{"uid":"cap_i826F1JCa8Jx2MG3rVfut","slug":"agentbit-app-x402-endpoint-payment-header-linter-db1092df","name":"agentbit.app x402 Endpoint & Payment Header Linter","description":"Lint any x402 endpoint or payment header against the v2 spec and real CDP facilitator behavior: CAIP-2 network ids, atomic amounts, the EIP-712 domain-name trap ('USD Coin' on Base mainnet vs 'USDC' on Sepolia — wrong name = every settlement fails), the extensions echo Coinbase Bazaar requires for indexing, expired authorizations. Findings as error/warning/info with what will actually break. Built by a seller that debugged all of these in production.","url":"https://agentbit.app/v1/x402/inspect","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"url":{"type":"string","description":"A paid x402 endpoint to probe live (GET, expects the 402 envelope)"},"payment_payload":{"type":"string","description":"Base64 PAYMENT-SIGNATURE header value to lint the client payload (optionally alongside payment_required)"},"payment_required":{"type":"string","description":"Base64 PAYMENT-REQUIRED header value to lint offline"}}},"responseSchema":{"type":"json","example":{"url":"https://agentbit.app/v1/web/search","mode":"live-probe","counts":{"infos":1,"errors":0,"warnings":0},"verdict":"pass","findings":[{"code":"EIP712_DOMAIN_OK","level":"info","message":"accepts[0]: extra.name matches USDC on Base mainnet."}],"http_status":402,"accepts_count":1}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_m1o61Xllhcr9FBbmmU__U","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Validates x402 payment endpoints and payment headers against the v2 spec, catching EIP-712 domain name mismatches, CAIP-2 errors, expired authorizations, and Coinbase Bazaar indexing requirements.","exampleAgentPrompt":"Can you lint my x402 payment endpoint at https://myapi.example.com/premium-data to check for EIP-712 domain name issues, CAIP-2 errors, and whether Coinbase Bazaar indexing extensions are present?","exampleUseCases":[{"title":"Debug failing x402 settlements on Base","prompt":"My x402 payments keep failing on Base mainnet — can you probe https://myapi.example.com/data and tell me if the EIP-712 domain name is set correctly for USDC versus USD Coin, and what else might be broken?"},{"title":"Validate offline PAYMENT-REQUIRED header","prompt":"I have a base64-encoded PAYMENT-REQUIRED header value from my x402 server — can you lint it offline and tell me if there are any spec violations or missing fields the Coinbase facilitator will reject?"},{"title":"Check client payment payload before submission","prompt":"Before I send this x402 payment, can you validate my base64-encoded PAYMENT-SIGNATURE header value against the v2 spec and flag any errors like expired authorization or wrong atomic amounts?"}],"resultDescription":"A JSON object containing a verdict (pass/fail), mode (live-probe or offline), per-category counts of errors/warnings/infos, a list of findings each with a code, severity level, and human-readable message explaining what will break and why, plus the HTTP status and number of accepted payment options.","failureModes":["Endpoint URL is unreachable or returns non-402 status — probe cannot complete","Malformed base64 input for payment_payload or payment_required — parse error returned","x402 endpoint times out — finding may be incomplete","Network connectivity issues reaching the target URL","No input provided (url, payment_payload, or payment_required required) — validation error"],"whenToPreferThis":"Choose this endpoint when debugging x402 payment integrations, specifically for catching EIP-712 domain name mismatches ('USD Coin' vs 'USDC'), CAIP-2 network ID errors, Coinbase Bazaar indexing extension requirements, expired authorizations, or malformed payment headers. Prefer this over manual inspection when you need production-validated rules derived from real facilitator behavior, not just spec text.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T03:42:39.081Z","isFirstParty":false}