A2A

Expose agents via Google’s Agent-to-Agent protocol.

The A2A interface exposes any Agno agent, team, or workflow via Google’s A2A protocol, enabling standardized inter-agent communication.

Quick Start

a2a_agent.py

from agno.agent import Agent
from agno.models.openai import OpenAIResponses
from agno.os.app import AgentOS

agent = Agent(name="Assistant", model=OpenAIResponses(id="gpt-5.4"))

agent_os = AgentOS(
    agents=[agent],
    a2a_interface=True,  # expose all agents via A2A
)
app = agent_os.get_app()

uv pip install 'agno[a2a]'
python -m agno.os.serve a2a_agent:app --port 9001

How It Works

Concept	Behavior
Discovery	/.well-known/agent-card.json describes agent capabilities
Messaging	message:stream and message:send endpoints
Multi-agent	Each agent/team/workflow gets its own endpoint namespace
Clients	Works with any A2A-compatible client

Setup

No external configuration required. Set a2a_interface=True on AgentOS.

Endpoints:

• Discovery: /a2a/agents/{id}/.well-known/agent-card.json
• Stream: /a2a/agents/{id}/v1/message:stream
• Send: /a2a/agents/{id}/v1/message:send

Next Steps

Full Guide

Agent cards, messaging, and client integration.

A2A Client

Connect to other A2A agents.

Examples

Basic agent, tools, and team examples.

A2A Protocol

Official protocol specification.