A2A (Agent2Agent) Tutorial (1): Building Google A2A Demo

What is the A2A (Agent2Agent) Protocol?

The A2A (Agent2Agent) protocol is Google's latest communication framework for AI agents, defining how agents can communicate efficiently and in a standardized way. This revolutionary A2A protocol marks a significant milestone in the evolution of AI agent communication systems.

A2A Protocol Workflow

Quick Start: Setting Up A2A Development Environment

1. Environment

First, clone the official Google A2A repository:

git clone https://github.com/google/A2A.git

2. Configuring A2A Remote Agents

The A2A framework provides two sample agents:

• Coder Agent (implemented in JavaScript): Specialized for code generation
• Currency Agent (implemented in Python): Designed for currency conversion

Running the A2A Coder Agent Example

cd samples/js
export GEMINI_API_KEY=<your_api_key>
npm run agents:coder
npm run a2a:cli

Upon successful execution, you'll see the following A2A interface:

3. Configuring the A2A Host Agent

The A2A Host Agent serves as the user interaction entry point, responsible for:

• Receiving user requests within the A2A ecosystem
• Selecting appropriate A2A Remote Agents
• Coordinating collaboration between multiple A2A agents

Launching the A2A Host Agent

cd demo/ui
echo "GOOGLE_API_KEY=your_api_key_here" > .env
uv run main.py

Access the A2A Host Agent interface at http://localhost:12000:

4. Connecting A2A Remote Agents

To add A2A Remote Agent addresses in the Host Agent:

1. Open the configuration interface
2. Add the Remote Agent address (e.g., for the Coder Agent: localhost:41241)
3. Verify the connection status

Hands-on: Experiencing the Complete A2A Workflow

Implementing a Bubble Sort Algorithm

1. Send a request to the A2A Host Agent: Write a bubble sort

2. Observe the A2A agent interaction process:

The A2A communication flow can be observed as follows:

1. User Request Phase in the A2A Framework

   • User describes requirements to the A2A Host Agent
   • A2A Host Agent analyzes request characteristics

2. A2A Agent Selection Phase

   • A2A Host Agent evaluates requirements
   • Selects the most suitable A2A Remote Agent

3. Task Execution Phase in A2A

   • A2A Remote Agent receives the task
   • Executes specific operations within the A2A framework
   • Returns execution results

4. Results Processing Phase in A2A

   • A2A Host Agent processes results returned by Remote Agent
   • Optimizes and delivers the final response to the user

Conclusion

This A2A tutorial has covered:

• Core concepts of the A2A protocol for agent communication
• Setting up a complete A2A development environment
• Experiencing a practical A2A agent collaboration workflow

As Google's cutting-edge A2A protocol for agent communication, A2A provides a standardized framework for agent collaboration. We can expect the A2A protocol to deliver significant value in future LLM application scenarios and transform how AI agents interact with each other.