A2a Setup

A2A Project Setup

Before writing code

Fetch live docs:

1. Fetch https://a2a-protocol.org/latest/specification/ for the latest protocol overview
2. Web-search site:github.com a2aproject a2a-python README or a2aproject a2a-js README for the target SDK's current installation and quickstart
3. Web-search site:github.com a2aproject a2a-samples for official sample project structures
4. Fetch the SDK's PyPI/npm page for the latest version number

Conceptual Architecture

What Setup Involves

A2A project setup creates the foundation for a multi-agent system:

1. Install the A2A SDK for your language (Python, JS/TS, Go, Java, .NET)
2. Create directory structure — agent server, client, Agent Card, configuration
3. Define the Agent Card — the discovery document describing your agent
4. Create a minimal server — HTTP endpoint that handles JSON-RPC 2.0 A2A methods
5. Create a minimal client — code to discover and call another A2A agent

Python Project Structure

my-a2a-agent/
├── agent_card.json          # Agent Card (also served at /.well-known/agent-card.json)
├── server.py                # A2A server entry point
├── client.py                # A2A client for testing
├── agent/
│   ├── __init__.py
│   └── handler.py           # Task processing logic
├── pyproject.toml           # or requirements.txt
└── tests/
    └── test_agent.py

JS/TS Project Structure

my-a2a-agent/
├── agent-card.json
├── src/
│   ├── server.ts            # A2A server entry point
│   ├── client.ts            # A2A client for testing
│   └── handler.ts           # Task processing logic
├── package.json
├── tsconfig.json
└── tests/
    └── agent.test.ts

Agent Card Skeleton

Every A2A agent needs an Agent Card. Minimal structure:

{
  "name": "My Agent",
  "description": "What this agent does",
  "url": "http://localhost:8000",
  "version": "1.0.0",
  "protocolVersion": "0.2.1",
  "capabilities": {
    "streaming": false,
    "pushNotifications": false,
    "stateTransitionHistory": false
  },
  "skills": [
    {
      "id": "skill-1",
      "name": "Skill Name",
      "description": "What this skill does",
      "tags": ["tag1", "tag2"],
      "examples": ["Example input"]
    }
  ],
  "defaultInputModes": ["text/plain"],
  "defaultOutputModes": ["text/plain"]
}

Key Setup Decisions

• Language/SDK — Python (a2a-sdk), JS/TS (@a2a-js/sdk), Go, Java, .NET
• HTTP framework — The SDK may provide a built-in server or integrate with frameworks (FastAPI, Express, etc.)
• Capabilities — Decide upfront: streaming? push notifications? state history?
• Authentication — None for local dev; API key or OAuth2 for production
• Agent Card hosting — Serve at /.well-known/agent-card.json or via a registry

Best Practices

• Start with a minimal Agent Card and expand as you add skills
• Use the SDK's built-in server utilities rather than building raw JSON-RPC handling
• Keep the Agent Card in a separate file, loaded at server startup
• Add proper logging from the start — A2A debugging requires visibility into message flow
• Set up a test client alongside the server for rapid development

Fetch the SDK README for exact installation commands, class names, and quickstart code before scaffolding.