{"uid":"cap_V_vpddVVFCHqCEZgNbqBr","slug":"verity-suite-faithful-faithfulness-checker-1ae4f402","name":"Verity Suite Faithful — Faithfulness Checker","description":"The trust fabric for AI agents — calibrated, fail-closed services agents pay per call.","url":"https://verity-suite.onrender.com/faithful","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":"0.06","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":"$0.06/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.06","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.06","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_e755YiRHvT-qq-K23xfaX","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.06","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks whether a candidate summary or translation faithfully preserves the meaning of a source text, returning a calibrated verdict and claim-level evidence.","exampleAgentPrompt":"Check if this summary is faithful to the source article — mode is 'summary'. Source: 'The company reported $4.2B in revenue for Q3, up 12% year-over-year, driven by cloud services.' Candidate: 'The company posted record Q3 revenue of $5B, mostly from cloud.' Flag any hallucinations or dropped claims and give me a faithfulness score.","exampleUseCases":null,"resultDescription":"Returns a verdict ('faithful', 'minor_drift', 'unfaithful', or 'uncertain'), a calibrated faithfulness probability (0–1), and structured arrays listing specific hallucinations (claims in the candidate not supported by the source), omissions (material source claims dropped), and concrete claim-level reasons explaining the assessment. Fails closed — never returns faithful or minor_drift when uncertain.","failureModes":["Empty, truncated, or gibberish inputs return verdict 'uncertain' with reasons explaining unreadability","Texts too misaligned in topic or language to meaningfully compare return 'uncertain'","A single confirmed factual defect drives faithfulness score well below 0.5 even if most content is accurate","Missing required 'source' or 'candidate' fields return a 400-level error","If 'mode' is absent, the stricter union of both summary and translation checks is applied, which may increase false-positive unfaithful verdicts"],"whenToPreferThis":"Use this endpoint when an AI agent needs to verify that a generated summary or translation has not hallucinated, omitted material claims, or distorted meaning relative to a known source text. Prefer this over generic LLM self-checks because it is calibrated, fail-closed, and returns structured evidence at the claim level rather than a freeform assessment.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T00:52:27.195Z","isFirstParty":false}