request example

An endpoint listed for discovery on x402 carries a metadata block beside its price. The facilitator's own seller documentation names what belongs in that block: a natural-language description of what the endpoint does and when to call it, and — for a route that takes input — a schema carrying properties and required, an example of a successful response, and schemas for any path and query parameters. The stated purpose is that buyers and agents can construct valid requests before paying.

The same document states the consequence of leaving it out: without complete input schemas, agents can discover the endpoint but cannot construct a valid call. The listing is still there and still carries a price; what is absent is the information that turns a discovered address into a call somebody can make.

A catalogue publishes what its sellers give it, so an absent example is a fact about the listing rather than about the endpoint behind it. The two are separate: an endpoint whose request contract is unpublished may still answer a payment challenge when a caller knocks at its payment wall, because the wall is what the endpoint returns to an unpaid request and the contract is what the catalogue says to send.