Let only POST narrate single-resource reports with Pulse Assistant

GET /api/admin/reports/generate resolved the tenant's AI narrator, so a PDF requested with GET made a paid provider call and appended a usage event to the AI cost ledger. GET passes the demo-mode guard and the CSRF check, and a SameSite=Lax session cookie rides a cross-site top-level GET navigation, so a link could spend a signed-in admin's AI budget. POST with a JSON body, decoded with the generate-multi rules, is now the canonical single-resource transport and the only one that may use the AI narrator. The settings UI sends it, following a new performanceReport.singleResourceMethod catalog field; a catalog without the field, and the legacy fallback catalog, keep the GET transport that older backends accept. GET stays available with the same query parameters but narrates deterministically, printing a note in place of the "Configure Pulse Assistant" tip, and other methods get 405 with Allow: GET, POST. GET also stops resolving the AI service at all: it reads Patrol findings through a new ExistingAIService lookup, because GetAIService constructs a tenant service on first use and that can list provider models or start background discovery. The router's reporting wiring moves into wireReportingAIResolvers so a test can drive it. Keeping GET rather than answering 405 avoids breaking documented API scripts (MSP.md pointed providers at it) for no security gain: CSV is never narrated and GET no longer reaches the provider.
2026-10-23 20:25:56 +00:00 · 2026-10-07 20:52:31 +01:00
parent 77d2119792
commit 9bd1b6e582
27 changed files with 739 additions and 84 deletions
@@ -836,9 +836,12 @@ delivery for all resources.
 - `GET /api/admin/reports/catalog` (admin, `settings:read`)
  - Returns the canonical reporting catalog for the settings surface, including locked-state teaser copy, enabled-surface guidance copy, performance-report options, canonical single-report filename subject, canonical fallback filename date style, and the nested VM inventory export definition.
  - Metadata route: readable without the `advanced_reporting` feature so locked admin surfaces can render the same reporting definition before upsell.
- `GET /api/admin/reports/generate` (admin, `settings:read`)
-  - Query params: `format` (pdf/csv, default `pdf`), `resourceType`, `resourceId`, `metricType` (optional), `start`/`end` (RFC3339, optional; defaults to last 24h), `title` (optional)
+- `POST /api/admin/reports/generate` (admin, `settings:read`)
+  - Body fields: `format` (pdf/csv, default `pdf`), `resourceType`, `resourceId`, `metricType` (optional), `start`/`end` (RFC3339, optional; defaults to last 24h), `title` (optional)
  - If `title` is omitted, the backend applies the canonical default title for that resource report.
+  - When Pulse Assistant is configured, the configured AI provider narrates a PDF's executive summary; each narration counts against the AI budget and appears in AI usage. If the call fails, times out or the budget is spent, the PDF falls back to the deterministic summary. CSV output is never narrated. The settings UI uses this method.
+- `GET /api/admin/reports/generate` (admin, `settings:read`)
+  - Takes the same fields as query params and returns the same report, except that it never calls an AI provider: a PDF carries the deterministic summary and a note saying AI narration needs `POST`. Other methods return `405` with `Allow: GET, POST`.
 - `POST /api/admin/reports/generate-multi` (admin, `settings:read`)
  - Body fields: `resources` (1-50 entries of `{resourceType,resourceId}`), `format`, `metricType` (optional), `start`/`end` (RFC3339, optional; defaults to last 24h), `title` (optional)
  - If `title` is omitted, the backend applies the canonical default fleet report title.
@@ -851,8 +854,8 @@ Validation and limits:
 - Malformed `start`/`end` values, `end` not strictly after `start`, or report windows over 366 days return `400 invalid_time_range`.
 - `metricType` must match `[a-zA-Z0-9._:-]+` and be <= 64 chars, otherwise `400 invalid_metric_type`.
 - `title` must be <= 256 chars, otherwise `400 invalid_title`.
- Multi-report body max size is 1MB; oversized payloads return `400 body_too_large`.
- Multi-report bodies reject trailing payload and unknown JSON fields with `400 invalid_body`.
+- Report body max size is 1MB; oversized payloads return `400 body_too_large`.
+- Report bodies reject trailing payload and unknown JSON fields with `400 invalid_body`.
 - VM inventory export only accepts `csv`.

 Common reporting error codes:
@@ -260,10 +260,12 @@ Each client runtime (or organization) generates its own reports, scoped to
 that client's resources:

 - **UI**: Settings → Data & Reports.
- **API**: `GET /api/admin/reports/generate` (single resource) and
+- **API**: `POST /api/admin/reports/generate` (single resource) and
  `POST /api/admin/reports/generate-multi` (up to 50 resources per report),
  returning PDF or CSV. In shared-process mode, scope with `X-Pulse-Org-ID`
-  or an org-bound token.
+  or an org-bound token. `GET /api/admin/reports/generate` with query
+  parameters still returns a single-resource report, but never adds the
+  Pulse Assistant narrative.
 - **Schedules**: `GET`/`POST /api/admin/reports/schedules`,
  `PUT`/`DELETE /api/admin/reports/schedules/{id}`, and
  `POST /api/admin/reports/schedules/{id}/run`. Schedules can target explicit
@@ -7639,6 +7639,16 @@ bounded and classified temperature nodes, and leaves the host report intact
 when the helper is absent or incompatible. It does not treat Windows ACPI
 thermal zones as hardware sensor evidence, accept remote provider locations,
 or grant Pulse hardware-control authority.
+### Single-resource report AI narration requires POST
+
+`internal/api/metrics_reporting_handlers.go`, `internal/api/router.go` and
+`internal/api/ai_handlers.go` changed only how `/api/admin/reports/generate`
+reads its fields (a `POST` JSON body or `GET` query parameters), which of those
+may use the tenant's AI narrator (`POST` only), and how a `GET` finds Patrol
+findings (`ExistingAIService`, which never constructs a tenant AI service). No
+agent registration, enrolment, install, update, removal or report ingest path
+changed.
+
 ### Agent profile adoption is reported as a count only

 The usage telemetry snapshot reads `LoadAgentProfiles` and reports
@@ -7510,6 +7510,18 @@ prompt budget. Reporting is therefore an additive consumer of AI
 runtime, not a new ownership boundary, and the narrator/findings
 surfaces inherit the same governance the rest of the canonical AI
 runtime already enforces.
+Report narration is caller-requested spend, so on the single-resource HTTP
+route only `POST /api/admin/reports/generate` reaches it (fleet reports, from
+`POST .../generate-multi` or a report schedule, use the fleet narrator). The
+reporting narrator resolver goes through `AISettingsHandler.GetAIService`,
+which constructs a tenant service on first use and can then list provider
+models or start background discovery. A GET single-resource report never calls
+that resolver:
+it narrates deterministically and reads Patrol findings through
+`AISettingsHandler.ExistingAIService`, which returns only a service that is
+already running and never constructs one
+(`TestAISettingsHandler_ExistingAIServiceNeverConstructs`, and through the
+router's real wiring `TestContract_SingleReportGETDoesNotConstructTenantAIService`).

 The same canonical AI runtime now also owns the fleet-level report
 narrative through `report_fleet_narrator.go`. `Service` implements
@@ -9650,6 +9650,32 @@ narrator must fail closed: nil provider, parse failure, timeout, or
 empty response causes the engine to fall back to the heuristic
 narrative without surfacing the AI failure to the caller, so reporting
 is never blocked by AI availability.
+Only `POST /api/admin/reports/generate` may hand the tenant's AI narrator to
+the engine, because a narrated PDF makes a paid provider call and appends a
+`cost.UsageEvent` to the cost ledger. The single-resource handler accepts
+`POST` with a JSON body (the `generate-multi` decoding rules: 1MB cap, unknown
+fields and trailing payload rejected, through `decodeReportingRequestBody`) and
+`GET` with the same fields as query parameters, and answers any other method
+with `405` and `Allow: GET, POST`. GET never calls `resolveNarrator`, whose
+`GetAIService` can construct a tenant AI service (and with it list provider
+models or start background discovery): it narrates through `getReportNarrator`,
+the heuristic summary whose `Disclaimer` replaces the "Configure Pulse
+Assistant" tip with a note that AI narration needs POST, and reads Patrol
+findings through `SetExistingFindingsResolver`, which `router.go` backs with
+`AISettingsHandler.ExistingAIService` so only an already running service is
+used. GET passes the demo-mode guard and the CSRF check, and a SameSite=Lax
+session cookie rides a cross-site top-level GET navigation, so a link must not
+be able to spend AI budget. The reporting catalog advertises the transport as
+`performanceReport.singleResourceMethod` (`POST`), and the settings UI follows
+it. `generate-multi` and the manual schedule run endpoint
+(`POST /api/admin/reports/schedules/{id}/run`) were already POST-only; due
+schedules run from the server's scheduler, not an HTTP request.
+`TestContract_SingleReportAINarrationRequiresPOST` pins the rule on a real
+engine: GET, HEAD, PUT and DELETE make no narrator call and no AI service
+resolution, while POST makes one of each.
+`TestContract_SingleReportGETDoesNotConstructTenantAIService` drives
+`Router.wireReportingAIResolvers` with an uncached tenant: GET constructs no
+tenant AI service and POST resolves one.
 Report alerts keep the alert engine's resolution. The node, VM and
 container enrichers in `internal/api/metrics_reporting_handlers.go` build
 every row through `reportActiveAlertInfo` and `reportResolvedAlertInfo`,
@@ -6101,6 +6101,14 @@ summaries whose scope, format, and attachments the server fixes. The delivery
 surface (`/api/admin/reports/schedules`) and tenant-local storage are
 unchanged.

+### Provider docs name POST for single-resource reports
+
+`docs/MSP.md` and its shipped copy now give `POST /api/admin/reports/generate`
+for per-client single-resource reports and say a `GET` with query parameters
+still returns the report without the Pulse Assistant narrative, matching the
+server, which lets only `POST` narrate. Install, upgrade and provider bundle
+delivery are unchanged.
+
 ### Convergence log-reader compatibility (5 September 2026)

 Scheduled reconciliation run 33939926237 failed when `gh api` refused terminal
@@ -4828,6 +4828,13 @@ performance-report transport (`/api/reporting` and `/api/reporting/generate-mult
 so the reporting panel does not go dead on mixed-version installs, but that
 compatibility path is intentionally report-only and must not invent the newer
 catalog-owned VM inventory export surface.
+`reportingPanelModel.ts` picks the single-resource transport from the catalog's
+`performanceReport.singleResourceMethod`: `POST` sends the request fields as a
+JSON body, which is the only transport the server lets narrate a PDF with Pulse
+Assistant, and `GET` sends the same fields as query parameters.
+`reportingCatalogModel.ts` reads a missing field as `GET`, the only method a
+backend that predates the field accepts, and the legacy compatibility catalog
+names `GET` for `/api/reporting`. Fleet reports stay `POST` on every backend.
 `ReportingPanel.tsx` must therefore treat `vmInventoryExport` as optional when
 it renders a governed reporting catalog. A legacy compatibility catalog with no
 inventory export still owns a valid enabled reporting surface and must continue
@@ -3025,6 +3025,18 @@ Removing the disconnected recorder does not alter alert, action approval or
 operator authority. An unrelated organization receives no default archive
 fallback.

+### Report GETs cannot spend AI budget
+
+`Router.wireReportingAIResolvers` in `internal/api/router.go` wires a second
+reporting resolver, `SetExistingFindingsResolver`, backed by
+`AISettingsHandler.ExistingAIService`.
+A `GET /api/admin/reports/generate` uses only that resolver and the
+deterministic narrator, so it makes no AI provider call, writes no cost-ledger
+entry and never constructs a tenant AI service. GET passes the demo-mode guard
+and the CSRF check, and a SameSite=Lax session cookie rides a cross-site
+top-level navigation, so AI narration of a single-resource report now requires
+a CSRF-checked `POST`. No authentication, scope or session rule changed.
+
 ### Node setup action v7 compatibility

 Workflow consumers pin `actions/setup-node` to
@@ -6247,6 +6247,19 @@ is in `applyLicensedFeatureConfigSnapshot`
 (`pkg/server/telemetry_licensed_features.go`), pinned by
 `TestApplyLicensedFeatureConfigSnapshot_CountsScheduledReportingAndProfiles`.

+### Single-resource report AI narration requires POST
+
+`internal/api/metrics_reporting_handlers.go` now accepts `POST` with a JSON
+body for `/api/admin/reports/generate` and lets only that method use the
+tenant's AI narrator; `GET` keeps working with query parameters and the
+deterministic summary. A narrated PDF records the same AI cost-ledger entry as
+before, and only a `POST` can now produce one. A `GET` reads Patrol findings
+only from an AI service that is already running
+(`AISettingsHandler.ExistingAIService`), so it no longer constructs a tenant AI
+service, whose construction opens that tenant's SQLite resource export store.
+Report content, backup and recovery enrichment, and tenant storage are
+otherwise unchanged.
+
 ### Audit-read activity is a bounded, content-free local history

 `audit_read_activity.json` follows the same shape as the existing external-agent
@@ -0,0 +1,42 @@
+{
+  "version": 1,
+  "base_sha": "77d21197927a670076a74e87634e73ea999a566a",
+  "verified_at": "2026-10-07T19:05:00Z",
+  "result": "passed",
+  "changed_paths": [
+    "frontend-modern/src/components/Settings/reportingCatalogModel.ts",
+    "frontend-modern/src/components/Settings/reportingPanelModel.ts"
+  ],
+  "content_sha256": {
+    "frontend-modern/src/components/Settings/reportingCatalogModel.ts": "fc3ab83f49ac62aaf7ef97b415a0bff1c4e445ca17771efc18304295e94e3df0",
+    "frontend-modern/src/components/Settings/reportingPanelModel.ts": "e4366a8c50ea897dcb4907b4e488a2c5f758e710d7a9be0d5fe0d3e047e2d9c5"
+  },
+  "routes": [
+    "/settings/support/reporting",
+    "/api/admin/reports/generate"
+  ],
+  "viewports": [
+    {
+      "width": 1280,
+      "height": 800
+    },
+    {
+      "width": 390,
+      "height": 844
+    }
+  ],
+  "states": [
+    "Pro dev licence active, Pulse Assistant enabled on a local stub OpenAI-compatible provider that logs each call, real admin session login (no admin bypass)",
+    "Data & Reports panel with one mock agent selected, then two",
+    "Downloaded single-resource PDF opened: POST copy carries the stub AI narrative and provenance footer; GET copy carries the deterministic summary and the new GET note in place of the Configure Pulse Assistant tip",
+    "AI usage summary after the run: report_narrative recorded only for the two UI POST downloads"
+  ],
+  "interactions": [
+    "Generate Report (1 resource) as PDF at 1280x800 and 390x844: one POST /api/admin/reports/generate with a JSON body, 200 application/pdf, download saved, stub provider called once each",
+    "Generate Report (1 resource) as CSV at both widths: POST, 200 text/csv, stub provider not called",
+    "Generate Report (2 resources) as PDF at both widths: POST /api/admin/reports/generate-multi unchanged, 200 application/pdf",
+    "Top-level browser navigation to GET /api/admin/reports/generate?format=pdf with the session cookie: PDF downloaded, stub provider not called",
+    "HEAD, PUT, DELETE and PATCH return 405 with Allow GET, POST; a session POST without the CSRF header returns 403",
+    "No console errors on the reporting panel at either width"
+  ]
+}
@@ -836,9 +836,12 @@ delivery for all resources.
 - `GET /api/admin/reports/catalog` (admin, `settings:read`)
  - Returns the canonical reporting catalog for the settings surface, including locked-state teaser copy, enabled-surface guidance copy, performance-report options, canonical single-report filename subject, canonical fallback filename date style, and the nested VM inventory export definition.
  - Metadata route: readable without the `advanced_reporting` feature so locked admin surfaces can render the same reporting definition before upsell.
- `GET /api/admin/reports/generate` (admin, `settings:read`)
-  - Query params: `format` (pdf/csv, default `pdf`), `resourceType`, `resourceId`, `metricType` (optional), `start`/`end` (RFC3339, optional; defaults to last 24h), `title` (optional)
+- `POST /api/admin/reports/generate` (admin, `settings:read`)
+  - Body fields: `format` (pdf/csv, default `pdf`), `resourceType`, `resourceId`, `metricType` (optional), `start`/`end` (RFC3339, optional; defaults to last 24h), `title` (optional)
  - If `title` is omitted, the backend applies the canonical default title for that resource report.
+  - When Pulse Assistant is configured, the configured AI provider narrates a PDF's executive summary; each narration counts against the AI budget and appears in AI usage. If the call fails, times out or the budget is spent, the PDF falls back to the deterministic summary. CSV output is never narrated. The settings UI uses this method.
+- `GET /api/admin/reports/generate` (admin, `settings:read`)
+  - Takes the same fields as query params and returns the same report, except that it never calls an AI provider: a PDF carries the deterministic summary and a note saying AI narration needs `POST`. Other methods return `405` with `Allow: GET, POST`.
 - `POST /api/admin/reports/generate-multi` (admin, `settings:read`)
  - Body fields: `resources` (1-50 entries of `{resourceType,resourceId}`), `format`, `metricType` (optional), `start`/`end` (RFC3339, optional; defaults to last 24h), `title` (optional)
  - If `title` is omitted, the backend applies the canonical default fleet report title.
@@ -851,8 +854,8 @@ Validation and limits:
 - Malformed `start`/`end` values, `end` not strictly after `start`, or report windows over 366 days return `400 invalid_time_range`.
 - `metricType` must match `[a-zA-Z0-9._:-]+` and be <= 64 chars, otherwise `400 invalid_metric_type`.
 - `title` must be <= 256 chars, otherwise `400 invalid_title`.
- Multi-report body max size is 1MB; oversized payloads return `400 body_too_large`.
- Multi-report bodies reject trailing payload and unknown JSON fields with `400 invalid_body`.
+- Report body max size is 1MB; oversized payloads return `400 body_too_large`.
+- Report bodies reject trailing payload and unknown JSON fields with `400 invalid_body`.
 - VM inventory export only accepts `csv`.

 Common reporting error codes:
@@ -260,10 +260,12 @@ Each client runtime (or organization) generates its own reports, scoped to
 that client's resources:

 - **UI**: Settings → Data & Reports.
- **API**: `GET /api/admin/reports/generate` (single resource) and
+- **API**: `POST /api/admin/reports/generate` (single resource) and
  `POST /api/admin/reports/generate-multi` (up to 50 resources per report),
  returning PDF or CSV. In shared-process mode, scope with `X-Pulse-Org-ID`
-  or an org-bound token.
+  or an org-bound token. `GET /api/admin/reports/generate` with query
+  parameters still returns a single-resource report, but never adds the
+  Pulse Assistant narrative.
 - **Schedules**: `GET`/`POST /api/admin/reports/schedules`,
  `PUT`/`DELETE /api/admin/reports/schedules/{id}`, and
  `POST /api/admin/reports/schedules/{id}/run`. Schedules can target explicit
@@ -35,6 +35,7 @@ const baseCatalog = {
    title: 'Performance Reports',
    description: 'Historical performance reporting',
    singleResourceEndpoint: '/api/admin/reports/generate',
+    singleResourceMethod: 'POST',
    multiResourceEndpoint: '/api/admin/reports/generate-multi',
    singleFilenamePrefix: 'report',
    singleFilenameSubject: 'resource_id',
@@ -42,6 +42,7 @@ const basePerformanceReport = () => ({
  title: 'Performance Reports',
  description: 'Historical performance reporting',
  singleResourceEndpoint: '/api/admin/reports/generate',
+  singleResourceMethod: 'POST',
  multiResourceEndpoint: '/api/admin/reports/generate-multi',
  singleFilenamePrefix: 'report',
  singleFilenameSubject: 'resource_id',
@@ -453,6 +454,19 @@ describe('parseReportingPerformanceReportDefinition (via catalog.performanceRepo
    });
  });

+  it('throws when singleResourceMethod is neither GET nor POST', () => {
+    expectInvalid({
+      ...baseCatalog(),
+      performanceReport: { ...basePerformanceReport(), singleResourceMethod: 'PUT' },
+    });
+  });
+
+  it('reads a missing singleResourceMethod as GET, the only method older backends accept', () => {
+    const { singleResourceMethod: _omitted, ...withoutMethod } = basePerformanceReport();
+    const parsed = parseReportingCatalog({ ...baseCatalog(), performanceReport: withoutMethod });
+    expect(parsed.performanceReport.singleResourceMethod).toBe('GET');
+  });
+
  it('throws when multiResourceEndpoint is not a string', () => {
    expectInvalid({
      ...baseCatalog(),
@@ -22,6 +22,7 @@ const baseCatalogPayload = {
    title: 'Performance Reports',
    description: 'Historical performance reporting',
    singleResourceEndpoint: '/api/admin/reports/generate',
+    singleResourceMethod: 'POST',
    multiResourceEndpoint: '/api/admin/reports/generate-multi',
    singleFilenamePrefix: 'report',
    singleFilenameSubject: 'resource_id',
@@ -74,6 +75,7 @@ describe('reporting catalog model', () => {
    const catalog = buildLegacyReportingCatalogFallback();

    expect(catalog.performanceReport.singleResourceEndpoint).toBe('/api/reporting');
+    expect(catalog.performanceReport.singleResourceMethod).toBe('GET');
    expect(catalog.performanceReport.multiResourceEndpoint).toBe('/api/reporting/generate-multi');
    expect(catalog.vmInventoryExport).toBeNull();
  });
@@ -14,6 +14,7 @@ const performanceDefinition: ReportingPerformanceReportDefinition = {
  title: 'Performance Reports',
  description: 'Historical performance reporting',
  singleResourceEndpoint: '/api/admin/reports/generate',
+  singleResourceMethod: 'POST',
  multiResourceEndpoint: '/api/admin/reports/generate-multi',
  singleFilenamePrefix: 'report',
  singleFilenameSubject: 'resource_id',
@@ -75,12 +76,52 @@ describe('reporting panel model', () => {
    );

    expect(request.filename).toBe('report-agent-1-20260320.pdf');
+    // POST, never GET: only POST may narrate the PDF with Pulse Assistant.
+    expect(request.request.url).toBe('/api/admin/reports/generate');
+    expect(request.request.init).toMatchObject({
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+    });
+    expect(JSON.parse(String(request.request.init?.body))).toEqual({
+      resourceType: 'agent',
+      resourceId: 'agent-1',
+      format: 'pdf',
+      start: '2026-03-19T12:34:56.000Z',
+      end: now.toISOString(),
+      metricType: 'cpu',
+    });
+  });
+
+  it('keeps the query-string GET transport for backends whose catalog names GET', () => {
+    const now = new Date('2026-03-20T12:34:56.000Z');
+    const request = buildReportingRequest(
+      {
+        end: now.toISOString(),
+        format: 'csv',
+        metricType: 'cpu',
+        now,
+        resources: [{ id: 'vm-1', type: 'vm', name: 'vm-a' }],
+        start: '2026-03-19T12:34:56.000Z',
+        title: '',
+      },
+      {
+        ...performanceDefinition,
+        singleResourceEndpoint: '/api/reporting',
+        singleResourceMethod: 'GET',
+      },
+    );
+
    expect(request.request.init).toBeUndefined();
-    expect(request.request.url).toContain('/api/admin/reports/generate?');
-    expect(request.request.url).toContain('resourceType=agent');
-    expect(request.request.url).toContain('resourceId=agent-1');
-    expect(request.request.url).toContain('metricType=cpu');
-    expect(request.request.url).not.toContain('title=');
+    const url = new URL(request.request.url, 'http://pulse.local');
+    expect(url.pathname).toBe('/api/reporting');
+    expect(Object.fromEntries(url.searchParams)).toEqual({
+      resourceType: 'vm',
+      resourceId: 'vm-1',
+      format: 'csv',
+      start: '2026-03-19T12:34:56.000Z',
+      end: now.toISOString(),
+      metricType: 'cpu',
+    });
  });

  it('builds a fleet reporting request body and filename', () => {
@@ -158,9 +199,9 @@ describe('reporting panel model', () => {
      },
    );

-    expect(request.request.url).not.toContain('title=');
-    expect(request.request.url).not.toContain('metricType=');
-    expect(request.request.url).not.toContain('Custom+fleet+title');
+    const body = JSON.parse(String(request.request.init?.body));
+    expect(body).not.toHaveProperty('title');
+    expect(body).not.toHaveProperty('metricType');
  });

  it('passes through explicit custom titles without inventing defaults', () => {
@@ -186,7 +227,7 @@ describe('reporting panel model', () => {
      performanceDefinition,
    );

-    expect(request.request.url).toContain('title=Custom+report+title');
+    expect(JSON.parse(String(request.request.init?.body)).title).toBe('Custom report title');
  });

  it('derives canonical range starts from the selected preset', () => {
@@ -28,6 +28,7 @@ const catalogPayload = {
    title: 'Performance Reports',
    description: 'Historical performance reporting',
    singleResourceEndpoint: '/api/admin/reports/generate',
+    singleResourceMethod: 'POST',
    multiResourceEndpoint: '/api/admin/reports/generate-multi',
    singleFilenamePrefix: 'report',
    singleFilenameSubject: 'resource_id',
@@ -478,6 +479,48 @@ describe('useReportingPanelState', () => {
    dispose();
  });

+  it('posts a single-resource report as a JSON body through apiFetch', async () => {
+    apiFetchMock.mockImplementation((url: string) => {
+      if (url === '/api/admin/reports/generate') {
+        return Promise.resolve(new Response('%PDF', { status: 200 }));
+      }
+      if (url === '/api/admin/reports/schedules') {
+        return Promise.resolve(jsonResponse(schedulesPayload));
+      }
+      return Promise.resolve(jsonResponse(catalogPayload));
+    });
+    const { createObjectURL, revokeObjectURL } = URL;
+    URL.createObjectURL = vi.fn(() => 'blob:report');
+    URL.revokeObjectURL = vi.fn();
+    try {
+      const { hookState, dispose } = mountHook();
+      await flushAsync();
+
+      hookState.setSelectedResources([{ id: 'vm-1', type: 'vm', name: 'vm-a' }]);
+      await hookState.handleGenerate();
+
+      const generate = apiFetchMock.mock.calls.filter(([url]) =>
+        String(url).startsWith('/api/admin/reports/generate'),
+      );
+      expect(generate).toHaveLength(1);
+      expect(generate[0][0]).toBe('/api/admin/reports/generate');
+      expect(generate[0][1]).toMatchObject({
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+      });
+      expect(JSON.parse(String(generate[0][1].body))).toMatchObject({
+        resourceType: 'vm',
+        resourceId: 'vm-1',
+        format: catalogPayload.performanceReport.defaultFormat,
+      });
+      expect(showWarningMock).not.toHaveBeenCalled();
+      dispose();
+    } finally {
+      URL.createObjectURL = createObjectURL;
+      URL.revokeObjectURL = revokeObjectURL;
+    }
+  });
+
  it('saves a Patrol weekly summary without a resource scope', async () => {
    const savedSchedule = {
      id: 'digest-1',
@@ -6,6 +6,7 @@ import {
 export type ReportingFormat = 'pdf' | 'csv';
 export type ReportingFilenameDateStyle = 'utc_yyyymmdd';
 export type ReportingFilenameSubject = 'resource_id';
+export type ReportingSingleResourceMethod = 'GET' | 'POST';

 export interface ReportingFormatDefinition {
  value: ReportingFormat;
@@ -24,6 +25,7 @@ export interface ReportingPerformanceReportDefinition {
  title: string;
  description: string;
  singleResourceEndpoint: string;
+  singleResourceMethod: ReportingSingleResourceMethod;
  multiResourceEndpoint: string;
  singleFilenamePrefix: string;
  singleFilenameSubject: ReportingFilenameSubject;
@@ -85,6 +87,7 @@ export function buildLegacyReportingCatalogFallback(): ReportingCatalog {
      description:
        'Generate PDF summaries or CSV metric exports from historical monitoring data for one or more selected resources.',
      singleResourceEndpoint: '/api/reporting',
+      singleResourceMethod: 'GET',
      multiResourceEndpoint: '/api/reporting/generate-multi',
      singleFilenamePrefix: 'report',
      singleFilenameSubject: 'resource_id',
@@ -176,6 +179,9 @@ function parseReportingPerformanceReportDefinition(
    typeof candidate.title !== 'string' ||
    typeof candidate.description !== 'string' ||
    typeof candidate.singleResourceEndpoint !== 'string' ||
+    (candidate.singleResourceMethod !== undefined &&
+      candidate.singleResourceMethod !== 'GET' &&
+      candidate.singleResourceMethod !== 'POST') ||
    typeof candidate.multiResourceEndpoint !== 'string' ||
    typeof candidate.singleFilenamePrefix !== 'string' ||
    candidate.singleFilenameSubject !== 'resource_id' ||
@@ -211,6 +217,8 @@ function parseReportingPerformanceReportDefinition(
    title: candidate.title,
    description: candidate.description,
    singleResourceEndpoint: candidate.singleResourceEndpoint,
+    // Backends that predate the field accept only GET.
+    singleResourceMethod: candidate.singleResourceMethod ?? 'GET',
    multiResourceEndpoint: candidate.multiResourceEndpoint,
    singleFilenamePrefix: candidate.singleFilenamePrefix,
    singleFilenameSubject: candidate.singleFilenameSubject,
@@ -96,6 +96,7 @@ export function buildReportingRequest(
    | 'singleFilenamePrefix'
    | 'singleFilenameSubject'
    | 'singleResourceEndpoint'
+    | 'singleResourceMethod'
    | 'supportsCustomTitle'
    | 'supportsMetricFilter'
  >,
@@ -105,23 +106,41 @@ export function buildReportingRequest(

  if (context.resources.length === 1) {
    const resource = context.resources[0];
-    const params = new URLSearchParams({
+    const fields = {
      resourceType: toReportingResourceType(resource.type),
      resourceId: resource.id,
      format: context.format,
      start: context.start,
      end: context.end,
-    });
+      title: customTitle || undefined,
+      metricType: metricType || undefined,
+    };
+    const filename = buildReportingFilename(context.format, resource.id, context.now, definition);

-    if (metricType) {
-      params.append('metricType', metricType);
-    }
-    if (customTitle) {
-      params.append('title', customTitle);
+    // Only POST may narrate a PDF with Pulse Assistant; the catalog names
+    // GET only for backends that accept nothing else.
+    if (definition.singleResourceMethod === 'POST') {
+      return {
+        filename,
+        request: {
+          url: definition.singleResourceEndpoint,
+          init: {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify(fields),
+          },
+        },
+      };
    }

+    const params = new URLSearchParams();
+    for (const [key, value] of Object.entries(fields)) {
+      if (value) {
+        params.append(key, value);
+      }
+    }
    return {
-      filename: buildReportingFilename(context.format, resource.id, context.now, definition),
+      filename,
      request: {
        url: `${definition.singleResourceEndpoint}?${params.toString()}`,
      },
@@ -566,6 +566,27 @@ describe('docsLinks', () => {
    expect(apiReference).not.toContain('Mobile Remote Access');
  });

+  it('documents POST as the only report transport that uses Pulse Assistant', () => {
+    const handler = readFileSync(
+      path.join(repoRoot, 'internal', 'api', 'metrics_reporting_handlers.go'),
+      'utf8',
+    );
+    expect(handler).toContain(
+      'if r.Method == http.MethodPost {\n\t\tnarrator, _, findings = h.resolveNarrator(r.Context())',
+    );
+    expect(handler).toContain('req.Narrator = getReportNarrator{}');
+    for (const guide of ['API.md', 'MSP.md']) {
+      const rootDoc = readFileSync(path.join(repoRoot, 'docs', guide), 'utf8');
+      expect(readFileSync(path.join(frontendRoot, 'public', 'docs', guide), 'utf8')).toBe(rootDoc);
+      expect(rootDoc).toContain('`POST /api/admin/reports/generate` (');
+    }
+    const apiReference = readFileSync(path.join(repoRoot, 'docs', 'API.md'), 'utf8');
+    expect(apiReference).toContain('it never calls an AI provider');
+    expect(apiReference).toContain('`405` with `Allow: GET, POST`');
+    const msp = readFileSync(path.join(repoRoot, 'docs', 'MSP.md'), 'utf8');
+    expect(msp).not.toContain('`GET /api/admin/reports/generate` (single resource)');
+  });
+
  it('ships credential-free Proxmox setup instructions and a separate token prompt', () => {
    const apiReference = readFileSync(path.join(repoRoot, 'docs', 'API.md'), 'utf8');
    const shipped = readFileSync(path.join(frontendRoot, 'public', 'docs', 'API.md'), 'utf8');
@@ -385,6 +385,25 @@ func (h *AISettingsHandler) loadAIConfig(ctx context.Context) (*config.AIConfig,
 }

 // GetAIService returns the underlying AI service
+// ExistingAIService returns the org's AI service only when one already exists
+// and never constructs one. GetAIService builds and configures a tenant service
+// on first use, which can list provider models and start background discovery,
+// so read paths that must not reach an AI provider use this instead.
+func (h *AISettingsHandler) ExistingAIService(ctx context.Context) *ai.Service {
+	if h == nil {
+		return nil
+	}
+	mtPersistence, mtMonitor, _, _, _, _ := h.stateRefs()
+	defaultAIService := h.providerSnapshot().defaultAIService
+	orgID := GetOrgID(ctx)
+	if orgID == "default" || orgID == "" || (mtPersistence == nil && mtMonitor == nil) {
+		return defaultAIService
+	}
+	h.aiServicesMu.RLock()
+	defer h.aiServicesMu.RUnlock()
+	return h.aiServices[orgID]
+}
+
 func (h *AISettingsHandler) GetAIService(ctx context.Context) *ai.Service {
 	mtPersistence, mtMonitor, _, _, _, _ := h.stateRefs()
 	providers := h.providerSnapshot()
@@ -303,6 +303,36 @@ func TestAISettingsHandler_GetAIService_MultiTenantProviders(t *testing.T) {
 	}
 }

+// Report GETs read Patrol findings through ExistingAIService, so it must never
+// construct a tenant service: construction can list provider models and start
+// background discovery.
+func TestAISettingsHandler_ExistingAIServiceNeverConstructs(t *testing.T) {
+	handler := NewAISettingsHandler(config.NewMultiTenantPersistence(t.TempDir()), nil, nil)
+	t.Cleanup(handler.StopServices)
+	tenant := context.WithValue(context.Background(), OrgIDContextKey, "tenant-1")
+
+	if svc := handler.ExistingAIService(tenant); svc != nil {
+		t.Fatalf("expected no service before the tenant's first GetAIService, got %p", svc)
+	}
+	handler.aiServicesMu.RLock()
+	built := len(handler.aiServices)
+	handler.aiServicesMu.RUnlock()
+	if built != 0 {
+		t.Fatalf("ExistingAIService constructed %d tenant services, want 0", built)
+	}
+
+	created := handler.GetAIService(tenant)
+	if created == nil {
+		t.Fatal("expected GetAIService to construct the tenant service")
+	}
+	if got := handler.ExistingAIService(tenant); got != created {
+		t.Fatalf("expected the running tenant service %p, got %p", created, got)
+	}
+	if got, want := handler.ExistingAIService(context.Background()), handler.GetAIService(context.Background()); got != want {
+		t.Fatalf("expected the default service %p, got %p", want, got)
+	}
+}
+
 func TestAISettingsHandler_GetAIService_UsesTenantReadState(t *testing.T) {
 	tmp := t.TempDir()
 	mtp := config.NewMultiTenantPersistence(tmp)
@@ -5081,6 +5081,7 @@ func TestContract_ReportingCatalogJSONSnapshot(t *testing.T) {
 			"title":"Performance Reports",
 			"description":"Generate PDF summaries or CSV metric exports from historical monitoring data for one or more selected resources.",
 			"singleResourceEndpoint":"/api/admin/reports/generate",
+			"singleResourceMethod":"POST",
 			"multiResourceEndpoint":"/api/admin/reports/generate-multi",
 			"singleFilenamePrefix":"report",
 			"singleFilenameSubject":"resource_id",
@@ -5227,6 +5228,169 @@ func TestContract_PerformanceReportTransportUsesCatalogDefinition(t *testing.T)
 	if engine.lastReq.MetricType != "cpu" || engine.lastReq.Title != "Node report" {
 		t.Fatalf("expected trimmed canonical optional fields, got %+v", engine.lastReq)
 	}
+
+	post := httptest.NewRequest(
+		http.MethodPost,
+		"/api/reporting",
+		strings.NewReader(`{"resourceType":"node","resourceId":"node-1","metricType":" cpu ","title":" Node report "}`),
+	)
+	rec = httptest.NewRecorder()
+	handler.HandleGenerateReport(rec, post)
+	if rec.Code != http.StatusOK {
+		t.Fatalf("expected POST 200, got %d body=%s", rec.Code, rec.Body.String())
+	}
+	if engine.lastReq.ResourceID != "node-1" || engine.lastReq.Format != definition.DefaultFormat ||
+		engine.lastReq.MetricType != "cpu" || engine.lastReq.Title != "Node report" {
+		t.Fatalf("expected POST body to carry the same canonical fields as GET, got %+v", engine.lastReq)
+	}
+}
+
+type recordingReportEngine struct {
+	*reporting.ReportEngine
+	requests []reporting.MetricReportRequest
+}
+
+func (e *recordingReportEngine) Generate(req reporting.MetricReportRequest) ([]byte, string, error) {
+	e.requests = append(e.requests, req)
+	return e.ReportEngine.Generate(req)
+}
+
+type countingReportNarrator struct{ calls atomic.Int32 }
+
+func (n *countingReportNarrator) Narrate(context.Context, reporting.NarrativeInput) (reporting.Narrative, error) {
+	n.calls.Add(1)
+	return reporting.Narrative{Source: reporting.NarrativeSourceAI, HealthStatus: "HEALTHY", HealthMessage: "narrated"}, nil
+}
+
+// A PDF single-resource report may be narrated by the tenant's Pulse
+// Assistant, a paid provider call recorded in the cost ledger. GET passes the
+// demo-mode guard and the CSRF check, and SameSite=Lax session cookies ride
+// cross-site top-level GET navigations, so only POST, the settings UI
+// transport, may reach the AI narrator. GET still returns the report, with
+// the deterministic summary and a note in place of the "Configure Pulse
+// Assistant" tip.
+func TestContract_SingleReportAINarrationRequiresPOST(t *testing.T) {
+	store, err := metrics.NewStore(metrics.DefaultConfig(t.TempDir()))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = store.Close() })
+	engine := &recordingReportEngine{ReportEngine: reporting.NewReportEngine(reporting.EngineConfig{MetricsStore: store})}
+	original := reporting.GetEngine()
+	reporting.SetEngine(engine)
+	t.Cleanup(func() { reporting.SetEngine(original) })
+
+	// The narrator resolver stands for GetAIService, which can construct a
+	// tenant AI service; GET must use only the existing-service findings path.
+	narrator := &countingReportNarrator{}
+	var narratorResolves, findingsResolves atomic.Int32
+	handler := NewReportingHandlers(nil, nil)
+	handler.SetNarratorResolver(func(context.Context) (reporting.Narrator, reporting.FleetNarrator, reporting.FindingsProvider) {
+		narratorResolves.Add(1)
+		return narrator, nil, nil
+	})
+	handler.SetExistingFindingsResolver(func(context.Context) reporting.FindingsProvider {
+		findingsResolves.Add(1)
+		return nil
+	})
+	generate := func(req *http.Request) *httptest.ResponseRecorder {
+		rec := httptest.NewRecorder()
+		handler.HandleGenerateReport(rec, req)
+		return rec
+	}
+	const query = "/api/admin/reports/generate?format=pdf&resourceType=node&resourceId=node-1"
+
+	rec := generate(httptest.NewRequest(http.MethodGet, query, nil))
+	if rec.Code != http.StatusOK || rec.Header().Get("Content-Type") != "application/pdf" {
+		t.Fatalf("GET report: status %d, content type %q, body=%s", rec.Code, rec.Header().Get("Content-Type"), rec.Body.String())
+	}
+	if got := narrator.calls.Load(); got != 0 {
+		t.Fatalf("GET report called the AI narrator %d times, want 0", got)
+	}
+	narrative, err := engine.NarrativeFor(engine.requests[len(engine.requests)-1])
+	if err != nil {
+		t.Fatalf("GET report narrative: %v", err)
+	}
+	if narrative.Source != reporting.NarrativeSourceHeuristic || narrative.Disclaimer != reportGETNarrativeNote {
+		t.Fatalf("GET report narrative = source %q disclaimer %q, want the deterministic summary with the GET note", narrative.Source, narrative.Disclaimer)
+	}
+
+	for _, method := range []string{http.MethodHead, http.MethodPut, http.MethodDelete} {
+		rec := generate(httptest.NewRequest(method, query, nil))
+		if rec.Code != http.StatusMethodNotAllowed || rec.Header().Get("Allow") != "GET, POST" {
+			t.Fatalf("%s report: status %d, Allow %q, want 405 with Allow GET, POST", method, rec.Code, rec.Header().Get("Allow"))
+		}
+	}
+	if got := narrator.calls.Load(); got != 0 {
+		t.Fatalf("GET, HEAD, PUT and DELETE called the AI narrator %d times, want 0", got)
+	}
+	if got := narratorResolves.Load(); got != 0 {
+		t.Fatalf("GET, HEAD, PUT and DELETE resolved the AI service %d times, want 0", got)
+	}
+	if got := findingsResolves.Load(); got != 1 {
+		t.Fatalf("GET looked up existing Patrol findings %d times, want 1", got)
+	}
+
+	rec = generate(httptest.NewRequest(
+		http.MethodPost,
+		"/api/admin/reports/generate",
+		strings.NewReader(`{"format":"pdf","resourceType":"node","resourceId":"node-1"}`),
+	))
+	if rec.Code != http.StatusOK || rec.Header().Get("Content-Type") != "application/pdf" {
+		t.Fatalf("POST report: status %d, content type %q, body=%s", rec.Code, rec.Header().Get("Content-Type"), rec.Body.String())
+	}
+	if got := narrator.calls.Load(); got != 1 {
+		t.Fatalf("POST report called the AI narrator %d times, want 1", got)
+	}
+	if got := narratorResolves.Load(); got != 1 {
+		t.Fatalf("POST report resolved the AI service %d times, want 1", got)
+	}
+}
+
+// The router's real resolvers: a GET report for a tenant whose AI service is
+// not running must not construct one, because construction can list provider
+// models and start background discovery. POST resolves it as before.
+func TestContract_SingleReportGETDoesNotConstructTenantAIService(t *testing.T) {
+	engine := &stubReportingEngine{data: []byte("report"), contentType: "application/pdf"}
+	original := reporting.GetEngine()
+	reporting.SetEngine(engine)
+	t.Cleanup(func() { reporting.SetEngine(original) })
+
+	router := &Router{
+		aiSettingsHandler: NewAISettingsHandler(config.NewMultiTenantPersistence(t.TempDir()), nil, nil),
+		reportingHandlers: NewReportingHandlers(nil, nil),
+	}
+	router.wireReportingAIResolvers()
+	t.Cleanup(router.aiSettingsHandler.StopServices)
+	tenantServices := func() int {
+		router.aiSettingsHandler.aiServicesMu.RLock()
+		defer router.aiSettingsHandler.aiServicesMu.RUnlock()
+		return len(router.aiSettingsHandler.aiServices)
+	}
+	generate := func(req *http.Request) *httptest.ResponseRecorder {
+		rec := httptest.NewRecorder()
+		router.reportingHandlers.HandleGenerateReport(rec, req.WithContext(context.WithValue(req.Context(), OrgIDContextKey, "tenant-1")))
+		return rec
+	}
+
+	rec := generate(httptest.NewRequest(http.MethodGet, "/api/admin/reports/generate?format=pdf&resourceType=node&resourceId=node-1", nil))
+	if rec.Code != http.StatusOK {
+		t.Fatalf("GET report: status %d, body=%s", rec.Code, rec.Body.String())
+	}
+	if got := tenantServices(); got != 0 {
+		t.Fatalf("GET report constructed %d tenant AI services, want 0", got)
+	}
+	if _, ok := engine.lastReq.Narrator.(getReportNarrator); !ok || engine.lastReq.FindingsProvider != nil {
+		t.Fatalf("GET report narrator %T, findings %v; want the deterministic narrator and no findings without a running service", engine.lastReq.Narrator, engine.lastReq.FindingsProvider)
+	}
+
+	rec = generate(httptest.NewRequest(http.MethodPost, "/api/admin/reports/generate", strings.NewReader(`{"format":"pdf","resourceType":"node","resourceId":"node-1"}`)))
+	if rec.Code != http.StatusOK {
+		t.Fatalf("POST report: status %d, body=%s", rec.Code, rec.Body.String())
+	}
+	if got := tenantServices(); got != 1 {
+		t.Fatalf("POST report resolved %d tenant AI services, want 1", got)
+	}
 }

 // Normalization keeps a disk's last-known temperature when the current
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"os"
 	"regexp"
 	"strings"
@@ -99,6 +100,7 @@ type ReportingHandlers struct {
 	mtMonitor                 *monitoring.MultiTenantMonitor
 	recoveryManager           *recoverymanager.Manager
 	narratorResolver          func(ctx context.Context) (reporting.Narrator, reporting.FleetNarrator, reporting.FindingsProvider)
+	existingFindingsResolver  func(ctx context.Context) reporting.FindingsProvider
 	settingsStore             reportingSystemSettingsStore
 	scheduleRunMu             sync.Mutex
 	commercialLicenseResolver func(ctx context.Context) *licenseService
@@ -168,6 +170,23 @@ func (h *ReportingHandlers) resolveNarrator(ctx context.Context) (reporting.Narr
 	return h.narratorResolver(ctx)
 }

+// SetExistingFindingsResolver wires the Patrol findings lookup that GET reports
+// use. Unlike the narrator resolver it must return only an AI service that is
+// already running, never construct one.
+func (h *ReportingHandlers) SetExistingFindingsResolver(resolver func(ctx context.Context) reporting.FindingsProvider) {
+	if h == nil {
+		return
+	}
+	h.existingFindingsResolver = resolver
+}
+
+func (h *ReportingHandlers) resolveExistingFindings(ctx context.Context) reporting.FindingsProvider {
+	if h == nil || h.existingFindingsResolver == nil {
+		return nil
+	}
+	return h.existingFindingsResolver(ctx)
+}
+
 func (h *ReportingHandlers) resolveReportBranding(ctx context.Context) reporting.ReportBranding {
 	service := getLicenseServiceForContext(ctx)
 	entitled := service != nil && service.HasFeature(featureWhiteLabelValue)
@@ -300,28 +319,33 @@ func normalizePerformanceReportTimeRange(
 	return start, end, nil
 }

-func decodeMultiReportRequestBody(w http.ResponseWriter, r *http.Request) (multiReportRequestBody, bool) {
+// decodeReportingRequestBody strictly decodes one JSON report request body:
+// at most 1MB, no unknown fields, no trailing payload.
+func decodeReportingRequestBody[T any](w http.ResponseWriter, r *http.Request) (T, bool) {
 	r.Body = http.MaxBytesReader(w, r.Body, reportingMultiReportBodyMax)

-	var body multiReportRequestBody
+	var body, zero T
 	decoder := json.NewDecoder(r.Body)
 	decoder.DisallowUnknownFields()
-	if err := decoder.Decode(&body); err != nil {
+	err := decoder.Decode(&body)
+	if err == nil {
+		// Anything after the value is invalid, and reading past it can also
+		// hit the size cap.
+		if trailing := decoder.Decode(&struct{}{}); trailing != io.EOF {
+			err = errors.New("trailing payload")
+			if trailing != nil {
+				err = trailing
+			}
+		}
+	}
+	if err != nil {
 		var maxBytesErr *http.MaxBytesError
 		if errors.As(err, &maxBytesErr) {
 			writeErrorResponse(w, http.StatusBadRequest, "body_too_large", "Request body must be 1MB or less", nil)
-			return multiReportRequestBody{}, false
+			return zero, false
 		}
 		writeErrorResponse(w, http.StatusBadRequest, "invalid_body", "Invalid request body", nil)
-		return multiReportRequestBody{}, false
-	}
-	if decoder.More() {
-		writeErrorResponse(w, http.StatusBadRequest, "invalid_body", "Invalid request body", nil)
-		return multiReportRequestBody{}, false
-	}
-	if err := decoder.Decode(&struct{}{}); err != io.EOF {
-		writeErrorResponse(w, http.StatusBadRequest, "invalid_body", "Invalid request body", nil)
-		return multiReportRequestBody{}, false
+		return zero, false
 	}

 	return body, true
@@ -539,9 +563,67 @@ func (h *ReportingHandlers) listBackupsForReport(ctx context.Context, orgID stri
 	return out
 }

-// HandleGenerateReport generates a report
+// singleReportRequestBody carries the single-resource report fields. POST
+// sends them as a JSON body; GET sends the same names as query parameters.
+type singleReportRequestBody struct {
+	ResourceType string `json:"resourceType"`
+	ResourceID   string `json:"resourceId"`
+	Format       string `json:"format"`
+	Start        string `json:"start"`
+	End          string `json:"end"`
+	Title        string `json:"title"`
+	MetricType   string `json:"metricType"`
+}
+
+func singleReportRequestFromQuery(q url.Values) singleReportRequestBody {
+	return singleReportRequestBody{
+		ResourceType: q.Get("resourceType"),
+		ResourceID:   q.Get("resourceId"),
+		Format:       q.Get("format"),
+		Start:        q.Get("start"),
+		End:          q.Get("end"),
+		Title:        q.Get("title"),
+		MetricType:   q.Get("metricType"),
+	}
+}
+
+// reportGETNarrativeNote takes the place of the PDF's "Configure Pulse
+// Assistant" tip on a GET report, which stays deterministic whatever the
+// Assistant settings.
+const reportGETNarrativeNote = "Tip: This report was requested with GET, which never uses Pulse Assistant. Generate it from Settings, or request it with POST, to include AI narration when Pulse Assistant is configured."
+
+// getReportNarrator narrates GET single-resource reports with the
+// deterministic summary and never calls an AI provider.
+type getReportNarrator struct{}
+
+func (getReportNarrator) Narrate(ctx context.Context, in reporting.NarrativeInput) (reporting.Narrative, error) {
+	out, err := reporting.HeuristicNarrator{}.Narrate(ctx, in)
+	out.Source = reporting.NarrativeSourceHeuristic
+	out.Disclaimer = reportGETNarrativeNote
+	return out, err
+}
+
+// HandleGenerateReport generates a single-resource report. POST with a JSON
+// body is the canonical transport, used by the settings UI, and the only one
+// that may narrate a PDF with the tenant's Pulse Assistant, which spends AI
+// budget and records usage in the cost ledger. GET takes the same fields as
+// query parameters and always narrates deterministically: GET passes the
+// demo-mode guard and the CSRF check, and SameSite=Lax session cookies ride
+// cross-site top-level GET navigations, so a link must not be able to spend
+// that budget.
 func (h *ReportingHandlers) HandleGenerateReport(w http.ResponseWriter, r *http.Request) {
-	if r.Method != http.MethodGet {
+	var params singleReportRequestBody
+	switch r.Method {
+	case http.MethodGet:
+		params = singleReportRequestFromQuery(r.URL.Query())
+	case http.MethodPost:
+		body, ok := decodeReportingRequestBody[singleReportRequestBody](w, r)
+		if !ok {
+			return
+		}
+		params = body
+	default:
+		w.Header().Set("Allow", "GET, POST")
 		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
 		return
 	}
@@ -553,15 +635,14 @@ func (h *ReportingHandlers) HandleGenerateReport(w http.ResponseWriter, r *http.
 	}

 	definition := performanceReportDefinition()
-	q := r.URL.Query()
-	format, err := normalizePerformanceReportFormat(q.Get("format"), definition)
+	format, err := normalizePerformanceReportFormat(params.Format, definition)
 	if err != nil {
 		writeErrorResponse(w, http.StatusBadRequest, "invalid_format", err.Error(), nil)
 		return
 	}

-	resourceTypeRaw := q.Get("resourceType")
-	resourceID := q.Get("resourceId")
+	resourceTypeRaw := params.ResourceType
+	resourceID := params.ResourceID
 	if resourceTypeRaw == "" || resourceID == "" {
 		writeErrorResponse(w, http.StatusBadRequest, "missing_params", "resourceType and resourceId are required", nil)
 		return
@@ -584,8 +665,8 @@ func (h *ReportingHandlers) HandleGenerateReport(w http.ResponseWriter, r *http.

 	metricType, title, err := normalizePerformanceReportOptionalFields(
 		definition,
-		q.Get("metricType"),
-		q.Get("title"),
+		params.MetricType,
+		params.Title,
 	)
 	if err != nil {
 		code := "invalid_metric_type"
@@ -599,8 +680,8 @@ func (h *ReportingHandlers) HandleGenerateReport(w http.ResponseWriter, r *http.

 	start, end, err := normalizePerformanceReportTimeRange(
 		definition,
-		q.Get("start"),
-		q.Get("end"),
+		params.Start,
+		params.End,
 		time.Now(),
 	)
 	if err != nil {
@@ -628,9 +709,18 @@ func (h *ReportingHandlers) HandleGenerateReport(w http.ResponseWriter, r *http.
 	// Wire the per-tenant AI narrator and Patrol findings provider when
 	// configured. Both are nil-safe at the engine layer; absence falls
 	// back to the heuristic narrator with no findings section. Single-
-	// resource reports do not use the FleetNarrator.
-	narrator, _, findings := h.resolveNarrator(r.Context())
-	req.Narrator = narrator
+	// resource reports do not use the FleetNarrator. Only POST resolves the
+	// AI service; GET narrates deterministically and reads findings only
+	// from an AI service that is already running.
+	var narrator reporting.Narrator
+	var findings reporting.FindingsProvider
+	if r.Method == http.MethodPost {
+		narrator, _, findings = h.resolveNarrator(r.Context())
+		req.Narrator = narrator
+	} else {
+		findings = h.resolveExistingFindings(r.Context())
+		req.Narrator = getReportNarrator{}
+	}
 	req.FindingsProvider = findings

 	data, contentType, err := engine.Generate(req)
@@ -647,6 +737,7 @@ func (h *ReportingHandlers) HandleGenerateReport(w http.ResponseWriter, r *http.
 	log.Info().
 		Str("event", "reporting.single.generated").
 		Str("org_id", orgID).
+		Str("method", r.Method).
 		Str("resource_type", resourceType).
 		Str("metric_type", metricType).
 		Str("format", string(format)).
@@ -1187,7 +1278,7 @@ func (h *ReportingHandlers) HandleGenerateMultiReport(w http.ResponseWriter, r *
 		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
 		return
 	}
-	body, ok := decodeMultiReportRequestBody(w, r)
+	body, ok := decodeReportingRequestBody[multiReportRequestBody](w, r)
 	if !ok {
 		return
 	}
@@ -75,7 +75,7 @@ func (p reportBrandLicenseProvider) Service(context.Context) *pkglicensing.Servi

 func TestReportingHandlers_MethodNotAllowed(t *testing.T) {
 	handler := NewReportingHandlers(nil, nil)
-	req := httptest.NewRequest(http.MethodPost, "/api/reporting", nil)
+	req := httptest.NewRequest(http.MethodPut, "/api/reporting", nil)
 	rr := httptest.NewRecorder()

 	handler.HandleGenerateReport(rr, req)
@@ -83,6 +83,47 @@ func TestReportingHandlers_MethodNotAllowed(t *testing.T) {
 	if rr.Code != http.StatusMethodNotAllowed {
 		t.Fatalf("expected status %d, got %d", http.StatusMethodNotAllowed, rr.Code)
 	}
+	if got := rr.Header().Get("Allow"); got != "GET, POST" {
+		t.Fatalf("expected Allow GET, POST, got %q", got)
+	}
+}
+
+func TestReportingHandlers_GenerateReportRejectsInvalidPOSTBody(t *testing.T) {
+	engine := &stubReportingEngine{data: []byte("report"), contentType: "application/pdf"}
+	original := reporting.GetEngine()
+	reporting.SetEngine(engine)
+	t.Cleanup(func() { reporting.SetEngine(original) })
+
+	handler := NewReportingHandlers(nil, nil)
+	for name, body := range map[string]string{
+		"empty":          ``,
+		"unknown field":  `{"resourceType":"node","resourceId":"node-1","narrate":true}`,
+		"trailing value": `{"resourceType":"node","resourceId":"node-1"} {}`,
+		"query shape":    `resourceType=node&resourceId=node-1`,
+	} {
+		req := httptest.NewRequest(http.MethodPost, "/api/reporting", strings.NewReader(body))
+		rr := httptest.NewRecorder()
+		handler.HandleGenerateReport(rr, req)
+		if rr.Code != http.StatusBadRequest || !strings.Contains(rr.Body.String(), "invalid_body") {
+			t.Fatalf("%s: expected 400 invalid_body, got %d body=%s", name, rr.Code, rr.Body.String())
+		}
+	}
+
+	req := httptest.NewRequest(http.MethodPost, "/api/reporting?resourceType=node&resourceId=node-1", strings.NewReader(`{}`))
+	rr := httptest.NewRecorder()
+	handler.HandleGenerateReport(rr, req)
+	if rr.Code != http.StatusBadRequest || !strings.Contains(rr.Body.String(), "missing_params") {
+		t.Fatalf("POST must read fields from the body, not the query: got %d body=%s", rr.Code, rr.Body.String())
+	}
+
+	// A valid value followed by padding past the cap is too large, not malformed.
+	padded := `{"resourceType":"node","resourceId":"node-1"}` + strings.Repeat(" ", reportingMultiReportBodyMax)
+	req = httptest.NewRequest(http.MethodPost, "/api/reporting", strings.NewReader(padded))
+	rr = httptest.NewRecorder()
+	handler.HandleGenerateReport(rr, req)
+	if rr.Code != http.StatusBadRequest || !strings.Contains(rr.Body.String(), "body_too_large") {
+		t.Fatalf("expected 400 body_too_large for an oversized body, got %d body=%s", rr.Code, rr.Body.String())
+	}
 }

 func TestReportingHandlers_EngineUnavailable(t *testing.T) {
@@ -805,33 +805,7 @@ func (r *Router) setupRoutes() {
 	// tenant services are refreshed when Router.SetMonitor replaces a monitor.
 	r.configureMetadataProviderFactory()

-	// Wire the per-tenant AI narrator, fleet narrator, and Patrol
-	// findings provider into reporting. The AI service implements all
-	// three interfaces; when not configured for the tenant the engine
-	// falls back to the heuristic narrators with no findings section.
-	if r.reportingHandlers != nil {
-		settings := r.aiSettingsHandler
-		r.reportingHandlers.SetPatrolDigestResolver(func(ctx context.Context, days int) (ai.PatrolDigest, bool) {
-			if settings == nil {
-				return ai.PatrolDigest{}, false
-			}
-			return settings.BuildPatrolDigest(ctx, days)
-		})
-		r.reportingHandlers.SetNarratorResolver(func(ctx context.Context) (reporting.Narrator, reporting.FleetNarrator, reporting.FindingsProvider) {
-			if settings == nil {
-				return nil, nil, nil
-			}
-			svc := settings.GetAIService(ctx)
-			if svc == nil {
-				return nil, nil, nil
-			}
-			cfg := svc.GetAIConfig()
-			if cfg == nil || !cfg.Enabled {
-				return nil, nil, nil
-			}
-			return svc, svc, svc
-		})
-	}
+	r.wireReportingAIResolvers()

 	// AI chat handler
 	r.aiHandler = NewAIHandler(r.multiTenant, r.mtMonitor, r.agentExecServer)
@@ -1031,6 +1005,50 @@ func (r *Router) setupRoutes() {
 	// See issue #334 - ServeMux redirects empty path to "./" which breaks reverse proxies
 }

+// wireReportingAIResolvers connects reporting to the per-tenant AI service.
+func (r *Router) wireReportingAIResolvers() {
+	// Wire the per-tenant AI narrator, fleet narrator, and Patrol
+	// findings provider into reporting. The AI service implements all
+	// three interfaces; when not configured for the tenant the engine
+	// falls back to the heuristic narrators with no findings section.
+	if r.reportingHandlers != nil {
+		settings := r.aiSettingsHandler
+		r.reportingHandlers.SetPatrolDigestResolver(func(ctx context.Context, days int) (ai.PatrolDigest, bool) {
+			if settings == nil {
+				return ai.PatrolDigest{}, false
+			}
+			return settings.BuildPatrolDigest(ctx, days)
+		})
+		r.reportingHandlers.SetNarratorResolver(func(ctx context.Context) (reporting.Narrator, reporting.FleetNarrator, reporting.FindingsProvider) {
+			if settings == nil {
+				return nil, nil, nil
+			}
+			svc := settings.GetAIService(ctx)
+			if svc == nil {
+				return nil, nil, nil
+			}
+			cfg := svc.GetAIConfig()
+			if cfg == nil || !cfg.Enabled {
+				return nil, nil, nil
+			}
+			return svc, svc, svc
+		})
+		r.reportingHandlers.SetExistingFindingsResolver(func(ctx context.Context) reporting.FindingsProvider {
+			if settings == nil {
+				return nil
+			}
+			svc := settings.ExistingAIService(ctx)
+			if svc == nil {
+				return nil
+			}
+			if cfg := svc.GetAIConfig(); cfg == nil || !cfg.Enabled {
+				return nil
+			}
+			return svc
+		})
+	}
+}
+
 // CleanupTenant removes all per-tenant resources (RBAC, AI, License) for a deleted org.
 func (r *Router) CleanupTenant(ctx context.Context, orgID string) error {
 	orgID = strings.TrimSpace(orgID)
@@ -2,6 +2,7 @@ package reporting

 import (
 	"fmt"
+	"net/http"
 	"strings"
 	"time"
 )
@@ -33,6 +34,7 @@ type PerformanceReportDefinition struct {
 	Title                  string                      `json:"title"`
 	Description            string                      `json:"description"`
 	SingleResourceEndpoint string                      `json:"singleResourceEndpoint"`
+	SingleResourceMethod   string                      `json:"singleResourceMethod"`
 	MultiResourceEndpoint  string                      `json:"multiResourceEndpoint"`
 	SingleFilenamePrefix   string                      `json:"singleFilenamePrefix"`
 	SingleFilenameSubject  string                      `json:"singleFilenameSubject"`
@@ -150,6 +152,7 @@ func DescribePerformanceReport() PerformanceReportDefinition {
 		Title:                  "Performance Reports",
 		Description:            "Generate PDF summaries or CSV metric exports from historical monitoring data for one or more selected resources.",
 		SingleResourceEndpoint: "/api/admin/reports/generate",
+		SingleResourceMethod:   http.MethodPost,
 		MultiResourceEndpoint:  "/api/admin/reports/generate-multi",
 		SingleFilenamePrefix:   "report",
 		SingleFilenameSubject:  FilenameSubjectResourceID,