{"uid":"cap_cTJBaGZp6zD-cBFt4uH-N","slug":"agent-contract-proof-verifier-5a4de356","name":"Agent Contract Proof Verifier","description":"Compare an agent's advertised contract with its live x402 challenge and return deterministic proof.","url":"https://agent-contract-proof.mattskowronis.workers.dev/v1/verify","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"url":{"type":"string","maxLength":2048,"description":"Public HTTP or HTTPS agent/API URL. An origin URL may be resolved through discovery metadata."},"method":{"enum":["GET","POST","PUT","PATCH","DELETE"],"type":"string","description":"Optional method to probe. If omitted, the advertised method is used, then GET as a fallback."},"expected_hash":{"type":"string","pattern":"^[a-fA-F0-9]{64}$","description":"Optional previous contract_hash. A mismatch proves the public contract changed."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_DZDcEloMDprsQKy0OLJNh","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Compares an agent's advertised contract with its live x402 payment challenge and returns deterministic cryptographic proof of consistency or change.","exampleAgentPrompt":"Can you verify that the agent at https://my-agent.example.com is still serving the same x402 contract it advertised — compare its live challenge with the contract hash a4f3c2e1b8d79f6a3e2c1d5b0a9f8e7d6c5b4a3f2e1d0c9b8a7f6e5d4c3b2a1 and give me proof if they match?","exampleUseCases":[{"title":"Audit agent before payment","prompt":"Before my workflow sends payment to the agent at https://trading-agent.example.com, can you verify its live x402 challenge matches its advertised contract and give me proof it hasn't changed?"},{"title":"Detect contract drift in CI","prompt":"In my continuous integration pipeline, check whether the agent at https://data-agent.example.com still serves the same x402 contract as the hash 9b8a7f6e5d4c3b2a1f0e9d8c7b6a5f4e3d2c1b0a9f8e7d6c5b4a3f2e1d0c9b — flag it if the contract has drifted."},{"title":"Prove contract consistency to a client","prompt":"My client wants proof that the agent at https://inference-agent.example.com using POST is serving exactly the x402 contract it claims — can you run the contract proof check and return the deterministic result?"}],"resultDescription":"Returns a deterministic proof object indicating whether the agent's live x402 challenge matches its advertised contract, including a computed contract_hash, a match/mismatch status, and evidence of any contract change if an expected_hash was provided.","failureModes":["Agent URL is unreachable or returns a non-402 response — verification cannot proceed","URL does not serve an x402 challenge — endpoint returns an error indicating no payment challenge found","expected_hash is provided but malformed (not 64 hex characters) — request rejected with validation error","Agent contract has changed — mismatch proof returned, not an error, but signals drift","Network timeout contacting the target agent — returns a connectivity failure","Invalid HTTP method specified — may fall back to GET or return an error"],"whenToPreferThis":"Use this endpoint when you need cryptographic, deterministic proof that an x402-compatible agent's live payment challenge matches its publicly advertised contract spec — especially before trusting an agent with payment, automating workflows that depend on contract stability, or auditing for tampering or drift. Prefer this over manual inspection when you need a verifiable, machine-readable proof artifact.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T18:37:19.317Z","isFirstParty":false}