# API contract

- The **OpenAPI document** generated from the code (`chronexus-server openapi`) is the
  contract. `api/openapi.json` and `api/types.ts` are generated by
  `python3 scripts/contract.py` and checked with `--check`; a drift fails the check.
- `GET /api/v1/meta` reports the API version and **capabilities**; clients refuse servers
  that lack what they need (for example `incremental-sync`).
- Human-readable reference: `docs/API.md`. The desktop client's view of the same contract:
  the app's `docs/SYNC_API.md`.
- Table APIs now cover GM-only creation, invitation sign-up, separate seats and
  explicit journal grants. Live WebSocket tickets are one-use and the current
  channel accepts public table activity only. See `docs/API.md` for frames.

## Compatibility rules

- Add, do not break: new fields are optional, new behaviour is announced by a capability.
- Requests reject unknown fields, so clients must not send fields the server does not
  document.
- Status codes carry meaning the client relies on: `401` sign in again, `403/404` on a
  campaign read means access is gone, `409` conflict (with the current revision), `410`
  expired invitation or stale cursor, `429` slow down.