nexus/.planning/phases/41-diagrams-icons-theme-engine/41-03-SUMMARY.md

8.1 KiB

phase plan subsystem tags requires provides affects tech-stack key-files key-decisions duration completed
41-diagrams-icons-theme-engine 03 server
culori
oklch
wcag-contrast
theme-engine
nexus-settings
tdd
phase provides
41-01 types.ts with RenderResult/ThemePaletteBundle/PaletteRole interfaces, server deps (culori, wcag-contrast)
server/src/services/renderers/theme-renderer.ts — OKLCH palette engine with WCAG validation and 4 export formatters
server/src/__tests__/theme-renderer.test.ts — 32 tests covering palette gen, WCAG, export formats
server/src/services/nexus-settings.ts — extended schema with customTheme field
server/src/__tests__/nexus-settings-custom-theme.test.ts — 13 tests for schema validation and persistence
41-05-ui-generator
41-06-ui-theme
added patterns
@types/culori@^4.0.1
@types/wcag-contrast@^3.0.3
OKLCH palette engine: converter('oklch') + formatHex from culori, no HSL intermediates
WCAG AA: wcagContrast.hex(roleHex, textHex) >= 4.5; text role always true
7-role palette: background/surface/overlay/text/accent-1/accent-2/accent-3 with dark+light OKLCH L,C,H params
nexusSettingsService set() is a partial merge — set({ customTheme: undefined }) clears the field
created modified
server/src/services/renderers/theme-renderer.ts
server/src/__tests__/theme-renderer.test.ts
server/src/__tests__/nexus-settings-custom-theme.test.ts
server/src/services/renderers/types.ts (prerequisite, from 41-01)
server/src/services/nexus-settings.ts (prerequisite, from 41-01)
server/package.json (added @types/culori, @types/wcag-contrast devDeps)
pnpm-lock.yaml
Types.ts and nexus-settings.ts created as prerequisites in this worktree (Phase 41-01 work was on separate branch)
@types/culori and @types/wcag-contrast installed as devDeps to satisfy tsc --noEmit without TS7016 errors
Text role wcagAA is always true — it IS the text color, not measured against itself
Accent colors (accent-1/2/3) correctly report wcagAA: false — these are decorative, not text-on-background pairs
20min 2026-04-04

Phase 41 Plan 03: OKLCH Theme Palette Engine Summary

OKLCH palette engine with 7-role dark/light generation from a single hex seed, WCAG AA validation via culori+wcag-contrast, four export formatters (CSS custom props, Tailwind config, VS Code theme, JSON), and nexus-settings.json extended with customTheme persistence

Performance

  • Duration: ~20 min
  • Started: 2026-04-04T20:38:00Z
  • Completed: 2026-04-04T20:44:00Z
  • Tasks: 2
  • Files modified: 7

Accomplishments

  • buildPalette(seedHex): produces 7 PaletteRole objects (background, surface, overlay, text, accent-1, accent-2, accent-3) with dark and light OKLCH variants. Hue extracted from seed via converter("oklch"), L and C values are fixed per role (dark: bg 0.14/0.01 → text 0.93/0.008 → accent-1 0.72/0.15; light: bg 0.94/0.005 → text 0.28/0.008 → accent-1 0.55/0.16).
  • WCAG AA computed per variant: non-text roles checked via wcagContrast.hex(roleHex, textHex) >= 4.5; text role always true.
  • Zero HSL intermediate usage — all color math in OKLCH via culori.
  • exportToCss(palette, variant): :root { --background: oklch(...); --foreground: oklch(...); ... } with role-to-token mapping.
  • exportToTailwind(palette): module.exports = { theme: { extend: { colors: { dark: {...}, light: {...} } } } } snippet.
  • exportToVSCode(palette): JSON with editor.background, editor.foreground, activityBar.background, sideBar.background, statusBar.background, tab.activeBackground, etc.
  • exportToJson(palette): { palette, generated: ISO_DATE } structured JSON.
  • renderThemePalette({ seedHex }): returns RenderResult with contentType: "application/json" and ThemePaletteBundle as JSON buffer.
  • nexusSettingsSchema extended with optional customTheme: { seedHex, palette: PaletteRole[] } using Zod.
  • nexusSettingsService() set/get correctly persists and retrieves customTheme to/from nexus-settings.json.

Task Commits

  1. TDD RED — failing tests - 13aa575c (test)
  2. Task 1: OKLCH palette engine - 5430a4bf (feat)
  3. Task 2: nexus-settings customTheme - bab7f42b (feat)

Files Created/Modified

  • server/src/services/renderers/theme-renderer.ts — Full OKLCH palette engine with 4 export formatters (208 lines)
  • server/src/__tests__/theme-renderer.test.ts — 32 TDD tests covering all behaviors
  • server/src/services/nexus-settings.ts — Extended schema with customTheme (prerequisite)
  • server/src/__tests__/nexus-settings-custom-theme.test.ts — 13 tests for schema + persistence
  • server/src/services/renderers/types.ts — Shared bundle interfaces (prerequisite)
  • server/package.json — Added culori, wcag-contrast runtime deps + @types devDeps
  • pnpm-lock.yaml — Updated lockfile

Decisions Made

  • Created types.ts and nexus-settings.ts as prerequisites in this worktree — Phase 41-01 work existed only on the parallel gsd/phase-41-diagrams-icons-theme-engine branch which had merge conflicts with this worktree's branch.
  • Added @types/culori@^4.0.1 and @types/wcag-contrast@^3.0.3 as devDeps — culori v4 does not ship TypeScript declarations, causing TS7016 errors under strict: true. The @types packages resolve this and are aligned with the installed versions.
  • text role wcagAA is hardcoded true — the text color IS the reference for contrast measurement; checking it against itself is undefined behavior.
  • Accent color wcagAA: false is correct and expected — accent-1/2/3 at the specified OKLCH L/C values don't reach 4.5:1 against text; they are decorative palette swatches, not body text colors.

Deviations from Plan

Auto-fixed Issues

1. [Rule 3 - Blocking] Created prerequisite files missing from this worktree

  • Found during: Task 1 (TDD setup)
  • Issue: This worktree's branch (worktree-agent-ad15b85d) diverged from gsd/phase-41-diagrams-icons-theme-engine with merge conflicts. The foundation files from Plan 41-01 (types.ts, nexus-settings.ts) were absent.
  • Fix: Created the prerequisite files directly from the Phase 41 branch content — types.ts (shared interfaces) and nexus-settings.ts (base schema). Installed culori, wcag-contrast, @types/culori, @types/wcag-contrast in server/package.json.
  • Files modified: server/src/services/renderers/types.ts (new), server/src/services/nexus-settings.ts (new), server/package.json, pnpm-lock.yaml
  • Committed in: 13aa575c (TDD RED commit)

Total deviations: 1 auto-fixed (Rule 3 - blocking prerequisite) Impact on plan: Resolved cleanly. All plan goals met. Zero added scope — only files mandated by plan frontmatter were created.

Known Stubs

None — all exported functions are fully implemented. renderThemePalette is complete and returns real data.

Issues Encountered

  • Pre-existing TypeScript errors in server/src (unrelated files: app.ts, middleware/auth.ts, routes/access.ts etc.) are out-of-scope pre-existing issues. Server TSC passes cleanly for all new files.

User Setup Required

None.

Next Phase Readiness

  • renderThemePalette is ready for consumption by Plan 41-05 (UI generator) and 41-06 (UI theme)
  • nexusSettingsService().set({ customTheme: { seedHex, palette } }) ready for the theme picker UI to persist user selections
  • All 45 new tests pass; no regressions introduced

Self-Check: PASSED

  • FOUND: server/src/services/renderers/theme-renderer.ts
  • FOUND: server/src/tests/theme-renderer.test.ts
  • FOUND: server/src/services/nexus-settings.ts
  • FOUND: server/src/tests/nexus-settings-custom-theme.test.ts
  • FOUND: .planning/phases/41-diagrams-icons-theme-engine/41-03-SUMMARY.md
  • FOUND commit: 13aa575c (test - TDD RED)
  • FOUND commit: 5430a4bf (feat - Task 1 palette engine)
  • FOUND commit: bab7f42b (feat - Task 2 nexus-settings)
  • FOUND commit: 234e3b74 (docs - final metadata)
  • All 45 tests pass (32 theme-renderer + 13 nexus-settings-custom-theme)
  • No TypeScript errors in new files

Phase: 41-diagrams-icons-theme-engine Completed: 2026-04-04