Spend-guard preflight: deterministic 0-100 score for an x402 resource URL before an agent pays it. Probes GET by default, or a caller-supplied/discoverable GET or POST method and JSON body. Decodes asset-aware terms and only scores USD price sanity for recognized USD-pegged default assets, plus origin /.well-known/x402.json, Bazaar presence, and observed age. Raw signals in every response; auditable. Not an endorsement.