Checks x402 endpoints before an AI agent pays them: a $0.001 pre-payment check (go / caution / no_go, payout address screened against OFAC), a $0.01 full diagnosis with a fix hint per check, the fix as code, and a $0.25 paid delivery check that buys the endpoint once. Pay in USDC on Base, Solana or Algorand, or RLUSD on the XRP Ledger.