# Todo 49.3 Stale Replay Token Order Plan

**Status:** done

## Goal

Make the replay generation guard directional: only a replay for the selected session may supersede the active replay.

## Scope

- Exit `loadSessionReplay()` before incrementing the generation token when `sessionId !== currentSessionId`.
- Add an executable JS regression where the current replay starts first and a stale replay is invoked second.
- Preserve the Todo 49.2 success/failure ordering coverage.

## Files

- Modify: `src/agent_lab/presentation/static/app.js`
- Modify: `tests/test_websocket_api.py`

## Verification

- `uv run pytest tests/test_websocket_api.py -q`
- `node --check src/agent_lab/presentation/static/app.js`
- `uv run pytest`
- `git diff --check`

## Observe / Update

- A replay for a non-selected session now exits before advancing the load generation or starting fetches.
- Reverse-order executable JS regression passes alongside Todo 49.2 race coverage.
- WebSocket tests passed (`78 passed`); full suite passed (`388 passed`) with the existing Starlette warning.