clock == null) throw new ArgumentNullException(nameof(clock));
@@ -72,7 +73,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                 traceIndices: traceIndices ?? new[] { 2 },
                 sources: sources ?? new[] { "provisioning_registry", "diagnostics_registry", "eventlog", "appworkload_log" },
                 sessionStalledAfterProbeIndex: sessionStalledAfterProbeIndex,
-                harmlessModernDeploymentEventIds: harmlessModernDeploymentEventIds);
+                harmlessModernDeploymentEventIds: harmlessModernDeploymentEventIds,
+                isDevicePreparation: isDevicePreparation);
 
             _adapter = new StallProbeCollectorAdapter(_collector, ingress, clock);
             _observableIngress = ingress as SignalIngress;

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

@@ -188,6 +188,26 @@ namespace AutopilotMonitor.Agent.V2.Core.Security
         /// </summary>
         public static string DetectEnrollmentType() => DetectEnrollmentTypeWithRule().enrollmentType;
 
+        /// <summary>
+        /// Rule string returned when the deterministic Device Preparation marker fired
+        /// (the WDP policy orchestration tree — see <see cref="DetectEnrollmentTypeWithRule"/>).
+        /// </summary>
+        public const string DevicePreparationExecutionContextRule =
+            @"DevicePreparation\BootstrapperAgent\ExecutionContext present";
+
+        /// <summary>
+        /// True only when the deterministic Device Preparation marker (BootstrapperAgent
+        /// ExecutionContext) is present. Scenario gates that DISABLE Autopilot/ESP-only
+        /// machinery must use this instead of the "v2" string: the CloudAssigned* fallback
+        /// rules describe a real Autopilot profile (just without ESP) where that machinery
+        /// still has data to observe — gates fail toward Classic behavior by design.
+        /// </summary>
+        public static bool IsDeterministicDevicePreparation()
+        {
+            var (enrollmentType, detectionRule) = DetectEnrollmentTypeWithRule();
+            return enrollmentType == "v2" && detectionRule == DevicePreparationExecutionContextRule;
+        }
+
         /// <summary>
         /// Same as <see cref="DetectEnrollmentType"/> but also returns WHICH rule fired, so the
         /// enrollment_type_detected event can name its evidence instead of re-implementing the
@@ -203,7 +223,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Security
                 {
                     var executionContext = wdpKey?.GetValue("ExecutionContext")?.ToString();
                     if (!string.IsNullOrEmpty(executionContext))
-                        return ("v2", @"DevicePreparation\BootstrapperAgent\ExecutionContext present");
+                        return ("v2", DevicePreparationExecutionContextRule);
                 }
 
                 using (var key = Registry.LocalMachine.OpenSubKey(AutopilotSettingsKey))

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

@@ -124,6 +124,17 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
         // in ImeLogTracker so the layers can never drift apart).
         private static readonly TimeSpan StaleSourceThreshold = ImeLogTracker.HistoricReplayThreshold;
 
+        /// <summary>
+        /// How far ahead of the agent clock a source timestamp may sit before it is rejected.
+        /// <para>
+        /// Writer and reader share one system clock, so a correctly converted line is always at
+        /// or behind "now"; this is pure jitter tolerance, not a skew allowance. Deliberately far
+        /// below one hour — the value that a timezone mistake produces — so that such a mistake
+        /// can actually trip it.
+        /// </para>
+        /// </summary>
+        private static readonly TimeSpan MaxFutureSourceSkew = TimeSpan.FromMinutes(2);
+
         // Matches the deterministic marker line the bootstrap script writes via Write-Log,
         // e.g. "Bootstrap script version: v2.0" — see scripts/Bootstrap/Install-AutopilotMonitor.ps1.
         // Same shape as the web-side regex in utils/bootstrapVersion.ts; kept in sync intentionally.
@@ -329,12 +340,28 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
 
                 var clockNow = _clock.UtcNow;
                 var ageHours = (clockNow - asUtc).TotalHours;
-                if (ageHours > StaleSourceThreshold.TotalHours || ageHours < -1.0)
+
+                // Future guard. A source timestamp can never legitimately be ahead of the agent
+                // clock: the writer stamps it from the SAME system clock, and the tracker only
+                // sees the line after it was written. Anything ahead means the local-to-UTC
+                // conversion was wrong.
+                //
+                // The previous threshold was ageHours < -1.0, which could not fire for the single
+                // most common timezone error: with a one-hour offset mistake the real value is
+                // parseLag - 3600 s, i.e. just ABOVE -1.0. It sat exactly on the boundary of the
+                // case it was meant to catch. It was also asymmetric — a past-shifted error had to
+                // exceed 24 h before anything noticed, while the measured field errors reached
+                // -17 h. The bound is now a small jitter tolerance in the direction that is
+                // physically impossible.
+                var isFutureSkewed = asUtc > clockNow + MaxFutureSourceSkew;
+
+                if (ageHours > StaleSourceThreshold.TotalHours || isFutureSkewed)
                 {
-                    // Pathologically stale (>24h old) or in the future (>1h skew) — log,
-                    // fall back, and let the caller flag the event.
+                    var reason = isFutureSkewed
+                        ? $"ahead of the agent clock by {(asUtc - clockNow).TotalMinutes:F1} min"
+                        : $"pathologically stale (ageHours={ageHours:F1})";
                     _logger?.Warning(
-                        $"ImeAdapter: source timestamp {asUtc:o} rejected (ageHours={ageHours:F1}); falling back to clock");
+                        $"ImeAdapter: source timestamp {asUtc:o} rejected — {reason}; falling back to clock");
                     derivedFromClock = true;
                     return clockNow;
                 }
@@ -347,12 +374,69 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
             return _clock.UtcNow;
         }
 
-        private static void TagDerivedTimestamp(IDictionary<string, string> data, bool derivedFromClock, DateTime? rawSourceTs)
+        /// <summary>
+        /// Attach the evidence for this event's timestamp: the raw local time as the writer wrote
+        /// it, the offset applied, and how that offset was obtained.
+        ///
+        /// <para>
+        /// Without this the only record of a conversion is the converted value itself, so a wrong
+        /// offset is indistinguishable from a correct one. Proving the field defect required the
+        /// diagnostics archive — and of the 5,386 sessions that went through a timezone change,
+        /// essentially none had one; the analysis had to fall back to median statistics across
+        /// thousands of sessions. These three fields make each session answer the question on its
+        /// own, and make a stored timestamp recomputable after the fact without an agent release.
+        /// </para>
+        ///
+        /// <para>
+        /// Only emitted for events whose time came from a CMTrace line. Agent-native events have
+        /// no second clock frame, so there is nothing to record.
+        /// </para>
+        /// </summary>
+        private void TagDerivedTimestamp(IDictionary<string, string> data, bool derivedFromClock, DateTime? rawSourceTs)
         {
+            var culture = System.Globalization.CultureInfo.InvariantCulture;
+
+            var sourceLocal = _tracker.LastMatchedSourceLocalTimestamp;
+            if (sourceLocal.HasValue)
+            {
+                // No zone suffix: the value genuinely carries none, and formatting one in would
+                // re-introduce the very assumption this whole change removes.
+                data["sourceLocalTs"] = sourceLocal.Value.ToString("yyyy-MM-ddTHH:mm:ss.fffffff", culture);
+                data["sourceOffsetOrigin"] = OriginTag(_tracker.LastMatchedSourceOffsetOrigin);
+
+                var offsetMinutes = _tracker.LastMatchedSourceOffsetMinutes;
+                if (offsetMinutes.HasValue)
+                    data["sourceOffsetMinutes"] = offsetMinutes.Value.ToString(culture);
+
+                // Observational only — what the calibrator measured, which since the 2026-08-20
+                // revert is deliberately NOT what was applied. Kept separate so the two can never
+                // be read as the same thing.
+                var measured = _tracker.LastMatchedMeasuredWriterOffsetMinutes;
+                if (measured.HasValue)
+                    data["measuredWriterOffsetMinutes"] = measured.Value.ToString(culture);
+            }
+
             if (!derivedFromClock) return;
             data["derivedTimestamp"] = "true";
             if (rawSourceTs.HasValue)
-                data["rejectedSourceTimestamp"] = rawSourceTs.Value.ToString("o", System.Globalization.CultureInfo.InvariantCulture);
+                data["rejectedSourceTimestamp"] = rawSourceTs.Value.ToString("o", culture);
+        }
+
+        private static string OriginTag(CmTraceOffsetOrigin origin)
+        {
+            switch (origin)
+            {
+                case CmTraceOffsetOrigin.Bias: return "bias";
+                // Per-FILE offset application, retired by the 2026-08-20 revert (04b1a7c6).
+                // Kept so stored 2.0.1410 events remain interpretable; no current path emits it.
+                case CmTraceOffsetOrigin.Calibrated: return "calibrated";
+                // The line anchored itself: read provably fresh, its own distance to the agent
+                // clock (grid-rounded) was applied as the writer's offset. Era-safe per line.
+                case CmTraceOffsetOrigin.LineAnchored: return "line-anchored";
+                // The line was not provably fresh (backlog, restart catch-up, replay), so this
+                // process's own zone was assumed — correct only if the writer happens to share it.
+                default: return "reader-zone-fallback";
+            }
         }
 
         // CMTrace Kind normalization — shared implementation lives on the tracker (used by its

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

@@ -228,7 +228,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
                     // Runs on every outcome; the live (esp_exited) path's dedupe set is
                     // consulted so no app is reported twice. Promoted likely-stuck apps are
                     // Error by now and excluded by the probe itself.
-                    EmitStarvedUserEspApps(args);
+                    EmitStarvedUserEspApps(state, args);
 
                     // Session 6b4993e5 / fc48c71a — on an ESP terminal Apps-subcategory failure,
                     // name the in-flight device app(s) (e.g. stuck Downloading at 0%) as the likely
@@ -557,7 +557,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
         /// wording; Failed/TimedOut keep the Warning + "starved" verdict.
         /// </para>
         /// </summary>
-        private void EmitStarvedUserEspApps(EnrollmentTerminatedEventArgs args)
+        private void EmitStarvedUserEspApps(DecisionState state, EnrollmentTerminatedEventArgs args)
         {
             if (_post == null) return;
 
@@ -566,6 +566,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Termination
                 var starved = _appTracking.GetStarvedUserEspApps();
                 if (starved == null || starved.Count == 0) return;
 
+                // Device Preparation has no ESP apps gate — installing after the desktop is
+                // the DESIGNED order there (only DPP-policy apps run during provisioning, the
+                // rest follow via IME). Reporting every pending app as "starved" turned a
+                // normal WDP session into 10+ noise events (afee7ae0); the same per-app data
+                // still reaches the backend via app_tracking_summary and final-status.json.
+                if (state?.ScenarioProfile.Mode == EnrollmentMode.DevicePreparation)
+                {
+                    _logger.Info(
+                        $"EnrollmentTerminationHandler: {starved.Count} app(s) pending at termination on a " +
+                        "DevicePreparation session — expected post-desktop install order, app_install_starved sweep skipped.");
+                    return;
+                }
+
                 var succeeded = args.Outcome == EnrollmentTerminationOutcome.Succeeded;
 
                 foreach (var app in starved)

src/Agent/AutopilotMonitor.Agent.V2.Core/Transport/Telemetry/BackendTelemetryUploader.cs

@@ -119,6 +119,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Transport.Telemetry
                 AddSecurityHeaders(request);
                 request.Headers.Add("X-Correlation-ID", correlationId);
 
+                // P14: device-clock send time, one value per request. Lets the backend separate
+                // spool delay (SentAt − OccurredUtc, both device frame) from device-vs-server
+                // clock offset (ReceivedAt − SentAt) — indistinguishable without this header.
+                // Stamped per attempt on purpose: a retry after backoff is a NEW send moment.
+                request.Headers.Add("X-Send-Time-Utc", DateTime.UtcNow.ToString("O"));
+
                 HttpResponseMessage response;
                 try
                 {

src/Agent/AutopilotMonitor.Agent.V2.Core/Transport/Telemetry/ITelemetrySpool.cs

@@ -59,10 +59,20 @@ namespace AutopilotMonitor.Agent.V2.Core.Transport.Telemetry
         /// </summary>
         int PeakPendingItemCount { get; }
 
+        /// <summary>
+        /// Serialized on-disk byte size of the pending (not-yet-uploaded) tail — the actual
+        /// upload backlog. Unlike <see cref="SpoolFileSizeBytes"/>, which grows append-only
+        /// over the whole session regardless of upload progress, this shrinks back to 0 as
+        /// <see cref="MarkUploaded"/> advances the cursor, so it is the correct input for
+        /// back-pressure thresholds.
+        /// </summary>
+        long PendingBytes { get; }
+
         /// <summary>
         /// Current size of the on-disk <c>spool.jsonl</c> file in bytes. Returns 0 when the
         /// file does not yet exist. Cheap (single <c>FileInfo.Length</c> call) and safe to
-        /// poll from periodic collectors.
+        /// poll from periodic collectors. Append-only cumulative — informational only, NOT a
+        /// backlog measure (use <see cref="PendingBytes"/> for that).
         /// </summary>
         long SpoolFileSizeBytes { get; }
 

src/Agent/AutopilotMonitor.Agent.V2.Core/Transport/Telemetry/TelemetrySpool.cs

@@ -56,9 +56,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Transport.Telemetry
         // Populated from disk in the ctor and kept in sync by Enqueue / MarkUploaded. Peek
         // reads from here so the periodic drain loop is O(batchSize) instead of O(N) per
         // call. Disk JSONL stays the source of truth — the cache is rebuilt on every
-        // process start.
-        private readonly LinkedList<TelemetryItem> _pending = new LinkedList<TelemetryItem>();
+        // process start. Each entry carries its on-disk line length (incl. trailing \n) so
+        // MarkUploaded can decrement _pendingBytes exactly.
+        private readonly LinkedList<PendingEntry> _pending = new LinkedList<PendingEntry>();
         private int _peakPendingCount;
+        private long _pendingBytes;
+
+        private readonly struct PendingEntry
+        {
+            public PendingEntry(TelemetryItem item, int byteLength)
+            {
+                Item = item;
+                ByteLength = byteLength;
+            }
+
+            public TelemetryItem Item { get; }
+            public int ByteLength { get; }
+        }
 
         public TelemetrySpool(string directoryPath, IClock clock, Logging.AgentLogger? logger = null)
         {
@@ -105,6 +119,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Transport.Telemetry
             get { lock (_lock) return _peakPendingCount; }
         }
 
+        public long PendingBytes
+        {
+            get { lock (_lock) return _pendingBytes; }
+        }
+
         public long SpoolFileSizeBytes
         {
             get
@@ -171,7 +190,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Transport.Telemetry
                 }
 
                 _lastAssignedItemId = itemId;
-                _pending.AddLast(item);
+                _pending.AddLast(new PendingEntry(item, bytes.Length));
+                _pendingBytes += bytes.Length;
                 if (_pending.Count > _peakPendingCount)
                     _peakPendingCount = _pending.Count;
 
@@ -209,7 +229,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Transport.Telemetry
                 var node = _pending.First;
                 while (node != null && batch.Count < max)
                 {
-                    batch.Add(node.Value);
+                    batch.Add(node.Value.Item);
                     node = node.Next;
                 }
                 return batch;
@@ -233,25 +253,38 @@ namespace AutopilotMonitor.Agent.V2.Core.Transport.Telemetry
                 // Trim the in-memory tail. The list is in TelemetryItemId-monotonic order
                 // (Enqueue only appends), so we can drop from the front until the first
                 // remaining item is past the cursor.
-                while (_pending.First != null && _pending.First.Value.TelemetryItemId <= upToItemIdInclusive)
+                while (_pending.First != null && _pending.First.Value.Item.TelemetryItemId <= upToItemIdInclusive)
                 {
+                    _pendingBytes -= _pending.First.Value.ByteLength;
                     _pending.RemoveFirst();
                 }
+
+                // _pendingBytes drives the spool-pressure trigger: negative drift would
+                // silently disarm it, a stale positive on an empty list would pin it on.
+                // The list is authoritative — on drift, recompute from it and log loudly.
+                if (_pendingBytes < 0 || (_pending.Count == 0 && _pendingBytes != 0))
+                {
+                    long recomputed = 0;
+                    foreach (var entry in _pending) recomputed += entry.ByteLength;
+                    _logger?.Warning(
+                        $"TelemetrySpool: pending-bytes accounting drifted to {_pendingBytes} with {_pending.Count} pending items after MarkUploaded({upToItemIdInclusive}) — recomputed to {recomputed}.");
+                    _pendingBytes = recomputed;
+                }
             }
         }
 
         /// <summary>
-        /// Single-pass scan of <c>spool.jsonl</c>: returns the highest <c>TelemetryItemId</c>
-        /// found AND populates <see cref="_pending"/> with every item past
-        /// <see cref="_lastUploadedItemId"/>. Called once from the ctor — replaces the
-        /// previous per-Peek <c>File.ReadAllLines</c> hot path.
+        /// Single-pass streaming scan of <c>spool.jsonl</c> (<c>File.ReadLines</c> — never
+        /// materializes the whole file): returns the highest <c>TelemetryItemId</c> found AND
+        /// populates <see cref="_pending"/> / <see cref="_pendingBytes"/> with every item past
+        /// <see cref="_lastUploadedItemId"/>. Called once from the ctor.
         /// </summary>
         private long ScanSpoolAndRehydratePending()
         {
             if (!File.Exists(_spoolPath)) return -1;
 
             long highest = -1;
-            foreach (var line in File.ReadAllLines(_spoolPath, Encoding.UTF8))
+            foreach (var line in File.ReadLines(_spoolPath, Encoding.UTF8))
             {
                 if (string.IsNullOrWhiteSpace(line)) continue;
                 TelemetryItem item;
@@ -270,7 +303,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Transport.Telemetry
                 if (item.TelemetryItemId > highest) highest = item.TelemetryItemId;
                 if (item.TelemetryItemId > _lastUploadedItemId)
                 {
-                    _pending.AddLast(item);
+                    // +1 = the trailing \n Enqueue writes after every line, so the rehydrated
+                    // byte count matches what Enqueue would have accumulated.
+                    var byteLength = Encoding.UTF8.GetByteCount(line) + 1;
+                    _pending.AddLast(new PendingEntry(item, byteLength));
+                    _pendingBytes += byteLength;
                 }
             }
             return highest;

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

@@ -79,13 +79,27 @@ namespace AutopilotMonitor.Agent.V2.Runtime
             // write to the same state file; per-enrollment lifecycle like the other state files.
             var startupEventGate = new AutopilotMonitor.Agent.V2.Core.Persistence.StartupEventGate(stateSubdir, logger);
 
+            // sits-d Cloud-PC fix (2026-08-19): a reboot_kill means the agent was down across the
+            // forced mid-ESP restart. Hand the boot timestamp to the factory so the Shell-Core
+            // ESP-exit backfill can reach back over the whole downtime instead of 5 minutes.
+            var previousBootUtc =
+                string.Equals(previousExit?.ExitType, "reboot_kill", StringComparison.OrdinalIgnoreCase)
+                    ? previousExit?.LastBootUtc
+                    : null;
+
             var componentFactory = new DefaultComponentFactory(
                 agentConfig: agentConfig,
                 remoteConfig: remoteConfig,
                 networkMetrics: auth.NetworkMetrics,
                 agentVersion: agentVersion,
                 stateDirectory: stateSubdir,
-                startupEventGate: startupEventGate);
+                startupEventGate: startupEventGate,
+                previousBootUtc: previousBootUtc,
+                previousExitType: previousExit?.ExitType,
+                // Measured, not guessed: the reducer snapshot is rewritten on every decision step,
+                // so its mtime is the last moment the previous run is known to have been alive —
+                // and unlike LastBootUtc it exists for every exit type, exception_crash included.
+                previousRunLastAliveUtc: DefaultComponentFactory.ReadPreviousRunLastAliveUtc(stateSubdir));
 
             var whiteGloveSealingPatternIds = (System.Collections.Generic.IReadOnlyCollection<string>)remoteConfig.WhiteGloveSealingPatternIds
                 ?? Array.Empty<string>();

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

@@ -306,7 +306,12 @@ namespace AutopilotMonitor.Agent.V2.Runtime
         {
             try
             {
-                var enrollmentType = EnrollmentRegistryDetector.DetectEnrollmentType();
+                var (enrollmentType, detectionRule) = EnrollmentRegistryDetector.DetectEnrollmentTypeWithRule();
+                // High-confidence WDP seed only for the deterministic marker — the
+                // CloudAssigned* fallback rules keep the Medium seed (see the payload
+                // key's doc on SignalPayloadKeys.EnrollmentTypeDeterministic).
+                var deterministicWdp = enrollmentType == "v2"
+                    && detectionRule == EnrollmentRegistryDetector.DevicePreparationExecutionContextRule;
                 var isHybridJoin = EnrollmentRegistryDetector.DetectHybridJoin();
                 var isSelfDeploying = EnrollmentRegistryDetector.DetectSelfDeployingProfile();
                 var isCloudPc = CloudPcDetector.DetectIsCloudPc();
@@ -314,6 +319,7 @@ namespace AutopilotMonitor.Agent.V2.Runtime
                 var payload = new Dictionary<string, string>(StringComparer.Ordinal)
                 {
                     ["enrollmentType"] = enrollmentType,
+                    ["enrollmentTypeDeterministic"] = deterministicWdp ? "true" : "false",
                     ["isHybridJoin"] = isHybridJoin ? "true" : "false",
                     ["isSelfDeployingProfile"] = isSelfDeploying ? "true" : "false",
                     ["isCloudPc"] = isCloudPc ? "true" : "false",

src/Agent/AutopilotMonitor.DecisionCore.Tests/ClassicEspExitingOnRestoredStateTests.cs

@@ -0,0 +1,141 @@
+using System;
+using System.Collections.Generic;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.DecisionCore.State;
+using Xunit;
+
+namespace AutopilotMonitor.DecisionCore.Tests
+{
+    /// <summary>
+    /// The reducer half of the "a replayed 62407 must never reach the decision engine" contract
+    /// (2026-08-19). The agent half — ShellCoreTracker never re-raising a replayed exit — lives in
+    /// <c>ShellCoreTrackerReplayScopeTests</c>; this file proves WHY that upstream restriction is
+    /// the only place the problem can be solved.
+    /// <para>
+    /// The reducer is itself a completion gate, and by design it cannot tell a replayed exit from
+    /// a live one:
+    /// </para>
+    /// <list type="bullet">
+    ///   <item><c>HandleEspExitingV1</c> passes <c>espFinalExitInFlight: true</c> for EVERY
+    ///     arriving exit — the signal carries no provenance.</item>
+    ///   <item><c>IsPostAccountSetupFinalExit</c> orders exits by INGEST ORDINAL rather than by
+    ///     timestamp (deliberately: replayed CMTrace lines carry backdated source times). A
+    ///     historic exit replayed today is assigned a fresher ordinal than reality, so it reads as
+    ///     post-AccountSetup by construction.</item>
+    /// </list>
+    /// <para>
+    /// After a restart the state is restored from the snapshot, so AccountSetupEntered, the IME
+    /// user-session completion and the desktop arrival are all already present. Arm C of
+    /// <c>ShouldTransitionToAwaitingHello</c> then needs exactly one more fact: an exit. These
+    /// tests pin that it opens — which is correct behaviour for a live exit and would be a
+    /// premature completion for a replayed one. Hence the upstream ban.
+    /// </para>
+    /// </summary>
+    public sealed class ClassicEspExitingOnRestoredStateTests
+    {
+        private static readonly DateTime Fixed = new DateTime(2026, 8, 19, 8, 43, 16, DateTimeKind.Utc);
+
+        [Fact]
+        public void Arm_C_opens_on_any_arriving_exit_once_restored_state_carries_the_other_three_facts()
+        {
+            // This is the danger, stated as a test: with restored facts in place, a single
+            // EspExiting signal is all that separates EspAccountSetup from AwaitingHello. The
+            // reducer has no way to ask "was that exit real, or did we dig it out of the event
+            // log?" — so the answer has to be that a replayed exit is never turned into a signal.
+            var engine = new DecisionEngine();
+            var state = BuildRestoredState(
+                accountSetupEntered: true,
+                imeUserSessionCompleted: true,
+                desktopArrived: true);
+
+            var step = engine.Reduce(state, MakeEspExitingSignal(ordinal: 10));
+
+            Assert.Equal(SessionStage.AwaitingHello, step.NewState.Stage);
+        }
+
+        [Theory]
+        // Each row drops exactly one of arm C's mandatory facts — the transition must not happen.
+        [InlineData(false, true, true)]
+        [InlineData(true, false, true)]
+        [InlineData(true, true, false)]
+        public void Arm_C_stays_shut_when_any_of_its_mandatory_facts_is_missing(
+            bool accountSetupEntered, bool imeUserSessionCompleted, bool desktopArrived)
+        {
+            var engine = new DecisionEngine();
+            var state = BuildRestoredState(accountSetupEntered, imeUserSessionCompleted, desktopArrived);
+
+            var step = engine.Reduce(state, MakeEspExitingSignal(ordinal: 10));
+
+            Assert.NotEqual(SessionStage.AwaitingHello, step.NewState.Stage);
+        }
+
+        [Fact]
+        public void A_historic_source_timestamp_does_not_hold_the_gate_shut()
+        {
+            // The exit's OccurredAtUtc is an hour older than the AccountSetup anchor — exactly the
+            // shape a replayed record has. It makes no difference: the ordering that arm C uses is
+            // the ingest ordinal, and the in-flight flag bypasses even that. Timestamps are not a
+            // defence, which is why the fix cannot live in the reducer.
+            var engine = new DecisionEngine();
+            var state = BuildRestoredState(
+                accountSetupEntered: true,
+                imeUserSessionCompleted: true,
+                desktopArrived: true);
+
+            var step = engine.Reduce(
+                state,
+                MakeEspExitingSignal(ordinal: 10, occurredAtUtc: Fixed.AddHours(-1)));
+
+            Assert.Equal(SessionStage.AwaitingHello, step.NewState.Stage);
+        }
+
+        // ------------------------------------------------------------------------------
+
+        private static DecisionState BuildRestoredState(
+            bool accountSetupEntered,
+            bool imeUserSessionCompleted,
+            bool desktopArrived)
+        {
+            var anchor = Fixed.AddMinutes(-90);
+
+            var builder = DecisionState.CreateInitial("s", "t", Fixed.AddDays(-1))
+                .ToBuilder()
+                .WithStage(SessionStage.EspAccountSetup)
+                .WithStepIndex(452)             // the restored StepIndex the sits-d sessions showed
+                .WithLastAppliedSignalOrdinal(9);
+
+            if (accountSetupEntered)
+                builder.AccountSetupEnteredUtc = new SignalFact<DateTime>(anchor, 1);
+
+            // IsImeUserSessionGenuine requires the completion to be at-or-after the AccountSetup
+            // anchor (the defaultuser0-ghost guard).
+            if (imeUserSessionCompleted)
+                builder.ImeUserSessionCompletedUtc = new SignalFact<DateTime>(anchor.AddMinutes(5), 2);
+
+            if (desktopArrived)
+                builder.DesktopArrivedUtc = new SignalFact<DateTime>(anchor.AddMinutes(6), 3);
+
+            return builder.Build();
+        }
+
+        private static DecisionSignal MakeEspExitingSignal(long ordinal, DateTime? occurredAtUtc = null) =>
+            new DecisionSignal(
+                sessionSignalOrdinal: ordinal,
+                sessionTraceOrdinal: ordinal,
+                kind: DecisionSignalKind.EspExiting,
+                kindSchemaVersion: 1,
+                occurredAtUtc: occurredAtUtc ?? Fixed,
+                sourceOrigin: "EspAndHelloTracker",
+                evidence: new Evidence(
+                    kind: EvidenceKind.Derived,
+                    identifier: "esp-hello-detector-v1",
+                    summary: "ESP exiting (coordinator-forwarded Shell-Core 62407)",
+                    derivationInputs: new Dictionary<string, string>(StringComparer.Ordinal)
+                    {
+                        ["subSource"] = "ShellCoreTracker",
+                        ["eventSource"] = "Microsoft-Windows-Shell-Core",
+                        ["eventId"] = "62407",
+                    }));
+    }
+}

src/Agent/AutopilotMonitor.DecisionCore.Tests/ClassicSkipUserEspUserSessionCompletionTests.cs

@@ -0,0 +1,286 @@
+using System;
+using System.Collections.Generic;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.DecisionCore.State;
+using Xunit;
+
+namespace AutopilotMonitor.DecisionCore.Tests
+{
+    /// <summary>
+    /// sits-d Cloud-PC fix (2026-08-20, sessions 8110e262 / a89aac2d / e7ba63c9 / cb4a485a /
+    /// 3d6278fb). On a SkipUser=true flow Windows never renders the user ESP page: Shell-Core
+    /// 62407 does not fire and the AccountSetup provisioning categories are never written —
+    /// verified live (Shell-Core watcher armed across three agent runs, zero 62407 in six
+    /// hours; SkipUserStatusPage read 10+ times across all runs, True every time). Arm B of
+    /// <c>ShouldTransitionToAwaitingHello</c> was therefore open from the bootstrap
+    /// EspConfigDetected onward, but every site that evaluates the gate hangs off a signal the
+    /// flow structurally cannot produce, so five sessions sat at "waiting on: hello_resolution"
+    /// until the max-lifetime watchdog.
+    /// <para>
+    /// The fix lets the observed skip stand in for the final-exit evidence inside
+    /// <c>HandleImeUserSessionCompletedV1</c>'s completion attempt. These tests replay the real
+    /// 8110e262 signal ordering end to end (including the Fix-10 AccountSetup bounce-back a
+    /// restart re-emission triggers) and pin the negative space: no skip observed, no desktop,
+    /// ghost IME completion, and Device Preparation flows are all unchanged.
+    /// </para>
+    /// </summary>
+    public sealed class ClassicSkipUserEspUserSessionCompletionTests
+    {
+        // 8110e262 run 1: agent_started 08:30:08Z.
+        private static readonly DateTime T0 = new DateTime(2026, 8, 19, 8, 30, 8, DateTimeKind.Utc);
+
+        [Fact]
+        public void Sits_d_signal_ordering_completes_via_hello_safety()
+        {
+            var engine = new DecisionEngine();
+            var state = DecisionState.CreateInitial(
+                "8110e262-da57-4282-9290-bb0c96d05614", "5ca2b350", T0);
+
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0, null)).NewState;
+
+            // Bootstrap EspConfigDetected — SkipUserStatusPage=True, read from FirstSync 2 s in.
+            state = engine.Reduce(state, MakeEspConfigSignal(1, skipUser: "true")).NewState;
+            Assert.True(state.ScenarioObservations.SkipUserEsp!.Value);
+
+            // Hello policy enabled (device-scoped CSP) — the reason the desktop fast-path
+            // could never take this flow.
+            state = engine.Reduce(state, MakeSignal(2, DecisionSignalKind.HelloPolicyDetected, T0.AddSeconds(1),
+                new Dictionary<string, string> { [SignalPayloadKeys.HelloEnabled] = "true" })).NewState;
+
+            // Desktop 5 s after agent start (the user ESP page does not exist — the user is
+            // simply logged on). Pins that desktop arrival alone does NOT promote: the knock
+            // deliberately lives on the IME user-session edge, because a desktop-side promotion
+            // would be undone by Fix 10's AccountSetup bounce-back two signals later (the IME
+            // AccountSetup phase line lands AFTER the desktop on this flow).
+            state = engine.Reduce(state, MakeSignal(3, DecisionSignalKind.DesktopArrived, T0.AddSeconds(5), null)).NewState;
+            Assert.NotEqual(SessionStage.AwaitingHello, state.Stage);
+            Assert.DoesNotContain(state.Deadlines, d => d.Name == DeadlineNames.HelloSafety);
+
+            // IME's AccountSetup phase line (source ts 08:29:56 — before agent start; the IME
+            // logs the phase for its user-session app processing even though no page is shown).
+            state = engine.Reduce(state, MakeSignal(4, DecisionSignalKind.EspPhaseChanged, T0.AddSeconds(-12),
+                new Dictionary<string, string> { [SignalPayloadKeys.EspPhase] = "AccountSetup" })).NewState;
+            Assert.Equal(SessionStage.EspAccountSetup, state.Stage);
+
+            // 08:36:59 — IME user session completed (138/138 apps, 0 failed). THE knock:
+            // skip-user stands in for the exit that cannot exist; Hello enabled + unresolved
+            // promotes to AwaitingHello with HelloSafety armed.
+            var promoted = engine.Reduce(state, MakeSignal(5, DecisionSignalKind.ImeUserSessionCompleted,
+                T0.AddMinutes(6).AddSeconds(51), null));
+            Assert.Equal(SessionStage.AwaitingHello, promoted.NewState.Stage);
+            var helloSafety = Assert.Single(promoted.NewState.Deadlines, d => d.Name == DeadlineNames.HelloSafety);
+            Assert.Contains(promoted.Effects,
+                e => e.Kind == DecisionEffectKind.ScheduleDeadline && e.Deadline?.Name == DeadlineNames.HelloSafety);
+
+            // The Hello wizard never appears over RDP — HelloSafety resolves synthetically.
+            var afterSafety = engine.Reduce(promoted.NewState,
+                MakeSignal(6, DecisionSignalKind.DeadlineFired, helloSafety.DueAtUtc,
+                    new Dictionary<string, string> { [SignalPayloadKeys.Deadline] = DeadlineNames.HelloSafety }));
+            Assert.Equal(SessionStage.Finalizing, afterSafety.NewState.Stage);
+            Assert.Equal("Timeout", afterSafety.NewState.HelloOutcome!.Value);
+
+            var completed = engine.Reduce(afterSafety.NewState,
+                MakeSignal(7, DecisionSignalKind.DeadlineFired, helloSafety.DueAtUtc.AddSeconds(5),
+                    new Dictionary<string, string> { [SignalPayloadKeys.Deadline] = DeadlineNames.FinalizingGrace }));
+            Assert.Equal(SessionStage.Completed, completed.NewState.Stage);
+            Assert.Equal(SessionOutcome.EnrollmentComplete, completed.NewState.Outcome);
+            Assert.Contains(completed.Effects,
+                e => e.Kind == DecisionEffectKind.EmitEventTimelineEntry
+                     && e.Parameters != null
+                     && e.Parameters.TryGetValue("eventType", out var et) && et == "enrollment_complete");
+        }
+
+        [Fact]
+        public void Fix10_bounceback_is_healed_by_the_ime_reemission()
+        {
+            // Restart shape (8110e262 run 3): the promoted AwaitingHello gets bounced back by a
+            // re-emitted AccountSetup phase line (Fix 10 cancels HelloSafety, deliberately — it
+            // guards the premature-promotion case). The IME phase line always precedes the
+            // user-session-complete line in log order, so the re-emitted completion re-knocks.
+            var engine = new DecisionEngine();
+            var state = ProgressToPromotedAwaitingHello(engine);
+
+            var bounced = engine.Reduce(state, MakeSignal(10, DecisionSignalKind.EspPhaseChanged,
+                T0.AddMinutes(18).AddSeconds(10),
+                new Dictionary<string, string> { [SignalPayloadKeys.EspPhase] = "AccountSetup" }));
+            Assert.Equal(SessionStage.EspAccountSetup, bounced.NewState.Stage);
+            Assert.DoesNotContain(bounced.NewState.Deadlines, d => d.Name == DeadlineNames.HelloSafety);
+
+            var reknocked = engine.Reduce(bounced.NewState,
+                MakeSignal(11, DecisionSignalKind.ImeUserSessionCompleted, T0.AddMinutes(6).AddSeconds(51), null));
+            Assert.Equal(SessionStage.AwaitingHello, reknocked.NewState.Stage);
+            Assert.Single(reknocked.NewState.Deadlines, d => d.Name == DeadlineNames.HelloSafety);
+        }
+
+        [Theory]
+        // No EspConfigDetected at all — SkipUserEsp unknown.
+        [InlineData(null)]
+        // Explicit SkipUser=false (the two sits-d machines that succeeded had this shape and
+        // a REAL page: exit + registry evidence. Without the exit the gate must stay shut.)
+        [InlineData("false")]
+        public void No_promotion_without_an_observed_skip(string? skipUser)
+        {
+            var engine = new DecisionEngine();
+            var state = DecisionState.CreateInitial("s", "t", T0);
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0, null)).NewState;
+            if (skipUser != null)
+            {
+                state = engine.Reduce(state, MakeEspConfigSignal(1, skipUser)).NewState;
+            }
+            state = engine.Reduce(state, MakeSignal(2, DecisionSignalKind.HelloPolicyDetected, T0.AddSeconds(1),
+                new Dictionary<string, string> { [SignalPayloadKeys.HelloEnabled] = "true" })).NewState;
+            state = engine.Reduce(state, MakeSignal(3, DecisionSignalKind.DesktopArrived, T0.AddSeconds(5), null)).NewState;
+            state = engine.Reduce(state, MakeSignal(4, DecisionSignalKind.EspPhaseChanged, T0.AddSeconds(10),
+                new Dictionary<string, string> { [SignalPayloadKeys.EspPhase] = "AccountSetup" })).NewState;
+
+            var step = engine.Reduce(state,
+                MakeSignal(5, DecisionSignalKind.ImeUserSessionCompleted, T0.AddMinutes(7), null));
+
+            Assert.Equal(SessionStage.EspAccountSetup, step.NewState.Stage);
+            Assert.DoesNotContain(step.NewState.Deadlines, d => d.Name == DeadlineNames.HelloSafety);
+        }
+
+        [Fact]
+        public void No_promotion_without_the_desktop()
+        {
+            var engine = new DecisionEngine();
+            var state = DecisionState.CreateInitial("s", "t", T0);
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0, null)).NewState;
+            state = engine.Reduce(state, MakeEspConfigSignal(1, skipUser: "true")).NewState;
+            state = engine.Reduce(state, MakeSignal(2, DecisionSignalKind.EspPhaseChanged, T0.AddSeconds(10),
+                new Dictionary<string, string> { [SignalPayloadKeys.EspPhase] = "AccountSetup" })).NewState;
+
+            var step = engine.Reduce(state,
+                MakeSignal(3, DecisionSignalKind.ImeUserSessionCompleted, T0.AddMinutes(7), null));
+
+            Assert.Equal(SessionStage.EspAccountSetup, step.NewState.Stage);
+            Assert.DoesNotContain(step.NewState.Deadlines, d => d.Name == DeadlineNames.HelloSafety);
+        }
+
+        [Fact]
+        public void A_ghost_pre_anchor_ime_completion_does_not_knock()
+        {
+            // defaultuser0-ghost guard stays load-bearing: an IME completion whose source time
+            // precedes the AccountSetup anchor is the OOBE/technician frame, not the user.
+            var engine = new DecisionEngine();
+            var state = DecisionState.CreateInitial("s", "t", T0);
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0, null)).NewState;
+            state = engine.Reduce(state, MakeEspConfigSignal(1, skipUser: "true")).NewState;
+            state = engine.Reduce(state, MakeSignal(2, DecisionSignalKind.DesktopArrived, T0.AddSeconds(5), null)).NewState;
+            state = engine.Reduce(state, MakeSignal(3, DecisionSignalKind.EspPhaseChanged, T0.AddMinutes(2),
+                new Dictionary<string, string> { [SignalPayloadKeys.EspPhase] = "AccountSetup" })).NewState;
+
+            var step = engine.Reduce(state,
+                MakeSignal(4, DecisionSignalKind.ImeUserSessionCompleted, T0.AddMinutes(1), null));
+
+            Assert.Equal(SessionStage.EspAccountSetup, step.NewState.Stage);
+            Assert.DoesNotContain(step.NewState.Deadlines, d => d.Name == DeadlineNames.HelloSafety);
+        }
+
+        [Fact]
+        public void Device_preparation_flows_keep_their_own_rails()
+        {
+            // WDP has no ESP at all — completion rides the Hello+Desktop conjunction and the
+            // DevicePrepCompletion backstop (afee7ae0). Even a (spurious) SkipUser=true read
+            // must not route WDP through the classic skip-user knock.
+            var engine = new DecisionEngine();
+            var seed = DecisionState.CreateInitial("s", "t", T0)
+                .ToBuilder()
+                .WithStage(SessionStage.SessionStarted)
+                .WithStepIndex(5)
+                .WithLastAppliedSignalOrdinal(4)
+                .WithScenarioProfile(EnrollmentScenarioProfile.Empty.With(
+                    mode: EnrollmentMode.DevicePreparation,
+                    confidence: ProfileConfidence.High,
+                    evidenceOrdinal: 1,
+                    reason: "test"));
+            seed.ScenarioObservations = EnrollmentScenarioObservations.Empty
+                .WithSkipUserEsp(true, 1);
+            seed.AccountSetupEnteredUtc = new SignalFact<DateTime>(T0.AddMinutes(1), 2);
+            seed.DesktopArrivedUtc = new SignalFact<DateTime>(T0.AddMinutes(2), 3);
+            var state = seed.Build();
+
+            var step = engine.Reduce(state,
+                MakeSignal(5, DecisionSignalKind.ImeUserSessionCompleted, T0.AddMinutes(3), null));
+
+            Assert.DoesNotContain(step.NewState.Deadlines, d => d.Name == DeadlineNames.HelloSafety);
+            Assert.NotEqual(SessionStage.AwaitingHello, step.NewState.Stage);
+        }
+
+        [Fact]
+        public void Hello_disabled_skip_user_completes_directly_from_the_knock()
+        {
+            // HelloSatisfiedForCompletion holds (policy disabled, no wizard observed) — the
+            // knock completes through Finalizing with the synthetic Skipped outcome instead of
+            // parking 5 minutes in AwaitingHello.
+            var engine = new DecisionEngine();
+            var state = DecisionState.CreateInitial("s", "t", T0);
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0, null)).NewState;
+            state = engine.Reduce(state, MakeEspConfigSignal(1, skipUser: "true")).NewState;
+            state = engine.Reduce(state, MakeSignal(2, DecisionSignalKind.HelloPolicyDetected, T0.AddSeconds(1),
+                new Dictionary<string, string> { [SignalPayloadKeys.HelloEnabled] = "false" })).NewState;
+            state = engine.Reduce(state, MakeSignal(3, DecisionSignalKind.EspPhaseChanged, T0.AddSeconds(10),
+                new Dictionary<string, string> { [SignalPayloadKeys.EspPhase] = "AccountSetup" })).NewState;
+            // Desktop arrives; the hello-disabled fast-path already promotes/completes via the
+            // gate's arm B on this ordering, so the knock is not even needed here — assert the
+            // flow terminates either way (belt for orderings where desktop precedes the config).
+            state = engine.Reduce(state, MakeSignal(4, DecisionSignalKind.DesktopArrived, T0.AddMinutes(5), null)).NewState;
+
+            if (state.Stage != SessionStage.Finalizing && !state.Stage.IsTerminal())
+            {
+                var step = engine.Reduce(state,
+                    MakeSignal(5, DecisionSignalKind.ImeUserSessionCompleted, T0.AddMinutes(7), null));
+                Assert.Equal(SessionStage.Finalizing, step.NewState.Stage);
+                Assert.Equal("Skipped", step.NewState.HelloOutcome!.Value);
+            }
+            else
+            {
+                Assert.Equal(SessionStage.Finalizing, state.Stage);
+            }
+        }
+
+        // ------------------------------------------------------------------------------
+
+        private static DecisionState ProgressToPromotedAwaitingHello(DecisionEngine engine)
+        {
+            var state = DecisionState.CreateInitial("s", "t", T0);
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0, null)).NewState;
+            state = engine.Reduce(state, MakeEspConfigSignal(1, skipUser: "true")).NewState;
+            state = engine.Reduce(state, MakeSignal(2, DecisionSignalKind.HelloPolicyDetected, T0.AddSeconds(1),
+                new Dictionary<string, string> { [SignalPayloadKeys.HelloEnabled] = "true" })).NewState;
+            state = engine.Reduce(state, MakeSignal(3, DecisionSignalKind.DesktopArrived, T0.AddSeconds(5), null)).NewState;
+            state = engine.Reduce(state, MakeSignal(4, DecisionSignalKind.EspPhaseChanged, T0.AddSeconds(-12),
+                new Dictionary<string, string> { [SignalPayloadKeys.EspPhase] = "AccountSetup" })).NewState;
+            state = engine.Reduce(state, MakeSignal(5, DecisionSignalKind.ImeUserSessionCompleted,
+                T0.AddMinutes(6).AddSeconds(51), null)).NewState;
+            Assert.Equal(SessionStage.AwaitingHello, state.Stage);
+            return state;
+        }
+
+        private static DecisionSignal MakeEspConfigSignal(long ordinal, string skipUser) =>
+            MakeSignal(ordinal, DecisionSignalKind.EspConfigDetected, T0.AddSeconds(ordinal),
+                new Dictionary<string, string>
+                {
+                    [SignalPayloadKeys.SkipUserEsp] = skipUser,
+                    [SignalPayloadKeys.SkipDeviceEsp] = "false",
+                });
+
+        private static DecisionSignal MakeSignal(
+            long ordinal,
+            DecisionSignalKind kind,
+            DateTime occurredAtUtc,
+            IReadOnlyDictionary<string, string>? payload)
+        {
+            return new DecisionSignal(
+                sessionSignalOrdinal: ordinal,
+                sessionTraceOrdinal: ordinal,
+                kind: kind,
+                kindSchemaVersion: 1,
+                occurredAtUtc: occurredAtUtc,
+                sourceOrigin: "test",
+                evidence: new Evidence(EvidenceKind.Synthetic, $"test-{kind}-{ordinal}", $"synthetic {kind}"),
+                payload: payload);
+        }
+    }
+}

src/Agent/AutopilotMonitor.DecisionCore.Tests/DevicePreparationEngineTests.cs

@@ -0,0 +1,257 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AutopilotMonitor.DecisionCore.Engine;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.DecisionCore.State;
+using Xunit;
+
+namespace AutopilotMonitor.DecisionCore.Tests
+{
+    /// <summary>
+    /// Device Preparation (WDP) engine semantics — afee7ae0 audit (2026-08-18).
+    /// WDP has no ESP, so the ESP-derived arms/gates/deadlines can never fire there.
+    /// Coverage:
+    /// <list type="bullet">
+    ///   <item>Profile seeding: the deterministic WDP marker seeds High confidence; the
+    ///         CloudAssigned* fallback rules stay Medium.</item>
+    ///   <item><c>completion_waiting</c> never lists <c>account_setup_provisioning_complete</c>
+    ///         on WDP (unsatisfiable by construction — no ESP categories).</item>
+    ///   <item>Desktop-first arming of the <see cref="DeadlineNames.DevicePrepCompletion"/>
+    ///         backstop, its fire semantics (synthetic Hello timeout + Finalizing), and the
+    ///         no-rearm/no-classic-leak guards.</item>
+    ///   <item>Arm D: the Hello-disabled fast-path completes at desktop arrival on WDP.</item>
+    /// </list>
+    /// </summary>
+    public sealed class DevicePreparationEngineTests
+    {
+        private static readonly DateTime T0 = new DateTime(2026, 8, 18, 9, 0, 0, DateTimeKind.Utc);
+
+        private static DecisionSignal MakeSignal(
+            long ordinal,
+            DecisionSignalKind kind,
+            DateTime occurredAtUtc,
+            IReadOnlyDictionary<string, string>? payload = null)
+        {
+            return new DecisionSignal(
+                sessionSignalOrdinal: ordinal,
+                sessionTraceOrdinal: ordinal,
+                kind: kind,
+                kindSchemaVersion: 1,
+                occurredAtUtc: occurredAtUtc,
+                sourceOrigin: "test",
+                evidence: new Evidence(EvidenceKind.Synthetic, $"{kind}-{ordinal}", "test"),
+                payload: payload);
+        }
+
+        private static DecisionSignal DeadlineFired(long ordinal, DateTime occurredAtUtc, string deadlineName) =>
+            MakeSignal(ordinal, DecisionSignalKind.DeadlineFired, occurredAtUtc,
+                new Dictionary<string, string> { [SignalPayloadKeys.Deadline] = deadlineName });
+
+        private static List<DecisionEffect> CompletionWaitingEffects(DecisionStep step) =>
+            step.Effects.Where(e =>
+                e.Kind == DecisionEffectKind.EmitEventTimelineEntry
+                && e.Parameters != null
+                && e.Parameters.TryGetValue("eventType", out var et)
+                && et == "completion_waiting").ToList();
+
+        /// <summary>Session seeded as WDP via the EnrollmentFactsObserved signal rail.</summary>
+        private static DecisionState SeedWdpSession(DecisionEngine engine, bool deterministic = true)
+        {
+            var state = DecisionState.CreateInitial("sess-wdp", "tenant-wdp", T0);
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0)).NewState;
+            state = engine.Reduce(state, MakeSignal(
+                1, DecisionSignalKind.EnrollmentFactsObserved, T0,
+                new Dictionary<string, string>
+                {
+                    [SignalPayloadKeys.EnrollmentType] = "v2",
+                    [SignalPayloadKeys.EnrollmentTypeDeterministic] = deterministic ? "true" : "false",
+                })).NewState;
+            return state;
+        }
+
+        // ===================================================== profile seeding
+
+        [Fact]
+        public void DeterministicV2Seed_SetsDevicePreparationAtHighConfidence()
+        {
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine, deterministic: true);
+
+            Assert.Equal(EnrollmentMode.DevicePreparation, state.ScenarioProfile.Mode);
+            Assert.Equal(ProfileConfidence.High, state.ScenarioProfile.Confidence);
+        }
+
+        [Fact]
+        public void FallbackV2Seed_StaysAtMediumConfidence()
+        {
+            // CloudAssigned* fallback rules (no deterministic marker) — Medium, as before
+            // d0ab3eee: an ESP-less classic profile could in principle trip them.
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine, deterministic: false);
+
+            Assert.Equal(EnrollmentMode.DevicePreparation, state.ScenarioProfile.Mode);
+            Assert.Equal(ProfileConfidence.Medium, state.ScenarioProfile.Confidence);
+        }
+
+        [Fact]
+        public void LegacyV2Payload_WithoutDeterministicKey_StaysAtMediumConfidence()
+        {
+            // Older agents post enrollmentType=v2 without the new key — must behave like
+            // the fallback (Medium), not throw or over-promote.
+            var engine = new DecisionEngine();
+            var state = DecisionState.CreateInitial("sess-legacy", "tenant-wdp", T0);
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0)).NewState;
+            state = engine.Reduce(state, MakeSignal(
+                1, DecisionSignalKind.EnrollmentFactsObserved, T0,
+                new Dictionary<string, string> { [SignalPayloadKeys.EnrollmentType] = "v2" })).NewState;
+
+            Assert.Equal(EnrollmentMode.DevicePreparation, state.ScenarioProfile.Mode);
+            Assert.Equal(ProfileConfidence.Medium, state.ScenarioProfile.Confidence);
+        }
+
+        // ===================================================== desktop-first backstop
+
+        [Fact]
+        public void DesktopFirst_OnWdp_ArmsDevicePrepCompletionBackstop()
+        {
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine);
+
+            var step = engine.Reduce(state, MakeSignal(10, DecisionSignalKind.DesktopArrived, T0.AddMinutes(9)));
+
+            // Hello policy unknown → no fast-path; stage parked, backstop armed.
+            var backstop = Assert.Single(step.NewState.Deadlines, d => d.Name == DeadlineNames.DevicePrepCompletion);
+            Assert.Equal(T0.AddMinutes(9).AddMinutes(30), backstop.DueAtUtc);
+            Assert.Contains(step.Effects,
+                e => e.Kind == DecisionEffectKind.ScheduleDeadline && e.Deadline?.Name == DeadlineNames.DevicePrepCompletion);
+        }
+
+        [Fact]
+        public void DesktopFirst_OnWdp_WaitingListsOnlyHello_NeverTheEspProvisioningGate()
+        {
+            // account_setup_provisioning_complete is unsatisfiable on WDP (no ESP categories)
+            // and must not appear as a missing prerequisite (afee7ae0 listed it).
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine);
+
+            var step = engine.Reduce(state, MakeSignal(10, DecisionSignalKind.DesktopArrived, T0.AddMinutes(9)));
+
+            var waiting = Assert.Single(CompletionWaitingEffects(step));
+            Assert.Equal("hello_resolution", waiting.Parameters!["missingPrerequisites"]);
+        }
+
+        [Fact]
+        public void DuplicateDesktopSignal_DoesNotRearmTheBackstop()
+        {
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine);
+            state = engine.Reduce(state, MakeSignal(10, DecisionSignalKind.DesktopArrived, T0.AddMinutes(9))).NewState;
+
+            var second = engine.Reduce(state, MakeSignal(11, DecisionSignalKind.DesktopArrived, T0.AddMinutes(10)));
+
+            Assert.Single(second.NewState.Deadlines, d => d.Name == DeadlineNames.DevicePrepCompletion);
+            Assert.DoesNotContain(second.Effects,
+                e => e.Kind == DecisionEffectKind.ScheduleDeadline && e.Deadline?.Name == DeadlineNames.DevicePrepCompletion);
+        }
+
+        [Fact]
+        public void ClassicDesktopFirst_DoesNotArmTheBackstop()
+        {
+            // Classic regression guard: a non-WDP session parked desktop-first keeps the
+            // pre-change deadline picture (nothing armed by this handler).
+            var engine = new DecisionEngine();
+            var state = DecisionState.CreateInitial("sess-classic", "tenant-classic", T0);
+            state = engine.Reduce(state, MakeSignal(0, DecisionSignalKind.SessionStarted, T0)).NewState;
+
+            var step = engine.Reduce(state, MakeSignal(10, DecisionSignalKind.DesktopArrived, T0.AddMinutes(9)));
+
+            Assert.DoesNotContain(step.NewState.Deadlines, d => d.Name == DeadlineNames.DevicePrepCompletion);
+        }
+
+        // ===================================================== backstop fire semantics
+
+        [Fact]
+        public void BackstopFired_WithoutHello_SynthesizesTimeoutAndCompletesThroughFinalizing()
+        {
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine);
+            state = engine.Reduce(state, MakeSignal(10, DecisionSignalKind.DesktopArrived, T0.AddMinutes(9))).NewState;
+
+            var fired = engine.Reduce(state, DeadlineFired(20, T0.AddMinutes(39), DeadlineNames.DevicePrepCompletion));
+
+            Assert.Equal(SessionStage.Finalizing, fired.NewState.Stage);
+            Assert.NotNull(fired.NewState.HelloResolvedUtc);
+            Assert.Equal("Timeout", fired.NewState.HelloOutcome!.Value);
+            Assert.DoesNotContain(fired.NewState.Deadlines, d => d.Name == DeadlineNames.DevicePrepCompletion);
+            Assert.Contains(fired.NewState.Deadlines, d => d.Name == DeadlineNames.FinalizingGrace);
+
+            // FinalizingGrace completes the session — the full WDP no-Hello resolution chain.
+            var completed = engine.Reduce(fired.NewState,
+                DeadlineFired(21, T0.AddMinutes(39).AddSeconds(5), DeadlineNames.FinalizingGrace));
+            Assert.Equal(SessionStage.Completed, completed.NewState.Stage);
+        }
+
+        [Fact]
+        public void BackstopFired_WithoutDesktop_ParksInAwaitingDesktopUntilDesktopCompletes()
+        {
+            // The arming site (HandleDesktopArrivedV1) guarantees desktop-first, so this
+            // fires only on a stale/replayed timer — Dispatch routes DeadlineFired purely on
+            // the payload name, no armed-state check. The fallback must keep the handler
+            // total: synthetic Hello timeout recorded, session parks in AwaitingDesktop, and
+            // a later real desktop arrival still completes it.
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine);
+
+            var fired = engine.Reduce(state, DeadlineFired(20, T0.AddMinutes(39), DeadlineNames.DevicePrepCompletion));
+
+            Assert.Equal(SessionStage.AwaitingDesktop, fired.NewState.Stage);
+            Assert.NotNull(fired.NewState.HelloResolvedUtc);
+            Assert.Equal("Timeout", fired.NewState.HelloOutcome!.Value);
+            Assert.DoesNotContain(fired.NewState.Deadlines, d => d.Name == DeadlineNames.DevicePrepCompletion);
+
+            // Hello is satisfied (synthetically) — only the desktop is still missing.
+            var waiting = Assert.Single(CompletionWaitingEffects(fired));
+            Assert.Equal("desktop_arrival", waiting.Parameters!["missingPrerequisites"]);
+
+            var completed = engine.Reduce(fired.NewState,
+                MakeSignal(21, DecisionSignalKind.DesktopArrived, T0.AddMinutes(45)));
+            Assert.Equal(SessionStage.Finalizing, completed.NewState.Stage);
+        }
+
+        [Fact]
+        public void HelloResolved_BeforeBackstopFires_CompletesNormally()
+        {
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine);
+            state = engine.Reduce(state, MakeSignal(10, DecisionSignalKind.DesktopArrived, T0.AddMinutes(9))).NewState;
+
+            var resolved = engine.Reduce(state, MakeSignal(
+                20, DecisionSignalKind.HelloResolved, T0.AddMinutes(10),
+                new Dictionary<string, string> { [SignalPayloadKeys.HelloOutcome] = "completed" }));
+
+            Assert.Equal(SessionStage.Finalizing, resolved.NewState.Stage);
+            Assert.Equal("completed", resolved.NewState.HelloOutcome!.Value);
+        }
+
+        // ===================================================== arm D fast-path
+
+        [Fact]
+        public void HelloDisabledFastPath_OnWdp_CompletesAtDesktopArrival()
+        {
+            // Arm D: no ESP facts exist on WDP, yet a disabled Hello policy + real-user
+            // desktop is a legitimate completion — previously arms A–C all failed and the
+            // session parked despite Hello being disabled.
+            var engine = new DecisionEngine();
+            var state = SeedWdpSession(engine);
+            state = engine.Reduce(state, MakeSignal(
+                5, DecisionSignalKind.HelloPolicyDetected, T0.AddMinutes(1),
+                new Dictionary<string, string> { [SignalPayloadKeys.HelloEnabled] = "false" })).NewState;
+
+            var step = engine.Reduce(state, MakeSignal(10, DecisionSignalKind.DesktopArrived, T0.AddMinutes(9)));
+
+            Assert.Equal(SessionStage.Finalizing, step.NewState.Stage);
+            Assert.Equal("Skipped", step.NewState.HelloOutcome!.Value);
+        }
+    }
+}

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

@@ -0,0 +1,235 @@
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.DataAccess;
+using AutopilotMonitor.Shared.Models;
+using AutopilotMonitor.Shared.Pagination;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// AgentEfficiencyMetricsService: per-agent-version bucketing, nearest-rank percentiles,
+/// crash tally per bucket, top-offender selection and the scanned/with-snapshots split.
+/// Distinct `days` values per test keep the static per-(days,limit,tenant) cache from
+/// cross-talking between tests.
+/// </summary>
+public class AgentEfficiencyMetricsServiceTests
+{
+    private const string Tenant = "11111111-1111-1111-1111-111111111111";
+
+    private static (AgentEfficiencyMetricsService Service, Mock<ISessionRepository> Repo) CreateService()
+    {
+        var repo = new Mock<ISessionRepository>();
+        repo
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .ReturnsAsync(new RawPage<SessionSummary>(new List<SessionSummary>(), null));
+        repo
+            .Setup(r => r.GetSessionEventsByTypesAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IReadOnlyCollection<string>>(), It.IsAny<IEnumerable<string>?>(), It.IsAny<int>()))
+            .ReturnsAsync(new List<EnrollmentEvent>());
+
+        var service = new AgentEfficiencyMetricsService(repo.Object, NullLogger<AgentEfficiencyMetricsService>.Instance);
+        return (service, repo);
+    }
+
+    private static SessionSummary MakeSession(int i, string agentVersion, double? avgLatency = null, int? requestCount = null) => new SessionSummary
+    {
+        SessionId = $"00000000-0000-0000-0000-{i:D12}",
+        TenantId = Tenant,
+        AgentVersion = agentVersion,
+        DeviceName = $"PC-{i}",
+        StartedAt = DateTime.UtcNow.AddHours(-i),
+        Status = SessionStatus.Succeeded,
+        AvgApiLatencyMs = avgLatency,
+        ApiRequestCount = requestCount
+    };
+
+    private static EnrollmentEvent Snapshot(double cpu, double ws, double handles = 0, double threads = 0, double spool = 0, long sequence = 1) => new EnrollmentEvent
+    {
+        EventType = "agent_metrics_snapshot",
+        Sequence = sequence,
+        Data = new Dictionary<string, object>
+        {
+            ["agent_cpu_percent"] = cpu,
+            ["agent_working_set_mb"] = ws,
+            ["agent_handle_count"] = handles,
+            ["agent_thread_count"] = threads,
+            ["spool_pending_item_count"] = spool
+        }
+    };
+
+    private static EnrollmentEvent AgentStarted(string exitType, string? exception = null)
+    {
+        var data = new Dictionary<string, object> { ["previousExitType"] = exitType };
+        if (exception != null) data["previousCrashException"] = exception;
+        return new EnrollmentEvent { EventType = "agent_started", Data = data };
+    }
+
+    private static void SetupSessions(Mock<ISessionRepository> repo, List<SessionSummary> sessions)
+    {
+        repo
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .ReturnsAsync(new RawPage<SessionSummary>(sessions, null));
+    }
+
+    private static void SetupEvents(Mock<ISessionRepository> repo, string sessionId, params EnrollmentEvent[] events)
+    {
+        repo
+            .Setup(r => r.GetSessionEventsByTypesAsync(It.IsAny<string>(), sessionId, It.IsAny<IReadOnlyCollection<string>>(), It.IsAny<IEnumerable<string>?>(), It.IsAny<int>()))
+            .ReturnsAsync(events.ToList());
+    }
+
+    [Fact]
+    public async Task Compute_buckets_by_agent_version_with_nearest_rank_percentiles()
+    {
+        var (service, repo) = CreateService();
+        var sessions = new List<SessionSummary>
+        {
+            MakeSession(1, "2.0.1400"), MakeSession(2, "2.0.1400"),
+            MakeSession(3, "2.0.1400"), MakeSession(4, "2.0.1400"),
+            MakeSession(5, "2.0.1402")
+        };
+        SetupSessions(repo, sessions);
+        // Per-session max working set for the 1400 bucket: 100, 200, 300, 400.
+        SetupEvents(repo, sessions[0].SessionId, Snapshot(cpu: 1, ws: 50), Snapshot(cpu: 3, ws: 100, sequence: 2));
+        SetupEvents(repo, sessions[1].SessionId, Snapshot(cpu: 2, ws: 200));
+        SetupEvents(repo, sessions[2].SessionId, Snapshot(cpu: 4, ws: 300));
+        SetupEvents(repo, sessions[3].SessionId, Snapshot(cpu: 8, ws: 400));
+        SetupEvents(repo, sessions[4].SessionId, Snapshot(cpu: 5, ws: 500));
+
+        var result = await service.ComputeAsync(days: 41, limit: 100);
+
+        Assert.Equal(5, result.SessionsScanned);
+        Assert.Equal(5, result.SessionsWithSnapshots);
+        Assert.Equal(2, result.ByVersion.Count);
+
+        var v1400 = result.ByVersion.Single(b => b.AgentVersion == "2.0.1400");
+        Assert.Equal(4, v1400.SessionsScanned);
+        Assert.Equal(4, v1400.SessionsWithSnapshots);
+        // Nearest-rank over sorted [100, 200, 300, 400]: p50 → 2nd (200), p95 → 4th (400).
+        Assert.Equal(200, v1400.MaxWorkingSetMb!.P50);
+        Assert.Equal(400, v1400.MaxWorkingSetMb.P95);
+        Assert.Equal(400, v1400.MaxWorkingSetMb.Max);
+        Assert.Equal(4, v1400.MaxWorkingSetMb.SampleCount);
+        // Session 1's max CPU is 3 (max over its two snapshots), not the last value.
+        Assert.Equal(8, v1400.MaxCpuPercent!.Max);
+
+        var v1402 = result.ByVersion.Single(b => b.AgentVersion == "2.0.1402");
+        Assert.Equal(1, v1402.SessionsScanned);
+        Assert.Equal(500, v1402.MaxWorkingSetMb!.Max);
+
+        Assert.NotNull(result.Overall);
+        Assert.Null(result.Overall!.AgentVersion);
+        Assert.Equal(5, result.Overall.SessionsScanned);
+        Assert.Equal(500, result.Overall.MaxWorkingSetMb!.Max);
+    }
+
+    [Fact]
+    public async Task Compute_tallies_crash_rate_per_version_bucket()
+    {
+        var (service, repo) = CreateService();
+        var sessions = new List<SessionSummary> { MakeSession(1, "2.0.1400"), MakeSession(2, "2.0.1402") };
+        SetupSessions(repo, sessions);
+        SetupEvents(repo, sessions[0].SessionId,
+            AgentStarted("first_run"),
+            AgentStarted("exception_crash", "System.IO.IOException"),
+            AgentStarted("clean"));
+        SetupEvents(repo, sessions[1].SessionId, AgentStarted("first_run"), AgentStarted("clean"));
+
+        var result = await service.ComputeAsync(days: 42, limit: 100);
+
+        var v1400 = result.ByVersion.Single(b => b.AgentVersion == "2.0.1400");
+        Assert.Equal(3, v1400.CrashRate!.TotalStarts);
+        Assert.Equal(1, v1400.CrashRate.ExceptionCrashes);
+        Assert.Equal("System.IO.IOException", Assert.Single(v1400.CrashRate.TopExceptions).ExceptionType);
+        // 2 non-first-run starts, 1 crash → 50%.
+        Assert.Equal(50, v1400.CrashRate.CrashRatePercent);
+
+        var v1402 = result.ByVersion.Single(b => b.AgentVersion == "2.0.1402");
+        Assert.Equal(0, v1402.CrashRate!.ExceptionCrashes);
+        Assert.Equal(0, v1402.CrashRate.CrashRatePercent);
+    }
+
+    [Fact]
+    public async Task Compute_selects_top_offenders_per_dimension_descending()
+    {
+        var (service, repo) = CreateService();
+        var sessions = Enumerable.Range(1, 5).Select(i => MakeSession(i, "2.0.1400")).ToList();
+        SetupSessions(repo, sessions);
+        for (var i = 0; i < 5; i++)
+        {
+            // Working sets 100..500 — top 3 must be sessions 5, 4, 3 in that order.
+            SetupEvents(repo, sessions[i].SessionId, Snapshot(cpu: 1, ws: (i + 1) * 100));
+        }
+
+        var result = await service.ComputeAsync(days: 43, limit: 100);
+
+        var bucket = result.ByVersion.Single();
+        var wsOffenders = bucket.TopOffenders!.Where(o => o.Dimension == "maxWorkingSetMb").ToList();
+        Assert.Equal(3, wsOffenders.Count);
+        Assert.Equal(new[] { 500d, 400d, 300d }, wsOffenders.Select(o => o.Value).ToArray());
+        Assert.Equal(sessions[4].SessionId, wsOffenders[0].SessionId);
+        Assert.Equal("PC-5", wsOffenders[0].DeviceName);
+    }
+
+    [Fact]
+    public async Task Compute_snapshotless_sessions_still_contribute_index_mirrored_latency()
+    {
+        var (service, repo) = CreateService();
+        var sessions = new List<SessionSummary>
+        {
+            MakeSession(1, "2.0.1400", avgLatency: 80, requestCount: 200),
+            MakeSession(2, "2.0.1400", avgLatency: 120, requestCount: 300) // no snapshots
+        };
+        SetupSessions(repo, sessions);
+        SetupEvents(repo, sessions[0].SessionId, Snapshot(cpu: 1, ws: 100));
+
+        var result = await service.ComputeAsync(days: 44, limit: 100);
+
+        Assert.Equal(2, result.SessionsScanned);
+        Assert.Equal(1, result.SessionsWithSnapshots);
+        var bucket = result.ByVersion.Single();
+        // Latency stats cover BOTH sessions (mirror-sourced), resource stats only the one with snapshots.
+        Assert.Equal(2, bucket.ApiLatencyMs!.SampleCount);
+        Assert.Equal(120, bucket.ApiLatencyMs.Max);
+        Assert.Equal(1, bucket.MaxWorkingSetMb!.SampleCount);
+    }
+
+    [Fact]
+    public async Task Compute_passes_projection_and_tenant_filter_to_repo_and_echoes_tenant()
+    {
+        var (service, repo) = CreateService();
+        string? capturedTenant = null;
+        IEnumerable<string>? capturedSelect = null;
+        repo
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .Callback<string?, int?, int, string?, IReadOnlyCollection<string>?, IEnumerable<string>?>((t, _, _, _, _, sel) => { capturedTenant = t; capturedSelect = sel; })
+            .ReturnsAsync(new RawPage<SessionSummary>(new List<SessionSummary>(), null));
+
+        var result = await service.ComputeAsync(days: 45, limit: 100, tenantId: Tenant);
+
+        Assert.Equal(Tenant, capturedTenant);
+        Assert.Same(AgentEfficiencyMetricsService.SessionIndexProjection, capturedSelect);
+        Assert.Equal(Tenant, result.TenantId);
+        Assert.Equal(45, result.WindowDays);
+        Assert.Equal(100, result.SessionLimit);
+    }
+
+    [Fact]
+    public async Task Compute_caches_per_days_limit_tenant_key()
+    {
+        var (service, repo) = CreateService();
+        int callCount = 0;
+        repo
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .Callback(() => callCount++)
+            .ReturnsAsync(new RawPage<SessionSummary>(new List<SessionSummary>(), null));
+
+        var first = await service.ComputeAsync(days: 46, limit: 100);
+        var second = await service.ComputeAsync(days: 46, limit: 100);   // cache hit
+        await service.ComputeAsync(days: 46, limit: 100, tenantId: Tenant); // miss — tenant-scoped
+
+        Assert.Equal(2, callCount);
+        Assert.False(first.FromCache);
+        Assert.True(second.FromCache);
+    }
+}

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

@@ -0,0 +1,93 @@
+using System;
+using System.Collections.Generic;
+using Azure.Data.Tables;
+using AutopilotMonitor.Functions.Services;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Pins that the column-projected SessionsIndex scan driving
+/// <c>AgentEfficiencyMetricsService</c> maps every field the aggregation reads
+/// (SessionId, TenantId, DeviceName, AgentVersion, AvgApiLatencyMs, ApiRequestCount,
+/// StartedAt) identically to the full-row drain. Same fixture discipline as
+/// <see cref="SessionStatsProjectionEquivalenceTests"/>: the projected row carries the
+/// projection's keys ONLY, so a getter for an omitted column returns null exactly as it
+/// would against live storage — and dropping a load-bearing column from the production
+/// array fails here immediately.
+/// </summary>
+public class AgentEfficiencyProjectionEquivalenceTests
+{
+    private const string TenantId = "00000000-0000-0000-0000-000000000abc";
+
+    private static readonly TableStorageService Sut =
+        new(new Mock<TableServiceClient>().Object, NullLogger<TableStorageService>.Instance);
+
+    private static string IndexRowKey(DateTime startedAt, string sessionId)
+        => $"{(DateTime.MaxValue.Ticks - startedAt.Ticks):D19}_{sessionId}";
+
+    private static TableEntity FullRow(string sessionId, DateTime startedAt)
+        => new TableEntity(TenantId, IndexRowKey(startedAt, sessionId))
+        {
+            ["SessionId"] = sessionId,
+            ["Status"] = "Succeeded",
+            ["StartedAt"] = new DateTimeOffset(startedAt),
+            ["AgentVersion"] = "2.0.1400",
+            ["DeviceName"] = "PC-EFF",
+            ["AvgApiLatencyMs"] = 84.5,
+            ["ApiRequestCount"] = 321,
+            // Representative noise the efficiency scan never reads.
+            ["SerialNumber"] = "SN-FULL",
+            ["Manufacturer"] = "Contoso",
+            ["Model"] = "Model-X",
+            ["OsName"] = "Windows 11",
+            ["GeoCountry"] = "DE",
+            ["EventCount"] = 123,
+            ["FailureSnapshotJson"] = "{\"big\":\"" + new string('x', 2000) + "\"}",
+        };
+
+    private static TableEntity Project(TableEntity full)
+    {
+        var keep = new HashSet<string>(AgentEfficiencyMetricsService.SessionIndexProjection, StringComparer.Ordinal);
+        var projected = new TableEntity(full.PartitionKey, full.RowKey);
+        foreach (var kv in full)
+        {
+            if (kv.Key is "PartitionKey" or "RowKey" or "Timestamp" or "odata.etag") continue;
+            if (keep.Contains(kv.Key)) projected[kv.Key] = kv.Value;
+        }
+        return projected;
+    }
+
+    [Fact]
+    public void Projected_row_maps_every_efficiency_relevant_field_identically()
+    {
+        var started = DateTime.UtcNow.AddHours(-2);
+        var sid = Guid.NewGuid().ToString();
+        var fullRow = FullRow(sid, started);
+
+        var full = Sut.MapIndexEntityToSessionSummary(fullRow);
+        var projected = Sut.MapIndexEntityToSessionSummary(Project(fullRow));
+
+        Assert.Equal(sid, projected.SessionId);
+        Assert.Equal(full.TenantId, projected.TenantId);
+        Assert.Equal(full.DeviceName, projected.DeviceName);
+        Assert.Equal(full.AgentVersion, projected.AgentVersion);
+        Assert.Equal(full.AvgApiLatencyMs, projected.AvgApiLatencyMs);
+        Assert.Equal(full.ApiRequestCount, projected.ApiRequestCount);
+        // StartedAt feeds the repo's cross-tenant merge-sort and next-page cursor.
+        Assert.Equal(full.StartedAt, projected.StartedAt);
+    }
+
+    [Fact]
+    public void Projection_contains_the_repo_cursor_columns()
+    {
+        // FetchAllSessionsPageInternalAsync merge-sorts on StartedAt and rebuilds the cursor
+        // from StartedAt + SessionId; a projection without them silently breaks pagination.
+        Assert.Contains("StartedAt", AgentEfficiencyMetricsService.SessionIndexProjection);
+        Assert.Contains("SessionId", AgentEfficiencyMetricsService.SessionIndexProjection);
+        Assert.Contains("PartitionKey", AgentEfficiencyMetricsService.SessionIndexProjection);
+        Assert.Contains("RowKey", AgentEfficiencyMetricsService.SessionIndexProjection);
+    }
+}

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

@@ -0,0 +1,162 @@
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// DO ingest fallback (IME ≥ 1.104 removed the [DO TEL] log line; the agent's DO collector
+/// only emits <c>do_telemetry</c> for downloads whose completion a poll itself observed).
+/// <c>download_progress</c> events carry the full <c>do*</c> set on every poll and must fold
+/// into the summary's Do* columns so interrupted / between-poll-completed downloads still
+/// reach the Delivery Optimization aggregates:
+///  - progress-only sessions populate Do* incl. a valid DoDownloadMode (DoAggregator gate),
+///  - a later do_telemetry stays authoritative,
+///  - replayed progress events are idempotent (Math.Max),
+///  - DownloadBytes prefers transferred bytes over file size.
+/// </summary>
+public class AppInstallDoFieldsFallbackTests
+{
+    private static readonly DateTime T0 = new(2026, 8, 19, 10, 0, 0, DateTimeKind.Utc);
+
+    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 DownloadProgress(
+        long bytesDownloaded, long doTotal, long doPeers, long doHttp, int doMode,
+        long doFileSize = 0, int doPct = 0, long doCacheServer = 0, DateTime? ts = null)
+        => new EnrollmentEvent
+        {
+            EventType = "download_progress",
+            Timestamp = ts ?? T0,
+            Data = new Dictionary<string, object>
+            {
+                ["appName"] = "App",
+                ["bytesDownloaded"] = bytesDownloaded,
+                ["doFileSize"] = doFileSize,
+                ["doTotalBytesDownloaded"] = doTotal,
+                ["doBytesFromPeers"] = doPeers,
+                ["doBytesFromHttp"] = doHttp,
+                ["doPercentPeerCaching"] = doPct,
+                ["doDownloadMode"] = doMode,
+                ["doBytesFromCacheServer"] = doCacheServer,
+            },
+        };
+
+    private static EnrollmentEvent DoTelemetry(
+        long doFileSize, long doTotal, long doPeers, long doHttp, int doMode,
+        string? duration = null)
+    {
+        var data = new Dictionary<string, object>
+        {
+            ["appName"] = "App",
+            ["doFileSize"] = doFileSize,
+            ["doTotalBytesDownloaded"] = doTotal,
+            ["doBytesFromPeers"] = doPeers,
+            ["doBytesFromHttp"] = doHttp,
+            ["doPercentPeerCaching"] = 50,
+            ["doDownloadMode"] = doMode,
+        };
+        if (duration != null) data["doDownloadDuration"] = duration;
+        return new EnrollmentEvent { EventType = "do_telemetry", Timestamp = T0, Data = data };
+    }
+
+    [Fact]
+    public void ProgressOnly_PopulatesDoColumns_AndSurvivesDoAggregator()
+    {
+        // An interrupted download: progress events observed, do_telemetry never fired.
+        var s = Aggregate(
+            DownloadProgress(bytesDownloaded: 1000, doTotal: 1000, doPeers: 600, doHttp: 400, doMode: 1, doFileSize: 5000, doPct: 60),
+            DownloadProgress(bytesDownloaded: 3000, doTotal: 3000, doPeers: 2000, doHttp: 1000, doMode: 1, doFileSize: 5000, doPct: 66)
+        )["App"].Summary;
+
+        Assert.Equal(3000, s.DoTotalBytesDownloaded);
+        Assert.Equal(2000, s.DoBytesFromPeers);
+        Assert.Equal(1000, s.DoBytesFromHttp);
+        Assert.Equal(5000, s.DoFileSize);
+        Assert.Equal(66, s.DoPercentPeerCaching);
+        Assert.Equal(1, s.DoDownloadMode);
+        Assert.Equal(3000, s.DownloadBytes); // from bytesDownloaded, not the file size
+
+        // The whole point: DoDownloadMode >= 0 keeps the row inside the DO aggregate.
+        var aggregate = DoAggregator.Compute(new[] { s });
+        Assert.Equal(1, aggregate.DoAppCount);
+        Assert.Equal(2000, aggregate.BytesFromPeers);
+    }
+
+    [Fact]
+    public void ProgressReplay_IsIdempotent_MaxFoldNeverRegresses()
+    {
+        // Out-of-order / replayed batch: the older (smaller) progress arrives again last.
+        var s = Aggregate(
+            DownloadProgress(bytesDownloaded: 3000, doTotal: 3000, doPeers: 2000, doHttp: 1000, doMode: 1),
+            DownloadProgress(bytesDownloaded: 1000, doTotal: 1000, doPeers: 600, doHttp: 400, doMode: 1)
+        )["App"].Summary;
+
+        Assert.Equal(3000, s.DoTotalBytesDownloaded);
+        Assert.Equal(2000, s.DoBytesFromPeers);
+        Assert.Equal(1000, s.DoBytesFromHttp);
+    }
+
+    [Fact]
+    public void DoTelemetry_StaysAuthoritative_OverEarlierProgress()
+    {
+        // Progress saw a partial state; the final telemetry read has the complete numbers
+        // (which can be LOWER per bucket than a transient progress max — telemetry wins).
+        var s = Aggregate(
+            DownloadProgress(bytesDownloaded: 4000, doTotal: 4000, doPeers: 3500, doHttp: 500, doMode: 1, doPct: 87),
+            DoTelemetry(doFileSize: 5000, doTotal: 5000, doPeers: 3000, doHttp: 2000, doMode: 1, duration: "00:01:40")
+        )["App"].Summary;
+
+        Assert.Equal(5000, s.DoTotalBytesDownloaded);
+        Assert.Equal(3000, s.DoBytesFromPeers);   // telemetry overwrote the higher progress value
+        Assert.Equal(2000, s.DoBytesFromHttp);
+        Assert.Equal(50, s.DoPercentPeerCaching);
+        Assert.Equal("00:01:40", s.DoDownloadDuration);
+        Assert.Equal(100, s.DownloadDurationSeconds);
+    }
+
+    [Fact]
+    public void DoTelemetry_WithUnsetMode_DoesNotRegressAKnownMode()
+    {
+        // A telemetry event whose DownloadMode property was absent parses as -1; it must not
+        // re-hide the row from DoAggregator after progress already established the mode.
+        var s = Aggregate(
+            DownloadProgress(bytesDownloaded: 1000, doTotal: 1000, doPeers: 600, doHttp: 400, doMode: 3),
+            DoTelemetry(doFileSize: 1000, doTotal: 1000, doPeers: 600, doHttp: 400, doMode: -1)
+        )["App"].Summary;
+
+        Assert.Equal(3, s.DoDownloadMode);
+    }
+
+    [Fact]
+    public void DownloadBytes_PrefersTransferredBytes_OverFileSize()
+    {
+        // Historic bug: DownloadBytes was max-ed with doFileSize, inflating the transfer
+        // measure. With a real transfer total present the file size must not win.
+        var s = Aggregate(
+            DoTelemetry(doFileSize: 9000, doTotal: 5000, doPeers: 3000, doHttp: 2000, doMode: 1)
+        )["App"].Summary;
+
+        Assert.Equal(5000, s.DownloadBytes);
+        Assert.Equal(9000, s.DoFileSize); // the file size column itself keeps the real value
+    }
+
+    [Fact]
+    public void DownloadBytes_FallsBackToFileSize_WhenNoTransferTotal()
+    {
+        var evt = new EnrollmentEvent
+        {
+            EventType = "do_telemetry",
+            Timestamp = T0,
+            Data = new Dictionary<string, object> { ["appName"] = "App", ["doFileSize"] = 7000L, ["doDownloadMode"] = 1 },
+        };
+        var s = Aggregate(evt)["App"].Summary;
+        Assert.Equal(7000, s.DownloadBytes);
+    }
+}

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

@@ -0,0 +1,152 @@
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Pins the CMTrace time-skew regression tripwire (CmTraceSkewTripwire.Evaluate): fires only
+/// when the IME-vs-other median delta divergence sits on the 15-minute offset grid (residual
+/// &lt; 2 min) AND both sides have enough samples over enough distinct upload batches. The
+/// tripwire's goal state is to never fire, so the must-stay-silent directions are the primary
+/// cases: off-grid replays, sub-grid divergence, thin samples, batch-composition artifacts,
+/// and common-mode spool latency must all pass without a hit.
+/// </summary>
+public class CmTraceSkewTripwireTests
+{
+    /// <summary>Scan with the given per-side medians, comfortably above all sample/batch minimums.</summary>
+    private static SessionSkewScan MakeScan(
+        double imeDeltaMinutes, double otherDeltaMinutes,
+        int imeSamples = 30, int otherSamples = 30,
+        int imeBatches = 5, int otherBatches = 5)
+    {
+        var scan = new SessionSkewScan
+        {
+            ImeDistinctBatchCount = imeBatches,
+            OtherDistinctBatchCount = otherBatches,
+        };
+        for (int i = 0; i < imeSamples; i++)
+            scan.ImeDeltaMinutes.Add(imeDeltaMinutes);
+        for (int i = 0; i < otherSamples; i++)
+            scan.OtherDeltaMinutes.Add(otherDeltaMinutes);
+        return scan;
+    }
+
+    // ── Must fire ──────────────────────────────────────────────────────────
+
+    [Fact]
+    public void Fires_OnLargeNegativeGridDivergence()
+    {
+        // −540 min = the field-measured E.-Australia-style skew (−9 h), exactly 36 grid steps.
+        // Both sides share 1.2 min upload latency — it cancels in the difference.
+        var result = CmTraceSkewTripwire.Evaluate(MakeScan(imeDeltaMinutes: -538.8, otherDeltaMinutes: 1.2));
+
+        Assert.NotNull(result);
+        Assert.Equal(-36, result!.GridSteps);
+        Assert.Equal(-540.0, result.DiffMinutes, 3);
+        Assert.True(result.ResidualMinutes < CmTraceSkewTripwire.ResidualToleranceMinutes);
+    }
+
+    [Fact]
+    public void Fires_OnSingleGridStepWithBoundaryResidual()
+    {
+        // +15 min divergence with residual 1.9 — just inside the 2-min tolerance.
+        var result = CmTraceSkewTripwire.Evaluate(MakeScan(imeDeltaMinutes: 16.9, otherDeltaMinutes: 0.0));
+
+        Assert.NotNull(result);
+        Assert.Equal(1, result!.GridSteps);
+        Assert.Equal(1.9, result.ResidualMinutes, 3);
+    }
+
+    // ── Must stay silent ───────────────────────────────────────────────────
+
+    [Fact]
+    public void Silent_WhenResidualOffGrid()
+    {
+        // 17.5 min divergence: nearest grid step is 15, residual 2.5 ≥ tolerance — the replay
+        // signature (old log lines re-read late land anywhere, not on the zone grid).
+        Assert.Null(CmTraceSkewTripwire.Evaluate(MakeScan(imeDeltaMinutes: 17.5, otherDeltaMinutes: 0.0)));
+    }
+
+    [Fact]
+    public void Silent_WhenDivergenceBelowOneGridStep()
+    {
+        // 9 min rounds to 1 step but with residual 6 — and 7 min rounds to 0 steps. Both silent.
+        Assert.Null(CmTraceSkewTripwire.Evaluate(MakeScan(imeDeltaMinutes: 9.0, otherDeltaMinutes: 0.0)));
+        Assert.Null(CmTraceSkewTripwire.Evaluate(MakeScan(imeDeltaMinutes: 7.0, otherDeltaMinutes: 0.0)));
+    }
+
+    [Fact]
+    public void Silent_WhenImeSampleCountBelowMinimum()
+    {
+        var scan = MakeScan(imeDeltaMinutes: -540.0, otherDeltaMinutes: 0.0,
+            imeSamples: CmTraceSkewTripwire.MinSamplesPerSide - 1);
+        Assert.Null(CmTraceSkewTripwire.Evaluate(scan));
+    }
+
+    [Fact]
+    public void Silent_WhenDistinctBatchesBelowMinimum()
+    {
+        // A perfect grid divergence backed by only 2 upload batches on one side is a
+        // batch-composition artifact (ReceivedAt is stamped per batch, not per event).
+        var scan = MakeScan(imeDeltaMinutes: -540.0, otherDeltaMinutes: 0.0,
+            otherBatches: CmTraceSkewTripwire.MinDistinctBatchesPerSide - 1);
+        Assert.Null(CmTraceSkewTripwire.Evaluate(scan));
+    }
+
+    [Fact]
+    public void Silent_OnCommonModeSpoolLatency()
+    {
+        // Offline spool: BOTH sides uploaded 45 min late. The difference of medians is ~0 —
+        // shared latency must cancel, never read as skew.
+        Assert.Null(CmTraceSkewTripwire.Evaluate(MakeScan(imeDeltaMinutes: 45.3, otherDeltaMinutes: 45.1)));
+    }
+
+    [Fact]
+    public void Silent_OnNullOrEmptyScan()
+    {
+        Assert.Null(CmTraceSkewTripwire.Evaluate(null));
+        Assert.Null(CmTraceSkewTripwire.Evaluate(new SessionSkewScan()));
+    }
+
+    [Fact]
+    public void MedianIsRobustAgainstMinorityOutliers()
+    {
+        // A handful of replayed old lines (huge off-grid deltas) inside an otherwise healthy
+        // IME stream must not drag the median onto the grid.
+        var scan = MakeScan(imeDeltaMinutes: 0.5, otherDeltaMinutes: 0.4);
+        scan.ImeDeltaMinutes.Add(-1327.0);
+        scan.ImeDeltaMinutes.Add(-738.0);
+        Assert.Null(CmTraceSkewTripwire.Evaluate(scan));
+    }
+
+    // ── Bias suppression predicate ─────────────────────────────────────────
+
+    [Fact]
+    public void BiasDominated_WhenBiasIsHalfOrMore()
+    {
+        Assert.True(CmTraceSkewTripwire.IsBiasDominated(new Dictionary<string, int>
+        {
+            ["bias"] = 50,
+            ["line-anchored"] = 50,
+        }));
+        Assert.True(CmTraceSkewTripwire.IsBiasDominated(new Dictionary<string, int>
+        {
+            ["Bias"] = 3, // case-insensitive
+        }));
+    }
+
+    [Fact]
+    public void NotBiasDominated_WhenAnchoredMajorityOrNoData()
+    {
+        Assert.False(CmTraceSkewTripwire.IsBiasDominated(new Dictionary<string, int>
+        {
+            ["bias"] = 10,
+            ["line-anchored"] = 80,
+            ["reader-zone-fallback"] = 11,
+        }));
+        // Empty/missing histogram fails open toward reporting — a storage error must not
+        // silently swallow a genuine regression hit.
+        Assert.False(CmTraceSkewTripwire.IsBiasDominated(new Dictionary<string, int>()));
+        Assert.False(CmTraceSkewTripwire.IsBiasDominated(null));
+    }
+}

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

@@ -0,0 +1,37 @@
+using AutopilotMonitor.Functions.Services;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Pins the OData filter composition behind <c>GetSessionEventsByTypesAsync</c>:
+/// partition scope AND-ed with a parenthesized or-chain, values escaped. The grouping
+/// parentheses are load-bearing — without them the or-branches escape the partition
+/// scope and the query degrades to a cross-partition table scan.
+/// </summary>
+public class EventTypesFilterTests
+{
+    [Fact]
+    public void Single_type_builds_scoped_equality()
+    {
+        var filter = TableStorageService.BuildEventTypesFilter("tenant_session", new[] { "agent_metrics_snapshot" });
+        Assert.Equal("PartitionKey eq 'tenant_session' and (EventType eq 'agent_metrics_snapshot')", filter);
+    }
+
+    [Fact]
+    public void Multiple_types_or_chain_stays_inside_the_partition_scope()
+    {
+        var filter = TableStorageService.BuildEventTypesFilter(
+            "tenant_session", new[] { "agent_metrics_snapshot", "agent_started", "spool_pressure_detected" });
+        Assert.Equal(
+            "PartitionKey eq 'tenant_session' and (EventType eq 'agent_metrics_snapshot' or EventType eq 'agent_started' or EventType eq 'spool_pressure_detected')",
+            filter);
+    }
+
+    [Fact]
+    public void Values_with_single_quotes_are_escaped()
+    {
+        var filter = TableStorageService.BuildEventTypesFilter("t'x", new[] { "a'b" });
+        Assert.Equal("PartitionKey eq 't''x' and (EventType eq 'a''b')", filter);
+    }
+}

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

@@ -33,6 +33,31 @@ public class IngestCriticalPathTests
         Assert.All(events, evt => Assert.Equal(receivedAt, evt.ReceivedAt));
     }
 
+    [Fact]
+    public void StampServerFields_SetsSentAtOnAllEvents_AndOverridesAgentValues()
+    {
+        // P14: SentAt is request-level and server-stamped — a per-event value coming off the
+        // wire (agent bug, forged payload) must never survive.
+        var sentAt = DateTime.UtcNow.AddSeconds(-4);
+        var events = MakeEvents(3);
+        events[1].SentAt = DateTime.UtcNow.AddYears(1);
+
+        EventIngestProcessor.StampServerFields(events, ValidTenantId, ValidSessionId, DateTime.UtcNow, sentAt);
+
+        Assert.All(events, evt => Assert.Equal(sentAt, evt.SentAt));
+    }
+
+    [Fact]
+    public void StampServerFields_WithoutSendTimeHeader_LeavesSentAtNull()
+    {
+        var events = MakeEvents(2);
+        events[0].SentAt = DateTime.UtcNow; // forged per-event value must be cleared, not kept
+
+        EventIngestProcessor.StampServerFields(events, ValidTenantId, ValidSessionId, DateTime.UtcNow);
+
+        Assert.All(events, evt => Assert.Null(evt.SentAt));
+    }
+
     [Fact]
     public void StampServerFields_SetsTenantIdOnAllEvents()
     {

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

@@ -43,6 +43,45 @@ public class IngestTelemetryFunctionTests
         Assert.Equal(string.Empty, session);
     }
 
+    // ============================================================ X-Send-Time-Utc parsing (P14)
+
+    [Fact]
+    public void ParseSendTimeHeader_RoundTripUtc_ParsesToUtc()
+    {
+        var parsed = IngestTelemetryFunction.ParseSendTimeHeader("2026-08-21T10:15:30.1234567Z");
+
+        Assert.Equal(new DateTime(2026, 8, 21, 10, 15, 30, DateTimeKind.Utc).AddTicks(1234567), parsed);
+        Assert.Equal(DateTimeKind.Utc, parsed!.Value.Kind);
+    }
+
+    [Fact]
+    public void ParseSendTimeHeader_OffsetValue_NormalizedToUtc()
+    {
+        var parsed = IngestTelemetryFunction.ParseSendTimeHeader("2026-08-21T12:15:30+02:00");
+
+        Assert.Equal(new DateTime(2026, 8, 21, 10, 15, 30, DateTimeKind.Utc), parsed);
+    }
+
+    [Fact]
+    public void ParseSendTimeHeader_FutureDatedValue_KeptVerbatim()
+    {
+        // A future send time IS the device-clock-error measurement — no upper clamp.
+        var parsed = IngestTelemetryFunction.ParseSendTimeHeader("2027-01-01T00:00:00Z");
+
+        Assert.Equal(new DateTime(2027, 1, 1, 0, 0, 0, DateTimeKind.Utc), parsed);
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData("not-a-date")]
+    [InlineData("1999-12-31T23:59:59Z")] // pre-2000 can only be garbage (Table Storage floor guard)
+    public void ParseSendTimeHeader_AbsentOrGarbage_ReturnsNull(string? headerValue)
+    {
+        Assert.Null(IngestTelemetryFunction.ParseSendTimeHeader(headerValue));
+    }
+
     // ============================================================ Payload size-cap guard
 
     [Fact]

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

@@ -0,0 +1,75 @@
+using System;
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests
+{
+    /// <summary>
+    /// Pins the clock-frame contract of the agent-silence sweep.
+    ///
+    /// <para>
+    /// <c>LastEventAt</c> is the maximum AGENT-supplied event timestamp and therefore lives in the
+    /// device clock frame — it carries the device's clock error and, for CMTrace-derived events,
+    /// the writing process's timezone belief. Field measurement over 11k sessions found skews from
+    /// -17 h to +1 h. Comparing that against a server-derived silence cutoff marked live agents
+    /// Stalled ("Agent silent for 1020min") and left genuinely silent ones undetected for the
+    /// duration of the skew. <c>LastIngestAt</c> is stamped from the server clock on every ingest
+    /// and is the only value such a comparison may use.
+    /// </para>
+    /// </summary>
+    public class MaintenanceServerFrameLastContactTests
+    {
+        private static readonly DateTime Now = new(2026, 08, 20, 12, 00, 00, DateTimeKind.Utc);
+
+        private static SessionSummary Session(DateTime? lastIngestAt, DateTime? lastEventAt, DateTime startedAt)
+            => new() { LastIngestAt = lastIngestAt, LastEventAt = lastEventAt, StartedAt = startedAt };
+
+        [Fact]
+        public void PrefersServerFrameIngestStamp_OverDeviceFrameEventStamp()
+        {
+            var s = Session(lastIngestAt: Now.AddMinutes(-1), lastEventAt: Now.AddHours(-17), startedAt: Now.AddHours(-2));
+            Assert.Equal(Now.AddMinutes(-1), MaintenanceService.ServerFrameLastContact(s));
+        }
+
+        [Fact]
+        public void NegativeSkew_DoesNotLookSilent_WhenIngestIsFresh()
+        {
+            // The exact field shape: IME-derived events landed 17 h in the past, so LastEventAt is
+            // far behind the 2 h silence cutoff while the agent is demonstrably still reporting.
+            var silenceCutoff = Now.AddHours(-2);
+            var s = Session(lastIngestAt: Now.AddSeconds(-30), lastEventAt: Now.AddHours(-17), startedAt: Now.AddHours(-1));
+
+            Assert.True(MaintenanceService.ServerFrameLastContact(s) > silenceCutoff,
+                "a session whose ingest stamp is 30 s old must never be classified as agent-silent");
+        }
+
+        [Fact]
+        public void PositiveSkew_DoesNotMaskSilence_WhenIngestIsStale()
+        {
+            // Mirror case: a +1 h skew pushes LastEventAt into the future, which previously made the
+            // sweep blind for an hour. The server frame still sees the silence.
+            var silenceCutoff = Now.AddHours(-2);
+            var s = Session(lastIngestAt: Now.AddHours(-3), lastEventAt: Now.AddHours(1), startedAt: Now.AddHours(-4));
+
+            Assert.True(MaintenanceService.ServerFrameLastContact(s) < silenceCutoff,
+                "a session with no ingest for 3 h must be detected as silent regardless of a future-dated event stamp");
+        }
+
+        [Fact]
+        public void FallsBackToEventStamp_OnRowsPredatingTheIngestStamp()
+        {
+            // Rollout safety: rows written before LastIngestAt existed must keep the old behaviour
+            // rather than dropping out of the sweep entirely.
+            var s = Session(lastIngestAt: null, lastEventAt: Now.AddHours(-3), startedAt: Now.AddHours(-5));
+            Assert.Equal(Now.AddHours(-3), MaintenanceService.ServerFrameLastContact(s));
+        }
+
+        [Fact]
+        public void FallsBackToStartedAt_WhenNoEventStampExists()
+        {
+            var s = Session(lastIngestAt: null, lastEventAt: null, startedAt: Now.AddHours(-4));
+            Assert.Equal(Now.AddHours(-4), MaintenanceService.ServerFrameLastContact(s));
+        }
+    }
+}

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

@@ -9,7 +9,10 @@ namespace AutopilotMonitor.Functions.Tests;
 
 /// <summary>
 /// Verifies PlatformMetricsService passes the requested window + session limit
-/// through to GetAllSessionsPageAsync and surfaces both on the response.
+/// through to GetAllSessionsPageAsync and surfaces both on the response, that
+/// SessionsScanned reports the honest scan count (not the has-snapshots subset),
+/// and that the split fetch (full events for the 20 latency-sample sessions,
+/// filtered three-type fetch for the rest) preserves the aggregation semantics.
 /// </summary>
 public class PlatformMetricsServiceWindowTests
 {
@@ -20,16 +23,36 @@ public class PlatformMetricsServiceWindowTests
     {
         var sessionRepo = new Mock<ISessionRepository>();
         sessionRepo
-            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>()))
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
             .ReturnsAsync(EmptyPage());
         sessionRepo
             .Setup(r => r.GetSessionEventsAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<int>()))
             .ReturnsAsync(new List<EnrollmentEvent>());
+        sessionRepo
+            .Setup(r => r.GetSessionEventsByTypesAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IReadOnlyCollection<string>>(), It.IsAny<IEnumerable<string>?>(), It.IsAny<int>()))
+            .ReturnsAsync(new List<EnrollmentEvent>());
 
         var service = new PlatformMetricsService(sessionRepo.Object, NullLogger<PlatformMetricsService>.Instance);
         return (service, sessionRepo);
     }
 
+    private static SessionSummary MakeSession(int i) => new SessionSummary
+    {
+        SessionId = $"00000000-0000-0000-0000-{i:D12}",
+        TenantId = "11111111-1111-1111-1111-111111111111",
+        AgentVersion = "2.0.1400",
+        StartedAt = DateTime.UtcNow.AddHours(-i),
+        Status = SessionStatus.Succeeded
+    };
+
+    private static EnrollmentEvent MakeEvent(string eventType, Dictionary<string, object>? data = null, long sequence = 1) => new EnrollmentEvent
+    {
+        EventType = eventType,
+        Data = data ?? new Dictionary<string, object>(),
+        Sequence = sequence,
+        Timestamp = DateTime.UtcNow
+    };
+
     [Theory]
     [InlineData(11)]
     [InlineData(13)]
@@ -41,8 +64,8 @@ public class PlatformMetricsServiceWindowTests
 
         int? capturedDays = null;
         repo
-            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>()))
-            .Callback<string?, int?, int, string?, IReadOnlyCollection<string>?>((_, d, _, _, _) => capturedDays = d)
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .Callback<string?, int?, int, string?, IReadOnlyCollection<string>?, IEnumerable<string>?>((_, d, _, _, _, _) => capturedDays = d)
             .ReturnsAsync(EmptyPage());
 
         var result = await service.ComputePlatformMetricsAsync(days, limit: 50);
@@ -66,8 +89,8 @@ public class PlatformMetricsServiceWindowTests
 
         int? capturedPageSize = null;
         repo
-            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>()))
-            .Callback<string?, int?, int, string?, IReadOnlyCollection<string>?>((_, _, ps, _, _) => capturedPageSize = ps)
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .Callback<string?, int?, int, string?, IReadOnlyCollection<string>?, IEnumerable<string>?>((_, _, ps, _, _, _) => capturedPageSize = ps)
             .ReturnsAsync(EmptyPage());
 
         var result = await service.ComputePlatformMetricsAsync(days: days, limit: limit);
@@ -83,8 +106,8 @@ public class PlatformMetricsServiceWindowTests
 
         int? capturedDays = null;
         repo
-            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>()))
-            .Callback<string?, int?, int, string?, IReadOnlyCollection<string>?>((_, d, _, _, _) => capturedDays = d)
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .Callback<string?, int?, int, string?, IReadOnlyCollection<string>?, IEnumerable<string>?>((_, d, _, _, _, _) => capturedDays = d)
             .ReturnsAsync(EmptyPage());
 
         var result = await service.ComputePlatformMetricsAsync(0);
@@ -117,7 +140,7 @@ public class PlatformMetricsServiceWindowTests
         var (service, repo) = CreateService();
         int callCount = 0;
         repo
-            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>()))
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
             .Callback(() => callCount++)
             .ReturnsAsync(EmptyPage());
 
@@ -128,4 +151,96 @@ public class PlatformMetricsServiceWindowTests
 
         Assert.Equal(3, callCount);
     }
+
+    [Fact]
+    public async Task ComputePlatformMetrics_reports_sessionsScanned_even_when_no_session_has_snapshots()
+    {
+        // The truncated check must be based on scanned sessions, not the has-snapshots
+        // subset — a window full of snapshot-less sessions previously read as "not truncated".
+        var (service, repo) = CreateService();
+        var sessions = Enumerable.Range(1, 7).Select(MakeSession).ToList();
+        repo
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .ReturnsAsync(new RawPage<SessionSummary>(sessions, null));
+
+        var result = await service.ComputePlatformMetricsAsync(days: 77, limit: 50);
+
+        Assert.Equal(7, result.SessionsScanned);
+        Assert.Empty(result.Sessions);
+    }
+
+    [Fact]
+    public async Task ComputePlatformMetrics_uses_full_fetch_for_latency_sample_and_filtered_fetch_for_rest()
+    {
+        // First 20 sessions form the delivery-latency sample (deltas over ALL events);
+        // every further session only needs the three metrics event types.
+        var (service, repo) = CreateService();
+        var sessions = Enumerable.Range(1, 25).Select(MakeSession).ToList();
+        repo
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .ReturnsAsync(new RawPage<SessionSummary>(sessions, null));
+
+        var fullFetchSessions = new List<string>();
+        var filteredFetchSessions = new List<string>();
+        IReadOnlyCollection<string>? capturedEventTypes = null;
+        repo
+            .Setup(r => r.GetSessionEventsAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<int>()))
+            .Callback<string, string, int>((_, sid, _) => { lock (fullFetchSessions) fullFetchSessions.Add(sid); })
+            .ReturnsAsync(new List<EnrollmentEvent>());
+        repo
+            .Setup(r => r.GetSessionEventsByTypesAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IReadOnlyCollection<string>>(), It.IsAny<IEnumerable<string>?>(), It.IsAny<int>()))
+            .Callback<string, string, IReadOnlyCollection<string>, IEnumerable<string>?, int>((_, sid, types, _, _) =>
+            {
+                lock (filteredFetchSessions) { filteredFetchSessions.Add(sid); capturedEventTypes = types; }
+            })
+            .ReturnsAsync(new List<EnrollmentEvent>());
+
+        await service.ComputePlatformMetricsAsync(days: 78, limit: 50);
+
+        Assert.Equal(20, fullFetchSessions.Count);
+        Assert.Equal(5, filteredFetchSessions.Count);
+        Assert.Equal(sessions.Take(20).Select(s => s.SessionId).ToHashSet(), fullFetchSessions.ToHashSet());
+        Assert.NotNull(capturedEventTypes);
+        Assert.Contains("agent_metrics_snapshot", capturedEventTypes!);
+        Assert.Contains("agent_started", capturedEventTypes!);
+        // Without spool_pressure_detected in the filter the SpoolPressureDetected flag
+        // silently dies on the filtered path.
+        Assert.Contains("spool_pressure_detected", capturedEventTypes!);
+    }
+
+    [Fact]
+    public async Task ComputePlatformMetrics_spool_pressure_and_crash_survive_the_filtered_path()
+    {
+        // A session outside the latency sample gets its events via the filtered fetch;
+        // the spool-pressure flag and crash tally must still work on that stream.
+        var (service, repo) = CreateService();
+        var sessions = Enumerable.Range(1, 21).Select(MakeSession).ToList();
+        repo
+            .Setup(r => r.GetAllSessionsPageAsync(It.IsAny<string?>(), It.IsAny<int?>(), It.IsAny<int>(), It.IsAny<string?>(), It.IsAny<IReadOnlyCollection<string>?>(), It.IsAny<IEnumerable<string>?>()))
+            .ReturnsAsync(new RawPage<SessionSummary>(sessions, null));
+
+        var session21 = sessions[20].SessionId;
+        repo
+            .Setup(r => r.GetSessionEventsByTypesAsync(It.IsAny<string>(), session21, It.IsAny<IReadOnlyCollection<string>>(), It.IsAny<IEnumerable<string>?>(), It.IsAny<int>()))
+            .ReturnsAsync(new List<EnrollmentEvent>
+            {
+                MakeEvent("agent_started", new Dictionary<string, object> { ["previousExitType"] = "exception_crash", ["previousCrashException"] = "System.NullReferenceException" }, sequence: 1),
+                MakeEvent("agent_metrics_snapshot", new Dictionary<string, object>
+                {
+                    ["agent_cpu_percent"] = 3.5,
+                    ["agent_working_set_mb"] = 90.0,
+                    ["spool_pending_item_count"] = 12.0
+                }, sequence: 2),
+                MakeEvent("spool_pressure_detected", sequence: 3)
+            });
+
+        var result = await service.ComputePlatformMetricsAsync(days: 79, limit: 50);
+
+        var metric = Assert.Single(result.Sessions);
+        Assert.Equal(session21, metric.SessionId);
+        Assert.True(metric.SpoolPressureDetected);
+        Assert.Equal(1, result.CrashRate!.ExceptionCrashes);
+        Assert.Equal("System.NullReferenceException", Assert.Single(result.CrashRate.TopExceptions).ExceptionType);
+        Assert.Equal(21, result.SessionsScanned);
+    }
 }

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

@@ -1023,6 +1023,7 @@ public class PolicyEnforcementMiddlewareTests
     // the GlobalReadOrDelegatedSubset tier — see GlobalSessions_IsBoundedSubsetTier below.)
     [InlineData("GET", "/api/global/audit/logs", TenantScoping.QueryParam)]
     [InlineData("GET", "/api/global/metrics/app", TenantScoping.QueryParam)]
+    [InlineData("GET", "/api/global/metrics/agent-efficiency", TenantScoping.QueryParam)]
     [InlineData("GET", "/api/global/metrics/fleet-health", TenantScoping.QueryParam)]
     [InlineData("GET", "/api/global/metrics/summary", TenantScoping.QueryParam)]
     [InlineData("GET", "/api/global/search/sessions", TenantScoping.QueryParam)]

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

@@ -200,4 +200,120 @@ public class ReportAgentErrorFunctionTests
 
         Assert.Empty(h.OpsEvents);
     }
+
+    // =========================================================================
+    // MaterializeIntegrityMismatchAsync — an IntegrityCheckFailed report becomes an
+    // AgentBinaryIntegrityMismatch ops event, UNLESS it is the known release race
+    // (agents comparing against hash snapshots that don't belong to their own binary;
+    // AdminConfig cache TTL 5 min). e9753578 proved the race: a genuine 1410 exe was
+    // compared against the cached 1409 hash and reported a "mismatch" that cost a day
+    // of mis-attributed root-causing while sitting invisible in App Insights.
+    // =========================================================================
+
+    private const string RunningExeSha = "5fca975e43fa5fca975e43fa5fca975e43fa5fca975e43fa5fca975e43fa0000";
+    private const string PublishedExeSha = "8ebaa060ad348ebaa060ad348ebaa060ad348ebaa060ad348ebaa060ad340000";
+
+    private static AgentErrorReport IntegrityReport(
+        string? sessionId = SessionId, string agentVersion = "2.0.1410", string? actualSha = null) => new()
+    {
+        SessionId = sessionId!,
+        TenantId = TenantId,
+        ErrorType = AgentErrorType.IntegrityCheckFailed,
+        Message = $"Running exe SHA-256 differs from backend-advertised hash. actual={actualSha ?? RunningExeSha}, expected={PublishedExeSha}",
+        AgentVersion = agentVersion,
+        Timestamp = Now,
+    };
+
+    private static Task RunIntegrityAsync(
+        Harness h, AgentErrorReport report,
+        string? latestVersion = "2.0.1410", string? latestExeSha = PublishedExeSha)
+        => ReportAgentErrorFunction.MaterializeIntegrityMismatchAsync(
+            report, TenantId, h.OpsService, latestVersion, latestExeSha,
+            NullLogger<ReportAgentErrorFunction>.Instance);
+
+    [Fact]
+    public async Task SameVersion_with_unknown_binary_records_ops_event()
+    {
+        // The real signal: an agent claiming the LATEST version whose running exe is NOT
+        // the published one — tamper, stale blob, or a build outside the release pipeline.
+        var h = new Harness();
+
+        await RunIntegrityAsync(h, IntegrityReport());
+
+        var ops = Assert.Single(h.OpsEvents);
+        Assert.Equal("AgentBinaryIntegrityMismatch", ops.EventType);
+        Assert.Equal(TenantId, ops.TenantId);
+        Assert.Contains("actual=5fca", ops.Message);
+        Assert.Contains("2.0.1410", ops.Message);
+    }
+
+    [Fact]
+    public async Task RunningHash_equal_to_published_exe_is_suppressed_as_stale_expectation()
+    {
+        // e9753578's exact shape: the device RUNS the published binary; only its cached
+        // expectation was the previous release's hash. Self-heals — must not alert.
+        var h = new Harness();
+
+        await RunIntegrityAsync(h, IntegrityReport(actualSha: PublishedExeSha));
+
+        Assert.Empty(h.OpsEvents);
+    }
+
+    [Fact]
+    public async Task Older_agent_version_than_latest_is_suppressed_as_update_race()
+    {
+        // The long-known direction: version N agent sees version N+1's hash right after a
+        // release; the forced self-update heals it.
+        var h = new Harness();
+
+        await RunIntegrityAsync(h, IntegrityReport(agentVersion: "2.0.1409+d43cfe2b"), latestVersion: "2.0.1410");
+
+        Assert.Empty(h.OpsEvents);
+    }
+
+    [Fact]
+    public async Task Version_with_commit_suffix_matches_latest_without_suffix()
+    {
+        // Agent versions carry "+<commit>", AdminConfiguration does not — the comparison
+        // must normalize, otherwise every genuine mismatch would look like a version race.
+        var h = new Harness();
+
+        await RunIntegrityAsync(h, IntegrityReport(agentVersion: "2.0.1410+3b59dab2df6c"));
+
+        Assert.Single(h.OpsEvents);
+    }
+
+    [Fact]
+    public async Task Missing_latest_config_fails_open_to_recording()
+    {
+        // No published-version info available → visibility wins over suppression.
+        var h = new Harness();
+
+        await RunIntegrityAsync(h, IntegrityReport(), latestVersion: null, latestExeSha: null);
+
+        Assert.Single(h.OpsEvents);
+    }
+
+    [Fact]
+    public async Task Integrity_mismatch_without_session_id_still_records_ops_event()
+    {
+        // The report can arrive before session registration — the binary evidence must
+        // never be dropped for lack of a session.
+        var h = new Harness();
+
+        await RunIntegrityAsync(h, IntegrityReport(sessionId: null));
+
+        var ops = Assert.Single(h.OpsEvents);
+        Assert.Equal("AgentBinaryIntegrityMismatch", ops.EventType);
+    }
+
+    [Fact]
+    public async Task Other_error_types_do_not_record_integrity_ops_event()
+    {
+        var h = new Harness();
+
+        await RunIntegrityAsync(h, Report(Now));
+
+        Assert.Empty(h.OpsEvents);
+    }
 }

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

@@ -0,0 +1,450 @@
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.DataAccess;
+using AutopilotMonitor.Shared.Models;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Pins the clock_skew condition source (EvaluateClockSkewCondition) behind ANALYZE-DEV-008.
+/// The evaluator measures d = Timestamp − ReceivedAt per event, reduces to per-upload-batch
+/// medians (wide-spread batches = spool backlogs are dropped), then detects either a persistent
+/// mid-session step between two flat plateaus (clock_jump) or a stable whole-session offset
+/// (sustained_offset). IME-log-derived events are excluded so a CMTrace anchoring regression
+/// (the e9753578 field incident) can never fire this customer-facing rule — that failure mode
+/// belongs to the operator-side CmTraceSkewTripwire.
+/// </summary>
+public class RuleEngineClockSkewTests
+{
+    private const string TenantId  = "a1b2c3d4-e5f6-7890-abcd-ef1234567890";
+    private const string SessionId = "b2c3d4e5-f6a7-8901-bcde-f12345678901";
+
+    private static readonly DateTime T0 = new(2026, 8, 20, 10, 0, 0, DateTimeKind.Utc);
+
+    // ── clock_jump: must fire ──────────────────────────────────────────────
+
+    [Fact]
+    public async Task ClockJump_ForwardStepBetweenStableFrames_Fires()
+    {
+        // 4 batches on frame 0, then 4 batches on frame +1800 s (+30 min) that hold to
+        // session end — the canonical "clock corrected forward mid-session".
+        var events = Batches(offsetsSeconds: new double[] { 0, 0, 0, 0, 1800, 1800, 1800, 1800 });
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        var result = Assert.Single(outcome.Results);
+        var evidence = Assert.IsAssignableFrom<IDictionary<string, object>>(result.MatchedConditions["clock_jump"]);
+        Assert.Equal("forward", evidence["direction"]);
+        Assert.Equal(1800, Convert.ToDouble(evidence["jumpSeconds"]), 0);
+        Assert.Equal("skewSummary", evidence["field"]);
+    }
+
+    [Fact]
+    public async Task ClockJump_BackwardStep_Fires()
+    {
+        var events = Batches(new double[] { 0, 0, 0, -1200, -1200, -1200 });
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        var result = Assert.Single(outcome.Results);
+        var evidence = Assert.IsAssignableFrom<IDictionary<string, object>>(result.MatchedConditions["clock_jump"]);
+        Assert.Equal("backward", evidence["direction"]);
+    }
+
+    [Fact]
+    public async Task ClockJump_WrongClockCorrectedMidSession_Fires()
+    {
+        // Device started 30 min behind, time sync fixed it: the CORRECTED frame is the
+        // persistent change, so this must fire (direction forward).
+        var events = Batches(new double[] { -1800, -1800, -1800, 0, 0, 0 });
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        var result = Assert.Single(outcome.Results);
+        var evidence = Assert.IsAssignableFrom<IDictionary<string, object>>(result.MatchedConditions["clock_jump"]);
+        Assert.Equal("forward", evidence["direction"]);
+    }
+
+    // ── clock_jump: must stay silent ───────────────────────────────────────
+
+    [Fact]
+    public async Task ClockJump_ImeDerivedSkew_ExcludedFromMeasurement_Silent()
+    {
+        // e9753578 replica: IME-derived events carry grid-multiple wrong timestamps (−7 h /
+        // +2 h writer eras) while the agent's own events are healthy. The IME events must be
+        // excluded up front — a CMTrace anchoring regression may NEVER fire the customer rule.
+        var events = Batches(new double[] { 0, 0, 0, 0, 0, 0 });
+        var seq = 1000;
+        foreach (var imeOffset in new double[] { -25200, -25200, 7200, 7200, -25200, 7200 })
+            events.Add(MakeEvent(seq++, T0.AddMinutes(seq % 7), imeOffset, source: "ImeLogTracker"));
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task ClockJump_WideSpreadSpoolBatch_DroppedAndSilent()
+    {
+        // One upload batch whose events span 30 min of emission time (offline spool flushed
+        // in a single request) — the internal spread disqualifies the batch entirely.
+        var events = Batches(new double[] { 0, 0, 0, 0, 0, 0 });
+        var flushReceivedAt = T0.AddMinutes(90);
+        for (int i = 0; i < 20; i++)
+            events.Add(MakeEvent(2000 + i, flushReceivedAt, offsetSeconds: -1800 + i * 90));
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task ClockJump_GradualBacklogDrainRamp_Silent()
+    {
+        // A chunked spool drain produces a RAMP of batch medians walking back to the live
+        // frame. No flat pre/post plateau pair exists, so the step detector must reject every
+        // candidate — this is a delivery artifact, not a clock change.
+        var events = Batches(new double[] { -1800, -1500, -1200, -900, -600, -300, 0, 0 });
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task ClockJump_TransientExcursionReturnsToFrame_Silent()
+    {
+        // Frame dips for two batches and returns — whatever it was, it is not a SUSTAINED
+        // clock change (end-state persistence fails).
+        var events = Batches(new double[] { 0, 0, 0, -1800, -1800, 0, 0, 0 });
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task ClockJump_BelowThreshold_Silent()
+    {
+        var events = Batches(new double[] { 0, 0, 0, 240, 240, 240 });
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task ClockJump_TooFewBatches_Silent()
+    {
+        // 5 batches < 2×ConfirmBatches — not enough for two comparison windows.
+        var events = Batches(new double[] { 0, 0, 1800, 1800, 1800 });
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task ClockJump_LegacyEventsWithoutReceivedAt_Silent()
+    {
+        var events = Batches(new double[] { 0, 0, 0, 1800, 1800, 1800 });
+        foreach (var e in events)
+            e.ReceivedAt = null;
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task ClockJump_ClampedEventsExcluded_Silent()
+    {
+        // The jumped frame exists only on clamped events (their OccurredUtc is already
+        // server-substituted in production) — excluding them leaves a single stable frame.
+        var events = Batches(new double[] { 0, 0, 0, 0, 0, 0 });
+        var seq = 3000;
+        foreach (var offset in new double[] { 1800, 1800, 1800 })
+        {
+            var evt = MakeEvent(seq, T0.AddMinutes(120 + seq % 5), offset);
+            evt.TimestampClamped = true;
+            events.Add(evt);
+            seq++;
+        }
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    // ── sustained_offset ───────────────────────────────────────────────────
+
+    [Fact]
+    public async Task SustainedOffset_ClockBehindWholeSession_Fires()
+    {
+        var events = Batches(new double[] { -1800, -1795, -1805, -1800, -1798 });
+
+        var outcome = await RunAsync(MakeRule("sustained_offset", "300"), events);
+
+        var result = Assert.Single(outcome.Results);
+        var evidence = Assert.IsAssignableFrom<IDictionary<string, object>>(result.MatchedConditions["sustained_offset"]);
+        Assert.Equal("behind", evidence["direction"]);
+        Assert.Equal(-30.0, Convert.ToDouble(evidence["offsetMinutes"]), 1);
+    }
+
+    [Fact]
+    public async Task SustainedOffset_HealthyUploadLatencyBaseline_Silent()
+    {
+        // Healthy devices sit a few seconds NEGATIVE (upload latency) — far below threshold.
+        var events = Batches(new double[] { -3, -5, -2, -4, -6 });
+
+        var outcome = await RunAsync(MakeRule("sustained_offset", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task SustainedOffset_UnstableBatchOffsets_Silent()
+    {
+        // Medians all over the place: no honest single-offset statement exists, even though
+        // the overall median magnitude clears the threshold.
+        var events = Batches(new double[] { -2400, 900, -1800, 300, -3600, -600 });
+
+        var outcome = await RunAsync(MakeRule("sustained_offset", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    // ── P14: SentAt direct measurement (X-Send-Time-Utc batches) ───────────
+
+    [Fact]
+    public async Task SentAt_SpoolFlushWithWideEventSpread_JumpStillMeasured_Fires()
+    {
+        // Every batch is a spool flush spanning 30 min of emission time — the legacy path
+        // drops ALL of them via the spread cap and stays blind. SentAt measures the frame
+        // crossing directly, so the +30 min step must fire regardless of event-timestamp
+        // spread, and every batch counts as a SentAt batch.
+        static double[] Wide(int _) => new double[] { -1800, -1350, -900, -450, 0 };
+        var events = SentAtBatches(new double[] { 0, 0, 0, 0, 1800, 1800, 1800, 1800 }, Wide);
+
+        var outcome = await RunAsync(MakeRule("clock_jump", "300"), events);
+
+        var result = Assert.Single(outcome.Results);
+        var evidence = Assert.IsAssignableFrom<IDictionary<string, object>>(result.MatchedConditions["clock_jump"]);
+        Assert.Equal("forward", evidence["direction"]);
+        Assert.Equal(8, Convert.ToInt32(evidence["sentAtBatchCount"]));
+    }
+
+    [Fact]
+    public async Task SentAt_UniformBacklogBatches_ReadAsHealthy_Silent()
+    {
+        // EXACTLY the event shape of SustainedOffset_ClockBehindWholeSession_Fires (tight
+        // −30 min Timestamp−ReceivedAt deltas), but the batches carry SentAt ≈ ReceivedAt:
+        // the device clock is fine, the events are merely OLD (uniform spool backlog).
+        // The legacy median cannot tell those apart — SentAt can, and must stay silent.
+        static double[] Backlog(int b) => new double[] { -1800, -1795, -1805, -1800, -1798 };
+        var events = SentAtBatches(new double[] { -3, -5, -2, -4, -6 }, Backlog);
+
+        var outcome = await RunAsync(MakeRule("sustained_offset", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task SentAt_SustainedOffset_MeasuredFromSendTime_Fires()
+    {
+        var events = SentAtBatches(new double[] { -1800, -1795, -1805, -1800, -1798 });
+
+        var outcome = await RunAsync(MakeRule("sustained_offset", "300"), events);
+
+        var result = Assert.Single(outcome.Results);
+        var evidence = Assert.IsAssignableFrom<IDictionary<string, object>>(result.MatchedConditions["sustained_offset"]);
+        Assert.Equal("behind", evidence["direction"]);
+        Assert.Equal(-30.0, Convert.ToDouble(evidence["offsetMinutes"]), 1);
+        Assert.Equal(5, Convert.ToInt32(evidence["sentAtBatchCount"]));
+    }
+
+    [Fact]
+    public async Task SentAt_ImeOnlyBatches_MeasurableViaSendTime_Fires()
+    {
+        // IME-source events are excluded from the LEGACY measurement (writer timezone
+        // belief), but a SentAt batch never reads event timestamps — the device clock is
+        // measured from the send moment, so IME-only sessions become measurable.
+        var events = SentAtBatches(
+            new double[] { -1800, -1800, -1800, -1800, -1800 }, source: "ImeLogTracker");
+
+        var outcome = await RunAsync(MakeRule("sustained_offset", "300"), events);
+
+        var result = Assert.Single(outcome.Results);
+        var evidence = Assert.IsAssignableFrom<IDictionary<string, object>>(result.MatchedConditions["sustained_offset"]);
+        Assert.Equal("behind", evidence["direction"]);
+    }
+
+    [Fact]
+    public async Task SentAt_HealthyUploadLatencyBaseline_Silent()
+    {
+        var events = SentAtBatches(new double[] { -3, -5, -2, -4, -6 });
+
+        var outcome = await RunAsync(MakeRule("sustained_offset", "300"), events);
+
+        Assert.Empty(outcome.Results);
+    }
+
+    [Fact]
+    public async Task SentAt_MixedWithLegacyBatches_ConsistentFrame_Fires()
+    {
+        // Mid-session agent update: first half legacy (event-median), second half SentAt.
+        // Both measure the same physical quantity, so a consistent −30 min frame across the
+        // mix must still produce a sustained-offset verdict.
+        var events = Batches(new double[] { -1800, -1795, -1805 });
+        long seq = 1000;
+        for (int b = 0; b < 3; b++)
+        {
+            var receivedAt = T0.AddMinutes(60 + b * 5);
+            var sentAt = receivedAt.AddSeconds(-1800);
+            for (int i = 0; i < 5; i++)
+            {
+                var evt = MakeEvent(seq++, receivedAt, -1800 + (i - 2));
+                evt.SentAt = sentAt;
+                events.Add(evt);
+            }
+        }
+
+        var outcome = await RunAsync(MakeRule("sustained_offset", "300"), events);
+
+        var result = Assert.Single(outcome.Results);
+        var evidence = Assert.IsAssignableFrom<IDictionary<string, object>>(result.MatchedConditions["sustained_offset"]);
+        Assert.Equal(-30.0, Convert.ToDouble(evidence["offsetMinutes"]), 1);
+        Assert.Equal(3, Convert.ToInt32(evidence["sentAtBatchCount"]));
+        Assert.Equal(6, Convert.ToInt32(evidence["batchCount"]));
+    }
+
+    // ── ANALYZE-DEV-008 shape: two optional conditions ─────────────────────
+
+    [Fact]
+    public async Task Dev008Shape_JumpOnlySession_FiresWithSingleMatchedCondition()
+    {
+        // Mirrors the shipped rule: both conditions required:false, baseConfidence 60,
+        // threshold 50 — one matching metric must be enough to fire.
+        var rule = MakeRule("clock_jump", "300");
+        rule.Conditions[0].Required = false;
+        rule.Conditions.Add(new RuleCondition
+        {
+            Signal = "sustained_offset",
+            Source = "clock_skew",
+            SkewMetric = "sustained_offset",
+            Operator = "gte",
+            Value = "300",
+            Required = false,
+        });
+
+        var events = Batches(new double[] { 0, 0, 0, 0, 1800, 1800, 1800, 1800 });
+
+        var outcome = await RunAsync(rule, events);
+
+        var result = Assert.Single(outcome.Results);
+        Assert.True(result.MatchedConditions.ContainsKey("clock_jump"));
+    }
+
+    // ===== Helpers =====
+
+    private static AnalyzeRule MakeRule(string skewMetric, string thresholdSeconds) => new()
+    {
+        RuleId = "ANALYZE-TST-CLK",
+        Title = "clock_skew test rule",
+        Severity = "warning",
+        Category = "device",
+        Enabled = true,
+        IsBuiltIn = false,
+        BaseConfidence = 60,
+        ConfidenceThreshold = 50,
+        Conditions = new List<RuleCondition>
+        {
+            new()
+            {
+                Signal = skewMetric,
+                Source = "clock_skew",
+                SkewMetric = skewMetric,
+                Operator = "gte",
+                Value = thresholdSeconds,
+                Required = true,
+            }
+        },
+        Explanation = "test {{skewSummary}}",
+    };
+
+    /// <summary>
+    /// One upload batch per entry: 5 events sharing the batch's ReceivedAt, each with
+    /// Timestamp = ReceivedAt + offsetSeconds (±2 s in-batch jitter, well under the spread cap).
+    /// </summary>
+    private static List<EnrollmentEvent> Batches(double[] offsetsSeconds)
+    {
+        var events = new List<EnrollmentEvent>();
+        long seq = 1;
+        for (int b = 0; b < offsetsSeconds.Length; b++)
+        {
+            var receivedAt = T0.AddMinutes(b * 5);
+            for (int i = 0; i < 5; i++)
+                events.Add(MakeEvent(seq++, receivedAt, offsetsSeconds[b] + (i - 2)));
+        }
+        return events;
+    }
+
+    /// <summary>
+    /// One SentAt-carrying upload batch per frame offset: SentAt = ReceivedAt + frameOffset
+    /// (the P14 direct measurement), event timestamps default to healthy in-batch jitter but
+    /// can be overridden per batch to simulate spool spreads or backlogs.
+    /// </summary>
+    private static List<EnrollmentEvent> SentAtBatches(
+        double[] frameOffsetsSeconds,
+        Func<int, double[]>? eventOffsetsForBatch = null,
+        string source = "DecisionEngine")
+    {
+        var events = new List<EnrollmentEvent>();
+        long seq = 1;
+        for (int b = 0; b < frameOffsetsSeconds.Length; b++)
+        {
+            var receivedAt = T0.AddMinutes(b * 5);
+            var sentAt = receivedAt.AddSeconds(frameOffsetsSeconds[b]);
+            var offsets = eventOffsetsForBatch?.Invoke(b) ?? new double[] { -2, -1, 0, 1, 2 };
+            foreach (var offset in offsets)
+            {
+                var evt = MakeEvent(seq++, receivedAt, offset, source);
+                evt.SentAt = sentAt;
+                events.Add(evt);
+            }
+        }
+        return events;
+    }
+
+    private static EnrollmentEvent MakeEvent(long sequence, DateTime receivedAt, double offsetSeconds,
+        string source = "DecisionEngine") => new()
+    {
+        EventId = Guid.NewGuid().ToString(),
+        TenantId = TenantId,
+        SessionId = SessionId,
+        EventType = "status_update",
+        Source = source,
+        Timestamp = receivedAt.AddSeconds(offsetSeconds),
+        ReceivedAt = receivedAt,
+        Sequence = sequence,
+        Data = new Dictionary<string, object>(),
+    };
+
+    private static async Task<AnalysisOutcome> RunAsync(AnalyzeRule rule, List<EnrollmentEvent> events)
+    {
+        var ruleRepo = new Mock<IRuleRepository>();
+        ruleRepo.Setup(r => r.GetAnalyzeRulesAsync("global")).ReturnsAsync(new List<AnalyzeRule> { rule });
+        ruleRepo.Setup(r => r.GetAnalyzeRulesAsync(TenantId)).ReturnsAsync(new List<AnalyzeRule>());
+        ruleRepo.Setup(r => r.GetRuleStatesAsync(It.IsAny<string>())).ReturnsAsync(new Dictionary<string, RuleState>());
+        ruleRepo.Setup(r => r.GetRuleResultsAsync(It.IsAny<string>(), It.IsAny<string>())).ReturnsAsync(new List<RuleResult>());
+
+        var sessionRepo = new Mock<ISessionRepository>();
+        sessionRepo.Setup(s => s.GetSessionEventsStrictAsync(TenantId, SessionId, It.IsAny<int>())).ReturnsAsync(events);
+
+        var ruleService = new AnalyzeRuleService(ruleRepo.Object, NullLogger<AnalyzeRuleService>.Instance);
+        var engine = new RuleEngine(ruleService, ruleRepo.Object, sessionRepo.Object, NullLogger<RuleEngineClockSkewTests>.Instance);
+
+        return await engine.AnalyzeSessionAsync(TenantId, SessionId);
+    }
+}

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

@@ -270,6 +270,59 @@ public class RuleEngineDryRunTests
         Assert.Contains(DryRunAnalyzeRuleFunction.ValidateDraftRule(rule), e => e.Contains("joinField"));
     }
 
+    [Fact]
+    public void Validate_ClockSkewMissingOrUnknownMetric_Error()
+    {
+        var rule = MakeRule();
+        rule.Conditions[0].Source = "clock_skew";
+        rule.Conditions[0].SkewMetric = null;
+        rule.Conditions[0].Operator = "gte";
+        rule.Conditions[0].Value = "300";
+        Assert.Contains(DryRunAnalyzeRuleFunction.ValidateDraftRule(rule), e => e.Contains("skewMetric"));
+
+        rule.Conditions[0].SkewMetric = "drift"; // not a known metric
+        Assert.Contains(DryRunAnalyzeRuleFunction.ValidateDraftRule(rule), e => e.Contains("skewMetric"));
+    }
+
+    [Theory]
+    [InlineData("lt")]
+    [InlineData("equals")]
+    public void Validate_ClockSkewUnsupportedOperator_Error(string op)
+    {
+        var rule = MakeRule();
+        rule.Conditions[0].Source = "clock_skew";
+        rule.Conditions[0].SkewMetric = "clock_jump";
+        rule.Conditions[0].Operator = op;
+        rule.Conditions[0].Value = "300";
+        Assert.Contains(DryRunAnalyzeRuleFunction.ValidateDraftRule(rule), e => e.Contains("only gt/gte"));
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("abc")]
+    [InlineData("-300")]
+    [InlineData("0")]
+    public void Validate_ClockSkewNonPositiveThreshold_Error(string value)
+    {
+        var rule = MakeRule();
+        rule.Conditions[0].Source = "clock_skew";
+        rule.Conditions[0].SkewMetric = "sustained_offset";
+        rule.Conditions[0].Operator = "gte";
+        rule.Conditions[0].Value = value;
+        Assert.Contains(DryRunAnalyzeRuleFunction.ValidateDraftRule(rule), e => e.Contains("positive numeric value"));
+    }
+
+    [Fact]
+    public void Validate_ClockSkewValidCondition_NoErrors()
+    {
+        var rule = MakeRule();
+        rule.Conditions[0].Source = "clock_skew";
+        rule.Conditions[0].SkewMetric = "clock_jump";
+        rule.Conditions[0].Operator = "gte";
+        rule.Conditions[0].Value = "300";
+        Assert.Empty(DryRunAnalyzeRuleFunction.ValidateDraftRule(rule));
+    }
+
     [Fact]
     public void Validate_InvalidRegex_Error()
     {

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

@@ -48,8 +48,8 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
         public Task<RawPage<SessionSummary>> GetSessionsPageAsync(string tenantId, int? days, int pageSize, string? continuation)
             => _storage.GetSessionsPageAsync(tenantId, days, pageSize, continuation);
 
-        public Task<RawPage<SessionSummary>> GetAllSessionsPageAsync(string? tenantIdFilter, int? days, int pageSize, string? continuation, IReadOnlyCollection<string>? allowedTenantIds = null)
-            => _storage.GetAllSessionsPageAsync(tenantIdFilter, days, pageSize, continuation, allowedTenantIds);
+        public Task<RawPage<SessionSummary>> GetAllSessionsPageAsync(string? tenantIdFilter, int? days, int pageSize, string? continuation, IReadOnlyCollection<string>? allowedTenantIds = null, IEnumerable<string>? select = null)
+            => _storage.GetAllSessionsPageAsync(tenantIdFilter, days, pageSize, continuation, allowedTenantIds, select);
 
         public Task<SessionStats> GetSessionStatsAsync(string tenantId, int days)
             => _storage.GetSessionStatsAsync(tenantId, days);
@@ -131,9 +131,12 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
                 earliestEventTimestamp, latestEventTimestamp, currentPhase,
                 platformScriptIncrement, remediationScriptIncrement, rebootIncrement);
 
-        public Task ReconcileSessionCountersAsync(string tenantId, string sessionId)
+        public Task<SessionSkewScan?> ReconcileSessionCountersAsync(string tenantId, string sessionId)
             => _storage.ReconcileSessionCountersAsync(tenantId, sessionId);
 
+        public Task<Dictionary<string, int>> GetImeOffsetOriginHistogramAsync(string tenantId, string sessionId, int maxRows = 500)
+            => _storage.GetImeOffsetOriginHistogramAsync(tenantId, sessionId, maxRows);
+
         public Task UpdateSessionDiagnosticsBlobAsync(
             string tenantId, string sessionId, string blobName, string? destination = null)
             => _storage.UpdateSessionDiagnosticsBlobAsync(tenantId, sessionId, blobName, destination);
@@ -201,6 +204,9 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
         public Task<List<EnrollmentEvent>> GetSessionEventsByTypeAsync(string tenantId, string sessionId, string eventType, int maxResults = 200)
             => _storage.GetSessionEventsByTypeAsync(tenantId, sessionId, eventType, maxResults);
 
+        public Task<List<EnrollmentEvent>> GetSessionEventsByTypesAsync(string tenantId, string sessionId, IReadOnlyCollection<string> eventTypes, IEnumerable<string>? select = null, int maxResults = 2000)
+            => _storage.GetSessionEventsByTypesAsync(tenantId, sessionId, eventTypes, select, maxResults);
+
         public Task<RawPage<EnrollmentEvent>> GetSessionEventsPageAsync(string tenantId, string sessionId, int pageSize, string? continuation)
             => _storage.GetSessionEventsPageAsync(tenantId, sessionId, pageSize, continuation);
 

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

@@ -606,16 +606,14 @@ namespace AutopilotMonitor.Functions.Functions.Apps
             return date.AddDays(-diff);
         }
 
-        // Internal so AppVersionRegressionRadar shares the same nearest-rank convention
-        // (a third percentile implementation would invite subtle median drift).
+        // Internal so AppVersionRegressionRadar shares the same nearest-rank convention.
+        // Thin delegation onto the single shared implementation (PercentileMath) — parallel
+        // implementations would invite subtle median drift.
         internal static int Percentile(List<int> values, double percentile)
         {
             if (values.Count == 0) return 0;
-            var sorted = values.OrderBy(v => v).ToList();
-            var rank = (int)Math.Ceiling(percentile * sorted.Count) - 1;
-            if (rank < 0) rank = 0;
-            if (rank >= sorted.Count) rank = sorted.Count - 1;
-            return sorted[rank];
+            var sorted = values.Select(v => (double)v).OrderBy(v => v).ToList();
+            return (int)Helpers.PercentileMath.Percentile(sorted, percentile);
         }
     }
 }

src/Backend/AutopilotMonitor.Functions/Functions/Ingest/IngestTelemetryFunction.cs

@@ -221,10 +221,17 @@ namespace AutopilotMonitor.Functions.Functions.Ingest
                 // EventIngestProcessor, saving one Sessions point-read per batch.
                 var preFetchedStatus = TryReadSessionStatus(guardSessionRow);
 
+                // P14: device-clock send time of this upload (one value per request). Separates
+                // spool delay from device-vs-server clock offset downstream; absent/garbage → null.
+                var sentAtHeader = req.Headers.Contains("X-Send-Time-Utc")
+                    ? req.Headers.GetValues("X-Send-Time-Utc").FirstOrDefault()
+                    : null;
+                var sentAt = ParseSendTimeHeader(sentAtHeader);
+
                 // Partition + persist. Events are routed through EventIngestProcessor which runs the
                 // full pipeline (rule engine / app-install aggregation / SignalR / webhooks / ...);
                 // Signal + Transition go straight to their repositories.
-                var outcome = await PersistItemsAsync(items, bodyTenantId, sessionId, validation, preFetchedStatus);
+                var outcome = await PersistItemsAsync(items, bodyTenantId, sessionId, validation, preFetchedStatus, sentAt);
 
                 _logger.LogInformation(
                     "IngestTelemetry: tenant={Tenant} session={Session} events={E} signals={S} transitions={T} unknown={U}",
@@ -349,7 +356,8 @@ namespace AutopilotMonitor.Functions.Functions.Ingest
             string tenantId,
             string sessionId,
             SecurityValidationResult validation,
-            SessionStatus? preFetchedStatus)
+            SessionStatus? preFetchedStatus,
+            DateTime? sentAt)
         {
             var events      = new List<EnrollmentEvent>();
             var signals     = new List<SignalRecord>();
@@ -435,6 +443,7 @@ namespace AutopilotMonitor.Functions.Functions.Ingest
                     SessionId = sessionId,
                     TenantId  = tenantId,
                     Events    = events,
+                    SentAt    = sentAt,
                 };
                 var processed = await _eventProcessor.ProcessEventsAsync(eventRequest, validation, preFetchedStatus);
 
@@ -570,6 +579,29 @@ namespace AutopilotMonitor.Functions.Functions.Ingest
             return false;
         }
 
+        /// <summary>
+        /// Parses the <c>X-Send-Time-Utc</c> header (agent device-clock send time, ISO-8601
+        /// round-trip). Returns null for absent/unparseable values and for anything before
+        /// year 2000 — Table Storage rejects pre-1601 DateTimes outright, and a sub-2000
+        /// value can only be garbage, never a measurable clock offset. Deliberately NO upper
+        /// clamp: a future-dated send time IS the device-clock-error measurement this field
+        /// exists to capture.
+        /// </summary>
+        internal static DateTime? ParseSendTimeHeader(string? headerValue)
+        {
+            if (string.IsNullOrWhiteSpace(headerValue)) return null;
+
+            if (!DateTimeOffset.TryParse(
+                    headerValue,
+                    System.Globalization.CultureInfo.InvariantCulture,
+                    System.Globalization.DateTimeStyles.RoundtripKind,
+                    out var parsed))
+                return null;
+
+            var utc = parsed.UtcDateTime;
+            return utc.Year >= 2000 ? utc : (DateTime?)null;
+        }
+
         /// <summary>
         /// PartitionKey convention is <c>{tenantId}_{sessionId}</c> — both GUIDs with dashes, so
         /// splitting on the single underscore between them is unambiguous. Returns false for any

src/Backend/AutopilotMonitor.Functions/Functions/Ingest/ReportAgentErrorFunction.cs

@@ -178,9 +178,90 @@ namespace AutopilotMonitor.Functions.Functions.Ingest
 
             await MaterializeEmergencyBreakArtifactsAsync(report, tenantId, _sessionRepo, _opsEventService, _logger);
 
+            var adminConfig = await _adminConfigService.GetConfigurationAsync();
+            await MaterializeIntegrityMismatchAsync(
+                report, tenantId, _opsEventService,
+                adminConfig?.LatestAgentV2Version, adminConfig?.LatestAgentV2ExeSha256, _logger);
+
             return req.CreateResponse(HttpStatusCode.OK);
         }
 
+        /// <summary>
+        /// Regex over OUR OWN report format (AgentRuntimeConfig.VerifyBinaryIntegrity):
+        /// "... actual=&lt;sha256&gt;, expected=&lt;sha256&gt;". Parsed leniently — an unparseable
+        /// message records rather than suppresses.
+        /// </summary>
+        private static readonly System.Text.RegularExpressions.Regex ActualHashRegex =
+            new(@"actual=([0-9a-fA-F]{64})", System.Text.RegularExpressions.RegexOptions.Compiled);
+
+        /// <summary>
+        /// Surfaces an <c>IntegrityCheckFailed</c> report as an <c>AgentBinaryIntegrityMismatch</c>
+        /// ops event. Before 2026-08-20 this report went to App Insights only — session e9753578's
+        /// agent reported a hash mismatch and no product surface showed it, which cost a day of
+        /// mis-attributed root-causing.
+        ///
+        /// <para>
+        /// KNOWN, ACCEPTED RACE (must not spam the ops feed): around every release, agents compare
+        /// against a hash snapshot that does not belong to their own binary — a freshly installed
+        /// latest agent can receive the PREVIOUS release's hashes from the 5-minute
+        /// AdminConfiguration cache (e9753578: genuine 1410 exe vs cached 1409 hash), and an
+        /// older agent's next config fetch sees the NEW release's hash. Both self-heal via the
+        /// forced self-update. Suppression, evaluated against the CURRENT config at receive time:
+        /// the reported RUNNING hash equals the published exe (stale expectation), or the
+        /// reporting agent's version is not the latest (update in flight). What remains — an agent
+        /// claiming the latest version whose binary is NOT the published one — is the real signal:
+        /// tamper, stale blob, or a build that never came from the release pipeline.
+        /// </para>
+        ///
+        /// <para>
+        /// Ops event only, no timeline event: the report is about the BINARY, not the enrollment,
+        /// and may arrive before the session is registered. No idempotency read: the agent-side
+        /// trigger is single-shot per process. Best-effort — a failure here must never turn the
+        /// always-200 channel into a retry loop.
+        /// </para>
+        /// </summary>
+        internal static async Task MaterializeIntegrityMismatchAsync(
+            AgentErrorReport report,
+            string tenantId,
+            OpsEventService opsEventService,
+            string? latestAgentVersion,
+            string? latestAgentExeSha256,
+            ILogger logger)
+        {
+            if (report.ErrorType != AgentErrorType.IntegrityCheckFailed)
+            {
+                return;
+            }
+
+            try
+            {
+                // "2.0.1410+3b59dab2..." → "2.0.1410" (the manifest/AdminConfig carry no +commit).
+                var reportedVersion = (report.AgentVersion ?? string.Empty).Split('+')[0];
+                if (!string.IsNullOrEmpty(latestAgentVersion)
+                    && !string.IsNullOrEmpty(reportedVersion)
+                    && !string.Equals(reportedVersion, latestAgentVersion, StringComparison.OrdinalIgnoreCase))
+                {
+                    return; // older agent vs newer release — the forced self-update heals this.
+                }
+
+                var actualMatch = ActualHashRegex.Match(report.Message ?? string.Empty);
+                if (actualMatch.Success
+                    && !string.IsNullOrEmpty(latestAgentExeSha256)
+                    && string.Equals(actualMatch.Groups[1].Value, latestAgentExeSha256, StringComparison.OrdinalIgnoreCase))
+                {
+                    return; // the running binary IS the published one — the agent's expectation was stale.
+                }
+
+                await opsEventService.RecordAgentBinaryIntegrityMismatchAsync(
+                    tenantId, report.SessionId, report.AgentVersion, report.Message ?? string.Empty);
+            }
+            catch (Exception ex)
+            {
+                logger.LogWarning(ex,
+                    "ReportAgentError: failed to record AgentBinaryIntegrityMismatch ops event for session {SessionId}", report.SessionId);
+            }
+        }
+
         /// <summary>
         /// Materializes the agent's silent 48h emergency break as (1) a timeline event so it shows
         /// in the session and the timeout classifier can see it, (2) the cross-session EventType

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

@@ -0,0 +1,85 @@
+using System.Net;
+using AutopilotMonitor.Functions.Services;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Azure.Functions.Worker.Http;
+using Microsoft.Extensions.Logging;
+
+namespace AutopilotMonitor.Functions.Functions.Metrics
+{
+    /// <summary>
+    /// Agent-efficiency aggregate (Global Admin / Global Reader): per-agent-version percentiles
+    /// for CPU, memory, handles, threads, spool and request metrics plus crash rates — computed
+    /// server-side so review tooling never has to pull raw snapshot rows. Honors <c>?tenantId=</c>
+    /// to scope the aggregate to one tenant (TenantScoping.QueryParam in the policy catalog).
+    /// </summary>
+    public class GetGlobalAgentEfficiencyFunction
+    {
+        private readonly ILogger<GetGlobalAgentEfficiencyFunction> _logger;
+        private readonly AgentEfficiencyMetricsService _efficiencyService;
+
+        public GetGlobalAgentEfficiencyFunction(
+            ILogger<GetGlobalAgentEfficiencyFunction> logger,
+            AgentEfficiencyMetricsService efficiencyService)
+        {
+            _logger = logger;
+            _efficiencyService = efficiencyService;
+        }
+
+        [Function("GetGlobalAgentEfficiency")]
+        public async Task<HttpResponseData> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "global/metrics/agent-efficiency")] HttpRequestData req)
+        {
+            try
+            {
+                // Authentication + GlobalReadOrAdmin authorization enforced by PolicyEnforcementMiddleware
+
+                var query = System.Web.HttpUtility.ParseQueryString(req.Url.Query);
+                var days = ParseIntParam(query["days"], defaultValue: 30, min: 1, max: 365);
+                var limit = ParseIntParam(query["limit"], defaultValue: 500, min: 1, max: 2000);
+
+                var tenantIdRaw = query["tenantId"];
+                string? tenantId = null;
+                if (!string.IsNullOrWhiteSpace(tenantIdRaw))
+                {
+                    // The repo's per-tenant route throws on malformed GUIDs — turn that
+                    // caller bug into a 400 instead of a 500.
+                    if (!Guid.TryParse(tenantIdRaw, out var parsedTenant))
+                    {
+                        var badRequest = req.CreateResponse(HttpStatusCode.BadRequest);
+                        await badRequest.WriteAsJsonAsync(new { success = false, message = "Invalid tenantId" });
+                        return badRequest;
+                    }
+                    tenantId = parsedTenant.ToString();
+                }
+
+                var metrics = await _efficiencyService.ComputeAsync(days, limit, tenantId);
+
+                var response = req.CreateResponse(HttpStatusCode.OK);
+                await response.WriteAsJsonAsync(metrics);
+                return response;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error computing agent efficiency metrics");
+
+                var errorResponse = req.CreateResponse(HttpStatusCode.InternalServerError);
+                await errorResponse.WriteAsJsonAsync(new
+                {
+                    success = false,
+                    message = "Failed to compute agent efficiency metrics"
+                });
+                return errorResponse;
+            }
+        }
+
+        private static int ParseIntParam(string? raw, int defaultValue, int min, int max)
+        {
+            var value = defaultValue;
+            if (!string.IsNullOrEmpty(raw) && int.TryParse(raw, out var parsed) && parsed > 0)
+                value = parsed;
+            if (value < min) value = min;
+            if (value > max) value = max;
+            return value;
+        }
+    }
+}

src/Backend/AutopilotMonitor.Functions/Functions/Rules/DryRunAnalyzeRuleFunction.cs

@@ -128,7 +128,12 @@ namespace AutopilotMonitor.Functions.Functions.Rules
         internal static readonly HashSet<string> KnownSources = new(StringComparer.Ordinal)
         {
             "event_type", "event_data", "event_data_array", "event_count",
-            "phase_duration", "app_install_duration", "event_correlation",
+            "phase_duration", "app_install_duration", "event_correlation", "clock_skew",
+        };
+
+        internal static readonly HashSet<string> KnownSkewMetrics = new(StringComparer.Ordinal)
+        {
+            "clock_jump", "sustained_offset",
         };
 
         internal static readonly HashSet<string> KnownOperators = new(StringComparer.OrdinalIgnoreCase)
@@ -196,6 +201,18 @@ namespace AutopilotMonitor.Functions.Functions.Rules
                         errors.Add($"{label}: event_correlation requires joinField");
                 }
 
+                if (string.Equals(c.Source, "clock_skew", StringComparison.Ordinal))
+                {
+                    if (string.IsNullOrWhiteSpace(c.SkewMetric) || !KnownSkewMetrics.Contains(c.SkewMetric))
+                        errors.Add($"{label}: clock_skew requires skewMetric (one of: {string.Join(", ", KnownSkewMetrics)})");
+                    if (!string.Equals(c.Operator, "gt", StringComparison.OrdinalIgnoreCase)
+                        && !string.Equals(c.Operator, "gte", StringComparison.OrdinalIgnoreCase))
+                        errors.Add($"{label}: clock_skew supports only gt/gte (magnitude vs threshold)");
+                    if (!double.TryParse(c.Value, System.Globalization.NumberStyles.Float,
+                            System.Globalization.CultureInfo.InvariantCulture, out var skewThreshold) || skewThreshold <= 0)
+                        errors.Add($"{label}: clock_skew requires a positive numeric value (threshold in seconds)");
+                }
+
                 if ((string.Equals(c.Operator, "regex", StringComparison.OrdinalIgnoreCase)
                         || string.Equals(c.Operator, "not_regex", StringComparison.OrdinalIgnoreCase))
                     && !string.IsNullOrEmpty(c.Value))

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

@@ -63,7 +63,7 @@ namespace AutopilotMonitor.Functions.Helpers
         private static readonly HashSet<string> KnownFieldKeys = new(StringComparer.OrdinalIgnoreCase)
         {
             "eventId", "sessionId", "tenantId", "eventType", "severity", "source", "phase",
-            "phaseName", "timestamp", "receivedAt", "message", "sequence", "rowKey",
+            "phaseName", "timestamp", "receivedAt", "sentAt", "message", "sequence", "rowKey",
             "originalTimestamp", "timestampClamped", "causedByTransitionStepIndex",
             "causedBySignalOrdinal", "data",
         };
@@ -86,6 +86,7 @@ namespace AutopilotMonitor.Functions.Helpers
             if (fields.Contains("phaseName")) dict["phaseName"] = e.PhaseName;
             if (fields.Contains("timestamp")) dict["timestamp"] = e.Timestamp;
             if (fields.Contains("receivedAt")) dict["receivedAt"] = e.ReceivedAt;
+            if (fields.Contains("sentAt")) dict["sentAt"] = e.SentAt;
             if (fields.Contains("message")) dict["message"] = e.Message;
             if (fields.Contains("sequence")) dict["sequence"] = e.Sequence;
             if (fields.Contains("rowKey")) dict["rowKey"] = e.RowKey;

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

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace AutopilotMonitor.Functions.Helpers
+{
+    /// <summary>
+    /// The single nearest-rank percentile implementation (rank = ceil(p·n) − 1, clamped).
+    /// AppsAnalyticsHelper.Percentile and PlatformMetricsService.Percentile delegate here;
+    /// keep it that way — parallel implementations invite subtle median drift between
+    /// surfaces that report the "same" statistic.
+    /// </summary>
+    internal static class PercentileMath
+    {
+        /// <summary>Nearest-rank percentile over an ascending-sorted list.</summary>
+        internal static double Percentile(IReadOnlyList<double> sortedValues, double percentile)
+        {
+            if (sortedValues.Count == 0) return 0;
+            var rank = (int)Math.Ceiling(percentile * sortedValues.Count) - 1;
+            return sortedValues[Math.Max(0, Math.Min(rank, sortedValues.Count - 1))];
+        }
+
+        /// <summary>Median (p50) over unsorted values.</summary>
+        internal static double Median(IEnumerable<double> values)
+        {
+            var sorted = values.OrderBy(v => v).ToList();
+            return Percentile(sorted, 0.50);
+        }
+    }
+}

src/Backend/AutopilotMonitor.Functions/Program.cs

@@ -242,6 +242,7 @@ builder.Services.AddSingleton<RateLimitService>();
 builder.Services.AddSingleton<DistressRateLimitService>();
 builder.Services.AddSingleton<UsageMetricsService>();
 builder.Services.AddSingleton<PlatformMetricsService>();
+builder.Services.AddSingleton<AgentEfficiencyMetricsService>();
 builder.Services.AddSingleton<SlaMetricsService>();
 builder.Services.AddSingleton<SlaBreachEvaluationService>();
 builder.Services.AddSingleton<GlobalAdminService>();

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

@@ -456,6 +456,7 @@ public static class EndpointAccessPolicyCatalog
         new("GET",    "global/presence",            EndpointPolicy.GlobalReadOrAdmin),
         new("GET",    "global/tenants-with-deletion-manifests", EndpointPolicy.GlobalReadOrAdmin),
         new("GET",    "global/metrics/platform",    EndpointPolicy.GlobalReadOrAdmin),
+        new("GET",    "global/metrics/agent-efficiency", EndpointPolicy.GlobalReadOrAdmin, TenantScoping.QueryParam),
         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),

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

@@ -0,0 +1,378 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Shared.DataAccess;
+using AutopilotMonitor.Shared.Models;
+using Microsoft.Extensions.Logging;
+
+namespace AutopilotMonitor.Functions.Services
+{
+    /// <summary>
+    /// Server-side agent-efficiency aggregation, bucketed by agent version: CPU, working set,
+    /// private bytes, thread/handle counts, spool depth/file size, API latency/request counts
+    /// and crash rates — as percentiles per version, so review tooling (MCP) gets the answer
+    /// directly instead of pulling thousands of raw snapshot rows. Raw per-session data only
+    /// surfaces as the top offenders per dimension.
+    /// Scan shape: one projected SessionsIndex page + one filtered, projected per-session
+    /// event query (agent_metrics_snapshot / agent_started / spool_pressure_detected only),
+    /// bounded to 32 concurrent storage calls. 5-minute per-(days, limit, tenant) cache.
+    /// </summary>
+    public class AgentEfficiencyMetricsService
+    {
+        private readonly ISessionRepository _sessionRepo;
+        private readonly ILogger<AgentEfficiencyMetricsService> _logger;
+
+        private static readonly Dictionary<(int days, int limit, string tenantKey), (AgentEfficiencyMetricsResponse metrics, DateTime expiry)> _cachedByKey = new();
+        private static readonly TimeSpan CacheDuration = TimeSpan.FromMinutes(5);
+        private static readonly object _cacheLock = new object();
+
+        private const int DefaultWindowDays = 30;
+        private const int DefaultSessionLimit = 500;
+        private const int MaxSessionLimit = 2000;
+        private const int PerSessionFetchConcurrency = 32;
+        private const int TopOffendersPerDimension = 3;
+
+        // SessionsIndex columns this scan consumes. PartitionKey (TenantId), RowKey, StartedAt and
+        // SessionId also feed the repo's merge/cursor mechanics; AgentVersion buckets, DeviceName
+        // labels the offender rows; AvgApiLatencyMs/ApiRequestCount are the mirrored per-session
+        // network aggregates (SessionIndexFieldManifest) so latency percentiles need no event
+        // fetch at all. Everything else on the ~40-column mirror maps to defaults via the
+        // null-safe getters and is never read here. Pinned by
+        // AgentEfficiencyProjectionEquivalenceTests.
+        internal static readonly string[] SessionIndexProjection =
+        {
+            "PartitionKey", "RowKey", "SessionId", "StartedAt",
+            "AgentVersion", "DeviceName", "AvgApiLatencyMs", "ApiRequestCount"
+        };
+
+        public AgentEfficiencyMetricsService(
+            ISessionRepository sessionRepo,
+            ILogger<AgentEfficiencyMetricsService> logger)
+        {
+            _sessionRepo = sessionRepo;
+            _logger = logger;
+        }
+
+        public async Task<AgentEfficiencyMetricsResponse> ComputeAsync(
+            int days = DefaultWindowDays,
+            int limit = DefaultSessionLimit,
+            string? tenantId = null)
+        {
+            days = Math.Clamp(days, 1, 365);
+            limit = Math.Clamp(limit, 1, MaxSessionLimit);
+            var key = (days, limit, tenantId ?? string.Empty);
+
+            lock (_cacheLock)
+            {
+                if (_cachedByKey.TryGetValue(key, out var entry) && DateTime.UtcNow < entry.expiry)
+                {
+                    // Shallow copy so flipping FromCache never mutates the instance an earlier
+                    // (fresh) caller may still be holding/serializing. The buckets are shared
+                    // read-only — nothing downstream writes into a response.
+                    return entry.metrics.CloneAsCacheHit();
+                }
+            }
+
+            _logger.LogInformation("Computing agent efficiency metrics for days={Days} limit={Limit} tenant={Tenant}...",
+                days, limit, tenantId ?? "(all)");
+            var stopwatch = Stopwatch.StartNew();
+
+            var metrics = await ComputeInternalAsync(days, limit, tenantId);
+
+            stopwatch.Stop();
+            metrics.ComputeDurationMs = (int)stopwatch.ElapsedMilliseconds;
+            metrics.ComputedAt = DateTime.UtcNow;
+            metrics.FromCache = false;
+            metrics.WindowDays = days;
+            metrics.SessionLimit = limit;
+            metrics.TenantId = tenantId;
+
+            _logger.LogInformation("Agent efficiency metrics computed in {Ms}ms (days={Days} limit={Limit} sessionsScanned={Scanned})",
+                metrics.ComputeDurationMs, days, limit, metrics.SessionsScanned);
+
+            lock (_cacheLock)
+            {
+                _cachedByKey[key] = (metrics, DateTime.UtcNow.Add(CacheDuration));
+            }
+
+            return metrics;
+        }
+
+        // Per-session intermediate: everything the bucket aggregation needs from one
+        // storage round-trip. Snapshot-derived values are meaningless when HasSnapshots
+        // is false — the aggregation only reads them behind that flag.
+        private sealed record SessionEfficiencyData(
+            string SessionId,
+            string TenantId,
+            string? DeviceName,
+            string ResolvedVersion,
+            bool HasSnapshots,
+            double AvgCpu,
+            double MaxCpu,
+            double MaxWorkingSetMb,
+            double MaxPrivateBytesMb,
+            double MaxThreads,
+            double MaxHandles,
+            double MaxSpoolDepth,
+            double MaxSpoolFileBytes,
+            double ApiLatencyMs,
+            double ApiRequestCount,
+            bool SpoolPressure,
+            List<Dictionary<string, object>> AgentStartedEvents);
+
+        private async Task<AgentEfficiencyMetricsResponse> ComputeInternalAsync(int days, int limit, string? tenantId)
+        {
+            var sessionPage = await _sessionRepo.GetAllSessionsPageAsync(
+                tenantIdFilter: tenantId, days: days, pageSize: limit, continuation: null,
+                allowedTenantIds: null, select: SessionIndexProjection);
+            var allSessions = sessionPage.Items;
+
+            if (allSessions.Count == 0)
+            {
+                return new AgentEfficiencyMetricsResponse();
+            }
+
+            var perSession = await AgentMetricsAggregation.RunWithBoundedConcurrencyAsync(
+                allSessions, PerSessionFetchConcurrency, ProcessSessionAsync);
+
+            var byVersion = perSession
+                .GroupBy(s => s.ResolvedVersion, StringComparer.Ordinal)
+                .Select(g => BuildBucket(g.Key, g.ToList()))
+                .OrderByDescending(b => b.SessionsScanned)
+                .ThenBy(b => b.AgentVersion, StringComparer.Ordinal)
+                .ToList();
+
+            return new AgentEfficiencyMetricsResponse
+            {
+                SessionsScanned = allSessions.Count,
+                SessionsWithSnapshots = perSession.Count(s => s.HasSnapshots),
+                ByVersion = byVersion,
+                Overall = BuildBucket(null, perSession)
+            };
+        }
+
+        private async Task<SessionEfficiencyData> ProcessSessionAsync(SessionSummary session)
+        {
+            List<Dictionary<string, object>> snapshots = new();
+            List<Dictionary<string, object>> agentStarts = new();
+            var spoolPressure = false;
+
+            try
+            {
+                var events = await _sessionRepo.GetSessionEventsByTypesAsync(
+                    session.TenantId, session.SessionId, AgentMetricsAggregation.MetricsEventTypes,
+                    TableStorageService.AgentMetricsEventProjection);
+
+                foreach (var e in events)
+                {
+                    if (e.EventType == Shared.Constants.EventTypes.AgentMetricsSnapshot && e.Data != null)
+                        snapshots.Add(e.Data);
+                    else if (e.EventType == Shared.Constants.EventTypes.AgentStarted && e.Data != null)
+                        agentStarts.Add(e.Data);
+                    else if (e.EventType == Shared.Constants.EventTypes.SpoolPressureDetected)
+                        spoolPressure = true;
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "Failed to fetch efficiency events for session {SessionId}", session.SessionId);
+            }
+
+            // Resolve the bucket version: snapshot payload first (authoritative for the run),
+            // SessionsIndex mirror second, "unknown" last. All of a session's agent_started
+            // events tally into this one bucket — a mid-session self-update attributes the
+            // pre-update exits to the final version, an accepted simplification.
+            var resolvedVersion = snapshots
+                .Select(s => AgentMetricsAggregation.GetString(s, "agent_version"))
+                .FirstOrDefault(v => !string.IsNullOrEmpty(v));
+            if (string.IsNullOrEmpty(resolvedVersion))
+                resolvedVersion = string.IsNullOrEmpty(session.AgentVersion) ? "unknown" : session.AgentVersion;
+
+            double avgCpu = 0, maxCpu = 0, maxWs = 0, maxPb = 0, maxThreads = 0, maxHandles = 0, maxSpool = 0, maxSpoolFile = 0;
+            double apiLatency = session.AvgApiLatencyMs ?? 0;
+            double apiRequests = session.ApiRequestCount ?? 0;
+
+            if (snapshots.Count > 0)
+            {
+                var cpuValues = snapshots.Select(s => AgentMetricsAggregation.GetDouble(s, "agent_cpu_percent")).ToList();
+                avgCpu = cpuValues.Average();
+                maxCpu = cpuValues.Max();
+                maxWs = snapshots.Max(s => AgentMetricsAggregation.GetDouble(s, "agent_working_set_mb"));
+                maxPb = snapshots.Max(s => AgentMetricsAggregation.GetDouble(s, "agent_private_bytes_mb"));
+                maxThreads = snapshots.Max(s => AgentMetricsAggregation.GetDouble(s, "agent_thread_count"));
+                maxHandles = snapshots.Max(s => AgentMetricsAggregation.GetDouble(s, "agent_handle_count"));
+                // V2 emits `spool_pending_item_count`; V1 emitted `spool_queue_depth`.
+                maxSpool = snapshots.Max(s => AgentMetricsAggregation.GetDoubleFirst(s, "spool_pending_item_count", "spool_queue_depth"));
+                maxSpoolFile = snapshots.Max(s => AgentMetricsAggregation.GetDouble(s, "spool_file_size_bytes"));
+
+                // The SessionsIndex mirror carries the exact session average for agents that
+                // emit the cumulative counters; fall back to computing it from the last
+                // snapshot for sessions whose mirror write never happened.
+                if (apiLatency <= 0)
+                {
+                    var last = snapshots[snapshots.Count - 1];
+                    var totalLatencyMs = AgentMetricsAggregation.GetDouble(last, "net_total_latency_ms");
+                    var totalRequests = AgentMetricsAggregation.GetDouble(last, "net_total_requests");
+                    if (totalLatencyMs > 0 && totalRequests > 0)
+                        apiLatency = totalLatencyMs / totalRequests;
+                    if (apiRequests <= 0)
+                        apiRequests = totalRequests;
+                }
+            }
+
+            return new SessionEfficiencyData(
+                session.SessionId, session.TenantId, session.DeviceName, resolvedVersion!,
+                HasSnapshots: snapshots.Count > 0,
+                avgCpu, maxCpu, maxWs, maxPb, maxThreads, maxHandles, maxSpool, maxSpoolFile,
+                apiLatency, apiRequests, spoolPressure, agentStarts);
+        }
+
+        // agentVersion == null builds the cross-version "overall" bucket (version omitted on the wire).
+        private static AgentVersionEfficiency BuildBucket(string? agentVersion, List<SessionEfficiencyData> sessions)
+        {
+            var withSnapshots = sessions.Where(s => s.HasSnapshots).ToList();
+
+            var bucket = new AgentVersionEfficiency
+            {
+                AgentVersion = agentVersion,
+                SessionsScanned = sessions.Count,
+                SessionsWithSnapshots = withSnapshots.Count,
+                SpoolPressureSessions = sessions.Count(s => s.SpoolPressure),
+                AvgCpuPercent = BuildStats(withSnapshots.Select(s => s.AvgCpu)),
+                MaxCpuPercent = BuildStats(withSnapshots.Select(s => s.MaxCpu)),
+                MaxWorkingSetMb = BuildStats(withSnapshots.Select(s => s.MaxWorkingSetMb)),
+                MaxPrivateBytesMb = BuildStats(withSnapshots.Select(s => s.MaxPrivateBytesMb)),
+                // Thread/handle counts only exist on agents that emit them (V2); zero-filtered so
+                // legacy sessions don't drag the percentiles to 0.
+                MaxThreadCount = BuildStats(withSnapshots.Select(s => s.MaxThreads).Where(v => v > 0)),
+                MaxHandleCount = BuildStats(withSnapshots.Select(s => s.MaxHandles).Where(v => v > 0)),
+                MaxSpoolDepth = BuildStats(withSnapshots.Select(s => s.MaxSpoolDepth)),
+                MaxSpoolFileBytes = BuildStats(withSnapshots.Select(s => s.MaxSpoolFileBytes)),
+                // Latency/requests come from the SessionsIndex mirror, so sessions without
+                // snapshots still contribute; zero means "no data", not "0 ms".
+                ApiLatencyMs = BuildStats(sessions.Select(s => s.ApiLatencyMs).Where(v => v > 0)),
+                ApiRequestCount = BuildStats(sessions.Select(s => s.ApiRequestCount).Where(v => v > 0)),
+                CrashRate = AgentMetricsAggregation.AggregateCrashRate(sessions.SelectMany(s => s.AgentStartedEvents))
+            };
+
+            var offenders = new List<EfficiencyOffender>();
+            AddTopOffenders(offenders, withSnapshots, "maxCpuPercent", s => s.MaxCpu);
+            AddTopOffenders(offenders, withSnapshots, "maxWorkingSetMb", s => s.MaxWorkingSetMb);
+            AddTopOffenders(offenders, withSnapshots, "maxHandleCount", s => s.MaxHandles);
+            bucket.TopOffenders = offenders.Count > 0 ? offenders : null;
+
+            return bucket;
+        }
+
+        private static void AddTopOffenders(
+            List<EfficiencyOffender> target,
+            List<SessionEfficiencyData> sessions,
+            string dimension,
+            Func<SessionEfficiencyData, double> value)
+        {
+            target.AddRange(sessions
+                .Where(s => value(s) > 0)
+                .OrderByDescending(value)
+                .Take(TopOffendersPerDimension)
+                .Select(s => new EfficiencyOffender
+                {
+                    SessionId = s.SessionId,
+                    TenantId = s.TenantId,
+                    DeviceName = string.IsNullOrEmpty(s.DeviceName) ? null : s.DeviceName,
+                    Dimension = dimension,
+                    Value = Math.Round(value(s), 1)
+                }));
+        }
+
+        private static PercentileStats? BuildStats(IEnumerable<double> values)
+        {
+            var sorted = values.OrderBy(v => v).ToList();
+            if (sorted.Count == 0) return null;
+
+            return new PercentileStats
+            {
+                P50 = MetricsMath.Percentile(sorted, 50),
+                P95 = MetricsMath.Percentile(sorted, 95),
+                Max = Math.Round(sorted[sorted.Count - 1], 1),
+                Avg = Math.Round(sorted.Average(), 1),
+                SampleCount = sorted.Count
+            };
+        }
+    }
+
+    // ── Response DTOs ────────────────────────────────────────────────────────────
+
+    public class AgentEfficiencyMetricsResponse
+    {
+        public int WindowDays { get; set; }
+        public int SessionLimit { get; set; }
+        /// <summary>Echo of the requested tenant filter; null = cross-tenant aggregate.</summary>
+        public string? TenantId { get; set; }
+        /// <summary>Sessions the scan covered — compare against <see cref="SessionLimit"/> for truncation.</summary>
+        public int SessionsScanned { get; set; }
+        public int SessionsWithSnapshots { get; set; }
+        public List<AgentVersionEfficiency> ByVersion { get; set; } = new();
+        public AgentVersionEfficiency? Overall { get; set; }
+        public DateTime ComputedAt { get; set; }
+        public int ComputeDurationMs { get; set; }
+        public bool FromCache { get; set; }
+
+        /// <summary>Shallow copy flagged as a cache hit — see the cache-read path.</summary>
+        internal AgentEfficiencyMetricsResponse CloneAsCacheHit() => new()
+        {
+            WindowDays = WindowDays,
+            SessionLimit = SessionLimit,
+            TenantId = TenantId,
+            SessionsScanned = SessionsScanned,
+            SessionsWithSnapshots = SessionsWithSnapshots,
+            ByVersion = ByVersion,
+            Overall = Overall,
+            ComputedAt = ComputedAt,
+            ComputeDurationMs = ComputeDurationMs,
+            FromCache = true
+        };
+    }
+
+    public class AgentVersionEfficiency
+    {
+        /// <summary>Null on the cross-version "overall" bucket (omitted on the wire).</summary>
+        public string? AgentVersion { get; set; }
+        public int SessionsScanned { get; set; }
+        public int SessionsWithSnapshots { get; set; }
+        public int SpoolPressureSessions { get; set; }
+        public PercentileStats? AvgCpuPercent { get; set; }
+        public PercentileStats? MaxCpuPercent { get; set; }
+        public PercentileStats? MaxWorkingSetMb { get; set; }
+        public PercentileStats? MaxPrivateBytesMb { get; set; }
+        public PercentileStats? MaxThreadCount { get; set; }
+        public PercentileStats? MaxHandleCount { get; set; }
+        public PercentileStats? MaxSpoolDepth { get; set; }
+        public PercentileStats? MaxSpoolFileBytes { get; set; }
+        public PercentileStats? ApiLatencyMs { get; set; }
+        public PercentileStats? ApiRequestCount { get; set; }
+        public CrashRateMetrics? CrashRate { get; set; }
+        public List<EfficiencyOffender>? TopOffenders { get; set; }
+    }
+
+    /// <summary>Distribution of a per-session statistic across a version bucket.</summary>
+    public class PercentileStats
+    {
+        public double P50 { get; set; }
+        public double P95 { get; set; }
+        public double Max { get; set; }
+        public double Avg { get; set; }
+        public int SampleCount { get; set; }
+    }
+
+    public class EfficiencyOffender
+    {
+        public string SessionId { get; set; } = string.Empty;
+        public string TenantId { get; set; } = string.Empty;
+        public string? DeviceName { get; set; }
+        public string Dimension { get; set; } = string.Empty;
+        public double Value { get; set; }
+    }
+}

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

@@ -0,0 +1,145 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace AutopilotMonitor.Functions.Services
+{
+    /// <summary>
+    /// Shared primitives for the agent-metrics aggregation services
+    /// (<see cref="PlatformMetricsService"/>, <see cref="AgentEfficiencyMetricsService"/>):
+    /// crash-rate tally over <c>agent_started</c> payloads, bounded fan-out, and the
+    /// loosely-typed payload getters. One home so the two services cannot drift on the
+    /// exit-type classification or the numeric coercion rules.
+    /// </summary>
+    internal static class AgentMetricsAggregation
+    {
+        /// <summary>
+        /// Event types the metrics aggregations consume. Everything else in a session's
+        /// Events partition is dead weight for these endpoints — pairs with
+        /// <see cref="TableStorageService.AgentMetricsEventProjection"/> for a filtered,
+        /// projected per-session fetch instead of a full-partition drain.
+        /// </summary>
+        internal static readonly string[] MetricsEventTypes =
+        {
+            Shared.Constants.EventTypes.AgentMetricsSnapshot,
+            Shared.Constants.EventTypes.AgentStarted,
+            Shared.Constants.EventTypes.SpoolPressureDetected
+        };
+
+        /// <summary>
+        /// Tallies crash classifications over <c>agent_started</c> event payloads.
+        /// Unknown/absent <c>previousExitType</c> counts as a first run (the agent only
+        /// omits it on its very first boot of a session).
+        /// </summary>
+        internal static CrashRateMetrics AggregateCrashRate(IEnumerable<Dictionary<string, object>> agentStartedEvents)
+        {
+            var metrics = new CrashRateMetrics();
+            var exceptionCounts = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
+
+            foreach (var data in agentStartedEvents)
+            {
+                metrics.TotalStarts++;
+                var exitType = GetString(data, "previousExitType");
+                switch (exitType)
+                {
+                    case "clean":
+                        metrics.CleanExits++;
+                        break;
+                    case "exception_crash":
+                        metrics.ExceptionCrashes++;
+                        var exType = GetString(data, "previousCrashException");
+                        if (!string.IsNullOrEmpty(exType))
+                        {
+                            exceptionCounts.TryGetValue(exType, out var count);
+                            exceptionCounts[exType] = count + 1;
+                        }
+                        break;
+                    case "hard_kill":
+                        metrics.HardKills++;
+                        break;
+                    case "reboot_kill":
+                        metrics.RebootKills++;
+                        break;
+                    default:
+                        metrics.FirstRuns++;
+                        break;
+                }
+            }
+
+            var nonFirstRuns = metrics.TotalStarts - metrics.FirstRuns;
+            metrics.CrashRatePercent = nonFirstRuns > 0
+                ? Math.Round((double)metrics.ExceptionCrashes / nonFirstRuns * 100, 1)
+                : 0;
+
+            metrics.TopExceptions = exceptionCounts
+                .OrderByDescending(kv => kv.Value)
+                .Take(5)
+                .Select(kv => new CrashExceptionSummary { ExceptionType = kv.Key, Count = kv.Value })
+                .ToList();
+
+            return metrics;
+        }
+
+        // Bounded fan-out: equivalent to Task.WhenAll over `body(item)` but with
+        // at most `maxConcurrency` tasks in flight. Without this guard a 1000-
+        // session metric query would fire 1000 simultaneous storage requests
+        // and either throttle Azure Tables or run the worker out of file
+        // handles before responding.
+        internal static async Task<List<TResult>> RunWithBoundedConcurrencyAsync<TInput, TResult>(
+            IReadOnlyList<TInput> items,
+            int maxConcurrency,
+            Func<TInput, Task<TResult>> body)
+        {
+            using var sem = new SemaphoreSlim(maxConcurrency);
+            var tasks = items.Select(async item =>
+            {
+                await sem.WaitAsync().ConfigureAwait(false);
+                try
+                {
+                    return await body(item).ConfigureAwait(false);
+                }
+                finally
+                {
+                    sem.Release();
+                }
+            });
+            var results = await Task.WhenAll(tasks).ConfigureAwait(false);
+            return results.ToList();
+        }
+
+        internal static double GetDouble(Dictionary<string, object> data, string key)
+        {
+            if (data.TryGetValue(key, out var value))
+            {
+                if (value is double d) return d;
+                if (value is int i) return i;
+                if (value is long l) return l;
+                if (value is float f) return f;
+                if (double.TryParse(value?.ToString(), out var parsed)) return parsed;
+            }
+            return 0;
+        }
+
+        // Returns the value of the first key that is present in `data`. Lets us read a V2 field
+        // name with a V1 fallback without conflating "key missing" with "key present but zero".
+        internal static double GetDoubleFirst(Dictionary<string, object> data, params string[] keys)
+        {
+            foreach (var key in keys)
+            {
+                if (data.ContainsKey(key)) return GetDouble(data, key);
+            }
+            return 0;
+        }
+
+        internal static string GetString(Dictionary<string, object> data, string key)
+        {
+            if (data.TryGetValue(key, out var value))
+            {
+                return value?.ToString() ?? string.Empty;
+            }
+            return string.Empty;
+        }
+    }
+}

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

@@ -0,0 +1,107 @@
+using System;
+using System.Collections.Generic;
+using AutopilotMonitor.Functions.Helpers;
+using AutopilotMonitor.Shared.Models;
+
+namespace AutopilotMonitor.Functions.Services
+{
+    /// <summary>
+    /// Regression tripwire for the agent's CMTrace time resolution (per-line self-anchoring,
+    /// docs/agent/cmtrace-time-resolution.md). Runs once per session on the terminal ingest
+    /// batch, over samples the counter reconcile collected in its existing partition scan.
+    ///
+    /// Detection: diff = median(Δ_IME) − median(Δ_other), where Δ = ReceivedAt − OccurredUtc.
+    /// Shared upload/spool latency is common-mode and cancels in the difference; a timezone
+    /// mis-conversion shifts only the IME side and lands on the 15-minute offset grid.
+    /// Replayed old log lines produce large OFF-grid deltas — the grid-residual test is what
+    /// separates the two (field measurement 2026-08-20: without it, 48 instead of 26 true hits).
+    ///
+    /// Goal state: this never fires. Any hit is either a case the per-line anchoring does not
+    /// cover or a detector bug — both are actionable findings, never noise to tune away.
+    /// </summary>
+    internal static class CmTraceSkewTripwire
+    {
+        // Same grid the agent anchors on and the same residual tolerance as its own grid
+        // guard (docs/agent/cmtrace-time-resolution.md) — keep these in lockstep with the
+        // agent so a future anchoring change stays traceable to this detector.
+        internal const int GridMinutes = 15;
+        internal const double ResidualToleranceMinutes = 2.0;
+        internal const int MinSamplesPerSide = 20;
+        // ReceivedAt is stamped per upload batch, not per event; a side backed by fewer
+        // distinct batches yields a batch-composition artifact, not a session property.
+        internal const int MinDistinctBatchesPerSide = 3;
+
+        internal sealed class Result
+        {
+            public double MedianImeDeltaMinutes { get; set; }
+            public double MedianOtherDeltaMinutes { get; set; }
+            public double DiffMinutes { get; set; }
+            public int GridSteps { get; set; }
+            public double ResidualMinutes { get; set; }
+            public int ImeSampleCount { get; set; }
+            public int OtherSampleCount { get; set; }
+            public int ImeBatchCount { get; set; }
+            public int OtherBatchCount { get; set; }
+        }
+
+        /// <summary>
+        /// Pure detector: non-null exactly when the session shows a grid-aligned divergence
+        /// between IME-derived and other event timestamps. All suppression inputs live in the
+        /// scan itself so the decision is fully unit-testable.
+        /// </summary>
+        internal static Result? Evaluate(SessionSkewScan? scan)
+        {
+            if (scan == null)
+                return null;
+            if (scan.ImeDeltaMinutes.Count < MinSamplesPerSide || scan.OtherDeltaMinutes.Count < MinSamplesPerSide)
+                return null;
+            if (scan.ImeDistinctBatchCount < MinDistinctBatchesPerSide || scan.OtherDistinctBatchCount < MinDistinctBatchesPerSide)
+                return null;
+
+            var medianIme = PercentileMath.Median(scan.ImeDeltaMinutes);
+            var medianOther = PercentileMath.Median(scan.OtherDeltaMinutes);
+            var diff = medianIme - medianOther;
+            var steps = (int)Math.Round(diff / GridMinutes, MidpointRounding.AwayFromZero);
+            var residual = Math.Abs(diff - steps * (double)GridMinutes);
+
+            if (Math.Abs(steps) < 1 || residual >= ResidualToleranceMinutes)
+                return null;
+
+            return new Result
+            {
+                MedianImeDeltaMinutes = medianIme,
+                MedianOtherDeltaMinutes = medianOther,
+                DiffMinutes = diff,
+                GridSteps = steps,
+                ResidualMinutes = residual,
+                ImeSampleCount = scan.ImeDeltaMinutes.Count,
+                OtherSampleCount = scan.OtherDeltaMinutes.Count,
+                ImeBatchCount = scan.ImeDistinctBatchCount,
+                OtherBatchCount = scan.OtherDistinctBatchCount,
+            };
+        }
+
+        /// <summary>
+        /// True when the session's IME events are dominated by writer-declared ("bias")
+        /// offsets — a bias offset comes verbatim from the log line's own zone marker and
+        /// cannot be an anchoring regression, so a grid hit there is not ours to alarm on.
+        /// measuredWriterOffsetMinutes is deliberately NOT consulted: the per-file
+        /// observation sticks to a stale value after an era flip-back (monotonicity guard),
+        /// making it non-authoritative for exactly the sessions this tripwire inspects.
+        /// </summary>
+        internal static bool IsBiasDominated(IReadOnlyDictionary<string, int>? originHistogram)
+        {
+            if (originHistogram == null || originHistogram.Count == 0)
+                return false;
+
+            int total = 0, bias = 0;
+            foreach (var kv in originHistogram)
+            {
+                total += kv.Value;
+                if (string.Equals(kv.Key, "bias", StringComparison.OrdinalIgnoreCase))
+                    bias += kv.Value;
+            }
+            return total > 0 && bias * 2 >= total;
+        }
+    }
+}

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

@@ -184,52 +184,109 @@ namespace AutopilotMonitor.Functions.Services
                         : evt.Data?.ContainsKey("bytes_downloaded") == true ? "bytes_downloaded" : null;
                     if (bytesKey != null && long.TryParse(evt.Data![bytesKey]?.ToString(), out var bytes))
                         summary.DownloadBytes = Math.Max(summary.DownloadBytes, bytes);
+                    // DO fallback: IME >= 1.104 removed the [DO TEL] log line, and the agent's
+                    // DO collector only emits do_telemetry for downloads whose completion a poll
+                    // itself observed — fast, interrupted or between-poll-completed downloads
+                    // never get one. The progress events carry the full do* set on every poll,
+                    // so fold them in monotonically; a do_telemetry (below) stays authoritative.
+                    if (evt.Data != null)
+                        ApplyDoFields(summary, evt.Data, isAuthoritative: false);
                     break;
 
                 case "do_telemetry":
                     if (evt.Data != null)
-                    {
-                        if (evt.Data.ContainsKey("doFileSize") && long.TryParse(evt.Data["doFileSize"]?.ToString(), out var doFs))
-                        {
-                            summary.DownloadBytes = Math.Max(summary.DownloadBytes, doFs);
-                            summary.DoFileSize = doFs;
-                        }
-                        if (evt.Data.ContainsKey("doTotalBytesDownloaded") && long.TryParse(evt.Data["doTotalBytesDownloaded"]?.ToString(), out var doTotalDl))
-                            summary.DoTotalBytesDownloaded = doTotalDl;
-                        if (evt.Data.ContainsKey("doBytesFromPeers") && long.TryParse(evt.Data["doBytesFromPeers"]?.ToString(), out var doPeers))
-                            summary.DoBytesFromPeers = doPeers;
-                        if (evt.Data.ContainsKey("doBytesFromHttp") && long.TryParse(evt.Data["doBytesFromHttp"]?.ToString(), out var doHttp))
-                            summary.DoBytesFromHttp = doHttp;
-                        if (evt.Data.ContainsKey("doPercentPeerCaching") && int.TryParse(evt.Data["doPercentPeerCaching"]?.ToString(), out var doPct))
-                            summary.DoPercentPeerCaching = doPct;
-                        if (evt.Data.ContainsKey("doDownloadMode") && int.TryParse(evt.Data["doDownloadMode"]?.ToString(), out var doMode))
-                            summary.DoDownloadMode = doMode;
-                        if (evt.Data.ContainsKey("doDownloadDuration"))
-                        {
-                            var doDurStr = evt.Data["doDownloadDuration"]?.ToString() ?? string.Empty;
-                            summary.DoDownloadDuration = doDurStr;
-                            if (TimeSpan.TryParse(doDurStr, out var doDurTs) && doDurTs.TotalSeconds >= 1)
-                                summary.DownloadDurationSeconds = Math.Max(summary.DownloadDurationSeconds, (int)doDurTs.TotalSeconds);
-                        }
-                        if (evt.Data.ContainsKey("doBytesFromLanPeers") && long.TryParse(evt.Data["doBytesFromLanPeers"]?.ToString(), out var doLan))
-                            summary.DoBytesFromLanPeers = doLan;
-                        if (evt.Data.ContainsKey("doBytesFromGroupPeers") && long.TryParse(evt.Data["doBytesFromGroupPeers"]?.ToString(), out var doGroup))
-                            summary.DoBytesFromGroupPeers = doGroup;
-                        if (evt.Data.ContainsKey("doBytesFromInternetPeers") && long.TryParse(evt.Data["doBytesFromInternetPeers"]?.ToString(), out var doInet))
-                            summary.DoBytesFromInternetPeers = doInet;
-                        if (evt.Data.ContainsKey("doBytesFromLinkLocalPeers") && long.TryParse(evt.Data["doBytesFromLinkLocalPeers"]?.ToString(), out var doLinkLocal))
-                            summary.DoBytesFromLinkLocalPeers = doLinkLocal;
-                        if (evt.Data.ContainsKey("doBytesFromCacheServer") && long.TryParse(evt.Data["doBytesFromCacheServer"]?.ToString(), out var doCache))
-                            summary.DoBytesFromCacheServer = doCache;
-                        if (evt.Data.ContainsKey("doCacheHost"))
-                            summary.DoCacheHost = evt.Data["doCacheHost"]?.ToString() ?? string.Empty;
-                    }
+                        ApplyDoFields(summary, evt.Data, isAuthoritative: true);
                     break;
             }
 
             RecalculateAppDurations(state);
         }
 
+        /// <summary>
+        /// Folds the <c>do*</c> Delivery Optimization fields of one event into the summary.
+        /// Two writers share this so they cannot drift:
+        /// <list type="bullet">
+        /// <item><c>do_telemetry</c> (<paramref name="isAuthoritative"/> = true) — the collector's
+        /// final per-app read: last-write-wins per present key (pre-existing semantics), except
+        /// <c>DoDownloadMode</c> never regresses to the -1 "unset" sentinel — that would re-hide
+        /// the row from <c>DoAggregator</c> after a progress event already established a mode.</item>
+        /// <item><c>download_progress</c> (false) — per-poll observations: byte counters and file
+        /// size fold via <c>Math.Max</c> (monotonic per download, so replays and out-of-order
+        /// batches stay idempotent); mode/percent/cacheHost are latest-observation writes.</item>
+        /// </list>
+        /// <c>DownloadBytes</c> prefers actually-transferred bytes (<c>doTotalBytesDownloaded</c>)
+        /// over <c>doFileSize</c> — the file size is only the fallback when no transfer total exists
+        /// (it used to unconditionally inflate the transfer measure).
+        /// </summary>
+        internal static void ApplyDoFields(AppInstallSummary summary, Dictionary<string, object> data, bool isAuthoritative)
+        {
+            static bool TryGetLong(Dictionary<string, object> d, string key, out long value)
+            {
+                value = 0;
+                return d.TryGetValue(key, out var raw) && long.TryParse(raw?.ToString(), out value);
+            }
+            static bool TryGetInt(Dictionary<string, object> d, string key, out int value)
+            {
+                value = 0;
+                return d.TryGetValue(key, out var raw) && int.TryParse(raw?.ToString(), out value);
+            }
+            static long Fold(bool authoritative, long current, long incoming)
+                => authoritative ? incoming : Math.Max(current, incoming);
+
+            var hasFileSize = TryGetLong(data, "doFileSize", out var doFs);
+            var hasTotalDl = TryGetLong(data, "doTotalBytesDownloaded", out var doTotalDl);
+
+            if (hasFileSize)
+                summary.DoFileSize = Fold(isAuthoritative, summary.DoFileSize, doFs);
+            if (hasTotalDl)
+                summary.DoTotalBytesDownloaded = Fold(isAuthoritative, summary.DoTotalBytesDownloaded, doTotalDl);
+
+            // Transfer measure: real transferred bytes when known, file size only as fallback.
+            // Progress events already fed DownloadBytes via their bytesDownloaded field, so only
+            // the authoritative telemetry contributes here.
+            if (isAuthoritative && (hasFileSize || hasTotalDl))
+                summary.DownloadBytes = Math.Max(summary.DownloadBytes, hasTotalDl && doTotalDl > 0 ? doTotalDl : doFs);
+
+            if (TryGetLong(data, "doBytesFromPeers", out var doPeers))
+                summary.DoBytesFromPeers = Fold(isAuthoritative, summary.DoBytesFromPeers, doPeers);
+            if (TryGetLong(data, "doBytesFromHttp", out var doHttp))
+                summary.DoBytesFromHttp = Fold(isAuthoritative, summary.DoBytesFromHttp, doHttp);
+            if (TryGetLong(data, "doBytesFromLanPeers", out var doLan))
+                summary.DoBytesFromLanPeers = Fold(isAuthoritative, summary.DoBytesFromLanPeers, doLan);
+            if (TryGetLong(data, "doBytesFromGroupPeers", out var doGroup))
+                summary.DoBytesFromGroupPeers = Fold(isAuthoritative, summary.DoBytesFromGroupPeers, doGroup);
+            if (TryGetLong(data, "doBytesFromInternetPeers", out var doInet))
+                summary.DoBytesFromInternetPeers = Fold(isAuthoritative, summary.DoBytesFromInternetPeers, doInet);
+            if (TryGetLong(data, "doBytesFromLinkLocalPeers", out var doLinkLocal))
+                summary.DoBytesFromLinkLocalPeers = Fold(isAuthoritative, summary.DoBytesFromLinkLocalPeers, doLinkLocal);
+            if (TryGetLong(data, "doBytesFromCacheServer", out var doCache))
+                summary.DoBytesFromCacheServer = Fold(isAuthoritative, summary.DoBytesFromCacheServer, doCache);
+
+            if (TryGetInt(data, "doPercentPeerCaching", out var doPct))
+                summary.DoPercentPeerCaching = doPct;
+
+            // -1 is the "unset" sentinel DoAggregator filters on — never let it clobber a
+            // known mode (a telemetry event without the DownloadMode property parses as -1).
+            if (TryGetInt(data, "doDownloadMode", out var doMode) && doMode >= 0)
+                summary.DoDownloadMode = doMode;
+
+            if (data.TryGetValue("doCacheHost", out var cacheHostRaw))
+            {
+                var cacheHost = cacheHostRaw?.ToString();
+                if (isAuthoritative || !string.IsNullOrEmpty(cacheHost))
+                    summary.DoCacheHost = cacheHost ?? string.Empty;
+            }
+
+            // Only do_telemetry carries a duration; progress events never have the key.
+            if (data.ContainsKey("doDownloadDuration"))
+            {
+                var doDurStr = data["doDownloadDuration"]?.ToString() ?? string.Empty;
+                summary.DoDownloadDuration = doDurStr;
+                if (TimeSpan.TryParse(doDurStr, out var doDurTs) && doDurTs.TotalSeconds >= 1)
+                    summary.DownloadDurationSeconds = Math.Max(summary.DownloadDurationSeconds, (int)doDurTs.TotalSeconds);
+            }
+        }
+
         internal static void RecalculateAppDurations(AppInstallAggregationState state)
         {
             var summary = state.Summary;

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

@@ -6,6 +6,7 @@ using AutopilotMonitor.Shared.DataAccess;
 using AutopilotMonitor.Shared.Models;
 using Microsoft.ApplicationInsights;
 using Microsoft.Azure.Functions.Worker;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging;
 
 namespace AutopilotMonitor.Functions.Services
@@ -44,6 +45,10 @@ namespace AutopilotMonitor.Functions.Services
         private readonly AutopilotMonitor.Functions.Services.Analyze.InterimTriggerRegistry _interimTriggerRegistry;
         private readonly IVulnerabilityCorrelateProducer _vulnProducer;
         private readonly Ime.IImeMsiArchiveProducer _imeMsiArchiveProducer;
+        private readonly IConfiguration _configuration;
+
+        /// <summary>App setting kill switch: set to "true" to skip the CMTrace skew tripwire entirely. Fail-open — the tripwire only notifies, it never mutates data.</summary>
+        internal const string CmTraceSkewTripwireKillSwitchSetting = "CmTraceSkewTripwireDisabled";
 
         public EventIngestProcessor(
             ILogger<EventIngestProcessor> logger,
@@ -60,7 +65,8 @@ namespace AutopilotMonitor.Functions.Services
             AutopilotMonitor.Functions.Services.Analyze.IAnalyzeOnEnrollmentEndProducer analyzeProducer,
             AutopilotMonitor.Functions.Services.Analyze.InterimTriggerRegistry interimTriggerRegistry,
             IVulnerabilityCorrelateProducer vulnProducer,
-            Ime.IImeMsiArchiveProducer imeMsiArchiveProducer)
+            Ime.IImeMsiArchiveProducer imeMsiArchiveProducer,
+            IConfiguration configuration)
         {
             _logger = logger;
             _sessionRepo = sessionRepo;
@@ -77,6 +83,7 @@ namespace AutopilotMonitor.Functions.Services
             _interimTriggerRegistry = interimTriggerRegistry;
             _vulnProducer = vulnProducer;
             _imeMsiArchiveProducer = imeMsiArchiveProducer;
+            _configuration = configuration;
         }
 
         /// <summary>
@@ -106,7 +113,7 @@ namespace AutopilotMonitor.Functions.Services
                 validation.RateLimitResult?.MaxRequests);
 
             var receivedAt = DateTime.UtcNow;
-            StampServerFields(request.Events, request.TenantId, request.SessionId, receivedAt);
+            StampServerFields(request.Events, request.TenantId, request.SessionId, receivedAt, request.SentAt);
             SanitizeEventTimestamps(request.Events, receivedAt, _logger);
 
             var storedEvents = await _sessionRepo.StoreEventsBatchAsync(request.Events);
@@ -247,7 +254,17 @@ namespace AutopilotMonitor.Functions.Services
             // replays where UpdateSessionStatusAsync no-ops.
             // Idempotent (no-ops when already correct) and fail-soft.
             if (isTerminalBatch)
-                await _sessionRepo.ReconcileSessionCountersAsync(request.TenantId, request.SessionId);
+            {
+                var skewScan = await _sessionRepo.ReconcileSessionCountersAsync(request.TenantId, request.SessionId);
+
+                // CMTrace time-skew tripwire (goal state: never fires). Gated on the actual
+                // status transition so terminal-batch REPLAYS (statusTransitioned == false)
+                // cannot re-emit — the reconcile above runs on replays by design, the
+                // tripwire must not. Fail-soft: ingest stays a 200 no matter what.
+                if (skewScan != null && (statusTransitioned || whiteGloveStatusTransitioned))
+                    await TryFireCmTraceSkewTripwireAsync(request.TenantId, request.SessionId,
+                        updatedSession?.AgentVersion, skewScan);
+            }
 
             // Auto-analyze fan-out: enqueue a queue message instead of running fire-and-forget
             // Task.Run inside the function. The previous in-function approach could be killed
@@ -545,18 +562,83 @@ namespace AutopilotMonitor.Functions.Services
                 System.Globalization.CultureInfo.InvariantCulture, out value);
         }
 
+        /// <summary>
+        /// CMTrace time-skew regression tripwire. Evaluates the per-source timestamp-delta
+        /// samples the counter reconcile collected and emits a CmTraceTimeSkewRegression ops
+        /// event when the IME-derived events diverge from the other sources by a clean
+        /// 15-minute-grid multiple (see <see cref="CmTraceSkewTripwire"/>). One extra bounded
+        /// storage read happens ONLY on the suspicion path (≈ never): the sourceOffsetOrigin
+        /// histogram that rules out writer-declared ("bias") offsets, which come verbatim
+        /// from the log line and cannot be an anchoring regression.
+        /// </summary>
+        private async Task TryFireCmTraceSkewTripwireAsync(
+            string tenantId, string sessionId, string? agentVersion, SessionSkewScan skewScan)
+        {
+            try
+            {
+                if (string.Equals(_configuration[CmTraceSkewTripwireKillSwitchSetting], "true", StringComparison.OrdinalIgnoreCase))
+                    return;
+
+                var result = CmTraceSkewTripwire.Evaluate(skewScan);
+                if (result == null)
+                    return;
+
+                var histogram = await _sessionRepo.GetImeOffsetOriginHistogramAsync(tenantId, sessionId);
+                if (CmTraceSkewTripwire.IsBiasDominated(histogram))
+                {
+                    _logger.LogInformation(
+                        "CMTrace skew tripwire suppressed for session {SessionId}: grid divergence {DiffMinutes:+0.0;-0.0} min, but IME offsets are bias-dominated (writer-declared)",
+                        sessionId, result.DiffMinutes);
+                    return;
+                }
+
+                var origins = string.Join(", ",
+                    histogram.OrderByDescending(kv => kv.Value).Select(kv => $"{kv.Key} {kv.Value}"));
+                var message =
+                    $"IME-derived events skewed {result.DiffMinutes:+0.0;-0.0} min vs other sources " +
+                    $"({result.GridSteps}x15min grid, residual {result.ResidualMinutes:0.0} min; " +
+                    $"median dIME {result.MedianImeDeltaMinutes:0.0} / dOther {result.MedianOtherDeltaMinutes:0.0} min; " +
+                    $"{result.ImeSampleCount}/{result.OtherSampleCount} samples over {result.ImeBatchCount}/{result.OtherBatchCount} batches; " +
+                    $"origins: {(origins.Length > 0 ? origins : "none")})";
+
+                await _opsEventService.RecordCmTraceTimeSkewRegressionAsync(tenantId, sessionId, agentVersion, message, new
+                {
+                    sessionId,
+                    agentVersion,
+                    diffMinutes = Math.Round(result.DiffMinutes, 2),
+                    gridSteps = result.GridSteps,
+                    residualMinutes = Math.Round(result.ResidualMinutes, 2),
+                    medianImeDeltaMinutes = Math.Round(result.MedianImeDeltaMinutes, 2),
+                    medianOtherDeltaMinutes = Math.Round(result.MedianOtherDeltaMinutes, 2),
+                    imeSampleCount = result.ImeSampleCount,
+                    otherSampleCount = result.OtherSampleCount,
+                    imeBatchCount = result.ImeBatchCount,
+                    otherBatchCount = result.OtherBatchCount,
+                    sourceOffsetOrigins = histogram,
+                });
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "CMTrace skew tripwire failed for session {SessionId}", sessionId);
+            }
+        }
+
         /// <summary>
         /// Stamps authoritative server-side fields onto all events before storage.
         /// TenantId and SessionId always come from the validated request metadata,
-        /// overriding any values the agent may have sent per-event.
+        /// overriding any values the agent may have sent per-event. SentAt is the
+        /// request-level device-clock send time (P14) — one value for every event of
+        /// the batch, null for agents that pre-date the X-Send-Time-Utc header.
         /// Exposed as internal for unit testing.
         /// </summary>
         internal static void StampServerFields(
-            List<EnrollmentEvent> events, string tenantId, string sessionId, DateTime receivedAt)
+            List<EnrollmentEvent> events, string tenantId, string sessionId, DateTime receivedAt,
+            DateTime? sentAt = null)
         {
             foreach (var evt in events)
             {
                 evt.ReceivedAt = receivedAt;
+                evt.SentAt = sentAt;
                 evt.TenantId = tenantId;
                 evt.SessionId = sessionId;
             }

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

@@ -351,8 +351,16 @@ namespace AutopilotMonitor.Functions.Services
                         int silentMarked = 0;
                         foreach (var silent in silentSessions)
                         {
-                            var lastEventAt = silent.LastEventAt ?? silent.StartedAt;
-                            var silentMinutes = (int)(now - lastEventAt).TotalMinutes;
+                            // The query is a permissive two-frame pre-filter; the decision is made
+                            // here on the SERVER frame. LastEventAt carries the device clock and,
+                            // for IME-derived events, a timezone skew (field-measured: -17 h to
+                            // +1 h). Trusting it marks a live agent Stalled — and puts a bogus
+                            // "silent for 1020min" in front of the customer.
+                            var lastContactAt = ServerFrameLastContact(silent);
+                            if (lastContactAt > silenceCutoff)
+                                continue; // provably alive on the server clock
+
+                            var silentMinutes = (int)(now - lastContactAt).TotalMinutes;
                             await _sessionRepo.UpdateSessionStatusAsync(
                                 silent.TenantId,
                                 silent.SessionId,
@@ -409,7 +417,7 @@ namespace AutopilotMonitor.Functions.Services
                             // legitimately exceed SessionTimeoutHours) and must never be terminalized here
                             // — without this, an actively-installing 6h enrollment could be classified
                             // Incomplete mid-run purely because it outlived the 5h window.
-                            if (session.LastEventAt.HasValue && session.LastEventAt.Value > silenceCutoff)
+                            if (ServerFrameLastContact(session) > silenceCutoff)
                                 continue;
 
                             // Fast path: an AwaitingUser session still inside the grace window needs no
@@ -774,5 +782,26 @@ namespace AutopilotMonitor.Functions.Services
         /// Aggregates metrics for any missed days in the last 7 days, plus yesterday.
         /// Checks the UsageMetrics table for existing snapshots to avoid re-aggregation.
         /// </summary>
+
+        /// <summary>
+        /// Last contact with the agent, expressed in the SERVER clock frame — the only value a
+        /// server-derived cutoff may legitimately be compared against.
+        /// <para>
+        /// Preference order:
+        /// <list type="number">
+        /// <item><c>LastIngestAt</c> — stamped from the server clock on every ingest. Authoritative.</item>
+        /// <item><c>LastEventAt</c> — device frame; used only for rows written before
+        /// <c>LastIngestAt</c> existed, so the rollout has no blind window. Carries the device's
+        /// clock error and any CMTrace timezone skew.</item>
+        /// <item><c>StartedAt</c> — last resort when a session has no event stamp at all.</item>
+        /// </list>
+        /// </para>
+        /// Mixing the two frames is what let a live agent be marked Stalled: a session whose
+        /// IME-derived events were skewed -17 h looked silent for 17 hours the moment it started.
+        /// </summary>
+        /// <remarks>internal (not private) purely as a unit-test seam — it is a pure function
+        /// over its argument, pinned by <c>MaintenanceServerFrameLastContactTests</c>.</remarks>
+        internal static DateTime ServerFrameLastContact(SessionSummary session)
+            => session.LastIngestAt ?? session.LastEventAt ?? session.StartedAt;
     }
 }

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

@@ -608,6 +608,36 @@ namespace AutopilotMonitor.Functions.Services
                 $"Agent emergency break on session {sessionId} (agent {agentVersion ?? "?"}): {message}",
                 tenantId, "System.EmergencyChannel", new { sessionId, agentVersion });
 
+        /// <summary>
+        /// An agent reported that its RUNNING exe's SHA-256 differs from the hash the backend
+        /// advertises for its version — the binary in the field is not the published build
+        /// (tamper, stale blob, or a build that never came from a committed tree). Session
+        /// e9753578 (2026-08-20) carried exactly this report, but it landed only in App
+        /// Insights and was invisible to every product surface while the field damage was
+        /// mis-attributed to committed code for hours. Warning-tier so operators can wire a
+        /// Telegram rule; the message carries both hashes verbatim.
+        /// </summary>
+        public Task RecordAgentBinaryIntegrityMismatchAsync(string tenantId, string? sessionId, string? agentVersion, string message)
+            => WriteAsync(OpsEventCategory.Agent, "AgentBinaryIntegrityMismatch", OpsEventSeverity.Warning,
+                $"Agent binary integrity mismatch on session {sessionId ?? "?"} (agent {agentVersion ?? "?"}): {message}",
+                tenantId, "System.EmergencyChannel", new { sessionId, agentVersion });
+
+        /// <summary>
+        /// The CMTrace time-skew tripwire fired: a terminal session's IME-derived event
+        /// timestamps diverge from its other events by a clean 15-minute-grid multiple —
+        /// the signature of a timezone mis-conversion the per-line self-anchoring
+        /// (docs/agent/cmtrace-time-resolution.md) failed to catch. Goal state: this event
+        /// NEVER fires; any occurrence is a real anchoring regression or a detector bug,
+        /// both actionable. Emitted by <see cref="EventIngestProcessor"/> once per session
+        /// (gated on the terminal status transition). The message carries the full numbers
+        /// so the event is verifiable without a portal round-trip.
+        /// Dual-register per memory feedback_ops_event_types_dual_register.
+        /// </summary>
+        public Task RecordCmTraceTimeSkewRegressionAsync(string tenantId, string sessionId, string? agentVersion, string message, object details)
+            => WriteAsync(OpsEventCategory.Agent, "CmTraceTimeSkewRegression", OpsEventSeverity.Warning,
+                $"CMTrace time-skew tripwire on session {sessionId} (agent {agentVersion ?? "?"}): {message}",
+                tenantId, "System.Ingest", details);
+
         public Task RecordExcessiveSessionEventsAsync(string tenantId, string sessionId, int eventCount, int threshold)
             => WriteAsync(OpsEventCategory.Agent, "ExcessiveSessionEvents", OpsEventSeverity.Warning,
                 $"Session {sessionId} has {eventCount} events (threshold {threshold}) — likely agent loop bug",

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

@@ -115,9 +115,9 @@ namespace AutopilotMonitor.Functions.Services
         private async Task<PlatformAgentMetricsResponse> ComputePlatformMetricsInternalAsync(int days, int limit)
         {
             // Fetch only the newest `limit` sessions in the window. Each session below
-            // triggers its own GetSessionEventsAsync call; the per-session work is
-            // bounded by PerSessionFetchConcurrency so even 1000-session limits
-            // don't fan out 1000 simultaneous storage requests.
+            // triggers its own event fetch; the per-session work is bounded by
+            // PerSessionFetchConcurrency so even 1000-session limits don't fan out
+            // 1000 simultaneous storage requests.
             var sessionPage = await _sessionRepo.GetAllSessionsPageAsync(
                 tenantIdFilter: null, days: days, pageSize: limit, continuation: null);
             var allSessions = sessionPage.Items;
@@ -135,7 +135,7 @@ namespace AutopilotMonitor.Functions.Services
                 .Select(s => s.SessionId)
                 .ToHashSet(StringComparer.Ordinal);
 
-            var perSessionResults = await RunWithBoundedConcurrencyAsync(
+            var perSessionResults = await AgentMetricsAggregation.RunWithBoundedConcurrencyAsync(
                 allSessions,
                 PerSessionFetchConcurrency,
                 session => ProcessSessionAsync(session, latencySampleSessionIds));
@@ -146,13 +146,18 @@ namespace AutopilotMonitor.Functions.Services
                 .ToList();
 
             var deliveryLatency = AggregateDeliveryLatency(perSessionResults);
-            var crashRate = AggregateCrashRate(perSessionResults);
+            var crashRate = AgentMetricsAggregation.AggregateCrashRate(
+                perSessionResults.SelectMany(r => r.AgentStartedEvents));
 
             return new PlatformAgentMetricsResponse
             {
                 Sessions = sessionMetrics,
                 DeliveryLatency = deliveryLatency,
-                CrashRate = crashRate
+                CrashRate = crashRate,
+                // Sessions actually scanned in the window — the honest basis for the
+                // caller's truncation check. Sessions.Count only counts sessions WITH
+                // snapshots, so comparing it against the limit understates truncation.
+                SessionsScanned = allSessions.Count
             };
         }
 
@@ -162,11 +167,20 @@ namespace AutopilotMonitor.Functions.Services
         {
             try
             {
-                var events = await _sessionRepo.GetSessionEventsAsync(session.TenantId, session.SessionId);
+                // Latency-sample sessions need the FULL event stream: the delivery-latency
+                // deltas are computed over every event of those 20 sessions, not just the
+                // metrics types — filtering them would shrink the sample ~50x and change the
+                // published percentiles. Everyone else gets the three-type projected fetch.
+                var isLatencySample = latencySampleSessionIds.Contains(session.SessionId);
+                var events = isLatencySample
+                    ? await _sessionRepo.GetSessionEventsAsync(session.TenantId, session.SessionId)
+                    : await _sessionRepo.GetSessionEventsByTypesAsync(
+                        session.TenantId, session.SessionId, AgentMetricsAggregation.MetricsEventTypes,
+                        TableStorageService.AgentMetricsEventProjection);
 
                 // ── Latency deltas (only for sample-set sessions) ───────────
                 List<double> latencyDeltas = new();
-                if (latencySampleSessionIds.Contains(session.SessionId))
+                if (isLatencySample)
                 {
                     foreach (var e in events)
                     {
@@ -266,33 +280,6 @@ namespace AutopilotMonitor.Functions.Services
             }
         }
 
-        // Bounded fan-out: equivalent to Task.WhenAll over `body(item)` but with
-        // at most `maxConcurrency` tasks in flight. Without this guard a 1000-
-        // session metric query would fire 1000 simultaneous storage requests
-        // and either throttle Azure Tables or run the worker out of file
-        // handles before responding.
-        private static async Task<List<TResult>> RunWithBoundedConcurrencyAsync<TInput, TResult>(
-            IReadOnlyList<TInput> items,
-            int maxConcurrency,
-            Func<TInput, Task<TResult>> body)
-        {
-            using var sem = new SemaphoreSlim(maxConcurrency);
-            var tasks = items.Select(async item =>
-            {
-                await sem.WaitAsync().ConfigureAwait(false);
-                try
-                {
-                    return await body(item).ConfigureAwait(false);
-                }
-                finally
-                {
-                    sem.Release();
-                }
-            });
-            var results = await Task.WhenAll(tasks).ConfigureAwait(false);
-            return results.ToList();
-        }
-
         // Aggregate over the latency deltas already extracted by the per-session
         // pass. No additional storage round-trips — the same events the metric
         // pass walked have been pre-binned into PerSessionData.LatencyDeltasMs
@@ -325,100 +312,20 @@ namespace AutopilotMonitor.Functions.Services
             };
         }
 
-        // Aggregate crash classifications over the agent_started events the
-        // per-session pass already collected — same idea as the latency
-        // aggregator: zero extra storage calls.
-        private static CrashRateMetrics AggregateCrashRate(IReadOnlyList<PerSessionData> perSession)
-        {
-            var metrics = new CrashRateMetrics();
-            var exceptionCounts = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
-
-            foreach (var r in perSession)
-            {
-                foreach (var data in r.AgentStartedEvents)
-                {
-                    metrics.TotalStarts++;
-                    var exitType = GetString(data, "previousExitType");
-                    switch (exitType)
-                    {
-                        case "clean":
-                            metrics.CleanExits++;
-                            break;
-                        case "exception_crash":
-                            metrics.ExceptionCrashes++;
-                            var exType = GetString(data, "previousCrashException");
-                            if (!string.IsNullOrEmpty(exType))
-                            {
-                                exceptionCounts.TryGetValue(exType, out var count);
-                                exceptionCounts[exType] = count + 1;
-                            }
-                            break;
-                        case "hard_kill":
-                            metrics.HardKills++;
-                            break;
-                        case "reboot_kill":
-                            metrics.RebootKills++;
-                            break;
-                        default:
-                            metrics.FirstRuns++;
-                            break;
-                    }
-                }
-            }
-
-            var nonFirstRuns = metrics.TotalStarts - metrics.FirstRuns;
-            metrics.CrashRatePercent = nonFirstRuns > 0
-                ? Math.Round((double)metrics.ExceptionCrashes / nonFirstRuns * 100, 1)
-                : 0;
-
-            metrics.TopExceptions = exceptionCounts
-                .OrderByDescending(kv => kv.Value)
-                .Take(5)
-                .Select(kv => new CrashExceptionSummary { ExceptionType = kv.Key, Count = kv.Value })
-                .ToList();
-
-            return metrics;
-        }
-
+        // Thin delegation onto the single shared nearest-rank implementation (PercentileMath).
         private static double Percentile(List<double> sortedValues, double percentile)
-        {
-            if (sortedValues.Count == 0) return 0;
-            var index = (int)Math.Ceiling(percentile * sortedValues.Count) - 1;
-            return sortedValues[Math.Max(0, Math.Min(index, sortedValues.Count - 1))];
-        }
+            => Helpers.PercentileMath.Percentile(sortedValues, percentile);
 
+        // Payload getters live in AgentMetricsAggregation (shared with the efficiency
+        // service); these thin wrappers keep the call sites above unchanged.
         private static double GetDouble(Dictionary<string, object> data, string key)
-        {
-            if (data.TryGetValue(key, out var value))
-            {
-                if (value is double d) return d;
-                if (value is int i) return i;
-                if (value is long l) return l;
-                if (value is float f) return f;
-                if (double.TryParse(value?.ToString(), out var parsed)) return parsed;
-            }
-            return 0;
-        }
+            => AgentMetricsAggregation.GetDouble(data, key);
 
-        // Returns the value of the first key that is present in `data`. Lets us read a V2 field
-        // name with a V1 fallback without conflating "key missing" with "key present but zero".
         private static double GetDoubleFirst(Dictionary<string, object> data, params string[] keys)
-        {
-            foreach (var key in keys)
-            {
-                if (data.ContainsKey(key)) return GetDouble(data, key);
-            }
-            return 0;
-        }
+            => AgentMetricsAggregation.GetDoubleFirst(data, keys);
 
         private static string GetString(Dictionary<string, object> data, string key)
-        {
-            if (data.TryGetValue(key, out var value))
-            {
-                return value?.ToString() ?? string.Empty;
-            }
-            return string.Empty;
-        }
+            => AgentMetricsAggregation.GetString(data, key);
     }
 
     // ── Response DTOs ────────────────────────────────────────────────────────────
@@ -433,6 +340,14 @@ namespace AutopilotMonitor.Functions.Services
         public bool FromCache { get; set; }
         public int WindowDays { get; set; }
         public int SessionLimit { get; set; }
+        /// <summary>
+        /// Sessions the scan actually covered in the window (before the has-snapshots filter
+        /// that shapes <see cref="Sessions"/>). Callers must compare THIS against
+        /// <see cref="SessionLimit"/> to decide whether the window was truncated —
+        /// <c>Sessions.Count</c> understates truncation on fleets where many sessions
+        /// emit no agent_metrics_snapshot.
+        /// </summary>
+        public int SessionsScanned { get; set; }
     }
 
     public class SessionAgentMetric

src/Backend/AutopilotMonitor.Functions/Services/RuleEngine.ConditionEvaluators.cs

@@ -98,6 +98,9 @@ namespace AutopilotMonitor.Functions.Services
                 case "event_correlation":
                     return EvaluateEventCorrelationCondition(condition, events);
 
+                case "clock_skew":
+                    return EvaluateClockSkewCondition(condition, events);
+
                 default:
                     return (false, "unknown source");
             }
@@ -752,7 +755,12 @@ namespace AutopilotMonitor.Functions.Services
 
         private (bool matched, object evidence) EvaluateAppInstallDurationCondition(RuleCondition condition, List<EnrollmentEvent> events)
         {
-            var sortedEvents = events.OrderBy(e => e.Timestamp).ThenBy(e => e.Sequence).ToList();
+            // Ordering key is Sequence, never Timestamp: Sequence is a persisted, strictly
+            // monotonic per-session counter assigned at emit time and is immune to every clock
+            // problem, whereas Timestamp carries the device clock frame plus — for CMTrace-derived
+            // events — the writer process's timezone belief. Timestamp stays in use below only
+            // where an actual ELAPSED DURATION is meant, which is what it is for.
+            var sortedEvents = events.OrderBy(e => e.Sequence).ToList();
 
             var completionEventTypes = string.IsNullOrWhiteSpace(condition.EventType)
                 ? new HashSet<string>(new[] { "app_install_completed", "app_install_failed" }, StringComparer.OrdinalIgnoreCase)
@@ -774,7 +782,7 @@ namespace AutopilotMonitor.Functions.Services
                 var startEvent = sortedEvents.LastOrDefault(e =>
                     (string.Equals(e.EventType, "app_install_started", StringComparison.OrdinalIgnoreCase) ||
                      string.Equals(e.EventType, "app_install_start", StringComparison.OrdinalIgnoreCase)) &&
-                    e.Timestamp <= completionEvent.Timestamp &&
+                    e.Sequence <= completionEvent.Sequence &&
                     string.Equals(GetDataFieldValue(e, "appId") ?? GetDataFieldValue(e, "appName"), appKey, StringComparison.OrdinalIgnoreCase));
 
                 if (startEvent == null)
@@ -803,6 +811,209 @@ namespace AutopilotMonitor.Functions.Services
             return (false, "no app install duration matched");
         }
 
+        // ===== clock_skew constants =====
+        // Named constants, deliberately NOT condition fields: promoting a constant to a field
+        // later is non-breaking, the reverse is not.
+        /// <summary>Frame windows (in upload batches) that must agree before/after a step for it to count as a clock jump.</summary>
+        internal const int ClockSkewConfirmBatches = 3;
+        /// <summary>Floor for the per-batch internal-spread cap, seconds.</summary>
+        internal const double ClockSkewSpoolSpreadFloorSeconds = 60;
+        /// <summary>Per-batch internal-spread cap as a fraction of the condition threshold.</summary>
+        internal const double ClockSkewSpoolSpreadCapFraction = 0.5;
+        /// <summary>Fraction of surviving batches that must sit near the overall median for a sustained-offset verdict.</summary>
+        internal const double ClockSkewStableBatchFraction = 0.75;
+
+        /// <summary>
+        /// Detects DEVICE clock problems from a per-upload-batch offset between the device's
+        /// clock frame and the server's receive frame (seconds; healthy baseline ≈
+        /// −upload-latency, i.e. a few seconds negative).
+        /// skewMetric "clock_jump": a persistent step in the device's clock frame mid-session
+        /// (time sync correcting a wrong RTC, Windows auto-timezone, manual change).
+        /// skewMetric "sustained_offset": the whole session ran on a clock off by ≥ threshold
+        /// — the during-enrollment complement of ANALYZE-DEV-007's one-shot NTP check.
+        ///
+        /// Batch offset, two measurement paths (P14):
+        /// - Events carrying SentAt (X-Send-Time-Utc header, one device-clock value per ingest
+        ///   request): offset = SentAt − ReceivedAt, a DIRECT frame-crossing measurement. No
+        ///   event timestamps involved → immune to spool backlog, CMTrace writer beliefs and
+        ///   clamping by construction, so no spread filter is needed and every batch counts.
+        /// - Legacy batches (agents without the header): median of per-event Timestamp −
+        ///   ReceivedAt with a spread cap that drops replayed spool backlogs, excluding
+        ///   CMTrace-derived events (Source == "ImeLogTracker") — their Timestamp carries the
+        ///   log WRITER's timezone belief, so an anchoring regression must fire the
+        ///   operator-side CmTraceSkewTripwire, never this customer-facing rule.
+        ///
+        /// Ordering key is Sequence, never Timestamp (see EvaluateAppInstallDurationCondition).
+        /// The legacy path then inspects Timestamp AGAINST that Sequence order ON PURPOSE — a
+        /// device-clock problem is precisely a Timestamp anomaly relative to the clock-immune
+        /// Sequence/ReceivedAt frame. Timestamp is a MEASUREMENT here, never a sort key.
+        /// </summary>
+        private (bool matched, object evidence) EvaluateClockSkewCondition(RuleCondition condition, List<EnrollmentEvent> events)
+        {
+            var metric = condition.SkewMetric ?? string.Empty;
+            if (!double.TryParse(condition.Value, System.Globalization.NumberStyles.Float,
+                    System.Globalization.CultureInfo.InvariantCulture, out var thresholdSeconds) || thresholdSeconds <= 0)
+                return (false, "clock_skew requires a positive numeric value (threshold in seconds)");
+
+            var usable = events
+                .Where(e => e.ReceivedAt.HasValue)
+                .OrderBy(e => e.Sequence)
+                .ToList();
+            if (usable.Count == 0)
+                return (false, "no events with a server receive frame");
+
+            // Group into upload batches (ReceivedAt is stamped once per ingest request). Legacy
+            // rationale for the spread cap: a clock offset shifts a whole batch uniformly
+            // (internal spread ≈ upload debounce, seconds); a spool-backlog batch spans the
+            // offline period (spread = minutes–hours). Dropping wide-spread batches is what
+            // makes replayed backlogs inert on the legacy path.
+            var spreadCap = Math.Max(ClockSkewSpoolSpreadFloorSeconds, thresholdSeconds * ClockSkewSpoolSpreadCapFraction);
+            var batches = new List<(double MedianOffsetSeconds, EnrollmentEvent FirstEvent)>();
+            int usedSamples = 0;
+            int sentAtBatchCount = 0;
+            foreach (var batch in usable.GroupBy(e => e.ReceivedAt!.Value))
+            {
+                // P14 direct path — SentAt is request-level, so any event's value speaks for
+                // the whole batch.
+                var sentAt = batch.Select(e => e.SentAt).FirstOrDefault(s => s.HasValue);
+                if (sentAt.HasValue)
+                {
+                    sentAtBatchCount++;
+                    usedSamples += batch.Count();
+                    batches.Add(((sentAt.Value - batch.Key).TotalSeconds, batch.First()));
+                    continue;
+                }
+
+                // Legacy path — see the method doc for the IME/clamped exclusions.
+                var measurable = batch
+                    .Where(e => !e.TimestampClamped
+                             && !string.Equals(e.Source, "ImeLogTracker", StringComparison.OrdinalIgnoreCase))
+                    .ToList();
+                if (measurable.Count == 0)
+                    continue;
+
+                var offsets = measurable.Select(e => (e.Timestamp - batch.Key).TotalSeconds).OrderBy(v => v).ToList();
+                if (offsets[offsets.Count - 1] - offsets[0] > spreadCap)
+                    continue;
+                usedSamples += offsets.Count;
+                batches.Add((Helpers.PercentileMath.Percentile(offsets, 0.50), measurable[0]));
+            }
+
+            switch (metric)
+            {
+                case "sustained_offset":
+                {
+                    if (batches.Count < 2)
+                        return (false, "insufficient upload batches for an offset measurement");
+
+                    var batchMedians = batches.Select(b => b.MedianOffsetSeconds).ToList();
+                    var overall = Helpers.PercentileMath.Median(batchMedians);
+
+                    // Constant offset, not drift chaos: most batches must individually sit near
+                    // the session median, otherwise no single "the clock was off by X" statement
+                    // is honest.
+                    var stable = batchMedians.Count(m => Math.Abs(m - overall) <= spreadCap);
+                    if (stable < Math.Max(2, (int)Math.Ceiling(batchMedians.Count * ClockSkewStableBatchFraction)))
+                        return (false, "batch offsets too unstable for a sustained-offset verdict");
+
+                    if (!CompareClockSkewThreshold(Math.Abs(overall), condition.Operator, thresholdSeconds))
+                        return (false, $"sustained offset {overall:0} s below threshold");
+
+                    var first = batches[0].FirstEvent;
+                    var offsetMinutes = Math.Round(overall / 60.0, 1);
+                    var direction = overall > 0 ? "ahead" : "behind";
+                    return (true, new Dictionary<string, object>
+                    {
+                        // field/value pair drives {{skewSummary}} template interpolation
+                        // (lib/interpolateRuleTemplate.ts resolves field→value first).
+                        ["field"] = "skewSummary",
+                        ["value"] = $"clock ran {Math.Abs(offsetMinutes)} min {direction} of server time throughout the session",
+                        ["offsetSeconds"] = Math.Round(overall, 0),
+                        ["offsetMinutes"] = offsetMinutes,
+                        ["direction"] = direction,
+                        ["eventId"] = first.EventId,
+                        ["sequence"] = first.Sequence,
+                        ["timestamp"] = first.Timestamp,
+                        ["sampleCount"] = usedSamples,
+                        ["batchCount"] = batches.Count,
+                        ["sentAtBatchCount"] = sentAtBatchCount,
+                    });
+                }
+
+                case "clock_jump":
+                {
+                    const int w = ClockSkewConfirmBatches;
+                    if (batches.Count < 2 * w)
+                        return (false, "insufficient upload batches for a frame comparison");
+
+                    var medians = batches.Select(b => b.MedianOffsetSeconds).ToList();
+                    (int Index, double Pre, double Post, double Jump)? best = null;
+                    for (int j = w - 1; j <= batches.Count - 1 - w; j++)
+                    {
+                        var preWindow = medians.Skip(j - w + 1).Take(w).ToList();
+                        var postWindow = medians.Skip(j + 1).Take(w).ToList();
+
+                        // Both comparison windows must be flat plateaus: a genuine clock change
+                        // is a step between two stable frames, while a gradually draining spool
+                        // backlog produces a RAMP of batch medians — sloping windows would let
+                        // any pre/post pair straddling the ramp fake a step.
+                        if (preWindow.Max() - preWindow.Min() > spreadCap || postWindow.Max() - postWindow.Min() > spreadCap)
+                            continue;
+
+                        var pre = Helpers.PercentileMath.Median(preWindow);
+                        var post = Helpers.PercentileMath.Median(postWindow);
+                        var jump = post - pre;
+                        if (CompareClockSkewThreshold(Math.Abs(jump), condition.Operator, thresholdSeconds)
+                            && (best == null || Math.Abs(jump) > Math.Abs(best.Value.Jump)))
+                            best = (j, pre, post, jump);
+                    }
+                    if (best == null)
+                        return (false, "no persistent clock step");
+
+                    // End-state persistence: a transient excursion that returns to the original
+                    // frame (spool backlog draining, historic replay) must stay silent; a genuine
+                    // clock change — including "wrong clock corrected by time sync mid-session" —
+                    // persists to session end, because the corrected frame IS the change.
+                    var tail = Helpers.PercentileMath.Median(medians.Skip(medians.Count - w).Take(w));
+                    var tailShift = tail - best.Value.Pre;
+                    if (Math.Abs(tailShift) < thresholdSeconds || Math.Sign(tailShift) != Math.Sign(best.Value.Jump))
+                        return (false, "transient timestamp excursion, not a sustained clock change");
+
+                    var boundary = batches[best.Value.Index + 1].FirstEvent;
+                    var jumpMinutes = Math.Round(best.Value.Jump / 60.0, 1);
+                    var direction = best.Value.Jump > 0 ? "forward" : "backward";
+                    return (true, new Dictionary<string, object>
+                    {
+                        // field/value pair drives {{skewSummary}} template interpolation
+                        // (lib/interpolateRuleTemplate.ts resolves field→value first).
+                        ["field"] = "skewSummary",
+                        ["value"] = $"clock jumped {Math.Abs(jumpMinutes)} min {direction} mid-session",
+                        ["jumpSeconds"] = Math.Round(best.Value.Jump, 0),
+                        ["jumpMinutes"] = jumpMinutes,
+                        ["direction"] = direction,
+                        ["beforeOffsetMinutes"] = Math.Round(best.Value.Pre / 60.0, 1),
+                        ["afterOffsetMinutes"] = Math.Round(best.Value.Post / 60.0, 1),
+                        ["eventId"] = boundary.EventId,
+                        ["sequence"] = boundary.Sequence,
+                        ["timestamp"] = boundary.Timestamp,
+                        ["eventType"] = boundary.EventType,
+                        ["sampleCount"] = usedSamples,
+                        ["batchCount"] = batches.Count,
+                        ["sentAtBatchCount"] = sentAtBatchCount,
+                    });
+                }
+
+                default:
+                    return (false, $"unknown skewMetric '{metric}' (expected clock_jump or sustained_offset)");
+            }
+        }
+
+        /// <summary>gt/gte magnitude comparison for clock_skew; unknown operators behave as gte (validation rejects them upstream).</summary>
+        private static bool CompareClockSkewThreshold(double magnitude, string? op, double thresholdSeconds)
+            => string.Equals(op, "gt", StringComparison.OrdinalIgnoreCase)
+                ? magnitude > thresholdSeconds
+                : magnitude >= thresholdSeconds;
+
         /// <summary>
         /// Generic event correlation: finds pairs of events (A before B) sharing
         /// the same value in a join field, with optional filters on each event
@@ -826,7 +1037,12 @@ namespace AutopilotMonitor.Functions.Services
                 return (false, "event_correlation requires EventType, CorrelateEventType, and JoinField");
             }
 
-            var sortedEvents = events.OrderBy(e => e.Timestamp).ThenBy(e => e.Sequence).ToList();
+            // Ordering key is Sequence, never Timestamp: Sequence is a persisted, strictly
+            // monotonic per-session counter assigned at emit time and is immune to every clock
+            // problem, whereas Timestamp carries the device clock frame plus — for CMTrace-derived
+            // events — the writer process's timezone belief. Timestamp stays in use below only
+            // where an actual ELAPSED DURATION is meant, which is what it is for.
+            var sortedEvents = events.OrderBy(e => e.Sequence).ToList();
 
             // Collect Event A candidates with optional filter
             var eventAList = sortedEvents
@@ -874,16 +1090,14 @@ namespace AutopilotMonitor.Functions.Services
 
                 // Find the latest Event A that occurred before Event B
                 var matchingA = eventAByJoinKey[bKey]
-                    .Where(a => a.Timestamp < eventB.Timestamp ||
-                                (a.Timestamp == eventB.Timestamp && a.Sequence < eventB.Sequence))
+                    .Where(a => a.Sequence < eventB.Sequence)
                     .Where(a =>
                     {
                         if (condition.TimeWindowSeconds == null || condition.TimeWindowSeconds <= 0)
                             return true;
                         return (eventB.Timestamp - a.Timestamp).TotalSeconds <= condition.TimeWindowSeconds.Value;
                     })
-                    .OrderByDescending(a => a.Timestamp)
-                    .ThenByDescending(a => a.Sequence)
+                    .OrderByDescending(a => a.Sequence)
                     .FirstOrDefault();
 
                 if (matchingA == null)

src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.Maintenance.cs

@@ -698,9 +698,19 @@ namespace AutopilotMonitor.Functions.Services
 
                 var silenceCutoffStr = silenceCutoff.ToString("yyyy-MM-ddTHH:mm:ss");
                 var hardCutoffStr = hardCutoff.ToString("yyyy-MM-ddTHH:mm:ss");
+
+                // Candidate pre-filter across BOTH clock frames, deliberately permissive:
+                // LastIngestAt is the server frame (authoritative, but absent on rows written
+                // before it existed), LastEventAt the device frame (always present, but carries
+                // the device's clock error and any CMTrace timezone skew). An OR keeps a session
+                // in the candidate set when EITHER frame looks silent; the caller then makes the
+                // authoritative call on the server frame. Filtering on LastIngestAt alone would
+                // silently drop every pre-rollout row, since Table Storage does not match a
+                // filter against a missing property.
                 var filter = $"PartitionKey eq '{tenantId}' " +
                              $"and Status eq 'InProgress' " +
-                             $"and LastEventAt lt datetime'{silenceCutoffStr}Z' " +
+                             $"and (LastIngestAt lt datetime'{silenceCutoffStr}Z' " +
+                             $"or LastEventAt lt datetime'{silenceCutoffStr}Z') " +
                              $"and (StartedAt ge datetime'{hardCutoffStr}Z' or ResumedAt ge datetime'{hardCutoffStr}Z')";
 
                 var query = tableClient.QueryAsync<TableEntity>(filter: filter);
@@ -772,7 +782,7 @@ namespace AutopilotMonitor.Functions.Services
                 var select = new[]
                 {
                     "PartitionKey", "RowKey", "Status", "StartedAt", "ResumedAt", "LastEventAt",
-                    "SerialNumber", "IsPreProvisioned"
+                    "LastIngestAt", "SerialNumber", "IsPreProvisioned"
                 };
 
                 var sessions = new List<SessionSummary>();

src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.Sessions.cs

@@ -815,6 +815,11 @@ namespace AutopilotMonitor.Functions.Services
                     ["TimestampClamped"] = evt.TimestampClamped
                 };
 
+                // P14: request-level device-clock send time; column stays unset for
+                // events from agents that pre-date the X-Send-Time-Utc header.
+                if (evt.SentAt.HasValue)
+                    entity["SentAt"] = EnsureUtc(evt.SentAt.Value);
+
                 if (evt.OriginalTimestamp.HasValue)
                     entity["OriginalTimestamp"] = EnsureUtc(evt.OriginalTimestamp.Value);
 
@@ -912,6 +917,10 @@ namespace AutopilotMonitor.Functions.Services
                                 ["TimestampClamped"] = evt.TimestampClamped
                             };
 
+                            // P14: see StoreEventAsync.
+                            if (evt.SentAt.HasValue)
+                                entity["SentAt"] = EnsureUtc(evt.SentAt.Value);
+
                             if (evt.OriginalTimestamp.HasValue)
                                 entity["OriginalTimestamp"] = EnsureUtc(evt.OriginalTimestamp.Value);
 
@@ -1099,7 +1108,8 @@ namespace AutopilotMonitor.Functions.Services
 
         public async Task<RawPage<SessionSummary>> GetAllSessionsPageAsync(
             string? tenantIdFilter, int? days, int pageSize, string? continuation,
-            IReadOnlyCollection<string>? allowedTenantIds = null)
+            IReadOnlyCollection<string>? allowedTenantIds = null,
+            IEnumerable<string>? select = null)
         {
             if (pageSize < 1) throw new ArgumentOutOfRangeException(nameof(pageSize));
 
@@ -1111,10 +1121,11 @@ namespace AutopilotMonitor.Functions.Services
             // the per-tenant SessionsIndex scan — natively-ordered, cheaper.
             if (!string.IsNullOrEmpty(tenantIdFilter))
             {
-                return await GetSessionsPageAsync(tenantIdFilter!, days, pageSize, continuation);
+                var tenantPage = await FetchSessionsPageInternalAsync(tenantIdFilter!, pageSize, continuation, days, select);
+                return new RawPage<SessionSummary>(tenantPage.Sessions, tenantPage.HasMore ? tenantPage.NextCursor : null);
             }
 
-            var page = await FetchAllSessionsPageInternalAsync(maxResults: pageSize, cursor: continuation, days: days, allowedTenantIds: allowedTenantIds);
+            var page = await FetchAllSessionsPageInternalAsync(maxResults: pageSize, cursor: continuation, days: days, allowedTenantIds: allowedTenantIds, select: select);
             return new RawPage<SessionSummary>(page.Sessions, page.HasMore ? page.NextCursor : null);
         }
 
@@ -1317,7 +1328,8 @@ namespace AutopilotMonitor.Functions.Services
         /// <see cref="GetAllSessionsPageAsync"/> (single page).
         /// </summary>
         private async Task<(List<SessionSummary> Sessions, bool HasMore, string? NextCursor)> FetchAllSessionsPageInternalAsync(
-            int maxResults, string? cursor, int? days, IReadOnlyCollection<string>? allowedTenantIds = null)
+            int maxResults, string? cursor, int? days, IReadOnlyCollection<string>? allowedTenantIds = null,
+            IEnumerable<string>? select = null)
         {
             try
             {
@@ -1393,7 +1405,7 @@ namespace AutopilotMonitor.Functions.Services
 
                     var tenantSessions = new List<SessionSummary>();
                     await foreach (var entity in indexTableClient.QueryAsync<TableEntity>(
-                        filter: filter, maxPerPage: Math.Min(fetchPerTenant, 1000)))
+                        filter: filter, maxPerPage: Math.Min(fetchPerTenant, 1000), select: select))
                     {
                         tenantSessions.Add(MapIndexEntityToSessionSummary(entity));
                         if (tenantSessions.Count >= fetchPerTenant) break;
@@ -2335,6 +2347,14 @@ namespace AutopilotMonitor.Functions.Services
                             update["LastEventAt"] = EnsureUtc(latestEventTimestamp.Value);
                     }
 
+                    // Server-frame ingest stamp. Reaching this method means a batch was just
+                    // received, so "now" on the SERVER clock is the honest answer to "when did we
+                    // last hear from this agent". LastEventAt above cannot answer that — it carries
+                    // the device's clock frame and its timezone skew. Written unconditionally (not
+                    // guarded by latestEventTimestamp) because an empty-timestamp batch is still
+                    // contact from the agent.
+                    update["LastIngestAt"] = EnsureUtc(DateTime.UtcNow);
+
                     // Increment script execution counters
                     if (platformScriptIncrement > 0)
                     {
@@ -2407,17 +2427,20 @@ namespace AutopilotMonitor.Functions.Services
         /// are left untouched rather than being zeroed. Idempotent: no-ops when the row is
         /// already correct. PlatformScriptCount/RemediationScriptCount stay increment-only (their
         /// drift is bounded and they feed no enforcement heuristics; EventCount does).
+        /// Returns the skew-scan samples collected during the authoritative count's partition
+        /// scan (CmTraceSkewTripwire input), or null when the scan itself failed — the counter
+        /// reconcile outcome does not affect the returned scan.
         /// </summary>
-        public async Task ReconcileSessionCountersAsync(string tenantId, string sessionId)
+        public async Task<SessionSkewScan?> ReconcileSessionCountersAsync(string tenantId, string sessionId)
         {
             SecurityValidator.EnsureValidGuid(tenantId, nameof(tenantId));
             SecurityValidator.EnsureValidGuid(sessionId, nameof(sessionId));
 
             var authoritative = await CountSessionEventRowsAsync(tenantId, sessionId);
             if (!authoritative.HasValue)
-                return; // storage error — keep the incremental live values, do not zero them
+                return null; // storage error — keep the incremental live values, do not zero them
 
-            var (totalEvents, rebootEvents) = authoritative.Value;
+            var (totalEvents, rebootEvents, skewScan) = authoritative.Value;
 
             const int maxRetries = 5;
             int retryCount = 0;
@@ -2429,7 +2452,7 @@ namespace AutopilotMonitor.Functions.Services
                     var tableClient = _tableServiceClient.GetTableClient(Constants.TableNames.Sessions);
                     var entityResponse = await tableClient.GetEntityIfExistsAsync<TableEntity>(tenantId, sessionId);
                     if (!entityResponse.HasValue)
-                        return;
+                        return skewScan;
                     var entity = entityResponse.Value!;
 
                     // No-op when already correct — avoids a needless write + index sync on the
@@ -2448,7 +2471,7 @@ namespace AutopilotMonitor.Functions.Services
                         drifted = true;
                     }
                     if (!drifted)
-                        return;
+                        return skewScan;
 
                     var currentStartedAt = entity.GetDateTimeOffset("StartedAt")?.UtcDateTime ?? DateTime.MaxValue;
 
@@ -2457,7 +2480,7 @@ namespace AutopilotMonitor.Functions.Services
                     // Dual-write: keep SessionsIndex in sync (merge — no StartedAt shift here).
                     await SyncSessionIndexAsync(tenantId, sessionId, entity, update, currentStartedAt, null);
 
-                    return;
+                    return skewScan;
                 }
                 catch (Azure.RequestFailedException ex) when (ex.Status == 412)
                 {
@@ -2465,7 +2488,7 @@ namespace AutopilotMonitor.Functions.Services
                     if (retryCount >= maxRetries)
                     {
                         _logger.LogWarning($"Failed to reconcile session counters for session {sessionId} after {maxRetries} retries due to ETag conflicts");
-                        return;
+                        return skewScan;
                     }
                     var baseDelay = 50 * (int)Math.Pow(2, retryCount - 1);
                     await Task.Delay(baseDelay + Random.Shared.Next(0, baseDelay));
@@ -2473,9 +2496,11 @@ namespace AutopilotMonitor.Functions.Services
                 catch (Exception ex)
                 {
                     _logger.LogError(ex, $"Failed to reconcile session counters for session {sessionId}");
-                    return;
+                    return skewScan;
                 }
             }
+
+            return skewScan;
         }
 
         /// <summary>
@@ -2612,6 +2637,70 @@ namespace AutopilotMonitor.Functions.Services
             }
         }
 
+        // Columns the metrics aggregation paths (PlatformMetricsService, AgentEfficiencyMetricsService)
+        // need from an event row: EventType routes the event to its aggregation, DataJson carries the
+        // snapshot payload, Sequence pins the authoritative sort, and the timestamp trio feeds
+        // ResolveEventTimestamp (OccurredUtc column → RowKey decode → system Timestamp) plus the
+        // ReceivedAt side of the delivery-latency delta. Severity/Phase/Message/Source are never read
+        // by the metrics math and map to defaults via MapToEnrollmentEvent's null-safe getters.
+        internal static readonly string[] AgentMetricsEventProjection =
+            { "PartitionKey", "RowKey", "EventType", "DataJson", "Sequence", "ReceivedAt", BusinessTimestamp.OccurredUtcColumn, "Timestamp" };
+
+        /// <summary>
+        /// Builds the OData filter for <see cref="GetSessionEventsByTypesAsync"/>: partition scope
+        /// plus an or-chain over the event types. Internal so the composition (escaping, grouping)
+        /// is unit-testable without a live table.
+        /// </summary>
+        internal static string BuildEventTypesFilter(string partitionKey, IReadOnlyCollection<string> eventTypes)
+        {
+            var typeClauses = string.Join(" or ", eventTypes.Select(t => $"EventType eq '{ODataSanitizer.EscapeValue(t)}'"));
+            return $"PartitionKey eq '{ODataSanitizer.EscapeValue(partitionKey)}' and ({typeClauses})";
+        }
+
+        /// <summary>
+        /// Multi-type sibling of <see cref="GetSessionEventsByTypeAsync"/>: one server-side query
+        /// matching ANY of <paramref name="eventTypes"/>, with an optional column projection.
+        /// <paramref name="maxResults"/> is a hard cap — the drain stops once reached (the
+        /// single-type variant only uses it as the storage page size and drains every page).
+        /// Fail-soft like the other event readers: storage errors log and return an empty list.
+        /// </summary>
+        public async Task<List<EnrollmentEvent>> GetSessionEventsByTypesAsync(
+            string tenantId, string sessionId, IReadOnlyCollection<string> eventTypes,
+            IEnumerable<string>? select = null, int maxResults = 2000)
+        {
+            SecurityValidator.EnsureValidGuid(tenantId, nameof(tenantId));
+            SecurityValidator.EnsureValidGuid(sessionId, nameof(sessionId));
+            if (eventTypes == null || eventTypes.Count == 0)
+                return new List<EnrollmentEvent>();
+
+            try
+            {
+                var tableClient = _tableServiceClient.GetTableClient(Constants.TableNames.Events);
+                var events = new List<EnrollmentEvent>();
+
+                var filter = BuildEventTypesFilter($"{tenantId}_{sessionId}", eventTypes);
+
+                var query = tableClient.QueryAsync<TableEntity>(
+                    filter: filter,
+                    maxPerPage: Math.Min(maxResults, 1000),
+                    select: select
+                );
+
+                await foreach (var entity in query)
+                {
+                    events.Add(MapToEnrollmentEvent(entity));
+                    if (events.Count >= maxResults) break;
+                }
+
+                return events.OrderBy(e => e.Sequence).ToList();
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Failed to get events by types for session {SessionId}", sessionId);
+                return new List<EnrollmentEvent>();
+            }
+        }
+
         /// <summary>
         /// Literal-row variant of <see cref="GetSessionEventsPageAsync"/> backing the single-session
         /// path of <c>/api/raw/events</c>. Emits the raw <c>Events</c> rows verbatim (DataJson as the
@@ -3008,6 +3097,7 @@ namespace AutopilotMonitor.Functions.Services
                 Data = DeserializeEventData(entity.GetString("DataJson")),
                 RowKey = entity.RowKey,
                 ReceivedAt = entity.GetDateTimeOffset("ReceivedAt")?.UtcDateTime,
+                SentAt = entity.GetDateTimeOffset("SentAt")?.UtcDateTime,
                 OriginalTimestamp = entity.GetDateTimeOffset("OriginalTimestamp")?.UtcDateTime,
                 TimestampClamped = entity.GetBoolean("TimestampClamped") ?? false,
                 // Codex follow-up #3 — forward-link columns (nullable for legacy rows).
@@ -3080,6 +3170,7 @@ namespace AutopilotMonitor.Functions.Services
                 // null as "CustomerSas" for back-compat.
                 DiagnosticsBlobDestination = entity.GetString("DiagnosticsBlobDestination"),
                 LastEventAt = SafeGetDateTime(entity, "LastEventAt"),
+                LastIngestAt = SafeGetDateTime(entity, "LastIngestAt"),
                 IsPreProvisioned = entity.GetBoolean("IsPreProvisioned") ?? false,
                 IsHybridJoin = entity.GetBoolean("IsHybridJoin") ?? false,
                 IsSelfDeployingProfile = entity.GetBoolean("IsSelfDeployingProfile") ?? false,
@@ -3211,9 +3302,10 @@ namespace AutopilotMonitor.Functions.Services
         /// and a unique RowKey per event, so the number of stored rows equals the true distinct
         /// count — making this an idempotent, retry-immune authoritative count (used to reconcile
         /// EventCount + RebootCount at the terminal transition). Single partition scan with a
-        /// RowKey+EventType projection so both counts cost one query.
+        /// slim projection so both counts cost one query. The CmTraceSkewTripwire's per-source
+        /// timestamp-delta samples piggyback on the same enumeration (zero extra reads).
         /// </summary>
-        private async Task<(int Total, int Reboots)?> CountSessionEventRowsAsync(string tenantId, string sessionId)
+        private async Task<(int Total, int Reboots, SessionSkewScan Skew)?> CountSessionEventRowsAsync(string tenantId, string sessionId)
         {
             try
             {
@@ -3221,17 +3313,38 @@ namespace AutopilotMonitor.Functions.Services
                 var partitionKey = $"{tenantId}_{sessionId}";
                 var query = tableClient.QueryAsync<TableEntity>(
                     filter: $"PartitionKey eq '{partitionKey}'",
-                    select: new[] { "RowKey", "EventType" }
+                    select: new[] { "RowKey", "EventType", "Source", "ReceivedAt", BusinessTimestamp.OccurredUtcColumn, "TimestampClamped" }
                 );
 
                 int total = 0, reboots = 0;
+                var skew = new SessionSkewScan();
+                var imeBatches = new HashSet<DateTime>();
+                var otherBatches = new HashSet<DateTime>();
+                const int maxSkewSamplesPerSide = 20_000;
                 await foreach (var entity in query)
                 {
                     total++;
                     if (entity.GetString("EventType") == Constants.EventTypes.SystemRebootDetected)
                         reboots++;
+
+                    // Skew sample. Clamped events carry a server-substituted OccurredUtc
+                    // (Δ ≈ 0) and would dilute the medians; legacy rows without ReceivedAt
+                    // have no server frame at all — both are skipped, never zero-filled.
+                    if (entity.GetBoolean("TimestampClamped") == true)
+                        continue;
+                    var receivedAt = entity.GetDateTimeOffset("ReceivedAt")?.UtcDateTime;
+                    var occurredAt = ResolveEventTimestampOrNull(entity);
+                    if (!receivedAt.HasValue || !occurredAt.HasValue)
+                        continue;
+                    var isIme = string.Equals(entity.GetString("Source"), "ImeLogTracker", StringComparison.OrdinalIgnoreCase);
+                    var side = isIme ? skew.ImeDeltaMinutes : skew.OtherDeltaMinutes;
+                    if (side.Count < maxSkewSamplesPerSide)
+                        side.Add((receivedAt.Value - occurredAt.Value).TotalMinutes);
+                    (isIme ? imeBatches : otherBatches).Add(receivedAt.Value);
                 }
-                return (total, reboots);
+                skew.ImeDistinctBatchCount = imeBatches.Count;
+                skew.OtherDistinctBatchCount = otherBatches.Count;
+                return (total, reboots, skew);
             }
             catch (Exception ex)
             {
@@ -3240,6 +3353,49 @@ namespace AutopilotMonitor.Functions.Services
             }
         }
 
+        /// <summary>
+        /// Bounded histogram of the <c>sourceOffsetOrigin</c> provenance values ("bias",
+        /// "line-anchored", "reader-zone-fallback", retired "calibrated") over a session's
+        /// IME-derived events. Only read on the CmTraceSkewTripwire suspicion path (≈ never),
+        /// so the row cap bounds the worst case rather than tuning the common one. Fail-soft:
+        /// storage errors return an empty map, which the caller treats as "not bias-dominated"
+        /// — the tripwire fails open toward reporting.
+        /// </summary>
+        public async Task<Dictionary<string, int>> GetImeOffsetOriginHistogramAsync(string tenantId, string sessionId, int maxRows = 500)
+        {
+            SecurityValidator.EnsureValidGuid(tenantId, nameof(tenantId));
+            SecurityValidator.EnsureValidGuid(sessionId, nameof(sessionId));
+
+            var histogram = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
+            try
+            {
+                var tableClient = _tableServiceClient.GetTableClient(Constants.TableNames.Events);
+                var partitionKey = $"{tenantId}_{sessionId}";
+                var query = tableClient.QueryAsync<TableEntity>(
+                    filter: $"PartitionKey eq '{partitionKey}' and Source eq 'ImeLogTracker'",
+                    select: new[] { "RowKey", "DataJson" });
+
+                int rows = 0;
+                await foreach (var entity in query)
+                {
+                    if (++rows > maxRows)
+                        break;
+                    var data = DeserializeEventData(entity.GetString("DataJson"));
+                    if (data != null && data.TryGetValue("sourceOffsetOrigin", out var origin))
+                    {
+                        var key = origin?.ToString();
+                        if (!string.IsNullOrEmpty(key))
+                            histogram[key!] = histogram.TryGetValue(key!, out var count) ? count + 1 : 1;
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogDebug(ex, $"Could not read IME offset-origin histogram for session {sessionId}");
+            }
+            return histogram;
+        }
+
         #region IME Version History
 
         /// <summary>