The existing handoff target user is not one of the participants

[easontsai]

https://microsoft.github.io/autogen/stable/user-guide/agentchat-user-guide/tutorial/state.html
https://microsoft.github.io/autogen/stable/user-guide/agentchat-user-guide/tutorial/human-in-the-loop.html

I followed the tutorials provided above to try using Human-in-the-loop and loading the team state in Swarm, but I encountered the following error.

python The existing handoff target user is not one of the participants ['travel_agent', 'flights_refunder']. If you are resuming Swarm with a new task make sure to include in your task a HandoffMessage with a valid participant as the target. For example, if you are resuming from a HandoffTermination, make sure the new task is a HandoffMessage with a valid participant as the target.

Here is the team state

{
    "type": "TeamState",
    "version": "1.0.0",
    "agent_states": {
      "group_chat_manager/f28c7a8c-2562-4287-8c26-1ab458841f6b": {
        "type": "SwarmManagerState",
        "version": "1.0.0",
        "message_thread": [
          {
            "source": "user",
            "models_usage": null,
            "content": "I need to refund my flight.",
            "type": "TextMessage"
          },
          {
            "source": "travel_agent",
            "models_usage": {
              "prompt_tokens": 119,
              "completion_tokens": 14
            },
            "content": [
              {
                "id": "call_rKkSyzWvq4SbbaW93nh1czeK",
                "arguments": "{}",
                "name": "transfer_to_flights_refunder"
              }
            ],
            "type": "ToolCallRequestEvent"
          },
          {
            "source": "travel_agent",
            "models_usage": null,
            "content": [
              {
                "content": "Transferred to flights_refunder, adopting the role of flights_refunder immediately.",
                "call_id": "call_rKkSyzWvq4SbbaW93nh1czeK",
                "is_error": false
              }
            ],
            "type": "ToolCallExecutionEvent"
          },
          {
            "source": "travel_agent",
            "models_usage": null,
            "target": "flights_refunder",
            "content": "Transferred to flights_refunder, adopting the role of flights_refunder immediately.",
            "context": [],
            "type": "HandoffMessage"
          },
          {
            "source": "flights_refunder",
            "models_usage": {
              "prompt_tokens": 191,
              "completion_tokens": 23
            },
            "content": "I can help you with that. Please provide me with your flight reference number so I can process the refund.",
            "type": "TextMessage"
          },
          {
            "source": "flights_refunder",
            "models_usage": {
              "prompt_tokens": 222,
              "completion_tokens": 11
            },
            "content": [
              {
                "id": "call_wWQ2y3l2dBtqurirWzxW4czo",
                "arguments": "{}",
                "name": "transfer_to_user"
              }
            ],
            "type": "ToolCallRequestEvent"
          },
          {
            "source": "flights_refunder",
            "models_usage": null,
            "content": [
              {
                "content": "Transferred to user, adopting the role of user immediately.",
                "call_id": "call_wWQ2y3l2dBtqurirWzxW4czo",
                "is_error": false
              }
            ],
            "type": "ToolCallExecutionEvent"
          },
          {
            "source": "flights_refunder",
            "models_usage": null,
            "target": "user",
            "content": "Transferred to user, adopting the role of user immediately.",
            "context": [],
            "type": "HandoffMessage"
          }
        ],
        "current_turn": 0,
        "current_speaker": "flights_refunder"
      },
      "collect_output_messages/f28c7a8c-2562-4287-8c26-1ab458841f6b": {},
      "travel_agent/f28c7a8c-2562-4287-8c26-1ab458841f6b": {
        "type": "ChatAgentContainerState",
        "version": "1.0.0",
        "agent_state": {
          "type": "AssistantAgentState",
          "version": "1.0.0",
          "llm_context": {
            "messages": [
              {
                "content": "I need to refund my flight.",
                "source": "user",
                "type": "UserMessage"
              },
              {
                "content": [
                  {
                    "id": "call_rKkSyzWvq4SbbaW93nh1czeK",
                    "arguments": "{}",
                    "name": "transfer_to_flights_refunder"
                  }
                ],
                "source": "travel_agent",
                "type": "AssistantMessage"
              },
              {
                "content": [
                  {
                    "content": "Transferred to flights_refunder, adopting the role of flights_refunder immediately.",
                    "call_id": "call_rKkSyzWvq4SbbaW93nh1czeK",
                    "is_error": false
                  }
                ],
                "type": "FunctionExecutionResultMessage"
              }
            ]
          }
        },
        "message_buffer": [
          {
            "source": "flights_refunder",
            "models_usage": {
              "prompt_tokens": 191,
              "completion_tokens": 23
            },
            "content": "I can help you with that. Please provide me with your flight reference number so I can process the refund.",
            "type": "TextMessage"
          },
          {
            "source": "flights_refunder",
            "models_usage": null,
            "target": "user",
            "content": "Transferred to user, adopting the role of user immediately.",
            "context": [],
            "type": "HandoffMessage"
          }
        ]
      },
      "flights_refunder/f28c7a8c-2562-4287-8c26-1ab458841f6b": {
        "type": "ChatAgentContainerState",
        "version": "1.0.0",
        "agent_state": {
          "type": "AssistantAgentState",
          "version": "1.0.0",
          "llm_context": {
            "messages": [
              {
                "content": "I need to refund my flight.",
                "source": "user",
                "type": "UserMessage"
              },
              {
                "content": "Transferred to flights_refunder, adopting the role of flights_refunder immediately.",
                "source": "travel_agent",
                "type": "UserMessage"
              },
              {
                "content": "I can help you with that. Please provide me with your flight reference number so I can process the refund.",
                "source": "flights_refunder",
                "type": "AssistantMessage"
              },
              {
                "content": [
                  {
                    "id": "call_wWQ2y3l2dBtqurirWzxW4czo",
                    "arguments": "{}",
                    "name": "transfer_to_user"
                  }
                ],
                "source": "flights_refunder",
                "type": "AssistantMessage"
              },
              {
                "content": [
                  {
                    "content": "Transferred to user, adopting the role of user immediately.",
                    "call_id": "call_wWQ2y3l2dBtqurirWzxW4czo",
                    "is_error": false
                  }
                ],
                "type": "FunctionExecutionResultMessage"
              }
            ]
          }
        },
        "message_buffer": []
      }
    },
    "team_id": "f28c7a8c-2562-4287-8c26-1ab458841f6b"
  }

travel_agent = AssistantAgent(
    "travel_agent",
    model_client=model_client,
    handoffs=["flights_refunder", "user"],
    system_message="""You are a travel agent.
    The flights_refunder is in charge of refunding flights.
    If you need information from the user, you must first send your message, then you can handoff to the user.
    Use TERMINATE when the travel planning is complete.""",
)

flights_refunder = AssistantAgent(
    "flights_refunder",
    model_client=model_client,
    handoffs=["travel_agent", "user"],
    tools=[refund_flight],
    system_message="""You are an agent specialized in refunding flights.
    You only need flight reference numbers to refund a flight.
    You have the ability to refund a flight using the refund_flight tool.
    If you need information from the user, you must first send your message, then you can handoff to the user.
    When the transaction is complete, handoff to the travel agent to finalize.""",
)

termination = HandoffTermination(target="user") | TextMentionTermination("TERMINATE")
team = Swarm([travel_agent, flights_refunder], termination_condition=termination)

async def run_team_stream() -> None:
    with open("team_state.json", "r") as f:
        team_state = json.load(f)
    await team.load_state(team_state)
    task_result = await Console(team.run_stream(task=task))
    team_state = await team.save_state()
    with open("team_state.json", "w") as f:
        json.dump(team_state, f)

[ekzhu]

As mentioned in the error message, you need to resume the team with a task that is a HandoffMessage. See: https://microsoft.github.io/autogen/stable/user-guide/agentchat-user-guide/swarm.html#workflow