Support 402utils — or use it as a parametric x402 payment-test endpoint: you set the price with ?amount= (USD, clamped to $0.001–$0.05) and the 402 demands exactly that, so you can assert a client pays the precise amount and the on-chain USDC tx matches. After payment returns {thanks, amount, message}. The amount is a pure function of ?amount, identical on the unpaid probe and the paid retry.