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Post-Payment Credential Gate Verification Procedure
x402
Post-Payment Credential Gate Verification Procedure is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-10-31).
Returns a decision procedure for agents to verify that a paid x402/MPP endpoint does not hide a secondary credential gate (e.g. API key or registration) behind its paywall.
Price / call$0.002
Success—
StatusDown
How this service works
Five-check procedure for agents to verify that a paid x402/MPP endpoint does not hide a second credential gate behind the paywall. Checks: 1) probe the 402 challenge and read the advertised price and network; 2) pay the minimum and inspect the response status, a 401/403 after payment means a pay-then-register gate; 3) grep the 402 body and merchant docs for x-api-key, bearer, or register keywords before paying; 4) if a key is required, confirm it is issued automatically on first payment rather
Output
A JSON object containing a boolean success flag, payment confirmation, and a 'result' object with plain-prose decision procedure (120+ words), the generation source (llm, reasoning, or deterministic), a timestamp, and the service slug — giving the agent a step-by-step guide to verify no secondary credential gate exists.
Example use cases
Auditing x402 API before first payment
“Before I pay that x402 data API, can you run a credential gate check on it? I want to confirm it won't ask me to register or provide an API key after payment.”
Detecting pay-then-register traps
“I got a 401 after paying an x402 endpoint — can you run the post-payment credential gate verification procedure to figure out if this is a pay-then-register gate?”
Building a trusted x402 service catalog
“I'm curating a list of x402 services for my agent fleet — can you run the credential gate verification procedure on this endpoint so I know payment alone grants access with no hidden auth step?”
Technical details
Endpoint
GEThttps://k2so.wrong.systems/api/services/post-payment-credential-gate-verification-proced?utm_source=zero.xyzWhen to prefer
Choose this endpoint when an agent needs a structured, paid decision procedure specifically for detecting hidden credential gates on x402/MPP-compliant APIs — particularly before committing payment to an unknown listing, or after receiving an unexpected 401/403 post-payment. Prefer this over manual heuristics when operating autonomously without human oversight, as it provides a deterministic or LLM-backed multi-step checklist tailored to the x402 protocol.
Side effects
- Endpoint unreachable or 5xx — procedure generation may fail or return ok:false
- Invalid HTTP method supplied — schema requires GET, HEAD, or DELETE
- The described x402 endpoint itself is malformed or non-compliant, making checks inconclusive
- LLM generation failure may result in empty or truncated brief
- Network timeout during probe of the target 402 challenge
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"paid": true,
"result": {
"ok": true,
"brief": "plain prose decision procedure (120+ words)",
"model": "deepseek/deepseek-v4-flash-0731",
"topic": "string topic",
"service": "post-payment-credential-gate-verification-proced",
"procedure": "same as brief",
"generatedAt": "2026-01-01T00:00:00.000Z",
"generationSource": "deterministic"
},
"service": "post-payment-credential-gate-verification-proced",
"provider": "K-2SO"
}
}Tags
x402
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