> 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/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md).

# Implementation Notes

**Session ID**: `phase27-session04-daily-time-series-persistence-and-sparklines` **Started**: 2026-06-12 22:43 **Last Updated**: 2026-06-12 23:59

***

## Session Progress

| Metric              | Value   |
| ------------------- | ------- |
| Tasks Completed     | 20 / 20 |
| Estimated Remaining | 0 hours |
| Blockers            | 0       |

***

### Task T001 - Verify analyzer state, Sessions 01-03 completion, and Session 04 source stub

**Started**: 2026-06-12 22:41 **Completed**: 2026-06-12 22:44 **Duration**: 3 minutes

**Notes**:

* Analyzer reported current session `phase27-session04-daily-time-series-persistence-and-sparklines`.
* Phase 27 Sessions 01-03 are listed as completed in deterministic state.
* Session 04 PRD stub confirms daily topic series, 14-entry sparkline output, and Hugging Face download delta scope.

**Files Changed**:

* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - started implementation log.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T001 complete and updated progress.

**BQC Fixes**:

* N/A - baseline verification only.

***

### Task T002 - Inspect snapshot, historical context, collector, schema, trend card, Workbench, and metric chip baselines

**Started**: 2026-06-12 22:44 **Completed**: 2026-06-12 22:45 **Duration**: 1 minute

**Notes**:

* Snapshot persistence already uses schema validation, path confinement, atomic writes, latest/dated files, and legacy defaults.
* Historical context already reads dated snapshots inside an 84-day window, excludes `latest.json`, and aggregates canonical topic history.
* Collector flow attaches source-local signals before AI analysis, resolves canonical identities, scores topics, attaches historical summaries, validates browser data, then writes snapshots.
* UI follows projected view-model patterns for evidence metric chips, trend cards, and Signal Workbench rows/table columns.
* ADR 0001 confirms static extension boundaries and no dynamic extension loading.

**Files Changed**:

* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T002 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged baseline inspection.

**BQC Fixes**:

* N/A - baseline inspection only.

***

### Task T003 - Create private trend-series helpers

**Started**: 2026-06-12 22:45 **Completed**: 2026-06-12 22:48 **Duration**: 3 minutes

**Notes**:

* Added UTC day bucket normalization and 14-day zero-filled sparkline window helpers.
* Added bounded per-topic daily count assembly and merge helpers that use max-per-day semantics to avoid duplicate snapshot overcounting.
* Added Hugging Face model download observation normalization, latest-baseline lookup, and delta calculation with explicit no-baseline, malformed, and decreased states.

**Files Changed**:

* `scripts/lib/ai-runtime/trend-series.ts` - new pure helper module.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T003 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged helper implementation.

**BQC Fixes**:

* Failure path completeness: invalid timestamps and malformed counts return explicit skipped/null states instead of guessed dates or silent positive deltas.
* Contract alignment: helper types define bounded public/private data contracts for later snapshot, historical, and browser schema tasks.

***

### Task T004 - Extend snapshot schema and compatibility for private series

**Started**: 2026-06-12 22:48 **Completed**: 2026-06-12 22:50 **Duration**: 2 minutes

**Notes**:

* Added bounded private `series.topicDailyCounts` and `series.modelDownloadObservations` schemas to trend snapshots.
* Kept `series` additive with defaults so legacy snapshot JSON and current callers that omit the branch still parse/write through schema defaults.
* Preserved existing path confinement and atomic latest/dated write behavior.

**Files Changed**:

* `scripts/lib/ai-runtime/snapshots.ts` - added private series schemas, defaults, and optional TypeScript write contract.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T004 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged snapshot schema work.

**BQC Fixes**:

* Contract alignment: additive schema default avoids breaking legacy snapshots or callers.
* Trust boundary enforcement: private series data is schema-validated and bounded before persistence.

***

### Task T005 - Extend historical context assembly

**Started**: 2026-06-12 22:50 **Completed**: 2026-06-12 22:53 **Duration**: 3 minutes

**Notes**:

* Added `topicSparklines` to historical context with 14-day zero-filled points and explicit missing-history state.
* Added `modelDownloadBaselines` from latest historical model download observations before the current run.
* Changed default future snapshot handling to exclude future-dated archives unless `includeFutureSnapshots` is explicitly true.
* Empty historical contexts now include empty sparkline and baseline arrays for stable callers.

**Files Changed**:

* `scripts/lib/ai-runtime/historical-context.ts` - added sparkline and download baseline assembly.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T005 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged historical context work.

**BQC Fixes**:

* State freshness on re-entry: future snapshots are excluded by default so a new run cannot reuse later archive data.
* Failure path completeness: missing series data becomes explicit missing-history context instead of guessed sparkline counts.

***

### Task T006 - Add browser schema fields for sparklines and download deltas

**Started**: 2026-06-12 22:53 **Completed**: 2026-06-12 22:56 **Duration**: 3 minutes

**Notes**:

* Added topic `sparkline` schema with 14-point cap, browser count bounds, state, and unavailable reason.
* Added evidence `downloadDelta` schema with explicit no-baseline, missing-current, invalid-current, invalid-baseline, decreased, and available states.
* Kept new fields additive so legacy topics default to a missing-history sparkline and legacy evidence can omit download deltas.

**Files Changed**:

* `src/extensions/trend-finder/schema.ts` - added constants, defaults, schemas, and topic/evidence fields.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T006 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged schema work.

**BQC Fixes**:

* Trust boundary enforcement: strict schema branches reject unknown private fields before browser rendering.
* Contract alignment: legacy payloads still parse with bounded defaults.

***

### Task T007 - Add fixture coverage for daily series and Hugging Face delta states

**Started**: 2026-06-12 22:56 **Completed**: 2026-06-12 23:03 **Duration**: 7 minutes

**Notes**:

* Added a 14-point available sparkline to the Structured Output Grammars fixture topic.
* Added an explicit missing-history sparkline state to Speculative Decoding Adoption.
* Added Hugging Face model evidence with available download delta context and first-seen no-baseline context.
* Added a Hugging Face Models source summary so fixture labels resolve through existing source maps.

**Files Changed**:

* `src/extensions/trend-finder/fixtures.ts` - added sparkline and Hugging Face download delta fixture states.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T007 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged fixture work.

**BQC Fixes**:

* Contract alignment: fixture topics use the new additive sparkline field and evidence uses the new download delta schema shape.
* Failure path completeness: missing-history and no-baseline states are represented explicitly for UI and test coverage.

***

### Task T008 - Build collector-side daily evidence count inputs

**Started**: 2026-06-12 23:03 **Completed**: 2026-06-12 23:10 **Duration**: 7 minutes

**Notes**:

* Added current-run daily series assembly from scored topics, canonical topic IDs, linked evidence IDs, and evidence `publishedAt` timestamps.
* Invalid or missing timestamps are filtered by the series helper and surfaced as collector warnings.
* Collector trace logs only aggregate warning/count metadata, not private archive paths.

**Files Changed**:

* `scripts/extensions/trend-finder/collector.ts` - added daily series input assembly and warning handling.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T008 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged collector daily series work.

**BQC Fixes**:

* Failure path completeness: malformed timestamps are excluded with explicit warnings.
* Trust boundary enforcement: only canonical topic IDs and browser-safe evidence timestamps cross into daily series assembly.

***

### Task T009 - Attach capped sparkline arrays to topics

**Started**: 2026-06-12 23:10 **Completed**: 2026-06-12 23:11 **Duration**: 1 minute

**Notes**:

* Added collector sparkline attachment that merges historical sparkline context with current-run daily counts.
* Available sparklines emit 14 UTC day points; missing counts emit the additive missing-history state and unavailable copy.
* Sparkline metadata is attached before `TrendFinderDataSchema` validation and snapshot writing.

**Files Changed**:

* `scripts/extensions/trend-finder/collector.ts` - attached topic sparklines from historical/current series.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T009 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged sparkline attachment work.

**BQC Fixes**:

* Contract alignment: topic sparkline output matches the browser schema state/points/days contract before validation.
* Failure path completeness: topics without counts get explicit missing-history state instead of an empty implicit chart.

***

### Task T010 - Attach Hugging Face download deltas to evidence metric context

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

**Notes**:

* Added Hugging Face model evidence detection through source-local model entities and public Hugging Face source/URL checks.
* Attached browser-safe download delta context with available, no-baseline, missing-current, invalid-current, invalid-baseline, and decreased states.
* Persisted only normalized model download observations into the private snapshot `series` branch.
* Snapshot writer now receives private daily topic counts and model download observations after browser data validation.

**Files Changed**:

* `scripts/extensions/trend-finder/collector.ts` - attached download deltas and private snapshot observations.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T010 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged Hugging Face delta work.

**BQC Fixes**:

* Error information boundaries: logs and warnings expose counts only, not private archive paths.
* Failure path completeness: missing/malformed downloads and first-seen baselines become explicit states.
* Contract alignment: snapshot private observations and browser delta contexts are separated.

***

### Task T011 - Extend Trend Finder view-model helpers

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

**Notes**:

* Added `TopicSparklineViewModel` projection with normalized points, SVG coordinate strings, labels, empty copy, and accessible summary text.
* Added download delta metric chip projection for available, decreased, no-baseline, missing-current, invalid-current, and invalid-baseline states.
* Topic card view models now include sparkline projections for component reuse.

**Files Changed**:

* `src/extensions/trend-finder/view-model.ts` - added sparkline and download-delta view-model helpers.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T011 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged view-model work.

**BQC Fixes**:

* Accessibility and platform compliance: generated sparkline and metric chip labels include explicit aria-ready copy.
* Contract alignment: exhaustive state label switches catch new delta/sparkline states at compile time.
* Failure path completeness: no-baseline, missing-current, invalid, and decreased deltas render as intentional states.

***

### Task T012 - Create reusable sparkline SVG component

**Started**: 2026-06-12 23:17 **Completed**: 2026-06-12 23:19 **Duration**: 2 minutes

**Notes**:

* Added a fixed `96x32` SVG sparkline renderer with a last-point marker and no charting dependency.
* Added stable empty-state rendering for missing-history topics.
* Component consumes `TopicSparklineViewModel` labels and coordinates.

**Files Changed**:

* `src/extensions/trend-finder/components/trend-sparkline.tsx` - new reusable sparkline component.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T012 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged component work.

**BQC Fixes**:

* Accessibility and platform compliance: component exposes a single descriptive aria label and hides decorative SVG internals.
* Resource cleanup: N/A - stateless render-only component.

***

### Task T013 - Render topic sparklines on trend cards

**Started**: 2026-06-12 23:19 **Completed**: 2026-06-12 23:20 **Duration**: 1 minute

**Notes**:

* Added the reusable sparkline component to the trend card metrics column.
* Visible copy shows peak count for available sparklines and history-unavailable state otherwise.
* Layout uses fixed component dimensions and existing dense card spacing.

**Files Changed**:

* `src/extensions/trend-finder/components/trend-card.tsx` - rendered daily signal sparkline section.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T013 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged trend card rendering.

**BQC Fixes**:

* Accessibility and platform compliance: card uses the sparkline component's aria label and visible unavailable state.
* Contract alignment: card consumes `TopicCardViewModel.sparkline`, not raw topic series data.

***

### Task T014 - Add Workbench sparkline row fields and sort/filter support

**Started**: 2026-06-12 23:20 **Completed**: 2026-06-12 23:24 **Duration**: 4 minutes

**Notes**:

* Added sparkline view model, state labels, total count, and peak count to Workbench topic rows.
* Added sparkline search text, `sparklineState` filter support, sparkline facets, and `sparklineTotal` deterministic sort key.
* Row projection uses the shared `getTopicSparklineViewModel` helper.

**Files Changed**:

* `src/extensions/trend-finder/signal-workbench-model.ts` - added Workbench sparkline row fields and model operations.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T014 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged Workbench model work.

**BQC Fixes**:

* Contract alignment: Workbench consumes the shared sparkline view model rather than duplicating raw topic parsing.
* State freshness on re-entry: filters default to `all` and row state is recomputed from current generated data.

***

### Task T015 - Render Workbench sparkline column and Hugging Face delta pills

**Started**: 2026-06-12 23:24 **Completed**: 2026-06-12 23:28 **Duration**: 4 minutes

**Notes**:

* Added evidence-level Hugging Face download delta labels to Workbench evidence row models.
* Added a sortable fixed-width Trend column to the Signal Workbench table.
* Rendered compact sparklines in table rows and HF delta pills in expanded evidence rows.

**Files Changed**:

* `src/extensions/trend-finder/signal-workbench-model.ts` - added evidence delta labels for table rendering.
* `src/extensions/trend-finder/components/signal-workbench-table.tsx` - added Trend column and HF delta pills.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T015 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged Workbench rendering.

**BQC Fixes**:

* Accessibility and platform compliance: Trend column uses sparkline aria labels and HF delta pills expose label/value aria text.
* Contract alignment: table renders projected row fields and does not inspect private snapshot data.

***

### Task T016 - Add trend-series tests

**Started**: 2026-06-12 23:28 **Completed**: 2026-06-12 23:34 **Duration**: 6 minutes

**Notes**:

* Added tests for UTC date bucketing across timezone edges and malformed dates.
* Added tests for bounded daily counts, cap enforcement, and 14-day zero-fill output.
* Added tests for model download observation normalization, latest baseline lookup, no-baseline, available, decreased, and invalid-current delta states.

**Files Changed**:

* `scripts/lib/ai-runtime/__tests__/trend-series.test.ts` - new helper test suite.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T016 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged trend-series tests.

**BQC Fixes**:

* Contract alignment: tests lock helper output shapes before collector and schema callers consume them.
* Failure path completeness: malformed date/count and no-baseline paths have direct coverage.

***

### Task T017 - Extend snapshot and historical-context tests

**Started**: 2026-06-12 23:34 **Completed**: 2026-06-12 23:40 **Duration**: 6 minutes

**Notes**:

* Added snapshot persistence coverage for private topic daily counts and model download observations.
* Added legacy snapshot default coverage for the new private `series` branch.
* Added historical context coverage for bounded 14-day sparkline assembly, future snapshot exclusion, latest model download baselines, and missing-history states.

**Files Changed**:

* `scripts/lib/ai-runtime/__tests__/snapshots.test.ts` - added private series persistence/default assertions.
* `scripts/lib/ai-runtime/__tests__/historical-context.test.ts` - added sparkline and baseline context assertions.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T017 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged snapshot/historical tests.

**BQC Fixes**:

* Contract alignment: tests verify private snapshot schema and historical browser-safe projections stay aligned.
* State freshness on re-entry: tests verify future snapshots are excluded from default historical reads.

***

### Task T018 - Extend schema and dashboard view-model tests

**Started**: 2026-06-12 23:40 **Completed**: 2026-06-12 23:45 **Duration**: 5 minutes

**Notes**:

* Added browser schema tests for legacy sparkline defaults, 14-point sparkline bounds, private-field fallback, and download delta parsing.
* Added dashboard/view-model tests for Hugging Face delta chips and sparkline SVG point projection.

**Files Changed**:

* `src/lib/__tests__/trend-finder-schema.test.ts` - added schema coverage.
* `src/lib/__tests__/trend-finder-dashboard.test.tsx` - added view-model coverage.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T018 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged schema/dashboard tests.

**BQC Fixes**:

* Trust boundary enforcement: tests verify private cache fields fall back instead of reaching browser-safe output.
* Accessibility and platform compliance: tests verify sparkline aria text and delta chip aria labels.

***

### Task T019 - Add component and Workbench tests

**Started**: 2026-06-12 23:45 **Completed**: 2026-06-12 23:50 **Duration**: 5 minutes

**Notes**:

* Added component tests for available sparkline SVG rendering and missing-history empty states.
* Added Workbench table test for the Trend column and Hugging Face delta pills.
* Added Workbench model test for sparkline filtering, facets, and deterministic sort order.

**Files Changed**:

* `src/extensions/trend-finder/components/__tests__/trend-sparkline.test.tsx` - new component/table test suite.
* `src/extensions/trend-finder/__tests__/signal-workbench-model.test.ts` - added sparkline model assertions.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T019 complete and updated progress.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged component/Workbench tests.

**BQC Fixes**:

* Accessibility and platform compliance: tests assert accessible sparkline labels and HF delta pill labels.
* Contract alignment: Workbench tests verify table rendering and model fields consume shared sparkline projections.

***

### Task T020 - Run focused validation, typechecks, budget check, and ASCII validation

**Started**: 2026-06-12 23:50 **Completed**: 2026-06-12 23:59 **Duration**: 9 minutes

**Notes**:

* Fixed validation-time TypeScript contract issues by allowing snapshot write contracts to accept in-flight topics before schema defaults fill `sparkline`, tightening collector sparkline inputs to non-null historical arrays, and making historical-context test assertions explicit about optional compatibility fields.
* Focused Trend Finder tests passed: 7 files and 151 tests.
* TypeScript application and scripts checks passed.
* Production build passed, then payload budget check passed with 0 violations.
* `git diff --check` and modified/untracked ASCII validation passed.

**Files Changed**:

* `scripts/lib/ai-runtime/snapshots.ts` - aligned `TrendSnapshot` topic typing with schema-defaulted writes.
* `scripts/extensions/trend-finder/collector.ts` - tightened `attachTopicSparklines` historical array input.
* `scripts/lib/ai-runtime/__tests__/historical-context.test.ts` - updated optional compatibility assertions.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/tasks.md` - marked T020 complete and checked the completion checklist.
* `.spec_system/specs/phase27-session04-daily-time-series-persistence-and-sparklines/implementation-notes.md` - logged final validation.

**Validation Commands**:

* `bun run typecheck` - passed.
* `bun run typecheck:scripts` - passed.
* `bun run test -- scripts/lib/ai-runtime/__tests__/trend-series.test.ts scripts/lib/ai-runtime/__tests__/snapshots.test.ts scripts/lib/ai-runtime/__tests__/historical-context.test.ts src/lib/__tests__/trend-finder-schema.test.ts src/lib/__tests__/trend-finder-dashboard.test.tsx src/extensions/trend-finder/__tests__/signal-workbench-model.test.ts src/extensions/trend-finder/components/__tests__/trend-sparkline.test.tsx` - passed, 151 tests.
* `bun run build` - passed.
* `bun run budget:check` - passed.
* `git diff --check` - passed.
* Modified/untracked ASCII validation - passed.

**BQC Fixes**:

* Contract alignment: snapshot typing now matches the parse boundary where Zod supplies additive topic defaults.
* Failure path completeness: optional historical compatibility fields are handled explicitly in tests and collector call sites.
* Quality gate coverage: focused tests, typechecks, build, payload budget, whitespace, and ASCII validation all passed before session closeout.

***

## Task Log

### 2026-06-12 - Session Start

**Environment verified**:

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

***


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