agentEmitter.requiresInput(a2aMessage) does not trigger a TaskStatusUpdateEvent

[mescaja]

I have come across an issue when setting the A2A Agent task to TaskState.TASK_STATE_INPUT_REQUIRED

These are the steps to reproduce with latest 1.2.0.Final version

Step 1: A2A client agent sends a a2aMessage1 with null contextId and null taskId
Step 2: A2A Server agent

agentEmitter.submit();
agentEmitter.startWork();
agentEmitter.updateStatus(TaskState.TASK_STATE_WORKING, null);

//Do some stuff, call APIs and MCPs endpoint to run tools feeding back the result
.....

//Send a message
agentEmitter.sendMessage(a2aMessage2);

//Do some more stuff, workout logic to see if the task status needs changing
....

// Change task status
agentEmitter.requiresInput(a2aMessage3);

//Do some more stuff, send an artifact and workout logic to see if the task needs to be completed
....
agentEmitter.addArtifact(List.of(textPart));
agentEmitter.complete(a2aMessage4);

Step 3: A2A Client agent

• Received MessageEvent and a2aMessage2 successfully returned using messageEvent.getMessage()
• taskStatusUpdateEvent was not received for the task status update to TaskState.TASK_STATE_INPUT_REQUIRED hence a2aMessage3 got lost.
• Received TaskArtifactUpdateEvent along with the TextPart using taskArtifactUpdateEvent.artifact().parts()
• Received taskStatusUpdateEvent and a2aMessage4 successfully returned using taskStatusUpdateEvent.status().message()

I tried setting a task status update using the code below. The outcome was the same

agentEmitter.updateStatus(TaskState.TASK_STATE_INPUT_REQUIRED, a2aMessage3);

i need to be able to send a few messages and for the A2A client to be able to stream the corresponing MessageEvent and also to be able to set the task status to TASK_STATE_INPUT_REQUIRED and stream the associated message with it afterwards.

For some reason setting a task to INPUT_REQUIRED does not trigger the TaskStatusUpdateEvent on the client side.

I think the combination of agentEmitter.sendMessage follow by an agentEmitter.requiresInput is what causes this issue.

[mescaja]

by the way, i was also able to reproduce the issue on 1.1.0.Final so i don't think this issue has anything to do with the latest version. I believe if it's a bug, it's been there in the product for while.