The exec endpoint implementation is complete and all tests pass. **Endpoints:** - `POST /api/containers/{name}/exec` - Synchronous command execution - `POST /api/containers/{name}/exec/async` - Async execution returning job ID **Implementation files:** - `app/api/exec.py:20-72` - Sync exec endpoint - `app/api/exec.py:75-129` - Async exec endpoint - `app/api/schemas.py:94-117` - Request/Response schemas - `app/services/incus.py:363-444` - IncusClient.exec() method **Request schema (ExecRequest):** - command: list[str] (required) - environment: dict[str, str] (optional) - cwd: str (optional) - user/group: int (optional) **Response schema (ExecResponse):** - return_code: int - stdout: str - stderr: str **Test results:** All 321 tests pass (including 10 exec-specific tests)