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The A2AClient provides a Python interface for communicating with any A2A protocol compatible server. This includes:
  • Agno AgentOS instances with A2A interface enabled
  • Google ADK agents
  • Any other A2A-compatible agent server

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Quick Start

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Connecting to Agno AgentOS via A2A interface

import asyncio
from agno.client.a2a import A2AClient

async def main():
    # Connect to an Agno AgentOS A2A endpoint
    client = A2AClient("http://localhost:7003/a2a/agents/my-agent")

    # Send a message
    result = await client.send_message(message="Hello!")
    print(result.content)

asyncio.run(main())

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Connecting to Google ADK

Google ADK uses JSON-RPC mode: 
from agno.client.a2a import A2AClient

client = A2AClient("http://localhost:8001/", protocol="json-rpc")
result = await client.send_message(message="Hello!")

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Streaming Responses

Stream responses in real-time: 
from agno.client.a2a import A2AClient

client = A2AClient("http://localhost:7003/a2a/agents/my-agent")

async for event in client.stream_message(message="Tell me a story"):
    if event.is_content and event.content:
        print(event.content, end="", flush=True)

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Authentication

AgentOS instances running with authorization=True require a JWT on every A2A request. Pass it via headers: 
import os

from agno.client.a2a import A2AClient

client = A2AClient("https://my-agent-os.com/a2a/agents/my-agent")
headers = {"Authorization": f"Bearer {os.environ['AGENT_OS_JWT']}"}

result = await client.send_message(message="Hello!", headers=headers)

async for event in client.stream_message(message="Hello!", headers=headers):
    ...
send_message, stream_message, and get_agent_card all accept headers. The token needs the target’s run scope (agents:run, or per-resource agents:my-agent:run) for message:send and message:stream. See Scopes for the full mapping. The user_id parameter sets userId in the message metadata. AgentOS honors it for anonymous callers only. When the request carries a JWT, the run is attributed to the token’s principal and user_id is ignored.

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Developer Resources