> 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/phase28-session05-signal-aging-half-lives-and-saturation-refinement/tasks.md).

# Task Checklist

**Session ID**: `phase28-session05-signal-aging-half-lives-and-saturation-refinement` **Total Tasks**: 24 **Estimated Duration**: 3-4 hours **Created**: 2026-06-14

***

## 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          | 3      | 3      | 0         |
| Foundation     | 7      | 7      | 0         |
| Implementation | 9      | 9      | 0         |
| Testing        | 5      | 5      | 0         |
| **Total**      | **24** | **24** | **0**     |

***

## Setup (3 tasks)

Initial verification and implementation notes.

* [x] T001 \[S2805] Verify prerequisite sessions, source mapping, and current target-file paths before edits (`.spec_system/PRD/phase_28/session_05_signal_aging_half_lives_and_saturation_refinement.md`)
* [x] T002 \[S2805] Create implementation-notes shell for scope decisions, scoring-version changes, validation commands, and deferred items (`.spec_system/specs/phase28-session05-signal-aging-half-lives-and-saturation-refinement/implementation-notes.md`)
* [x] T003 \[S2805] Compare Trends-Finderz signal-aging, lifecycle freshness, and saturation constants to current Trend Finder scales without copying uncalibrated thresholds (`EXAMPLES/trends-finderz/lib/product/signal-aging.ts`)

***

## Foundation (7 tasks)

Core contracts and pure deterministic helpers.

* [x] T004 \[S2805] Add optional source `halfLifeHours` declaration metadata and role default types with schema-validated bounds (`scripts/extensions/trend-finder/sources/types.ts`)
* [x] T005 \[S2805] Wire source half-life defaults and declaration override validation with explicit warning messages for invalid values (`scripts/extensions/trend-finder/sources/apify-source-config.ts`)
* [x] T006 \[S2805] \[P] Create pure signal-aging helper for half-life freshness, age bands, unavailable states, and bounded role contributions with schema-validated input and explicit error mapping (`scripts/lib/ai-runtime/signal-aging.ts`)
* [x] T007 \[S2805] \[P] Add signal-aging unit tests for per-role decay differences, status transitions, unavailable states, contribution bounds, and lifecycle threshold fixtures (`scripts/lib/ai-runtime/__tests__/signal-aging.test.ts`)
* [x] T008 \[S2805] Define additive `signalAging` schema enums, bounded contribution arrays, default unavailable state, and parsed topic fields with legacy-safe defaults (`src/extensions/trend-finder/schema.ts`)
* [x] T009 \[S2805] Add signal-aging and refined-saturation view-model helpers with bounded labels, accessible descriptions, and deterministic ordering (`src/extensions/trend-finder/view-model.ts`)
* [x] T010 \[S2805] Refine saturation helper inputs and constants for diffusion, mention density, mainstream-term pressure, and single-source/developer dominance while preserving null unavailable behavior (`scripts/lib/ai-runtime/scoring.ts`)

***

## Implementation (9 tasks)

Runtime wiring and user-facing surfaces.

* [x] T011 \[S2805] Replace uniform recency buckets with half-life weighted recency inside momentum scoring while preserving six-factor weights and fallback behavior (`scripts/lib/ai-runtime/scoring.ts`)
* [x] T012 \[S2805] Derive and publish per-topic `signalAging` from scoring evidence with bounded source-role contributions and no raw source leaks (`scripts/lib/ai-runtime/scoring.ts`)
* [x] T013 \[S2805] Bump scoring version and preserve cross-version movement flags for the recency and saturation math change (`scripts/lib/ai-runtime/scoring.ts`)
* [x] T014 \[S2805] Render signal-aging and refined-saturation chips on Trend cards with platform-appropriate accessibility labels, focus behavior, and compact text (`src/extensions/trend-finder/components/trend-card.tsx`)
* [x] T015 \[S2805] Add Signal Workbench aging fields, facets, filters, search text, and sort keys with validated filters and deterministic ordering (`src/extensions/trend-finder/signal-workbench-model.ts`)
* [x] T016 \[S2805] Add Signal Workbench aging controls with accessible labels, keyboard input support, and explicit unavailable option handling (`src/extensions/trend-finder/components/signal-workbench-controls.tsx`)
* [x] T017 \[S2805] Update Trend Finder fixtures with fresh, active, cooling, stale, and unavailable aging examples while preserving legacy parse coverage (`src/extensions/trend-finder/fixtures.ts`)
* [x] T018 \[S2805] Document shipped half-life aging, unavailable states, refined saturation inputs, and non-goals without planned-feature language (`docs/extensions/trend-finder-scoring.md`)
* [x] T019 \[S2805] Record implementation decisions, scoring-version rationale, validation commands, and residual risks as work proceeds (`.spec_system/specs/phase28-session05-signal-aging-half-lives-and-saturation-refinement/implementation-notes.md`)

***

## Testing (5 tasks)

Verification and quality assurance.

* [x] T020 \[S2805] \[P] Add source-config tests for half-life metadata defaulting, bounds, override validation, and invalid warnings (`scripts/extensions/trend-finder/sources/__tests__/apify-source-config.test.ts`)
* [x] T021 \[S2805] \[P] Add scoring integration tests for role-specific recency, saturation refinement, scoring-version bump, and no hidden multiplier (`scripts/lib/ai-runtime/__tests__/scoring.test.ts`)
* [x] T022 \[S2805] \[P] Add schema and view-model tests for legacy defaults, aging labels, bounded contributions, and unavailable projections (`src/extensions/trend-finder/__tests__/view-model.test.ts`)
* [x] T023 \[S2805] \[P] Add Workbench model and Trend card component tests for aging filters, ordering, chip rendering, and accessible labels (`src/extensions/trend-finder/__tests__/signal-workbench-model.test.ts`, `src/extensions/trend-finder/components/__tests__/trend-card.test.tsx`)
* [x] T024 \[S2805] Run focused tests, ASCII validation, and any necessary manual UI check, then record results and residual risks (`.spec_system/specs/phase28-session05-signal-aging-half-lives-and-saturation-refinement/implementation-notes.md`)

***

## 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 validate workflow step for final review.


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