Is Human-in-the-Loop Fully Supported in Agno When Outputting in AG-UI Format?

General
1

Hi everyone,
I’ve been building a multi-agent system using Agno + AG-UI, and I’ve run into a major issue that’s quite confusing to me:

I noticed that Agno’s AgentOS has a fully functional implementation of human-in-the-loop (HITL).
However, when Agno converts the output into AG-UI format, things seem to break. From the code, it appears that the AG-UI conversion layer is not fully implemented, and at this point I’m not sure how Agno expects HITL to work when using AG-UI.

To be more specific, I checked the related event-conversion code inside Agno, but it seems that it only outputs tool-call events, without reflecting the essential HITL sequence of:

pause → wait for user → resume execution

\# emit frontend tool calls, i.e. external_execution=True

if isinstance(chunk, RunPausedEvent) and chunk.tools is not None:

    \# First, emit an assistant message for external tool calls

    assistant_message_id = str(uuid.uuid4())

    assistant_start_event = TextMessageStartEvent(

        type=EventType.TEXT_MESSAGE_START,

        message_id=assistant_message_id,

        role="assistant",

    )

    events_to_emit.append(assistant_start_event)



    \# Add any text content if present for the assistant message

    if chunk.content:

        content_event = TextMessageContentEvent(

            type=EventType.TEXT_MESSAGE_CONTENT,

            message_id=assistant_message_id,

            delta=str(chunk.content),

        )

        events_to_emit.append(content_event)



    \# End the assistant message

    assistant_end_event = TextMessageEndEvent(

        type=EventType.TEXT_MESSAGE_END,

        message_id=assistant_message_id,

    )

    events_to_emit.append(assistant_end_event)



    \# Now emit the tool call events with the assistant message as parent

    for tool in chunk.tools:

        if tool.tool_call_id is None or tool.tool_name is None:

            continue



        start_event = ToolCallStartEvent(

            type=EventType.TOOL_CALL_START,

            tool_call_id=tool.tool_call_id,

            tool_call_name=tool.tool_name,

            parent_message_id=assistant_message_id,  # Use the assistant message as parent

        )

        events_to_emit.append(start_event)



        args_event = ToolCallArgsEvent(

            type=EventType.TOOL_CALL_ARGS,

            tool_call_id=tool.tool_call_id,

            delta=json.dumps(tool.tool_args),

        )

        events_to_emit.append(args_event)

        end_event = ToolCallEndEvent(

            type=EventType.TOOL_CALL_END,

            tool_call_id=tool.tool_call_id,

        )

        events_to_emit.append(end_event)
2

Hi @lhc, thanks for reaching out and supporting Agno. I’ve shared this with the team, we’re working through all requests one by one and will get back to you soon.If it’s urgent, please let us know. We appreciate your patience!

3

Hey @lhc - Sorry to hear that - HITL is not yet fully supported with AG-UI. Thanks for raising this and we’ve added this to our roadmap. Let me know if you’re interested in taking it up.