PayStabl Agent Demo - A2A Protocol

This project demos the paystabl's paywalled payment handling for other agent on the A2A protocol using x402 payment required. This system allows agents to automatically handle paywalled content by facilitating secure payments through the PayStabl agent.

Overview

This application contains three main agents:

• Host Agent: The primary orchestrator that facilitates communication between agents
• Carfax Agent: Fetches vehicle data using VIN numbers from paywalled Carfax content Demonstrates X402 payment by fetching vehicle data using VIN numbers from paywalled Carfax content
• PayStabl Agent: Handles the X402 payment protocol when content is behind a paywall (HTTP 402 status)

How It Works

1. The Carfax Agent attempts to fetch vehicle information using a VIN number
2. When encountering a 402 paywall status, the agent automatically calls the PayStabl Agent
3. The PayStabl Agent processes the payment and retrieves the content
4. The Carfax Agent then extracts vehicle details (VIN, make, model, year, mileage) from the retrieved content
5. The Host Agent orchestrates the entire process and provides the final results

Setup and Deployment

Prerequisites

Before running the application locally, ensure you have the following installed:

1. Python 3.13: Python 3.13 is required to run a2a-sdk
2. uv: The Python package management tool used in this project. Follow the installation guide: https://docs.astral.sh/uv/getting-started/installation/

 ```curl -LsSf https://astral.sh/uv/install.sh | sh ``` 

5. Environment Configuration

Create a .env file in the root of the a2a directory with the following variables:

GOOGLE_API_KEY="your_google_api_key_here"
AGENT_TOKEN="your_agent_token_here"
PAYSTABL_CARD_URL="http://localhost:10002"

Run the Agents

You will need to run each agent in a separate terminal window. The first time you run these commands, uv will create a virtual environment and install all necessary dependencies before starting the agent.

Terminal 1: Run PayStabl Agent

cd paystabl_agent
uv venv
source .venv/bin/activate
uv run --active .

Terminal 2: Run Carfax Agent

cd carfax_agent 
uv venv
source .venv/bin/activate
uv run --active .

Terminal 3: Run Host Agent

cd host_agent_adk
uv venv
source .venv/bin/activate
uv run --active adk web      

A

Interact with the System

Once all agents are running, you can interact with the Host Agent to demonstrate the X402 payment protocol:

1. The Host Agent will be available at the endpoint shown in the terminal output
2. Send a request to fetch vehicle information using a VIN number
3. Watch as the system automatically handles the paywall through the PayStabl Agent
4. Receive the extracted vehicle information in JSON format

Project Structure

a2a_friend_scheduling/
├── host_agent_adk/          # Host Agent - orchestrates conversations
├── carfax_agent/       # Carfax Agent - fetches vehicle data
├── paystable_agent_adk/        # PayStabl Agent - handles X402 payments
└── scripts/                 # Documentation and scripts

Key Features

• Automatic Paywall Detection: Agents automatically detect HTTP 402 status codes
• Seamless Payment Processing: PayStabl Agent handles payment without user intervention
• Content Extraction: Intelligent parsing of vehicle information from retrieved content
• Agent Orchestration: Host Agent manages the entire workflow
• Secure Token Management: Environment-based configuration for sensitive data

References

• A2A Python SDK
• A2A Purchasing Concierge Codelab
• X402 Payment Protocol Documentation