stack/scratchpads/ri-4-001-prd-authority.md

Scratchpad — RI-4-001 One transitional PRD authority (RI-N3, #1275)

• Objective: single PrdService authority in @mosaicstack/prdy; mosaic prdy and mission --plan become thin adapters; mission↔PRD linkage persisted on disk; Markdown export is a labeled generated view (never read back); import is validated/conflict-aware with typed refusals.
• Budget: ~35K tokens (card cap). Baselines: prdy build/lint rc=0, 0 tests; mosaic build rc=0 (after root turbo build), lint rc=0, 1548 tests pass; root build rc=0.
• Plan: (1) extend store schema (version, missions linkage) (2) PrdService + typed errors (3) wizard/cli route through service (4) mosaic adapters (5) contract specs both packages (6) gates (7) sabotage control (8) report to /var/tmp/ri-050/ri-4-001-report.md.
• Decisions:
  • Linkage lives ON the PRD document (missions array) — one authority file, survives restart, no sidecar sync problems.
  • version = content revision of sections/status (bumped by update/import accept). Linkage writes bump updatedAt only, so ids/versions stay stable for the card's "stable ids/versions" contract.
  • Mission version marker = mission.updatedAt (gateway MissionInfo has no numeric version field).
  • Import reads YAML documents only — never the exported Markdown (keeps the "no code path reads exported Markdown" invariant).
  • Import of an existing id with identical core content → identical no-op; divergent → typed PrdImportConflictError carrying proposed successor (existing.version + 1, status draft, linkages preserved). Original bytes untouched until explicit acceptSuccessor.
  • requirementIds default [] at the mission command (no requirement selection UI yet) — service accepts ids when a caller has them.
• Progress log:
  • [16:35] baselines captured (see above)
  • [in progress] implementation