The handshake is the easy part. Agent payments still haven't named the custody split.

Short summary

The x402 payment protocol is converging as a standard for AI agent commerce, backed by major players like Coinbase, Stripe, and Visa. However, while the payment handshake is standardizing, the assurance semantics—specifically the custody split between execution evidence and independent verification—are not yet defined. The author argues for a conformance layer that binds security verdicts to reproducible evidence, enabling independent verifiers to confirm results rather than trust attestations.

• •x402 protocol is standardizing agent payment handshakes but lacks normative adversarial security suites
• •The key gap is separation of duties: detection evidence is not assurance evidence
• •A conformance layer should bind each security verdict to reproducible evidence for independent verification

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