# 2026-07-06 — Core scope split

- Intent: take the tick finding seriously instead of letting `spec/core.md`
  contradict the roadmap.
- Finding: B1 said the core dies with no rollback and B2 gets sync-lag
  fallback copies, but the READY B1 `spec/core.md` acceptance criteria
  required fallback sync, migration, rollback snapshots, and sidebar
  fallback freshness immediately.
- Changed: narrowed `spec/core.md` to B1: physical core host, overhead,
  degraded mode, no-fallback core death, and a future rollback seam. Added
  `spec/core-sync-migration.md` for B2: fallback sites, sync cadence,
  rollback with world-ledger persistence, migration, and player-facing
  fallback freshness. Also fixed two adjacent stale spec references:
  compute's optimize route now points B2 migration speedups at the deferred
  core-sync spec, and detection's audit criterion no longer references the
  deleted raid system. Added `.obsidian/` to `.gitignore` and added the
  constitution's "What lives in the tree" section to state what files are
  permitted in the repository. Updated `AGENT.md` and
  `knowledge/workflows.md` with the standing repo rule: always work in
  worktrees, commit coherent completed work aggressively unless a real
  question/check/review gate is pending, and clean up completed worktrees.
- Design/spec impact: B1 now makes Rack 3 feel mortal before adding the
  reincarnation machinery. The sync-lag rollback mechanic remains decided,
  just no longer first-slice scope.
- Checks: docs-only; searched for core/fallback/sync references after edit.
- Next: implement B1 core host state and death event seam, then compute
  allocation.