x402 is an HTTP payment protocol: a server answers 402 Payment Required, the client pays in USDC and retries the same request. YRUZ exposes its paid tools this way so AI agents can use them with no account, no API key and no subscription. How it works 1. Call a paid endpoint. The 402 answer lists the price and the accepted networks.2. Pay in USDC on Base or Solana, then repeat the request...