A2A Server

Exposes the agent as an inbound A2A server — agent card at /.well-known/agent-card.json and JSON-RPC on POST / (PascalCase methods such as SendMessage, SendStreamingMessage). Source: examples/agent_with_a2a_server/

What it demonstrates

WithA2ADefaultServer or WithA2AServer with host, port, bearer tokens
RunA2A(ctx) blocking until shutdown
Pair with A2A Config as a client

Run

From examples/:

go run ./agent_with_a2a_server

The process prints the base URL and agent card URL to stderr. Ctrl+C to stop. Defaults: localhost:9999 — override with A2A_SERVER_HOST, A2A_SERVER_PORT (see Configuration). Optional A2A_SERVER_BEARER_TOKENS — comma-separated secrets; JSON-RPC calls must send Authorization: Bearer <token>. Agent card GET stays unauthenticated.

Quick checks

curl -sS "http://localhost:9999/.well-known/agent-card.json" | head

Test as a client from this repo

Second terminal, examples/:

export A2A_URL=http://localhost:9999
go run ./agent_with_a2a_config "What tools do you have?"

Test with the `a2a` CLI

go install github.com/a2aproject/a2a-go/v2/cmd/a2a@latest

a2a discover http://localhost:9999
a2a send http://localhost:9999 "Hello, what can you do?"

With bearer tokens configured, see a2a help send for auth flags.

Learn more

A2A

Server and client feature docs

A2A Config

Outbound client example

Before You Begin

Basic Agents

Configuration

Tools & MCP

Streaming & AG-UI

Memory & RAG

Observability & Hooks

A2A

Multi-agent

Durable & Distributed

What it demonstrates

Run

Quick checks

Test as a client from this repo

Test with the `a2a` CLI

Learn more

A2A

A2A Config

​What it demonstrates

​Run

​Quick checks

​Test as a client from this repo

​Test with the a2a CLI

​Learn more

A2A

A2A Config

What it demonstrates

Run

Quick checks

Test as a client from this repo

Test with the `a2a` CLI

Learn more