Quick Start Guide¶

Get up and running with the Agent2Agent (A2A) protocol in under 10 minutes.

What You'll Build¶

By the end of this quick start, you'll have: - ✅ A running A2A agent registry - ✅ A cryptocurrency price agent - ✅ A client that discovers and connects to the agent - ✅ Understanding of basic A2A concepts

Prerequisites¶

# Python 3.10 or higher
python3 --version

# pip package manager
pip --version

5-Minute Setup¶

Step 1: Clone the Repository¶

git clone https://github.com/robertfischer3/fischer3_a2a_introduction.git
cd fischer3_a2a_introduction

Step 2: Install Dependencies¶

# Create virtual environment (recommended)
python3 -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

# Install core dependencies
pip install httpx asyncio

Step 3: Start the Registry¶

The registry is the central directory where agents register themselves.

cd examples/a2a_crypto_simple_registry_example_1/registry
python registry_server.py

You should see:

🚀 Starting Agent Registry Server...
✅ Registry is ready
INFO:     Uvicorn running on http://0.0.0.0:8000

Keep this terminal running.

Step 4: Start the Agent¶

In a new terminal, start the cryptocurrency price agent:

cd examples/a2a_crypto_simple_registry_example_1/server
python crypto_agent_server.py

You should see:

✅ Registered with A2A Registry
🚀 Crypto Agent Server started on 127.0.0.1:8888
💰 Supported currencies: BTC, ETH, XRP
💓 Heartbeat sent to registry

Keep this terminal running.

Step 5: Run the Client¶

In a third terminal, run the client to interact with the agent:

cd examples/a2a_crypto_simple_registry_example_1/client
python a2a_client.py

You should see:

🔍 Discovering agents with 'get_price' capability...
✅ Found 1 agent(s)
📡 Selected: CryptoPriceAgent
🔗 Connecting to localhost:8888...
✅ Connected successfully

💱 A2A Crypto Price Client
──────────────────────────────────────────
Commands:
  price <currency>  - Get current price
  list             - List supported currencies
  help             - Show this help
  quit             - Exit

crypto> price BTC

Try It Out¶

Now that everything is running, try these commands:

# Get Bitcoin price
price BTC

# Get Ethereum price  
price ETH

# List all supported currencies
list

# View agent information
info

What Just Happened?¶

1. Registry Started: Central directory for agent discovery
2. Agent Registered: Crypto agent announced its capabilities (price_query)
3. Client Discovered: Client found the agent via capability search
4. Connection Established: Client connected directly to the agent
5. Messages Exchanged: Using A2A protocol for communication

Architecture Overview¶

┌──────────┐         ┌──────────┐         ┌──────────┐
│  Client  │────────>│ Registry │<────────│  Agent   │
└──────────┘         └──────────┘         └──────────┘
     │                    ^                     │
     │                    │                     │
     │                    │                     │
     └────────────────────┴─────────────────────┘

Step 1: Agent registers with Registry
Step 2: Client discovers agent via Registry
Step 3: Client connects directly to Agent
Step 4: Client and Agent communicate via A2A protocol

View the Registry Dashboard¶

Open your browser to see registered agents: - Registry Info: http://localhost:8000/ - API Docs: http://localhost:8000/docs - List Agents: http://localhost:8000/agents

Common Commands¶

List Available Agents¶

python a2a_client.py --list

Test Registry Directly¶

# Check registry health
curl http://localhost:8000/health

# List all agents
curl http://localhost:8000/agents

# Discover by capability
curl "http://localhost:8000/agents/discover?capability=get_price"

Troubleshooting¶

"Could not connect to registry"¶

Solution: Start the registry first:

cd registry && python registry_server.py

"No agents found"¶

Solution: Start the agent server:

cd server && python crypto_agent_server.py

"ImportError: No module named 'httpx'"¶

Solution: Install dependencies:

pip install httpx

"Port already in use"¶

Solution: Either stop the existing process or change the port:

# Find process using port 8000
lsof -i :8000  # macOS/Linux
netstat -ano | findstr :8000  # Windows

# Kill the process or change port in code

Next Steps¶

Now that you have the basics working:

1. Installation Guide - Set up a production environment
2. First Agent Tutorial - Build your own agent from scratch
3. A2A Overview - Understand the protocol deeply
4. Security Best Practices - Learn secure patterns

What You've Learned¶

✅ How to start an A2A registry
✅ How agents register their capabilities
✅ How clients discover agents dynamically
✅ Basic A2A message protocol
✅ Service discovery patterns

Experiment Further¶

Try these to learn more:

1. Start multiple agents on different ports
2. Stop one agent and watch the registry mark it unhealthy
3. Modify the agent to add new capabilities
4. Create a new agent for a different service (weather, news, etc.)

Getting Help¶

• 📖 Documentation: Browse the complete documentation
• 💬 Examples: Explore the example projects
• 🔒 Security: Read the security guides

🎉 Congratulations! You've successfully set up your first A2A multi-agent system.

Ready to build your own agent? Continue to the First Agent Tutorial.