x402fix check: deep x402 endpoint audit

Overview

x402 endpoint doctor for sellers: give it the URL of a paid route and it probes it without paying (GET, HEAD, empty POST, POST {}, CORS preflight), then grades it A to F with a numbered list of paste-ready fixes. Checks the v2 PAYMENT-REQUIRED header and v1 body, CAIP-2 networks, the USDC asset and EIP-712 domain, Solana feePayer, atomic amounts, payTo, discovery metadata and multichain drift. Check ($0.02): lite plus validation of the payment terms, /openapi.json vs /.well-known/x402 consistency, payee checks, and a generated, self-validated discovery block with multichain accepts and a code snippet. Limits: it reads only what an unpaid client sees, so it can't confirm settlement end to end; fixes are suggestions, and a passing grade does not guarantee listing or settlement. USDC on Base, Polygon, Arbitrum One or Solana via x402, or prepaid YourAITools credit keys. Built by YourAITools (youraitools.co).

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