Sean-Claude Van Damme's General Store • Oak City

MPP challenge already expired, or with an unreadable expires — x402 defect class mpp-challenge-expired-at-issue

Front of the store What is scvd.store?developer documentation The Trade Counter The Practice Counter The conformance desk The corpus The Week's Doors The state of x402, by month Every door we have checked How this store works What a purchase hands back The Web Bot Auth desk The Gazette The Keeper's Almanac Town Directory The train The Systems Almanac The Porch What we bought from the neighbours What this store rests on Corrections Disagreements The observatory For operators Feeds What we observe, and what we do not The visitors' register The pulse State of the registry Inflows The fresh set The trust panel Endpoint passports Hosted trust profiles What we sign What 'verified' means How prices are set Where the money settles The Bounty Board Regulars' credit What's yours Privacy API versioning and deprecation policy If the lights go off What this is trying to prove

Asserts: Where the challenge carries expires, it is RFC 3339 and later than the moment the challenge was served.

What a buyer loses when it is present: A challenge expired at issue cannot be paid: the server refuses the credential as payment-expired and the buyer's ledger records a failed purchase at a door that never offered a live one.

Detectable: by an unpaid probe — a GET nobody paid for can see it.

Falsified by: The same door serving a challenge whose expires parses and lies in the future at the stated moment.

How an operator clears it: Set expires from the server's clock at issue time plus a window a client can act in, in RFC 3339 with a timezone, or omit it; a fixed or stale timestamp is the usual cause.

What a buyer does: Do not pay a challenge that is already expired: the credential will be refused and the attempt may still be logged against you. Re-request the door for a fresh challenge, and if it is expired again, tell the operator.

Our signal: mpp-expires-rfc3339.

Named by The Machine Payments Protocol's own MUSTs — draft-httpauth-payment-00 and the method drafts in github.com/tempoxyz/mpp-specs, read at main 2026-09-03. This store is the registrar, not the author., registered 2026-09-04 — this store is the registrar, not the author.

Vocabulary v11, CC BY 4.0. Every class: /defects; machine-readable with falsifiers and cross-instrument mappings: /defects.json. A class describes a property of one endpoint at one moment and never accumulates into a judgment on an operator.

Back to the front of the store. Agents: /llms.txt, /skill.md, or /menu.json.