[Question] Streaming vs Invocation

[carmine-sacco]

Can an agent offer a streaming interface and an invocation interface? If it is so, is there any way to understand the type of request on AgentExecutor?

Let me say that I'm trying to build an Agent which performs two type of operations:

1. Very long and complex operation which provides status updates every time that it completes an operation
2. Fast and simple operation like print the content of the file X.

I'd like to provide the first operation as streaming and the second one as a simple invocation. How can I do it using A2A which sends request to the same interface.

Should I create a different executor for each AgentInterface?

[rohityan]

Hi @carmine-sacco , No, you don't need to create different executors for each interface. You only need one. The A2A framework automatically handles streaming vs. non-streaming in the background. In your single executor, you just have to choose how to reply:

1. For fast operations: Have your agent send back a single Message object. The user will receive the answer instantly.
2. For long operations: Have your agent send back a Task object (which tells the system "I'm working on it"), andthen send Status Updates over the stream as it completes each step.

For the agent to know if the request is streaming, You can check if the incoming request hit a streaming endpoint by checking the request context metadata. By default, this isn't exposed in the executor, but you can easily pass it through by adding a simple check in a
custom context builder:

is_streaming = context.call_context.state.get("is_streaming", False)

If is_streaming is True , run the slow task with progress updates. If False , run the fast task and return a
single message immediately.

[carmine-sacco]

Hi @rohityan,

Thanks a lot for your response. Yesterday I found a similar solution during the investigation looking to the type of request made by the a2a-inspector. Briefly, I'm checking the field method inside ServerCallContext.state if the method is message/send I'm invoking the method invoke of the agent otherwise I'll invoke the streaming one.

I have just discover that the streaming method will be different according to the type of protocol:

Protocol	Version	Streaming Method	Notes
JSONRPC	0.3	message/stream
JSONRPC	1.0	SendStreamingMessage
HTTP+JSON	all	v1/message:stream
GRPC	all	SendStreamingMessage	To be confirmed (I saw it from official documentation