Agent Run Cancellation

"""
Example demonstrating how to cancel a running agent execution.

This example shows how to:
1. Start an agent run in a separate thread
2. Cancel the run from another thread
3. Handle the cancelled response
"""

import threading
import time
from uuid import uuid4

from agno.agent import Agent
from agno.models.openai import OpenAIResponses
from agno.run.agent import RunEvent
from agno.run.base import RunStatus


def long_running_task(agent: Agent, run_id_container: dict):
    """Consume the parent run's stream and retain its terminal outcome."""
    run_id = run_id_container["run_id"]
    status = "unknown"
    content_pieces = []
    try:
        for chunk in agent.run(
            "Write a detailed story about a dragon who learns to code.",
            run_id=run_id,
            stream=True,
            stream_events=True,
        ):
            # Member/step runs have their own IDs and do not determine parent status.
            if chunk.run_id != run_id:
                continue
            if chunk.event == RunEvent.run_cancelled:
                status = "cancelled"
            elif chunk.event == RunEvent.run_error:
                status = "error"
            elif chunk.event == RunEvent.run_paused:
                status = "paused"
            elif chunk.event == RunEvent.run_completed and status == "unknown":
                status = "completed"
            content = getattr(chunk, "content", None)
            if isinstance(content, str):
                content_pieces.append(content)
        run_id_container["result"] = {
            "status": status,
            "run_id": run_id,
            "cancelled": status == "cancelled",
            "content": "".join(content_pieces)[:200],
        }
    except Exception as exc:
        run_id_container["result"] = {
            "status": "error", "run_id": run_id, "cancelled": False,
            "error": str(exc), "content": "Run raised an exception",
        }


def cancel_after_delay(agent: Agent, run_id_container: dict, delay_seconds: int = 3):
    """
    Cancel the agent run after a specified delay.

    Args:
        agent: The agent whose run should be cancelled
        run_id_container: Dictionary containing the run_id to cancel
        delay_seconds: How long to wait before cancelling
    """
    print(f"Will cancel run in {delay_seconds} seconds...")
    time.sleep(delay_seconds)

    run_id = run_id_container.get("run_id")
    if run_id:
        print(f"Cancelling run: {run_id}")
        success = agent.cancel_run(run_id)
        if success:
            print(f"Run {run_id} marked for cancellation")
        else:
            print(
                f"Failed to cancel run {run_id} (may not exist or already completed)"
            )
    else:
        print("No run_id found to cancel")


def main():
    """Main function demonstrating agent run cancellation."""

    # Initialize the agent with a model
    agent = Agent(
        name="StorytellerAgent",
        model=OpenAIResponses(id="gpt-5.2"),  # Use a model that can generate long responses
        description="An agent that writes detailed stories",
    )

    print("Starting agent run cancellation example...")
    print("=" * 50)

    # Container to share run_id between threads
    run_id_container = {"run_id": str(uuid4())}

    # Start the agent run in a separate thread
    agent_thread = threading.Thread(
        target=lambda: long_running_task(agent, run_id_container), name="AgentRunThread"
    )

    # Start the cancellation thread
    cancel_thread = threading.Thread(
        target=cancel_after_delay,
        args=(agent, run_id_container, 8),  # Cancel after 8 seconds
        name="CancelThread",
    )

    # Start both threads
    print("Starting agent run thread...")
    agent_thread.start()

    print("Starting cancellation thread...")
    cancel_thread.start()

    # Wait for both threads to complete
    print("Waiting for threads to complete...")
    agent_thread.join()
    cancel_thread.join()

    # Print the results
    print("\n" + "=" * 50)
    print("RESULTS:")
    print("=" * 50)

    result = run_id_container.get("result")
    if result:
        print(f"Status: {result['status']}")
        print(f"Run ID: {result['run_id']}")
        print(f"Was Cancelled: {result['cancelled']}")

        if result.get("error"):
            print(f"Error: {result['error']}")
        else:
            print(f"Content Preview: {result['content']}")

        if result["cancelled"]:
            print("\nSUCCESS: Run was successfully cancelled!")
        elif result["status"] == "completed":
            print("Run completed before cancellation")
        else:
            print(f"Run ended with status: {result['status']}")
    else:
        print("No result obtained - check if cancellation happened during streaming")

    print("\nExample completed!")


if __name__ == "__main__":
    # Run the main example
    main()

POST /agents/{agent_id}/runs/{run_id}/cancel

curl --location 'http://localhost:7777/agents/story-writer-agent/runs/123/cancel' \
  --request POST