> 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/tasks.md).

# Task Checklist

**Session ID**: `phase29-session09-source-death-baseline-alarm` **Total Tasks**: 20 **Estimated Duration**: 3-4 hours **Created**: 2026-06-20

***

## Legend

* `[x]` = Completed
* `[ ]` = Pending
* `[P]` = Parallelizable (can run with other \[P] tasks)
* `[SNNMM]` = Session reference (NN=phase number, MM=session number)
* `TNNN` = Task ID

***

## Progress Summary

| Category       | Total  | Done   | Remaining |
| -------------- | ------ | ------ | --------- |
| Setup          | 2      | 2      | 0         |
| Foundation     | 5      | 5      | 0         |
| Implementation | 9      | 9      | 0         |
| Testing        | 4      | 4      | 0         |
| **Total**      | **20** | **20** | **0**     |

***

## Setup (2 tasks)

Initial configuration and environment preparation.

* [x] T001 \[S2909] Verify analyzer state, completed Session 07 prerequisite, and Session 09 stub scope before implementation (`.spec_system/PRD/phase_29/session_09_source_death_baseline_alarm.md`)
* [x] T002 \[S2909] Inspect current collector source flow, source setup state, collection health, Engine Replay trace mapping, private diagnostics, and related tests (`scripts/extensions/trend-finder/collector.ts`)

***

## Foundation (5 tasks)

Core structures and base implementations.

* [x] T003 \[S2909] \[P] Create private source-death baseline helper contract with schema, atomic read/write dependencies, safe path handling, and explicit corrupt-baseline fallback (`scripts/extensions/trend-finder/source-death-baseline.ts`)
* [x] T004 \[S2909] \[P] Add defaulted browser-safe schema fields for source-death alarm count, label, and source warning projection without exposing baseline counts or private paths (`src/extensions/trend-finder/schema.ts`)
* [x] T005 \[S2909] \[P] Add Engine Replay trace schema defaults for source-death collection-health fields with schema-validated input and explicit error mapping (`src/extensions/trend-finder/engine-trace.ts`)
* [x] T006 \[S2909] Define deterministic source eligibility rules for configured, enabled, reviewed, non-skipped sources with disabled/unconfigured/fallback exclusions (`scripts/extensions/trend-finder/source-death-baseline.ts`)
* [x] T007 \[S2909] Add fixture variants for normal, zeroed-live, first-run, disabled-source, and skipped-fallback source states (`src/extensions/trend-finder/fixtures.ts`)

***

## Implementation (9 tasks)

Main feature implementation.

* [x] T008 \[S2909] Implement baseline read, validation, missing/corrupt fallback, and atomic private write behavior with cleanup on scope exit for temp files (`scripts/extensions/trend-finder/source-death-baseline.ts`)
* [x] T009 \[S2909] Implement zeroed-live alarm derivation from current accepted evidence counts and private last-good source baselines with deterministic ordering (`scripts/extensions/trend-finder/source-death-baseline.ts`)
* [x] T010 \[S2909] Implement browser-safe warning projection that excludes baseline file names, private paths, prior counts, raw diagnostics, tokens, and credential-shaped strings (`scripts/extensions/trend-finder/source-death-baseline.ts`)
* [x] T011 \[S2909] Wire collector source-death evaluation after source setup and collection health, before Engine Replay and browser payload handoff, with idempotency protection for repeated run assembly (`scripts/extensions/trend-finder/collector.ts`)
* [x] T012 \[S2909] Update source summaries and collection health with safe source-death warning labels while preserving existing source errors and degraded states (`scripts/extensions/trend-finder/collector.ts`)
* [x] T013 \[S2909] Map sanitized source-death collection-health fields through Engine Replay trace building with private-path and unsafe-value filtering (`scripts/extensions/trend-finder/engine-trace.ts`)
* [x] T014 \[S2909] Project source-death warning labels and tones into view models for Sources and Engine Replay with explicit loading, empty, error, and unavailable states (`src/extensions/trend-finder/view-model.ts`)
* [x] T015 \[S2909] Surface source-death warning copy in Sources source health tiles and warning panel without layout shift or private details (`src/extensions/trend-finder/views/sources-view.tsx`)
* [x] T016 \[S2909] Surface source-death warning metric in Engine Replay source rail with accessible labels, deterministic ordering, and no private baseline detail (`src/extensions/trend-finder/engine-replay-model.ts`)

***

## Testing (4 tasks)

Verification and quality assurance.

* [x] T017 \[S2909] \[P] Add helper unit tests for zeroed-live, first-run, disabled, unconfigured, skipped fallback, corrupt-baseline, atomic write, and private sentinel exclusion (`scripts/extensions/trend-finder/__tests__/source-death-baseline.test.ts`)
* [x] T018 \[S2909] \[P] Add collector and Engine Replay trace tests for alarm propagation, safe warning labels, baseline update behavior, and disabled/skipped no-op cases (`scripts/extensions/trend-finder/__tests__/collector.test.ts`)
* [x] T019 \[S2909] \[P] Add schema, view-model, Sources, and Engine Replay component tests for legacy defaults, visible source-death labels, and no private strings (`src/extensions/trend-finder/__tests__/view-model.test.ts`)
* [x] T020 \[S2909] Run focused Vitest suites, payload-size check, private-artifact scan, type checks as needed, and ASCII validation for session files (`package.json`)

***

## Completion Checklist

Before marking session complete:

* [x] All tasks marked `[x]`
* [x] All tests passing
* [x] All files ASCII-encoded
* [x] implementation-notes.md updated
* [x] Ready for the validate workflow step

***

## Next Steps

Run the implement workflow step to begin AI-led implementation.


---

# 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/tasks.md?ask=<question>&goal=<endgoal>
```

`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.