> 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-session04-corroboration-gate/implementation_summary.md).

# Implementation Summary

**Session ID**: `phase29-session04-corroboration-gate` **Completed**: 2026-06-19 **Duration**: 0.5 hours

***

## Overview

Completed Phase 29 Session 04 by adding Trend Finder's deterministic `corroboration` gate. The runtime now derives independent-origin context from reviewed source-local, competitor, signal identity, and source fallback metadata, then publishes bounded status, count, caution, and explanation fields. Originator-dominated topics receive a distinct `originator-only` risk signal, a bounded `corroboration_gate` score adjustment, and action-priority caps that keep single-origin evidence from producing `act_now`.

Live source summaries, static Brief export/rendering, payload reporting, fixtures, schema defaults, tests, and docs now explain corroboration without publishing raw entity IDs, unreviewed identity internals, private paths, prompt text, provider output, or raw source rows.

***

## Deliverables

### Files Created

| File                                                                                | Purpose                                                                                               | Lines |
| ----------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- | ----- |
| `.spec_system/specs/phase29-session04-corroboration-gate/spec.md`                   | Session specification and scope.                                                                      | 294   |
| `.spec_system/specs/phase29-session04-corroboration-gate/tasks.md`                  | Completed task checklist.                                                                             | 96    |
| `.spec_system/specs/phase29-session04-corroboration-gate/implementation-notes.md`   | Task-by-task implementation notes.                                                                    | 441   |
| `.spec_system/specs/phase29-session04-corroboration-gate/security-compliance.md`    | Security and GDPR review for the session.                                                             | 97    |
| `.spec_system/specs/phase29-session04-corroboration-gate/validation.md`             | Validation report and command evidence.                                                               | 259   |
| `.spec_system/specs/phase29-session04-corroboration-gate/IMPLEMENTATION_SUMMARY.md` | Completion summary for updateprd.                                                                     | \~130 |
| `scripts/lib/ai-runtime/corroboration.ts`                                           | Corroboration helper with reviewed identity inputs and bounded output.                                | 351   |
| `scripts/lib/ai-runtime/__tests__/corroboration.test.ts`                            | Helper coverage for unavailable, originator-only, weak, confirmed, competitor, and syndication cases. | 209   |
| `src/extensions/trend-finder/components/__tests__/source-breakdown.test.tsx`        | Source summary component coverage for corroboration rendering.                                        | 33    |

### Files Modified

| File                                                                      | Changes                                                                                                                                    |
| ------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
| `src/extensions/trend-finder/schema.ts`                                   | Added corroboration constants/defaults, topic field parsing, `originator-only`, score adjustment, action reason, and action cap contracts. |
| `scripts/lib/ai-runtime/source-breakdown.ts`                              | Attached corroboration after source/role derivation and merged `originator-only` in deterministic risk order.                              |
| `scripts/lib/ai-runtime/scoring.ts`                                       | Added bounded `corroboration_gate` score downrank/cap while keeping confirmed topics neutral.                                              |
| `scripts/lib/ai-runtime/action-priority.ts`                               | Added originator-only warnings, next steps, score penalty, and `act_now` cap.                                                              |
| `scripts/lib/ai-runtime/action-consistency.ts`                            | Reused canonical risk flag parsing so `originator-only` is accepted by consistency QA.                                                     |
| `scripts/extensions/trend-finder/collector.ts`                            | Passed analyst identity evidence into source-breakdown derivation.                                                                         |
| `scripts/trend-finder-replay-backhistory.ts`                              | Passed replay analyst identity evidence into source-breakdown derivation.                                                                  |
| `src/extensions/trend-finder/view-model.ts`                               | Added corroboration labels, tones, descriptions, risk copy, action reason label, and aria text.                                            |
| `src/extensions/trend-finder/components/source-breakdown.tsx`             | Rendered corroboration beside consensus, builder signal, and role shares.                                                                  |
| `src/extensions/trend-finder/fixtures.ts`                                 | Added fixture topics for confirmed and originator-only corroboration states.                                                               |
| `scripts/extensions/trend-finder/static-brief-export.ts`                  | Projected bounded corroboration fields into static Brief output.                                                                           |
| `scripts/extensions/trend-finder/static-brief-renderer.ts`                | Rendered escaped corroboration markup in static Brief HTML.                                                                                |
| `scripts/extensions/trend-finder/measure-payload-size.ts`                 | Added `data.topics[].corroboration` payload reporting.                                                                                     |
| `scripts/lib/ai-runtime/__tests__/source-breakdown.test.ts`               | Covered source-breakdown corroboration assignment and risk flag propagation.                                                               |
| `scripts/lib/ai-runtime/__tests__/scoring.test.ts`                        | Covered originator-only downrank and confirmed-topic neutral adjustment.                                                                   |
| `scripts/lib/ai-runtime/__tests__/scoring-calibration.test.ts`            | Expected the neutral `corroboration_gate` adjustment row.                                                                                  |
| `scripts/lib/ai-runtime/__tests__/action-priority.test.ts`                | Covered originator-only action caps.                                                                                                       |
| `src/lib/__tests__/trend-finder-schema.test.ts`                           | Covered legacy defaults, enum rejection, and `originator-only` parsing.                                                                    |
| `src/extensions/trend-finder/__tests__/view-model.test.ts`                | Covered labels, tones, accessibility text, and source summary projection.                                                                  |
| `scripts/extensions/trend-finder/__tests__/static-brief-export.test.ts`   | Covered static projection and private identity exclusion.                                                                                  |
| `scripts/extensions/trend-finder/__tests__/static-brief-renderer.test.ts` | Covered escaped renderer output and identity-field exclusion.                                                                              |
| `docs/extensions/trend-finder-scoring.md`                                 | Documented corroboration statuses, score downrank, action cap, and relationship to `single-source-signal`.                                 |
| `docs/extensions/trend-finder-ui-surfaces.md`                             | Documented live/static corroboration display and privacy boundary.                                                                         |
| `.spec_system/state.json`                                                 | Marked the session complete and reset the active session.                                                                                  |
| `.spec_system/PRD/phase_29/PRD_phase_29.md`                               | Updated Phase 29 progress to 4/18 sessions complete.                                                                                       |
| `package.json`                                                            | Bumped version from `0.1.348` to `0.1.349`.                                                                                                |
| `README.md`                                                               | Synced visible version line to `0.1.349`.                                                                                                  |
| `docs/CHANGELOG.md`                                                       | Added Phase 29 Session 04 release notes.                                                                                                   |

***

## Technical Decisions

1. **Reuse reviewed identity sources only**: Corroboration derives from existing source-local metadata, competitor matches, signal syndication groups, and source fallback keys instead of adding an entity extractor or identity provider.
2. **Keep originator scarcity separate from source scarcity**: `originator-only` is additive and can appear independently from `single-source-signal`, preserving the distinction between source count and independent-origin count.
3. **Publish bounded projections**: Browser and static surfaces receive status, counts, tones, labels, and explanations only, leaving raw identity internals and source rows out of public payloads.

***

## Test Results

| Metric   | Value         |
| -------- | ------------- |
| Tests    | 3734          |
| Passed   | 3734          |
| Coverage | Not collected |

***

## Lessons Learned

1. Action consistency needed canonical risk flag parsing once `originator-only` became a first-class risk flag.
2. The static Brief projection boundary remains the right place to prove corroboration labels do not leak raw entity IDs or private identity details.

***

## Future Considerations

Items for future sessions:

1. Session 05 can use corroboration status when deciding whether weak evidence rationale should be hidden, softened, or marked for independent confirmation.
2. Session 08 should include `corroboration` in the required-derived-field closeout gate so future regressions cannot silently drop the field.

***

## Session Statistics

* **Tasks**: 22 completed
* **Files Created**: 9
* **Files Modified**: 28
* **Tests Added**: 9 suites or guards
* **Blockers**: 0 resolved


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