Halt `Runner` on specific tool call

[illia-botscrew]

Question

Is there any way to stop the execution of the Runner based on the tool result or when the specific tool is called?

Why do I need this?

My system has a requirement that the AI answer generation should be stopped when my X tool is called. Once my X tool is called, I should be able to stop the agents and yield a text chunk with SKIP_AI_ANSWER text.

The tool I need to "track" and halt execution is called by agent-as-a-tool.

I've tried to do this by throwing an exception in the Agent hook like this:

class SkipAiToolResult(UserError):
    """Exception to indicate that the AI tool result should be skipped."""
    pass

class MyHooks(AgentHooks):
  async def on_tool_end(self, context: RunContextWrapper, agent: Agent, tool: Tool, result: str) -> None:
    if tool.name == 'X':
      raise SkipAiToolResult("Skipping answer")

and trying to catch it like this:

  try:
    result = await Runner.run(
      starting_agent=orchestrator_agent,
      input=chat_messages_to_sdk_items(messages),
      context=AgentContext(),
    )
  except SkipAiToolResult as e:
    yield 'data: SKIP_AI_ANSWER'

The problem is that this catch case doesn't seem to work. Runner still generates an answer, ignoring the exception thrown in MyHooks.

Do you have any other ideas on how I can completely halt the execution of the Runner and do my custom logic in case it happens?

Thanks ahead!

[seratch]

Thanks for asking the question. tool_use_behavior.stop_at_tool_names may be useful for your use case:

• openai-agents-python/tests/test_tool_use_behavior.py

  Line 166 in 1f2dc81

  tool_use_behavior={"stop_at_tool_names": ["tool1"]},

• https://openai.github.io/openai-agents-python/ref/agent/#agents.agent.StopAtTools

[illia-botscrew]

Thanks for this! Haven't seen this option.

I'm a bit closer to the solution with this option, but it's still not it :(

It stopped executing my agent-as-a-tool, but my router agent, which called agent-as-a-tool, still produced an answer. So, will need to keep exploring this.

Would you happen to have anything in your release plans that will fit my problem description?

[seratch]

Thanks for clarifying. As far as I know, we don't have immediate plans to add some built-in feature to support your use case. That being said, we're open to any viable and relevant ideas on the SDK side if there is any.

[github-actions]

This issue is stale because it has been open for 7 days with no activity.