Echo Agent

What you'll learn

• Agent card discovery via /.well-known/agent-card.json
• SendMessage and GetTask operations
• Basic A2A::Server and A2A::Agent setup with Rack

Step 1: Start the agent

git clone https://github.com/general-intelligence-systems/a2a.git
cd a2a/examples/basic
docker compose up -d --build

Expected output:

[+] Building 12.3s (9/9) FINISHED
[+] Running 1/1
 ✔ Container basic-agent-1  Started

Step 2: Check the logs

docker compose logs

Expected output:

agent-1  |   0.0s     info: main [pid=1] [2025-05-01 12:00:00 +0000]
agent-1  |                | Echo Agent starting...
agent-1  |   0.0s     info: main [pid=1] [2025-05-01 12:00:00 +0000]
agent-1  |                | Agent card: Echo Agent
agent-1  |   0.01s     info: Falcon::Controller [pid=1] [2025-05-01 12:00:00 +0000]
agent-1  |                | Starting Falcon Host ...

Step 3: Fetch the agent card

curl http://localhost:9292/.well-known/agent-card.json

Expected output:

{
  "name": "Echo Agent",
  "description": "A simple echo agent that repeats your message.",
  "url": "http://localhost:9292",
  "version": "1.0.0"
}

Step 4: Send a message

curl -X POST http://localhost:9292/a2a \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"SendMessage","params":{}}'

Expected output:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {}
}

This is a bare-bones echo agent -- it returns an empty response object. See the full example for a complete implementation with all 11 operations.

Step 5: Cleanup

docker compose down

Files

View source on GitHub