A2A Duplicate first part of text in the response from a2a agent

[nguoithichkhampha]

Steps to Reproduce:

1. Integrate a2a agent into adk by using class RemoteA2aAgent config with streaming mode
2. Use adk web to test
3. check the response

Expected Behavior:
No duplication in the response from a2a agent

Observed Behavior:
Duplicate first part of text in the respinse

Environment Details:

• ADK Library Version (pip show google-adk): 2.2.0
• Python Version (python -V): 3.12

How often has this issue occurred?:

• Always (100%)

[sanketpatil06]

Hi @nguoithichkhampha , We attempted to replicate the streaming duplication issue using a local client-server A2A setup, but the stream returned correctly without duplication on our end. To help us narrow down the cause and reproduce this behavior, could you please provide a minimal, runnable code snippet or configuration showing how both your remote server and client-side RemoteA2aAgent are set up?
workaround worth trying :
The legacy execution pathway sometimes suffers from stream-chunk synchronization races. You can bypass the legacy pipeline and activate the newer execution flow by setting use_legacy=False:

from google.adk.agents.remote_a2a_agent import AGENT_CARD_WELL_KNOWN_PATH, RemoteA2aAgent

remote_agent = RemoteA2aAgent(
    name="my_agent",
    agent_card=f"http://<host>:<port>/{AGENT_CARD_WELL_KNOWN_PATH}",
    use_legacy=False,
)

[nguoithichkhampha]

@sanketpatil06 , I think in your example code missing config to use streaming mode

a2a_client_factory = A2AClientFactory(
        config=A2AClientConfig(httpx_client=httpx_client, streaming=True),
    )