{"uid":"cap_D4jIArYxLo7V2lG1AWEbC","slug":"x402-payment-response-binding-and-refund-verification-decision-360035b1","name":"x402 Payment-Response Binding and Refund Verification Decision Procedure","description":"Agent-facing decision procedure for x402 payment-response binding and refund verification. When the receipt stops at paid, refunds fail. This procedure covers: what PAYMENT-RESPONSE must contain to bind the AP2 Payment Mandate and merchant quote, how to verify the PAYMENT-SIGNATURE at the edge before trusting a receipt, thresholds for accepting a response as refund-proof, failure modes (mandate-quote mismatch, stale signature, facilitator non-cooperation), and when to escalate to a","url":"https://k2so.wrong.systems/api/services/x402-payment-response-binding-and-refund-verific?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","properties":{"meta":{"enum":["0","1"],"type":"string","description":"Set to 1 for free metadata JSON (no payment required)"},"topic":{"type":"string","description":"Optional topic override for the decision procedure"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","title":"x402 payment-response binding and refund verification procedure paid response","$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":"x402-payment-response-binding-and-refund-verific","procedure":"same as brief","generatedAt":"2026-01-01T00:00:00.000Z","generationSource":"deterministic"},"service":"x402-payment-response-binding-and-refund-verific","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_Up14YqEfIyD4DoldmRQ3d","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 paid LLM-generated decision procedure brief explaining how to verify that an x402 payment response is correctly bound to a request and how to handle refund eligibility.","exampleAgentPrompt":"Give me the decision procedure for verifying that an x402 payment response is correctly bound to the original request and checking whether a refund is valid.","exampleUseCases":[{"title":"Refund eligibility check after failed service","prompt":"My agent paid for an x402 API call but got an empty or broken response — walk me through the procedure for deciding whether that payment is eligible for a refund."},{"title":"Payment-response correlation audit","prompt":"I need a clear decision procedure my agent can follow to confirm that a USDC settlement on Base actually corresponds to the specific x402 API request it was meant for, and not some other call."},{"title":"Building x402 payment verification into agent workflow","prompt":"I'm building an autonomous agent that calls x402 services and I need the official procedure for binding payment responses to requests and handling any refund claims that come up."}],"resultDescription":"A JSON object containing a plain-prose decision procedure (120+ words) generated by an LLM, covering how to bind an x402 payment response to its originating request and verify refund eligibility. Includes the model used, topic, service slug, ISO-8601 generation timestamp, and generation source (llm, reasoning, or deterministic). Also returns payment metadata including payer address and transaction hash.","failureModes":["HTTP 402 returned if payment has not been settled — must pay exact USDC amount and retry with PAYMENT-SIGNATURE header","Invalid or missing method enum value causes schema validation error","Payment signature mismatch or replay attack detection causes rejection","Service may return ok:false with error detail if LLM generation fails","Stale or cached procedure may be returned depending on generation source"],"whenToPreferThis":"Choose this endpoint when an autonomous agent needs authoritative, prose-format guidance on x402 payment-response binding and refund verification — especially when building compliance logic, dispute resolution flows, or payment integrity checks into an agent. Prefer this over generic documentation when you need a machine-readable structured response with a timestamped, sourced procedure that an agent can act on directly.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-03T06:27:33.186Z","isFirstParty":false,"canonicalSlug":"x402-payment-response-binding-and-refund-verification-decision-360035b1"}