{"uid":"cap_j92Ko-cFtg2XfZ3pbfIzr","slug":"s2ar-assert-6f5dc020","name":"s2ar Assert","description":"Assert an agent's output — JSON schema, terms, lengths, citations, quotes in a source; a signed record. GET ?text=&checks=","url":"https://api.s2ar.dev/x402/v1/assert?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method","queryParams"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"headers":{"type":"object","additionalProperties":{"type":"string"}},"queryParams":{"type":"object","properties":{"text":{"type":"string","description":"the output to assert (or `json`, an object)"},"checks":{"type":"string","description":"the checks; on GET, a JSON list in one parameter"},"rubric":{"type":"string","description":"a named check list; `schema`, `domains` fill its slots"},"schema":{"type":"string","description":"for json_schema / api-response"},"source":{"type":"string","description":"the source for quotes_in_source"}},"additionalProperties":{"type":"string"}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","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":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_0-WjHEPfHB02CeNgztP-s","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Validates agent output against JSON schema, term lists, length constraints, citation rules, and source quotes, returning a signed verification record.","exampleAgentPrompt":"Can you assert my agent's JSON output against the schema '{\"type\":\"object\",\"required\":[\"answer\",\"confidence\"]}' and also check it's under 500 characters, using the checks '[\"json_schema\",\"max_length\"]'? Here's the text: '{\"answer\":\"Paris\",\"confidence\":0.95}'","exampleUseCases":[{"title":"Verify grounded answer citations","prompt":"My agent just wrote an answer about climate change — can you check whether all the quotes in that answer actually appear in the source article I'll paste? Run a quotes_in_source check and give me a signed record I can share."},{"title":"Validate API response schema","prompt":"I got this JSON back from a third-party API: '{\"id\":123,\"status\":\"active\"}' — can you assert it matches the schema '{\"type\":\"object\",\"required\":[\"id\",\"status\",\"name\"]}' so I know if it's well-formed before I process it?"},{"title":"LLM output term and length gate","prompt":"Before I use this LLM-generated product description in production, assert that it contains the terms 'warranty' and 'free shipping' and that it's under 300 characters — run those checks and give me a signed pass/fail record."}],"resultDescription":"A signed record containing per-check pass/fail verdicts for each requested assertion (e.g. json_schema, max_length, terms_present, quotes_in_source), along with a cryptographic signature that any party can verify to confirm the checks were run and what the outcome was.","failureModes":["Missing required 'text' or 'checks' parameter returns an error","Malformed JSON in 'checks' list causes a parse error","Schema provided in 'schema' param is invalid JSON Schema, resulting in a schema-parse error","Source document not provided when quotes_in_source check is requested","Unknown rubric name returns a not-found error","Text too long for the endpoint to process causes a payload error"],"whenToPreferThis":"Choose this endpoint when you need a tamper-proof, signed record proving that a piece of generated or received content passed specific structural or semantic checks — especially JSON schema conformance, keyword presence, length constraints, or quote grounding in a source. It is ideal for agent pipelines that must produce auditable output QA receipts, or when downstream consumers need to verify that an AI agent's output was validated before use.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-11T12:37:53.277Z","isFirstParty":false,"canonicalSlug":"s2ar-assert-6f5dc020"}