{"uid":"cap_FLEY_3MOxdifqyBm6rpyr","slug":"source-claim-proof-verifier-e9d3dad2","name":"Source Claim Proof Verifier","description":"Verify whether a supplied public source page currently supports one atomic factual claim. Returns supported, contradicted, or insufficient-evidence plus source snippets, or explicit blocked/unreachable/unsupported states. Not a general fact checker or web search.","url":"https://source-claim-proof.mattskowronis.workers.dev/v1/verify","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"url":{"type":"string","maxLength":2048,"description":"Public HTTP or HTTPS source page URL to inspect."},"claim":{"type":"string","maxLength":500,"minLength":3,"description":"One atomic factual assertion to check against that source only."}}},"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_62M4n_W90-MOT-xzizYEm","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":"Verifies whether a specific public web page currently supports, contradicts, or provides insufficient evidence for a single atomic factual claim.","exampleAgentPrompt":"Can you check whether this Wikipedia page — https://en.wikipedia.org/wiki/Mount_Everest — actually supports the claim that Mount Everest is 8,849 meters tall?","exampleUseCases":[{"title":"Citation audit for research paper","prompt":"I'm reviewing a paper that cites https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight and claims 'more than 1 billion people worldwide are obese' — can you verify if that source page actually supports that specific claim?"},{"title":"Journalist source validation","prompt":"Before I publish, can you check whether https://www.bls.gov/news.release/empsit.nr0.htm currently supports the claim that US unemployment was 3.9% in April 2024?"},{"title":"Misinformation flagging in social post","prompt":"Someone shared an article at https://example-news.com/article/climate-study and claimed it says 'global temperatures rose 2°C in the last decade' — does that page actually say that, or is it being misrepresented?"}],"resultDescription":"Returns a verdict of 'supported', 'contradicted', or 'insufficient-evidence' indicating whether the source page backs the claim, plus relevant text snippets from the page. May also return explicit states: 'blocked' (page denied access), 'unreachable' (page unavailable), or 'unsupported' (page type cannot be analyzed).","failureModes":["blocked — the target URL returned a 403 or bot-blocking response, so content could not be read","unreachable — the target URL timed out or returned a 404/5xx error","unsupported — the URL points to a PDF, video, or non-parseable content type","insufficient-evidence — the page loads but contains no content clearly related to the claim","claim too broad or compound — multi-part claims may get ambiguous verdicts; only atomic claims are supported","URL exceeds 2048 characters or claim is fewer than 3 characters — returns validation error"],"whenToPreferThis":"Use this endpoint when you need to verify whether a specific, already-known source URL actually substantiates a single discrete factual claim — especially for citation auditing, misinformation detection, or fact-checking pipelines where the source is already identified. This is not a web search tool; you must provide both the URL and the exact claim. Prefer this over general fact-checkers when provenance matters and you need snippet-level evidence from a specific page.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T00:30:56.216Z","isFirstParty":false}