{"uid":"cap_9g6FFH7sSHGf7Tebod2nM","slug":"agent-evidence-api-claim-verification-d5e18b5a","name":"Agent Evidence API – Claim Verification","description":"Verify a claim or fact check a statement against public web sources: send a question and up to 5 URLs, get cited evidence - passages that support, contradict or fail to settle it. Claim verification with a citation for every excerpt: source URL, retrieval time, content hash. Never charges when nothing is retrieved. Free to evaluate: the `sample` tool returns one real response at no cost, so you can judge the output before paying for your own question.","url":"https://agent-evidence.thx93.dev/v1/evidence?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method","bodyType","body"],"properties":{"body":{"properties":{}},"type":{"type":"string","const":"http"},"method":{"enum":["POST"],"type":"string"},"bodyType":{"enum":["json","form-data","text"],"type":"string"}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"sources":[{"title":"Company X - About","status":200,"evidence":[{"context":"h2:Products > p[1]","excerpt":"Company X manufactures centrifugal pumps at its facility.","relevance":"direct"}],"language":"en","warnings":[],"final_url":"https://company.example/about","publisher":"Company X","word_count":412,"content_type":"text/html; charset=utf-8","retrieved_at":"2026-01-01T00:00:00.000Z","canonical_url":"https://company.example/about","requested_url":"https://company.example/about","content_hash_sha256":"9f2c…"}],"version":"1","question":"Is Company X a manufacturer of centrifugal pumps?","assessment":{"basis":"1 source(s) contained passages matching the question (company.example) with no contradicting passages found.","status":"supported"},"request_id":"req_1f2e3d4c5b6a7988","limitations":["Assessment is derived from deterministic lexical matching, not semantic reasoning."],"processing_ms":812}},"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_yeSsl4e9sEM5KdmIRowVA","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 a factual claim or question against up to 5 provided URLs, returning cited evidence passages that support, contradict, or fail to settle the claim.","exampleAgentPrompt":"Can you verify whether 'Acme Corp is the largest producer of industrial valves in North America' is supported by what's on these two pages: https://acmecorp.com/about and https://acmecorp.com/manufacturing?","exampleUseCases":[{"title":"Verify competitor claim before publication","prompt":"Before we publish this blog post, can you check if the claim 'BrightSolar has installed over 50,000 panels in Texas' is actually supported by https://brightsolar.com/about and https://brightsolar.com/projects? I need a cited excerpt for each source."},{"title":"Fact-check a sourced news assertion","prompt":"Someone sent me an article claiming that 'the FDA approved drug X for pediatric use in 2023' — can you verify that against https://fda.gov/drugs/drugx-approval and https://fda.gov/news/2023 and tell me whether those pages support, contradict, or don't settle it?"},{"title":"Due diligence on a vendor's stated credentials","prompt":"We're evaluating a vendor who says they're ISO 9001 certified. Can you check whether https://vendorco.com/certifications and https://isoregistry.org/vendorco actually support that claim and give me the relevant quoted passages?"}],"resultDescription":"A structured JSON response containing an assessment status (supported, contradicted, or unresolved), one or more evidence excerpts with source URL, content context, relevance classification, retrieval timestamp, and SHA-256 content hash per source, plus a plain-English basis statement, processing time in milliseconds, and a unique request ID. Nothing is charged if no content is retrieved.","failureModes":["URLs are inaccessible or return non-200 status — source flagged with warning, no excerpt returned","Question is too vague for lexical matching — assessment may be 'unresolved' even with relevant pages","Content behind paywalls or requiring authentication cannot be retrieved","Non-HTML content types may not be parsed — warnings included in response","Rate limiting or network timeouts on target URLs may result in partial results"],"whenToPreferThis":"Choose this endpoint when you need verifiable, cited evidence from specific URLs to support or refute a factual claim — particularly when auditability matters (content hashes, retrieval times). It is ideal for due diligence workflows, pre-publication fact-checking, or any scenario where you need traceable sourcing rather than a generative answer. Prefer it over general web search APIs when you already have candidate URLs and need passage-level citations. Note that matching is lexical, not semantic, so it works best for specific, concrete factual claims.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-22T12:40:43.415Z","isFirstParty":false,"canonicalSlug":"agent-evidence-api-claim-verification-d5e18b5a"}