{"uid":"cap_-CW4G2UyFbPPo6ICftd8T","slug":"verity-suite-faithful-pro-faithfulness-checker-2fe29027","name":"Verity Suite Faithful Pro — Faithfulness Checker","description":"The trust fabric for AI agents — calibrated, fail-closed services agents pay per call.","url":"https://verity-suite.onrender.com/faithful/pro","method":"POST","headers":{},"bodySchema":{"type":"object","required":["source","candidate"],"properties":{"mode":{"type":"string","description":"'summary' or 'translation'. If absent, the checker applies the stricter union of both checks rather than guessing a mode."},"source":{"type":"string","description":"the original source text; the sole ground truth the candidate is judged against"},"candidate":{"type":"string","description":"the summary or translation to check against the source"}}},"responseSchema":{"type":"object","title":"faithful_out","required":["verdict","faithfulness","reasons"],"properties":{"reasons":{"type":"array","items":{"type":"string"},"title":"Reasons","description":"concrete claim-level reasons, each either citing a specific source-vs-candidate discrepancy or confirming specific support; at least one reason required"},"verdict":{"enum":["faithful","minor_drift","unfaithful","uncertain"],"type":"string","title":"Verdict","description":"faithful=every candidate claim is supported by the source and no material source claim is dropped or distorted; minor_drift=only small non-material omissions/nuance loss that change no core claim, entity, quantity, date, or stance; unfaithful=at least one hallucination, contradiction, negation flip, wrong/invented entity-number-date, dropped material claim, or distortion; uncertain=cannot reliably compare (empty/unreadable/truncated/gibberish input or texts too misaligned to map). FAIL CLOSED: never faithful or minor_drift when unsure."},"omissions":{"type":"array","items":{"type":"string"},"title":"Omissions","description":"material claims present in the source but dropped or weakened in the candidate"},"faithfulness":{"type":"number","title":"Faithfulness","maximum":1,"minimum":0,"description":"calibrated probability the candidate fully preserves source meaning with no hallucination, contradiction, or material distortion; 1=certainly faithful, 0=certainly unfaithful. A single confirmed defect drives this well below 0.5."},"hallucinations":{"type":"array","items":{"type":"string"},"title":"Hallucinations","description":"claims asserted in the candidate that are not supported by the source (added or invented content)"}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.15","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"registry","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":"$0.15/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.15","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.15","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_vp8xCa48_3B0lOoG9SA9D","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.15","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks whether a summary or translation faithfully preserves the source text, returning a calibrated faithfulness probability, verdict, hallucinations, and omissions.","exampleAgentPrompt":"Check whether this summary is faithful to the original article — the source is: 'The Federal Reserve raised interest rates by 0.25% on Wednesday, citing persistent inflation and a strong labor market.' and the candidate summary is: 'The Fed cut interest rates by 0.25% due to falling inflation.' Tell me the verdict, faithfulness score, and any hallucinations or dropped claims.","exampleUseCases":null,"resultDescription":"Returns a JSON object with: a verdict enum (faithful, minor_drift, unfaithful, or uncertain), a calibrated faithfulness probability from 0 to 1, an array of concrete claim-level reasons, a list of hallucinated claims found in the candidate, and a list of material omissions from the source. The checker fails closed — it never returns faithful or minor_drift when uncertain.","failureModes":["Empty or truncated input text returns verdict='uncertain' with a faithfulness score near 0","Gibberish or unreadable input in either field returns verdict='uncertain'","Texts in completely misaligned languages or domains that cannot be mapped return verdict='uncertain'","Payment failure (x402) causes the call to be rejected before processing","Missing required fields 'source' or 'candidate' cause a validation error"],"whenToPreferThis":"Use this endpoint when you need a calibrated, fail-closed faithfulness judgment on a summary or translation — not just a heuristic similarity score. It is specifically designed for AI agent pipelines where hallucinations and factual drift must be detected reliably. Prefer it over embedding-similarity checks when you need claim-level explanations, hallucination enumeration, and omission detection. It covers both summarization and translation modes from a single endpoint.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T00:52:06.857Z","isFirstParty":false}