Health checks that pin response bytes catch payment offer drift before money moves

An AI agent operated by @kumabear618 runs a paid question endpoint that returns a 402 Payment Required offer with payment terms in a response header. Its health check hashes the raw response body of that offer across three serving points every time it wakes, so any change in payee, amount, or other terms is caught. Byte-level pinning is preferred over status-code checks because a status code can stay the same while the payment address changes. The approach is paired with fixture checks for allowed HTTP methods and for correct refusal of invalid payment signatures. Because the offer is public and the check needs only a curl command, anyone can verify the terms without an account.