> 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-session05-per-evidence-rationale/implementation-notes.md).

# Implementation Notes

**Session ID**: `phase29-session05-per-evidence-rationale` **Started**: 2026-06-19 23:05 **Last Updated**: 2026-06-19 23:27

***

## Session Progress

| Metric              | Value   |
| ------------------- | ------- |
| Tasks Completed     | 22 / 22 |
| Estimated Remaining | 0 hours |
| Blockers            | 0       |

***

### Task T022 - Run focused suites, payload-size check, type checks, and ASCII validation

**Started**: 2026-06-19 23:25 **Completed**: 2026-06-19 23:27 **Duration**: 2 minutes

**Notes**:

* Ran final typechecks, focused Vitest suites, payload-size reporting, formatting, and ASCII validation.
* Payload report confirmed `extensions.items["trend-finder"].data` is 14,138 bytes against the 1,048,576 byte boundary for `src/data/live-data.example.json`.
* Payload report now includes `data.topics[].evidenceRationales`, even when the current example payload has zero rationale records.

**Files Changed**:

* `scripts/extensions/trend-finder/measure-payload-size.ts` - Ensures rationale map branch is visible in size reporting.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked final verification task and completion checklist complete.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/implementation-notes.md` - Logged final verification results.

**Verification Commands**:

* `bun run typecheck` - Passed.
* `bun run typecheck:scripts` - Passed.
* `bun run test scripts/lib/ai-runtime/__tests__/evidence-rationale.test.ts scripts/lib/ai-runtime/__tests__/trend-analyst.test.ts scripts/extensions/trend-finder/__tests__/collector.test.ts src/lib/__tests__/trend-finder-schema.test.ts src/extensions/trend-finder/__tests__/view-model.test.ts src/extensions/trend-finder/components/__tests__/trend-card.test.tsx scripts/extensions/trend-finder/__tests__/static-brief-export.test.ts scripts/extensions/trend-finder/__tests__/static-brief-renderer.test.ts` - Passed, 8 files and 255 tests.
* `bun run scripts/extensions/trend-finder/measure-payload-size.ts src/data/live-data.example.json --threshold-kb=0 --json` - Passed, 14,138 bytes for Trend Finder data.
* `LC_ALL=C rg` ASCII scan with inverted exit status - Passed with no non-ASCII matches.

**BQC Fixes**:

* Contract alignment: Final checks covered helper, analyst, collector, browser, and static Brief rationale contracts.

***

## Session Summary

* Added bounded per-evidence rationale schema defaults and deterministic fallback projection.
* Extended analyst output and validation so AI rationale IDs must be known, cited, bounded, and grounded in the cited evidence row.
* Added collector projection that keeps valid AI rationale text, fills fallback rationales, and omits weak unjustified topic links without deleting raw evidence rows.
* Rendered rationale copy in live Evidence to verify cards and static Brief evidence rows through safe view-model/export boundaries.
* Added payload reporting and fixtures for AI rationale, deterministic fallback rationale, and preserved raw weak evidence.
* Added focused tests across helper, analyst, collector, schema, view-model, component, static export, and static renderer behavior.

***

### Task T018 - Add evidence-rationale helper tests

**Started**: 2026-06-19 23:19 **Completed**: 2026-06-19 23:25 **Duration**: 6 minutes

**Notes**:

* Added helper coverage for deterministic fallback generation, weak-link omission, bounded text, unsafe text, and grounded AI rationale projection.
* Verification: `bun run test scripts/lib/ai-runtime/__tests__/evidence-rationale.test.ts scripts/lib/ai-runtime/__tests__/trend-analyst.test.ts` passed.

**Files Changed**:

* `scripts/lib/ai-runtime/__tests__/evidence-rationale.test.ts` - New helper test suite.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked helper tests complete.

***

### Task T019 - Add analyst validator tests

**Started**: 2026-06-19 23:20 **Completed**: 2026-06-19 23:25 **Duration**: 5 minutes

**Notes**:

* Added analyst tests for accepted grounded rationales, missing rationale fallback paths, unknown rationale IDs, non-cited rationale IDs, and fabricated metadata repair.
* Verification: `bun run test scripts/lib/ai-runtime/__tests__/evidence-rationale.test.ts scripts/lib/ai-runtime/__tests__/trend-analyst.test.ts` passed.

**Files Changed**:

* `scripts/lib/ai-runtime/__tests__/trend-analyst.test.ts` - Added rationale validator cases.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked analyst tests complete.

***

### Task T020 - Add collector, schema, view-model, and component tests

**Started**: 2026-06-19 23:20 **Completed**: 2026-06-19 23:25 **Duration**: 5 minutes

**Notes**:

* Added collector coverage proving weak evidence is omitted from topic links while raw evidence remains.
* Added schema default coverage, view-model rationale projection coverage, and Evidence card accessibility coverage.
* Verification: `bun run test scripts/extensions/trend-finder/__tests__/collector.test.ts` passed.
* Verification: `bun run test src/lib/__tests__/trend-finder-schema.test.ts src/extensions/trend-finder/__tests__/view-model.test.ts src/extensions/trend-finder/components/__tests__/trend-card.test.tsx` passed.

**Files Changed**:

* `scripts/extensions/trend-finder/__tests__/collector.test.ts` - Added weak-link preservation test.
* `src/lib/__tests__/trend-finder-schema.test.ts` - Added rationale schema default test.
* `src/extensions/trend-finder/__tests__/view-model.test.ts` - Added rationale projection and legacy-default tests.
* `src/extensions/trend-finder/components/__tests__/trend-card.test.tsx` - Added rendered rationale accessibility test.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked projection tests complete.

***

### Task T021 - Add static Brief export and renderer tests

**Started**: 2026-06-19 23:21 **Completed**: 2026-06-19 23:25 **Duration**: 4 minutes

**Notes**:

* Added static export coverage for rationale projection and privacy cleanliness.
* Added static renderer coverage for escaped rationale text and no raw/private leakage.
* Verification: `bun run test scripts/extensions/trend-finder/__tests__/static-brief-export.test.ts scripts/extensions/trend-finder/__tests__/static-brief-renderer.test.ts` passed.

**Files Changed**:

* `scripts/extensions/trend-finder/__tests__/static-brief-export.test.ts` - Added rationale projection and privacy assertions.
* `scripts/extensions/trend-finder/__tests__/static-brief-renderer.test.ts` - Added rationale escaping assertions.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked static tests complete.

***

### Task T014 - Render rationale copy in Evidence to verify cards

**Started**: 2026-06-19 23:17 **Completed**: 2026-06-19 23:19 **Duration**: 2 minutes

**Notes**:

* Added compact rationale rendering inside existing evidence cards with tone styling and aria labels.
* Verification: `bun run typecheck` passed.

**Files Changed**:

* `src/extensions/trend-finder/components/evidence-links.tsx` - Renders rationale copy in live evidence cards.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked live rendering task complete.

**BQC Fixes**:

* Accessibility and platform compliance: Rationale text has a dedicated accessible label.

***

### Task T015 - Project rationale into static Brief evidence rows

**Started**: 2026-06-19 23:17 **Completed**: 2026-06-19 23:19 **Duration**: 2 minutes

**Notes**:

* Static Brief evidence rows now receive bounded rationale text, label, and tone from the evidence view-model.
* Top-evidence projection now looks up topic rationale maps, preserving existing safe public URL filtering.
* Verification: `bun run typecheck` and `bun run typecheck:scripts` passed.

**Files Changed**:

* `src/extensions/trend-finder/view-model.ts` - Added rationale lookup for top evidence links.
* `scripts/extensions/trend-finder/static-brief-export.ts` - Projects bounded rationale fields into static rows.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked static projection task complete.

**BQC Fixes**:

* Error information boundaries: Static export receives display-safe rationale text, not raw analyst payload.

***

### Task T016 - Render escaped rationale markup in static Brief

**Started**: 2026-06-19 23:18 **Completed**: 2026-06-19 23:19 **Duration**: 1 minute

**Notes**:

* Static Brief evidence cards now render escaped rationale markup with an accessible label.
* Verification: `bun run typecheck:scripts` passed.

**Files Changed**:

* `scripts/extensions/trend-finder/static-brief-renderer.ts` - Renders escaped rationale text in static evidence cards.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked static rendering task complete.

**BQC Fixes**:

* Error information boundaries: Rationale label and text are escaped before HTML output.

***

### Task T017 - Update payload reporting and fixtures

**Started**: 2026-06-19 23:18 **Completed**: 2026-06-19 23:19 **Duration**: 1 minute

**Notes**:

* Payload size reporting now always surfaces `data.topics[].evidenceRationales`.
* Fixture data includes AI rationale, deterministic fallback rationale, and an unlinked weak raw evidence row.
* Verification: `bun run typecheck` and `bun run typecheck:scripts` passed.

**Files Changed**:

* `scripts/extensions/trend-finder/measure-payload-size.ts` - Adds rationale payload reporting.
* `src/extensions/trend-finder/fixtures.ts` - Adds rationale and omitted weak evidence fixture examples.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked fixture and payload task complete.

**BQC Fixes**:

* Contract alignment: Fixtures now cover all rationale projection states used by tests.

***

### Task T013 - Project rationale fields through joined evidence links

**Started**: 2026-06-19 23:12 **Completed**: 2026-06-19 23:17 **Duration**: 5 minutes

**Notes**:

* `joinEvidenceLinks()` passes topic rationale records into evidence link view models.
* Missing evidence and missing rationale data both project safe empty rationale fields.
* Verification: `bun run typecheck` passed after view-model changes.

**Files Changed**:

* `src/extensions/trend-finder/view-model.ts` - Projects rationale text, label, tone, and accessibility copy through joined evidence links.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked rationale view-model projection task complete.

**BQC Fixes**:

* State freshness on re-entry: Legacy and missing rationale states always reset to empty view-model fields.
* Error information boundaries: Rationale display text uses existing secret redaction and length limiting.

***

### Task T011 - Merge AI and fallback rationales in collector projection

**Started**: 2026-06-19 23:14 **Completed**: 2026-06-19 23:16 **Duration**: 2 minutes

**Notes**:

* Added a collector projection pass after scoring and before `assignTopicIds()`.
* Valid AI rationale text wins when available; deterministic fallback fills safe gaps.
* Weak or missing evidence links are omitted from topic `evidenceIds` and recorded as safe warnings, while `sourceCollection.evidence` remains intact.
* Verification: `bun run typecheck:scripts` passed.

**Files Changed**:

* `scripts/extensions/trend-finder/collector.ts` - Added rationale projection pass and omission warnings.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked collector projection task complete.

**BQC Fixes**:

* Failure path completeness: Omitted evidence gets a warning with a bounded omission reason.
* Contract alignment: Downstream source breakdowns and evidence links receive filtered topic evidence IDs.

***

### Task T012 - Add fallback rationale assignment for deterministic topics

**Started**: 2026-06-19 23:15 **Completed**: 2026-06-19 23:16 **Duration**: 1 minute

**Notes**:

* Frequency and similarity fallback topics now attach fallback rationale maps when evidence rows are available.
* The same projection helper applies safe omission behavior for weak fallback links.
* Verification: `bun run typecheck:scripts` passed.

**Files Changed**:

* `scripts/extensions/trend-finder/topics.ts` - Added fallback rationale projection for deterministic topic builders.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked deterministic topic rationale task complete.

**BQC Fixes**:

* Contract alignment: All topic creation paths can produce the same rationale map shape.

***

### Task T010 - Implement analyst rationale validation

**Started**: 2026-06-19 23:11 **Completed**: 2026-06-19 23:14 **Duration**: 3 minutes

**Notes**:

* Added validator checks for rationale keys that are unknown, not cited by the topic, unsafe, or unsupported by the cited evidence row.
* Bounded text is enforced by the analyst Zod schema before output reaches scoring.
* Existing invented metadata checks still walk rationale strings for URLs, dates, source names, and metrics, with the new per-evidence helper enforcing cited-row grounding.

**Files Changed**:

* `scripts/lib/ai-runtime/trend-analyst.ts` - Added rationale validation path and issue codes.
* `scripts/lib/ai-runtime/evidence-rationale.ts` - Supplies per-evidence grounding checks.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked analyst rationale validation task complete.

**BQC Fixes**:

* Trust boundary enforcement: AI rationale text is validated at the runtime boundary.
* Error information boundaries: Unsafe rationale wording is rejected before browser or static export projection.

***

### Task T009 - Implement deterministic rationale fallback

**Started**: 2026-06-19 23:06 **Completed**: 2026-06-19 23:14 **Duration**: 8 minutes

**Notes**:

* The fallback builder uses topic identity, source role, relevance score, evidence quality, source-local cues, competitor matches, and metrics where present.
* Weak evidence without relevance, entity, metric, or quality support returns an explicit `weak-unjustified` omission instead of display copy.
* Verification: `bun run typecheck:scripts` passed after helper and analyst integration.

**Files Changed**:

* `scripts/lib/ai-runtime/evidence-rationale.ts` - Implemented deterministic fallback text and weak-link omission logic.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked deterministic fallback task complete.

**BQC Fixes**:

* Failure path completeness: Unjustified evidence returns an omission reason rather than empty rationale text.
* Contract alignment: Fallback records use the same bounded schema as AI rationale records.

***

### Task T007 - Prepare evidence link view-model rationale fields

**Started**: 2026-06-19 23:12 **Completed**: 2026-06-19 23:13 **Duration**: 1 minute

**Notes**:

* Added rationale text, label, tone, accessibility label, and presence fields to `EvidenceLinkViewModel`.
* `joinEvidenceLinks()` now reads topic-level rationale maps and falls back to empty display-safe defaults.
* Verification: `bun run typecheck` passed.

**Files Changed**:

* `src/extensions/trend-finder/view-model.ts` - Added rationale view-model projection fields and defaults.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked view-model foundation task complete.

**BQC Fixes**:

* Accessibility and platform compliance: Rationale copy has an explicit aria label when present.
* State freshness on re-entry: Missing rationale data always projects as empty fields.

***

### Task T008 - Prepare static Brief evidence-row schema and size limits

**Started**: 2026-06-19 23:13 **Completed**: 2026-06-19 23:13 **Duration**: 1 minute

**Notes**:

* Added a static Brief rationale budget tied to the shared rationale max length.
* Added rationale text, label, and tone fields to the static evidence row schema and projection.
* Verification: `bun run typecheck` passed.

**Files Changed**:

* `scripts/extensions/trend-finder/static-brief-export.ts` - Added bounded rationale row fields and size limit.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked static Brief foundation task complete.

**BQC Fixes**:

* Contract alignment: Static Brief evidence rows now have the same bounded rationale field as live evidence cards.

***

### Task T005 - Extend analyst output types, prompt example, and Zod schema

**Started**: 2026-06-19 23:10 **Completed**: 2026-06-19 23:12 **Duration**: 2 minutes

**Notes**:

* Added optional `evidenceRationales` to analyst topic output keyed by existing evidence ID.
* Updated prompt, repair instructions, and schema hint to ask for one short reason per cited item.
* Added bounded Zod record parsing for rationale text.

**Files Changed**:

* `scripts/lib/ai-runtime/trend-analyst.ts` - Extended analyst output contract and prompt guidance.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked analyst output task complete.

**BQC Fixes**:

* Contract alignment: Analyst rationale output is schema-bounded and keyed by evidence ID.

***

### Task T006 - Add rationale validator helpers

**Started**: 2026-06-19 23:11 **Completed**: 2026-06-19 23:12 **Duration**: 1 minute

**Notes**:

* Added validation for unknown evidence IDs, rationales for non-cited IDs, unsupported claims, and unsafe text.
* Reused the rationale helper grounding checks before analyst output can reach scoring or browser projection.
* Verification: `bun run typecheck:scripts` passed.

**Files Changed**:

* `scripts/lib/ai-runtime/trend-analyst.ts` - Added rationale validation and voice checks.
* `scripts/lib/ai-runtime/evidence-rationale.ts` - Reused grounding issue types in analyst validation.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked rationale validator task complete.

**BQC Fixes**:

* Trust boundary enforcement: AI rationale keys must be known, cited evidence IDs.
* Failure path completeness: Invalid rationale output returns explicit validation issue codes.
* Error information boundaries: Unsafe path, prompt, provider, and secret-like text is rejected before display.

***

### Task T003 - Create evidence-rationale helper contract

**Started**: 2026-06-19 23:06 **Completed**: 2026-06-19 23:10 **Duration**: 4 minutes

**Notes**:

* Added bounded rationale sanitization, per-evidence grounding checks, deterministic fallback output, and explicit omission results.
* Added weak-unjustified classification so topic projection can omit unsupported links while preserving raw evidence rows.

**Files Changed**:

* `scripts/lib/ai-runtime/evidence-rationale.ts` - Created rationale helper contract and fallback projection helpers.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked helper task complete.

**BQC Fixes**:

* Contract alignment: Helper returns explicit included or omitted states instead of nullable strings.
* Error information boundaries: Unsafe prompt, provider, path, and secret text is rejected before display projection.

***

### Task T004 - Add rationale constants, topic schema defaults, and legacy-safe parsing

**Started**: 2026-06-19 23:08 **Completed**: 2026-06-19 23:10 **Duration**: 2 minutes

**Notes**:

* Added rationale provenance constants, bounded text limits, rationale record schema, and topic-level `evidenceRationales` default map.
* Kept `TrendTopic` construction backward-compatible by making the field optional at the TypeScript construction boundary while schema parsing defaults it to `{}`.

**Files Changed**:

* `src/extensions/trend-finder/schema.ts` - Added additive rationale schema and topic defaults.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked schema foundation task complete.

**BQC Fixes**:

* State freshness on re-entry: Legacy payloads parse with an empty rationale map instead of stale or missing state.
* Contract alignment: Rationale payloads have explicit provenance and bounded label/text fields.

***

### Task T002 - Inspect current analyst validation, topic projection, and Evidence to verify rendering paths

**Started**: 2026-06-19 23:05 **Completed**: 2026-06-19 23:06 **Duration**: 1 minute

**Notes**:

* Confirmed analyst output currently carries topic `evidenceIds` only and validates unknown evidence IDs, source mismatches, invented URLs, dates, source names, and metrics.
* Confirmed scored topics are assigned to raw evidence with `assignTopicIds()` and then projected through `joinEvidenceLinks()`.
* Confirmed static Brief evidence rows derive from `getTopEvidenceLinks()` and already filter URLs through `filterSafePublicUrl()`.
* Reviewed ADR 0002 and confirmed this session should remain dependency-free, deterministic, and browser-payload safe.

**Files Changed**:

* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked setup inspection task complete.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/implementation-notes.md` - Logged setup inspection findings.

***

## Task Log

### 2026-06-19 - Session Start

**Environment verified**:

* [x] Prerequisites confirmed
* [x] Tools available
* [x] Directory structure ready

***

### Task T001 - Verify analyzer state, completed prerequisites, and Session 05 stub scope

**Started**: 2026-06-19 23:04 **Completed**: 2026-06-19 23:05 **Duration**: 1 minute

**Notes**:

* Confirmed analyzer current session is `phase29-session05-per-evidence-rationale`.
* Confirmed Phase 29 is in progress and prior Phase 29 sessions 01-04 are completed.
* Confirmed Session 05 stub scope matches the active spec: per-evidence rationale, deterministic fallback, weak-link omission, and payload safety.
* Confirmed Bun 1.3.14, jq, git, and spec-system prerequisites pass.

**Files Changed**:

* `.spec_system/specs/phase29-session05-per-evidence-rationale/implementation-notes.md` - Created implementation progress log.
* `.spec_system/specs/phase29-session05-per-evidence-rationale/tasks.md` - Marked setup task complete.

***


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