> 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/phase24-session01-source-local-scoring-signals/implementation_summary.md).

# Implementation Summary

**Session ID**: `phase24-session01-source-local-scoring-signals` **Completed**: 2026-06-07 **Duration**: 0.3 hours

***

## Overview

Implemented Trend Finder source-local scoring signals with browser-safe entity identity, placement-aware exclusions, bounded ratio support, actionability banding, and sanitized Engine Replay summaries. The session preserved the existing six-factor score as authoritative and kept legacy payloads valid.

***

## Deliverables

### Files Created

| File                                                                                          | Purpose                                                                   | Lines |
| --------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------- | ----- |
| `scripts/extensions/trend-finder/source-local-signals.ts`                                     | Source-local baseline, ratio, band, actionability, and trace helper logic | \~220 |
| `scripts/extensions/trend-finder/__tests__/source-local-signals.test.ts`                      | Focused unit coverage for ratios, low samples, exclusions, and bands      | \~220 |
| `.spec_system/specs/phase24-session01-source-local-scoring-signals/IMPLEMENTATION_SUMMARY.md` | Session completion summary                                                | \~50  |

### Files Modified

| File                                                                          | Changes                                                                            |
| ----------------------------------------------------------------------------- | ---------------------------------------------------------------------------------- |
| `scripts/extensions/trend-finder/normalize.ts`                                | Preserved unsupported Hacker News baseline behavior without author identity        |
| `scripts/extensions/trend-finder/sources/types.ts`                            | Added source-local entity, placement, baseline, and actionability contracts        |
| `scripts/extensions/trend-finder/sources/apify-normalizers.ts`                | Extracted reviewed entity identity and placement flags from safe public fields     |
| `scripts/extensions/trend-finder/collector.ts`                                | Applied source-local signals before analysis and scoring, then emitted safe counts |
| `scripts/extensions/trend-finder/engine-trace.ts`                             | Added sanitized source-local trace summary mapping                                 |
| `scripts/lib/ai-runtime/trend-analyst.ts`                                     | Added additive source-local fields to analyst evidence input                       |
| `scripts/lib/ai-runtime/scoring.ts`                                           | Applied bounded source-local lift without replacing the six-factor score           |
| `src/extensions/trend-finder/schema.ts`                                       | Added additive Zod defaults for source-local browser payload fields                |
| `src/extensions/trend-finder/engine-trace.ts`                                 | Added browser-safe baseline and exclusion summary fields                           |
| `src/extensions/trend-finder/view-model.ts`                                   | Built ratio, band, and actionability chip models                                   |
| `src/extensions/trend-finder/components/evidence-metric-chips.tsx`            | Rendered source-local metric chips accessibly                                      |
| `src/extensions/trend-finder/engine-replay-model.ts`                          | Surfaced baseline availability and exclusion summaries                             |
| `src/extensions/trend-finder/components/score-breakdown.tsx`                  | Showed bounded-lift context without changing factor semantics                      |
| `docs/extensions/trend-finder-scoring.md`                                     | Documented source-local ratio formula, bands, and bounded lift                     |
| `docs/extensions/trend-finder-sources.md`                                     | Documented reviewed entity fields and pinned/promoted handling                     |
| `docs/extensions/trend-finder-runtime-and-provenance.md`                      | Documented Engine Replay baseline and exclusion labels                             |
| `scripts/extensions/trend-finder/sources/__tests__/apify-normalizers.test.ts` | Extended entity, placement, and private-field coverage                             |
| `scripts/lib/ai-runtime/__tests__/scoring.test.ts`                            | Extended bounded lift coverage                                                     |
| `src/lib/__tests__/trend-finder-schema.test.ts`                               | Extended schema and trace source-local coverage                                    |

***

## Technical Decisions

1. **Bounded support only**: Source-local lift influences existing scoring factors but never replaces the six-factor model.
2. **Safe degradation**: Missing, unsupported, and low-sample baselines use explicit unavailable states instead of inferred ratios.

***

## Test Results

| Metric   | Value                       |
| -------- | --------------------------- |
| Tests    | 4 focused commands          |
| Passed   | 4                           |
| Coverage | Not collected in validation |

***

## Lessons Learned

1. Additive schema defaults kept the legacy Trend Finder payloads stable.
2. Keeping source-local trace output to counts and labels avoided browser privacy regressions.

***

## Future Considerations

1. Later Phase 24 sessions can reuse the source-local contract for broader enrichment and workbench surfaces.
2. Keep reviewed source declarations current before exposing any new identity or placement flags.

***

## Session Statistics

* **Tasks**: 25 completed
* **Files Created**: 3
* **Files Modified**: 17
* **Tests Added**: 2
* **Blockers**: 0 resolved


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