Any tips on how to make the Agent more likely to delegate wihtout prompting?

[Allena101]

I have in my instructions that the sub-agent should delegate back when the task is done and very seldom does it do this.
Though if the user asks for it , then the Agent always does it.

I have had to come up with workaround that are either that I manually delegate through a callback (e.g. after tool use with transfer_to_agent) or I use the sub-agent as a tool so that the results are directly returned to the root agent.

To clarify , the major problems is when a sub-agent should delegate back to the root agent after its task is done. Have not really encountered the same problem with the root agent delegating to the sub-agents.

[takashikik]

I've been facing the same issue, and after trying various approaches, I found that creating the following Callback and adding it to the after_agent_callback of each child agent worked successfully for me.

def TransferToParentCallback(callback_context: CallbackContext):
    """
    A callback that always performs TransferToAgent to the parent Agent.
    """
    from google.genai import types
    current_agent = callback_context._invocation_context.agent
    if current_agent.parent_agent:
        return types.Content(
                    parts=[
                        types.Part(
                            function_call=types.FunctionCall(
                                name="transfer_to_agent",
                                args={"agent_name": current_agent.parent_agent.name}
                            )
                        )
                    ]
                )

As I proposed this in #2234 , I believe the ideal solution would be for an enforce_transfer_to_parent feature to be implemented.

[Allena101]

I've been facing the same issue, and after trying various approaches, I found that creating the following Callback and adding it to the after_agent_callback of each child agent worked successfully for me.

def TransferToParentCallback(callback_context: CallbackContext):
    """
    A callback that always performs TransferToAgent to the parent Agent.
    """
    from google.genai import types
    current_agent = callback_context._invocation_context.agent
    if current_agent.parent_agent:
        return types.Content(
                    parts=[
                        types.Part(
                            function_call=types.FunctionCall(
                                name="transfer_to_agent",
                                args={"agent_name": current_agent.parent_agent.name}
                            )
                        )
                    ]
                )

As I proposed this in #2234 , I believe the ideal solution would be for an enforce_transfer_to_parent feature to be implemented.

Thanks for the suggestion! I did create something similar myself but the callback was before tool i think . The issue here is that this would only work if you only want the agent to run once (before delegating back). But if the sub-agent is an assistant where multiple chat changes are very likely I don't think your callback would work (since then the sub-agent would delegate back way to early). And if the sub-agent is only needed to perform a task without user input then using the Agent as a tool accomplishes the same thing I think.

The best way I can think of now is to use an after_agent_callback like you suggested , but together with several flags e.g. agent_task_done = True . This can be difficult to get working well too since the agent still has to detect when the task is done in some way and set the flag (the flag would be set in the callback function but there need to be some kind of trigger).

[Bastianciito]

I'm facing the same issue. As far as I know, there's no way to do that — ADK doesn't support that kind of interaction either. It looks like every workflow follows a single path, and the only way to switch between agents is by starting a new chat, What worked for me was using agents as tools, which gives more control and allows the root agent to decide which agent should be used.

[takashikik]

I created a PR to solve this problem, #2253
If you'd like, please try it out to see if it solves your issue.