In a Swarm team the tool call output of an agent is not transferred to the next agent.

[ekzhu]

Originally discovered via #5038

How to reproduce?

import asyncio
from datetime import datetime
from autogen_agentchat.agents import AssistantAgent
from autogen_agentchat.teams import Swarm
from autogen_agentchat.messages import HandoffMessage
from autogen_agentchat.ui import Console
from autogen_ext.models.openai import OpenAIChatCompletionClient
from autogen_agentchat.conditions import HandoffTermination, MaxMessageTermination


def execute_git_current_time():
    return datetime.now().strftime("%H:%M:%S")

def get_current_day():
    return datetime.now().strftime("%A")


async def main() -> None:
    model_client = OpenAIChatCompletionClient(model="gpt-4o")

    router = AssistantAgent(
        name="router",
        system_message="""You are a router agent that analyzes user questions and directs them to the appropriate agent.

        Your role is to:
        1. Analyze the user's input
        2. Determine if they're asking about:
            - handoff to time_agent for questions about time
            - handoff to day_agent for questions about date
        """,
        model_client=model_client,
        handoffs=["day_agent", "time_agent"],
    )

    time_agent = AssistantAgent(
        name="time_agent",
        system_message="""You are a time agent that provides the current time. Send the time information to the formatter agent.""",
        model_client=model_client,
        tools=[execute_git_current_time],
        handoffs=["formatter"],
    )

    day_agent = AssistantAgent(
        name="day_agent",
        system_message="""You are a day agent that provides the current day. Send the day information to the formatter agent.""",
        model_client=model_client,
        tools=[get_current_day],
        handoffs=["formatter"],
    )

    formatter = AssistantAgent(
        name="formatter",
        system_message="""You are a formatter agent that formats time and day information. Send the formatted information to the user.""",
        model_client=model_client,
        handoffs=["user"],
    )

    # Create a team with all agents
    handoff_termination = HandoffTermination(target="user")
    max_messages_termination = MaxMessageTermination(max_messages=100)
    termination = handoff_termination | max_messages_termination
    
    team = Swarm(
        participants=[router, time_agent, day_agent, formatter],
        termination_condition=termination,
    )

    await Console(team.run_stream(
       task=HandoffMessage(
            source="user",
            target="router",
            content="What time is it?",
       )
    ))

asyncio.run(main())

---------- user ----------
What time is it?
---------- router ----------
[FunctionCall(id='call_5KY9tHOOWodejGtz4nYYoL0R', arguments='{}', name='transfer_to_time_agent')]
---------- router ----------
[FunctionExecutionResult(content='Transferred to time_agent, adopting the role of time_agent immediately.', call_id='call_5KY9tHOOWodejGtz4nYYoL0R')]
---------- router ----------
Transferred to time_agent, adopting the role of time_agent immediately.
---------- time_agent ----------
[FunctionCall(id='call_NonawoVdSBG55rBC83cdBFiB', arguments='{}', name='execute_git_current_time'), FunctionCall(id='call_H77Mry5mJmoqCt6jkYjjAYX9', arguments='{}', name='transfer_to_formatter')]
---------- time_agent ----------
[FunctionExecutionResult(content='10:40:07', call_id='call_NonawoVdSBG55rBC83cdBFiB'), FunctionExecutionResult(content='Transferred to formatter, adopting the role of formatter immediately.', call_id='call_H77Mry5mJmoqCt6jkYjjAYX9')]
---------- time_agent ----------
Transferred to formatter, adopting the role of formatter immediately.
---------- formatter ----------
[FunctionCall(id='call_1zPjDwrcRMZggaJ84inYbjOg', arguments='{}', name='transfer_to_user')]
---------- formatter ----------
[FunctionExecutionResult(content='Transferred to user, adopting the role of user immediately.', call_id='call_1zPjDwrcRMZggaJ84inYbjOg')]
---------- formatter ----------
Transferred to user, adopting the role of user immediately.

You can see the tool call result of getting the current time is not transferred to the formatter in the handoff.

[ekzhu]

Note, this problem will still arise when parallel tool call is disabled, as the transfer message doesn't let agent reflect on the tool call.

[jochenvw]

+1

[ekzhu]

Note, this problem will still arise when parallel tool call is disabled, as the transfer message doesn't let agent reflect on the tool call.

Actually this is False, the tool result summary message will share the context. We just need to handle the case when tool calls happen in the same turn when handoff happens.