{"uid":"cap_XW78SJLuOD-xAAGqRzN-M","slug":"x402-field-instruments-source-proof-25ce6560","name":"x402 Field Instruments – Source Proof","description":"Seven account-free paid tools for source integrity, x402 catalog search, preflight, liveness, routing, price drift, and batch verification.","url":"https://bj7e26lfpo4fthvr35hczdipby.srv.us/v1/source-proof","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["url"],"properties":{"url":{"type":"string","description":"Public HTTPS URL to inspect"},"expected_sha256":{"type":"string","pattern":"^[A-Fa-f0-9]{64}$"}},"additionalProperties":false}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"bytes":1256,"sha256":"64-character SHA-256 digest","finalUrl":"https://example.com/robots.txt","httpStatus":200,"observedAt":"2026-08-27T00:00:00.000Z","proofVersion":"1.0"}},"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":"unknown","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_JY0HQe0Ogp7jyirDyApdY","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":"Fetches a public HTTPS URL and returns a cryptographic SHA-256 proof of its content, byte count, final URL, and HTTP status at a given moment.","exampleAgentPrompt":"Can you fetch https://example.com/report.pdf and give me a SHA-256 proof of exactly what it contains right now, along with the byte count and final URL?","exampleUseCases":[{"title":"Audit published document integrity","prompt":"I need to verify that the policy document at https://acme.org/terms.pdf still has the SHA-256 hash a3f1...bb92 and hasn't been altered — can you run a source proof on it?"},{"title":"Detect silent URL redirect changes","prompt":"Please check https://data.gov/dataset/census2020.csv and tell me the final URL it resolves to, the current SHA-256, and the HTTP status so I can confirm it hasn't been silently redirected."},{"title":"Timestamp a live web resource","prompt":"I want an official proof of what https://blog.openai.com/latest contained right now — SHA-256, byte count, and exact observation time — so I can reference it in my research notes."}],"resultDescription":"A JSON object containing: the 64-character SHA-256 digest of the fetched content, total byte count, the final resolved URL (after any redirects), the HTTP status code, the ISO-8601 timestamp of observation, and a proof version string. Together these fields constitute a verifiable, timestamped fingerprint of the resource.","failureModes":["URL is not publicly accessible or returns a non-2xx status — httpStatus field reflects the error code","URL uses HTTP instead of HTTPS — rejected by schema validation","Provided expected_sha256 does not match actual content — mismatch surfaced in response","Network timeout or DNS failure for the target URL — error response returned","Malformed or non-64-character expected_sha256 pattern — schema validation error before call"],"whenToPreferThis":"Choose this endpoint when you need a cryptographically verifiable, timestamped record of what a public URL served at a specific moment — especially for source integrity auditing, tamper detection, or provenance documentation. It is account-free and pay-per-call at $0.002 USDC, making it ideal for on-demand spot checks without subscription overhead. Prefer it over a plain HTTP fetch when you need the SHA-256 digest and observation timestamp as structured proof artifacts, not just the raw content.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T12:36:07.598Z","isFirstParty":false}