> For the complete documentation index, see [llms.txt](https://ai-os-and-trend-finder.gitbook.io/ai-os-and-trend-finder-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ai-os-and-trend-finder.gitbook.io/ai-os-and-trend-finder-docs/.spec_system/archive/sessions/phase29-session09-source-death-baseline-alarm/implementation_summary.md). # Implementation Summary **Session ID**: `phase29-session09-source-death-baseline-alarm` **Completed**: 2026-06-21 **Duration**: 0.5 hours *** ## Overview Session 09 added a private source-death baseline alarm for Trend Finder. The runtime now tracks private last-good accepted-evidence state per eligible source, detects previously live configured sources that return zero accepted evidence, and exposes only safe warning labels through collection health, Sources, and Engine Replay. *** ## Deliverables ### Files Created | File | Purpose | Lines | | ------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- | ----- | | `scripts/extensions/trend-finder/source-death-baseline.ts` | Private baseline persistence, eligibility, alarm derivation, safe projection, and atomic write handling. | \~381 | | `scripts/extensions/trend-finder/__tests__/source-death-baseline.test.ts` | Unit coverage for zeroed-live, first-run, ineligible-source, corrupt-baseline, write-failure, and privacy cases. | \~332 | ### Files Modified | File | Changes | | ------------------------------------------------------------------------------ | ------------------------------------------------------------------------------- | | `scripts/extensions/trend-finder/collector.ts` | Wired source-death evaluation into source collection and browser/trace handoff. | | `scripts/extensions/trend-finder/engine-trace.ts` | Added sanitized source-death collection-health and source-summary trace fields. | | `src/extensions/trend-finder/schema.ts` | Added defaulted browser-safe source-death schema fields. | | `src/extensions/trend-finder/engine-trace.ts` | Added Engine Replay trace schema defaults for source-death fields. | | `src/extensions/trend-finder/view-model.ts` | Projected source-death warning counts, labels, and source warning state. | | `src/extensions/trend-finder/views/sources-view.tsx` | Rendered source-death health and warning copy without private detail. | | `src/extensions/trend-finder/engine-replay-model.ts` | Added source-death source rail metric and source warning labels. | | `src/extensions/trend-finder/components/engine-source-rail.tsx` | Added accessible metric labeling for source rail metrics. | | `src/extensions/trend-finder/fixtures.ts` | Added source-death, first-run, disabled-source, and skipped-fallback fixtures. | | `scripts/extensions/trend-finder/__tests__/collector.test.ts` | Covered collector warning propagation and safe browser/trace state. | | `scripts/extensions/trend-finder/__tests__/engine-trace.test.ts` | Covered sanitized trace mapping and private sentinel exclusion. | | `src/extensions/trend-finder/__tests__/view-model.test.ts` | Covered legacy defaults and safe warning projection. | | `src/extensions/trend-finder/__tests__/visibility-views.test.tsx` | Covered Sources rendering without private baseline details. | | `src/extensions/trend-finder/components/__tests__/engine-source-rail.test.tsx` | Covered Engine Replay metric and source warning rendering. | | `docs/extensions/trend-finder-pipeline.md` | Documented private source-death baseline pipeline behavior. | | `docs/extensions/trend-finder-sources.md` | Documented source-death warning semantics and excluded states. | | `docs/extensions/trend-finder-runtime-and-provenance.md` | Documented Engine Replay source-death surfacing and privacy limits. | *** ## Technical Decisions 1. **Private baseline helper**: Baseline state is script-only and stored under the collector cache boundary so browser payloads never need private paths, file names, or prior counts. 2. **Explicit eligibility rules**: Disabled, unconfigured, credential-missing, restricted, placeholder, skipped fallback, and first-run sources are excluded to avoid false-positive alarms. 3. **Additive schema defaults**: Browser and Engine Replay contracts default source-death fields to neutral values for legacy payload compatibility. 4. **Safe warning projection**: UI surfaces receive bounded labels and counts only; raw diagnostics, private baseline metadata, prompts, provider responses, tokens, and credential-shaped strings stay out of browser-safe data. *** ## Test Results | Metric | Value | | -------- | ------------------------------- | | Tests | 3798 | | Passed | 3798 | | Coverage | Not generated by `bun run test` | Quality gates passed: | Command | Result | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------- | | `bun run test` | PASS - 322 files, 3798 tests | | `bun run typecheck` | PASS | | `bun run typecheck:scripts` | PASS | | `bun run lint` | PASS | | `bunx prettier --check scripts/extensions/trend-finder/source-death-baseline.ts scripts/extensions/trend-finder/engine-trace.ts .spec_system/specs/phase29-session09-source-death-baseline-alarm/spec.md` | PASS | | `bun run runtime:check-private` | PASS | | Payload byte check | PASS - source-death fixture 96805 bytes; example Trend Finder payload 2 bytes; limit 1048576 bytes | | `git diff --check` | PASS | | `bun audit` | WARN - existing repo-level dependency advisories; no dependency files changed | *** ## Lessons Learned 1. Source-death detection needs source setup state, current accepted evidence counts, and private historical baseline state at the same collector boundary. 2. Alarm labels are useful to operators only when they stay distinct from disabled, skipped, and first-run states. 3. Defaulted schemas and privacy sentinel tests are the simplest way to protect browser and Engine Replay consumers from private baseline leakage. *** ## Future Considerations Items for future sessions: 1. Keep source-death warnings read-only; auto-disable and re-enable behavior remains out of scope. 2. Reuse the safe warning projection pattern for upcoming seed-candidate, industry-events, and security-lens sessions. 3. Continue running payload-size and private-artifact checks as later Phase 29 sessions add richer surfaces. *** ## Session Statistics * **Tasks**: 20 completed * **Files Created**: 2 * **Files Modified**: 17 * **Tests Added**: 6 focused coverage areas * **Blockers**: 0 resolved --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://ai-os-and-trend-finder.gitbook.io/ai-os-and-trend-finder-docs/.spec_system/archive/sessions/phase29-session09-source-death-baseline-alarm/implementation_summary.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.