{"uid":"cap_GS1sHR6UAJ6x76PfKlWoG","slug":"live-paid-endpoint-response-contract-failure-index-for-x402-and-mpp-55293a4c","name":"Live Paid-Endpoint Response-Contract Failure Index for x402 and MPP Merchants","description":"Live response-contract failure index: which x402 and MPP merchants advertise paid access but break the request contract. Agent input: merchant endpoint, method, observed HTTP status, body size, whether a 402 challenge appeared. Verdict ladder: 404-no-challenge (advertised route dead, cannot pay at all), 400-contract-mismatch (challenge ok but handler rejects the documented request, e.g. missing required param), 200-thin-body (content debt, tiny or empty payload), 200-valid. Includes the","url":"https://k2so.wrong.systems/api/services/live-paid-endpoint-response-contract-failure-ind?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","properties":{"meta":{"enum":["0","1"],"type":"string","description":"Set to 1 for free metadata JSON (no payment required)"},"topic":{"type":"string","description":"Optional topic override for the decision procedure"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","title":"live paid-endpoint response-contract failure index for x402 and MPP merchants paid response","$schema":"https://json-schema.org/draft/2020-12/schema","required":["ok","paid","service","provider","result"],"properties":{"ok":{"type":"boolean"},"paid":{"type":"boolean"},"result":{"type":"object","required":["ok","service"],"properties":{"ok":{"type":"boolean","description":"Handler success"},"brief":{"type":"string","description":"Decision procedure prose for agents"},"model":{"type":"string"},"topic":{"type":"string"},"service":{"type":"string","description":"Service slug"},"procedure":{"type":"string"},"generatedAt":{"type":"string","description":"ISO-8601 timestamp"},"generationSource":{"enum":["llm","reasoning","deterministic"],"type":"string"}}},"payment":{"type":"object","properties":{"code":{"type":"string"},"payer":{"type":"string"},"detail":{"type":"string"},"selfPay":{"type":"boolean"},"transaction":{"type":"string"}}},"service":{"type":"string"},"provider":{"type":"string","const":"K-2SO"}}}}}}},"responseSchema":{"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":"live-paid-endpoint-response-contract-failure-ind","procedure":"same as brief","generatedAt":"2026-01-01T00:00:00.000Z","generationSource":"deterministic"},"service":"live-paid-endpoint-response-contract-failure-ind","provider":"K-2SO"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"down","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_NehDpfxaYIT-Gdp_pxNt3","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns a verdict on whether a specific x402 or MPP merchant endpoint correctly fulfills its paid-access contract, classifying failures as dead routes, contract mismatches, or thin-body content debt.","exampleAgentPrompt":"Can you check if this x402 merchant endpoint is actually honoring its paid-access contract — I want to know if it's a dead route, a contract mismatch where the handler rejects valid requests, or returning a suspiciously thin body after payment?","exampleUseCases":[{"title":"Diagnosing a dead x402 merchant route","prompt":"I tried to pay to access an x402 endpoint at a merchant but I'm getting a 404 with no 402 challenge showing up at all — can you check if that route is simply dead and can't be paid?"},{"title":"Catching content debt on a paid API","prompt":"A merchant's x402 endpoint is accepting payment and returning 200, but the response body seems almost empty — can you verify whether this counts as content debt and flag it as a thin-body failure?"},{"title":"Auditing contract mismatch after 400 error","prompt":"I'm getting a 400 error from an MPP merchant's paid endpoint even though the 402 challenge looks fine — can you diagnose whether this is a contract mismatch where the handler is rejecting my documented request?"}],"resultDescription":"A JSON object containing a boolean success flag, payment confirmation, a verdict classification (404-no-challenge, 400-contract-mismatch, 200-thin-body, or 200-valid), a prose decision procedure of 120+ words explaining the verdict, the model used, a timestamp, and generation source (llm, reasoning, or deterministic).","failureModes":["Missing required 'type' or 'method' fields returns a 400 contract error","Invalid method value outside GET/HEAD/DELETE enum causes validation failure","Payment not completed results in a 402 challenge response rather than verdict","Merchant endpoint unreachable causes upstream timeout or error","Empty or malformed merchant input leads to indeterminate verdict"],"whenToPreferThis":"Choose this endpoint when you need to systematically audit whether x402 or MPP merchant endpoints are genuinely delivering on their paid-access promises — especially before routing agent payments to a new merchant, after observing anomalous payment outcomes, or when building a compliance index of merchant endpoint health. Prefer it over generic HTTP testing tools because it applies the specific x402/MPP verdict ladder and produces agent-readable prose rationale.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-20T06:26:48.894Z","isFirstParty":false,"canonicalSlug":"live-paid-endpoint-response-contract-failure-index-for-x402-and-mpp-55293a4c"}