- Select one storage backend per instance via AGENT_STORAGE, retaining
memory as the backward-compatible default. Manage the selected async
repository, official checkpointer and connection pools in lifespan;
fail startup on unavailable or uninitialized storage without fallback.
- Add SQLite and PostgreSQL adapters, schema initialization CLI, sample
PostgreSQL compose configuration and a Windows-compatible serve entry.
SQLite enforces single-instance file ownership; PostgreSQL uses a
dedicated pool for session advisory locks plus version/epoch fencing.
- Make repository IO and commit callbacks awaitable. Persist business
fields, a complete committed graph snapshot and turn result/version in
one business transaction before success. Rebuild execution checkpoints
from that snapshot, discarding uncommitted progress after interruption.
- Support optional Idempotency-Key on durable chat requests. Replay
committed results and return 409 on changed request content; delete
removes business/history data and replay records while retaining only
an epoch/version tombstone to reject stale commits.
- Document migration, database switching boundaries, backup/deployment
expectations and crash recovery. Ignore generated database files.
Validation: 315 tests passed with real SQLite and isolated PostgreSQL,
including abrupt child-process exits before/after business commit;
both backends passed CLI migration and actual HTTP server restart smoke.
Existing API tests were rechecked after isolating them from user storage.
An initial Windows CreateProcess permission failure did not recur in the
full diagnostic run; failure assertions were not skipped or relaxed.
