cancel_flow_run
Stop an active workflow execution in Prefect by providing the flow run ID to halt processing and free resources.
Instructions
Cancel a flow run.
Args:
flow_run_id: ID of the flow run to cancel.Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| flow_run_id | Yes |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Implementation Reference
- prefect_mcp_server_pkg/server.py:223-239 (handler)The handler function for the 'cancel_flow_run' MCP tool. It is decorated with @mcp.tool() for automatic registration. The function validates the flow_run_id input, uses the Prefect client to cancel the flow run by UUID, and returns success or error details.
@mcp.tool() async def cancel_flow_run(ctx: Context, flow_run_id: str) -> Dict[str, Any]: """Cancel a flow run. Args: flow_run_id: ID of the flow run to cancel. """ if not flow_run_id: return {"error": "Missing required argument: flow_run_id"} async with get_client() as client: try: result = await client.cancel_flow_run(UUID(flow_run_id)) return {"success": True, "result": str(result)} except Exception as e: return {"error": f"Failed to cancel flow run: {str(e)}"}