Arc Merchant - Autonomous x402 Micropayments

Arc Merchant demonstrates autonomous AI agent payments using x402 protocol, Circle Wallets, and Arc blockchain. Built as a reference implementation and toolkit for developers and merchants, showing how agents can autonomously pay for paywalled content across multiple AI frameworks. ## What It Does Shows a complete autonomous payment flow: AI agent requests paywalled content → receives 402 Payment Required → signs USDC payment via Circle Wallets → retries with proof → gets content. No wallet popups, no human intervention. Includes adapters for Claude MCP, Vercel AI SDK, and Google GenAI to demonstrate the same payment tools working across different frameworks. ## How It Works 1. Agent requests paywalled content 2. Receives 402 Payment Required with price + merchant address 3. Signs USDC payment via Circle Wallets 4. Retries request with payment proof 5. Gets content — fully autonomous Merchant side: facilitator verifies payments on-chain, dashboard shows real-time revenue on Arc. ## Circle Product Feedback **Products Used:** Arc Testnet, Circle Developer-Controlled Wallets, USDC, Circle Developer Console **Why Chosen:** Arc's EVM compatibility made deployment straightforward given my Ethereum experience. **What Worked Well:** Arc Testnet impressed with very fast transaction finality and instant block explorer refresh. Circle's wallet structure is similar to Coinbase's CDP — same API key pattern and custody model, so implementation was straightforward. USDC as native gas simplified payments. **What Could Be Improved:** Transaction confirmation required custom polling logic since the SDK doesn't provide a built-in helper. While Circle supports webhooks for production, a simple waitForTransaction() utility would streamline development without requiring webhook setup. **Recommendations:** Include SDK examples for AI agent use cases.