{"$schema":"https://static.modelcontextprotocol.io/schemas/mcp-server-card/v1.json","serverInfo":{"name":"claim-grounding","title":"Claim Grounding","version":"1.5.0","description":"Fact-check AI answers against cited public sources. Pay per call in USDC on Base via x402. No API key.","websiteUrl":"https://claim-grounding.prospectintel.workers.dev/docs","icons":[{"src":"https://claim-grounding.prospectintel.workers.dev/icon.svg","mimeType":"image/svg+xml","sizes":["any"]}]},"description":"$0.05: split any AI answer into checkable claims, then a $0.15 Quick check per claim. Fact-check AI answers. Extract claims and verify them against cited public sources (Wikipedia, Wikidata, Google News, Europe PMC, FRED, SEC EDGAR via Deep verify). Says \"not enough evidence\" instead of guessing. Pay per call in USDC on Base via x402. No API key.","homepage":"https://claim-grounding.prospectintel.workers.dev/docs","websiteUrl":"https://claim-grounding.prospectintel.workers.dev/docs","iconUrl":"https://claim-grounding.prospectintel.workers.dev/icon.svg","icons":[{"src":"https://claim-grounding.prospectintel.workers.dev/icon.svg","mimeType":"image/svg+xml","sizes":["any"]}],"transport":{"type":"streamable-http","url":"https://claim-grounding.prospectintel.workers.dev/mcp"},"authentication":{"required":false,"schemes":[]},"configSchema":{"type":"object","properties":{},"additionalProperties":false},"payment":{"protocol":"x402","network":"eip155:8453","asset":"USDC","note":"Each paid tool lists its price. No API key."},"instructions":"Claim Grounding checks factual claims against public sources and returns a verdict (supported, contradicted, outdated, mixed, insufficient_evidence) with quotes and source URLs. Typical flow: extract_claims ($0.05) to split an answer into atomic claims (each checkable claim carries a ready-to-send next_step), then quick_check ($0.15) per claim for a fast supported/contradicted/unsure verdict, or verify_claim ($1.00) per claim, or check_answer ($1.00) for a whole answer, or deep_verify ($0.75, async) for a multi-source check across Wikipedia, Wikidata, Google News, Europe PMC, FRED and SEC EDGAR. All tools are read-only. Each tools/call returns structured x402 payment instructions (status payment_required) instead of charging inside MCP: POST the given body to the given URL with an x402 client paying USDC on Base (eip155:8453). Read resource claim-grounding://pricing for prices and claim-grounding://verdicts for verdict meanings.","capabilities":{"tools":{"listChanged":false},"prompts":{"listChanged":false},"resources":{"listChanged":false,"subscribe":false}},"tools":[{"name":"extract_claims","title":"Extract claims","description":"Split a text (for example an AI-generated answer) into atomic factual claims. Each claim includes span, grounding_required, claim_type (number|date|quantity|quote|named_entity_fact|comparison|opinion|prediction|other), check_worthiness (high|medium|low), and the source sentence. Hedges are stripped, pronouns are resolved across sentences, and compound sentences are split. Questions, greetings, opinions and predictions are marked grounding_required false. Up to 3 checkable factual claims (opinions skipped) get a next_step: a ready-to-send quick_check request ($0.15, fast verdict with 1-2 sources), with deep_verify ($0.75) and verify_claim ($1.00) bodies in next_step.alternatives, so you can check them in one more call. Price: $0.05 USDC on Base per call via x402; this MCP call returns payment instructions and POST /v1/extract_claims returns the claims. Read-only.","inputSchema":{"type":"object","properties":{"text":{"type":"string","description":"The text to split into claims, for example a chatbot answer. Up to a few thousand characters.","minLength":1,"examples":["The Eiffel Tower is in Paris and was completed in 1889."]}},"required":["text"],"additionalProperties":false},"outputSchema":{"type":"object","properties":{"status":{"type":"string","enum":["payment_required","ok"],"description":"payment_required: pay the HTTP route with x402 to get the result. ok: result is included."},"tool":{"type":"string","description":"Tool name."},"payment":{"type":"object","description":"Payment instructions. MCP tools/call does not charge or run the paid work; call the HTTP route with x402.","properties":{"protocol":{"type":"string","description":"Payment protocol, always x402 (v2)."},"method":{"type":"string","description":"HTTP method for the paid route."},"url":{"type":"string","description":"Paid HTTP route to call."},"price":{"type":"string","description":"Price in USD, paid as USDC."},"amount":{"type":"string","description":"Price in USDC base units (6 decimals)."},"network":{"type":"string","description":"CAIP-2 network id (eip155:8453 = Base mainnet)."},"asset":{"type":"string","description":"USDC contract address on Base."},"pay_to":{"type":"string","description":"Receiving wallet address."},"body":{"type":"object","description":"JSON body to POST (the tool arguments you sent).","additionalProperties":true},"how":{"type":"string","description":"Step-by-step payment flow."}},"required":["protocol","method","url","price","network"]},"result":{"type":"object","description":"Paid result: { claims: [{ claim_id, text, span, grounding_required, claim_type, check_worthiness, sentence, sentence_index, next_step?: { tool, why, price_usd, endpoint, method, body, alternatives[] } }], recommended_next_steps: { tool, count, total_price_usd, options[] }, summary, priced_usd }.","properties":{"claims":{"type":"array","items":{"type":"object","properties":{"next_step":{"type":"object","description":"Present only on unsure or low-confidence claims (check_answer) or unverified high/medium-worthiness factual claims (extract_claims; opinions and predictions skipped; max 3 per response). A ready-to-send request for this claim (optional, paid separately): Quick check ($0.15) from extract_claims, Deep verify from check_answer and quick_check. extract_claims adds alternatives[] with ready-to-send Quick check ($0.15), Deep verify ($0.75) and Verify claim ($1.00) requests.","properties":{"tool":{"type":"string","enum":["quick_check","deep_verify"],"description":"1.5.0: quick_check from extract_claims; deep_verify from check_answer and quick_check."},"why":{"type":"string"},"price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"method":{"type":"string","const":"POST"},"body":{"type":"object","properties":{"claim":{"type":"object","properties":{"text":{"type":"string"}},"required":["text"]}},"required":["claim"]},"alternatives":{"type":"array","description":"1.4.9 (extract_claims): every ready-to-send paid check for this claim. POST body to endpoint with an x402 client.","items":{"type":"object","properties":{"tool":{"type":"string","enum":["quick_check","deep_verify","verify_claim"]},"price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"method":{"type":"string","const":"POST"},"body":{"type":"object"},"when":{"type":"string"}},"required":["tool","price_usd","endpoint","method","body"]}}},"required":["tool","why","price_usd","endpoint","method","body"]}}}},"recommended_next_steps":{"type":"object","description":"1.4.8: summary of claim-level next_step suggestions.","properties":{"tool":{"type":"string"},"count":{"type":"integer","minimum":0},"total_price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"options":{"type":"array","description":"1.4.9 (extract_claims): cost to check all suggested claims with each tool.","items":{"type":"object","properties":{"tool":{"type":"string"},"price_usd_each":{"type":"number"},"total_price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"}}}},"note":{"type":"string"}},"required":["tool","count","total_price_usd"]},"summary":{"type":"object"},"priced_usd":{"type":"number"}},"additionalProperties":true},"message":{"type":"string","description":"Human-readable summary."}},"required":["status","tool","message"],"additionalProperties":true},"annotations":{"title":"Extract claims","readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}},{"name":"quick_check","title":"Quick check","description":"Fast, low-cost check of ONE factual claim. Returns verdict supported, contradicted or unsure, a confidence score, a short reason and 1-2 public sources (Wikipedia, plus Wikidata structured facts where they apply) with quote and URL. Synchronous. Cheaper and faster than deep_verify; use it on the claims extract_claims returns (its next_step gives the exact body). Unsure or low-confidence results include a next_step to deep_verify. Price: $0.15 USDC on Base per call via x402; this MCP call returns payment instructions and POST /v1/quick_check returns the verdict. Read-only.","inputSchema":{"type":"object","properties":{"claim":{"type":"object","description":"The single factual claim to check.","properties":{"text":{"type":"string","description":"One atomic factual claim, up to 1000 characters, for example a claim text returned by extract_claims.","minLength":1,"maxLength":1000,"examples":["The Eiffel Tower opened in 1889."]}},"required":["text"],"additionalProperties":false}},"required":["claim"],"additionalProperties":false},"outputSchema":{"type":"object","properties":{"status":{"type":"string","enum":["payment_required","ok"],"description":"payment_required: pay the HTTP route with x402 to get the result. ok: result is included."},"tool":{"type":"string","description":"Tool name."},"payment":{"type":"object","description":"Payment instructions. MCP tools/call does not charge or run the paid work; call the HTTP route with x402.","properties":{"protocol":{"type":"string","description":"Payment protocol, always x402 (v2)."},"method":{"type":"string","description":"HTTP method for the paid route."},"url":{"type":"string","description":"Paid HTTP route to call."},"price":{"type":"string","description":"Price in USD, paid as USDC."},"amount":{"type":"string","description":"Price in USDC base units (6 decimals)."},"network":{"type":"string","description":"CAIP-2 network id (eip155:8453 = Base mainnet)."},"asset":{"type":"string","description":"USDC contract address on Base."},"pay_to":{"type":"string","description":"Receiving wallet address."},"body":{"type":"object","description":"JSON body to POST (the tool arguments you sent).","additionalProperties":true},"how":{"type":"string","description":"Step-by-step payment flow."}},"required":["protocol","method","url","price","network"]},"result":{"type":"object","description":"Paid result: { mode: 'quick', verdict: supported|contradicted|unsure, verdict_detail, confidence, claim, reason, sources: [{ url, title, quote, source_type }] (max 2), next_step|null, receipt }.","properties":{"verdict":{"type":"string","enum":["supported","contradicted","unsure"],"description":"Three-way verdict. contradicted includes outdated; unsure covers mixed and insufficient_evidence."},"verdict_detail":{"type":"string","description":"Full verdict: supported, contradicted, outdated, mixed or insufficient_evidence."},"confidence":{"type":"number","description":"0 to 1."},"claim":{"type":"string"},"reason":{"type":"string"},"sources":{"type":"array","maxItems":2,"items":{"type":"object","properties":{"url":{"type":"string"},"title":{"type":"string"},"quote":{"type":"string"},"source_type":{"type":"string"}}}},"next_step":{"anyOf":[{"type":"object","description":"Present only on unsure or low-confidence claims (check_answer) or unverified high/medium-worthiness factual claims (extract_claims; opinions and predictions skipped; max 3 per response). A ready-to-send request for this claim (optional, paid separately): Quick check ($0.15) from extract_claims, Deep verify from check_answer and quick_check. extract_claims adds alternatives[] with ready-to-send Quick check ($0.15), Deep verify ($0.75) and Verify claim ($1.00) requests.","properties":{"tool":{"type":"string","enum":["quick_check","deep_verify"],"description":"1.5.0: quick_check from extract_claims; deep_verify from check_answer and quick_check."},"why":{"type":"string"},"price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"method":{"type":"string","const":"POST"},"body":{"type":"object","properties":{"claim":{"type":"object","properties":{"text":{"type":"string"}},"required":["text"]}},"required":["claim"]},"alternatives":{"type":"array","description":"1.4.9 (extract_claims): every ready-to-send paid check for this claim. POST body to endpoint with an x402 client.","items":{"type":"object","properties":{"tool":{"type":"string","enum":["quick_check","deep_verify","verify_claim"]},"price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"method":{"type":"string","const":"POST"},"body":{"type":"object"},"when":{"type":"string"}},"required":["tool","price_usd","endpoint","method","body"]}}},"required":["tool","why","price_usd","endpoint","method","body"]},{"type":"null"}]},"receipt":{"type":"object"}},"additionalProperties":true},"message":{"type":"string","description":"Human-readable summary."}},"required":["status","tool","message"],"additionalProperties":true},"annotations":{"title":"Quick check","readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}},{"name":"verify_claim","title":"Verify claim","description":"Check one factual claim against public Wikipedia sources and return a verdict (supported, contradicted, outdated, mixed or insufficient_evidence), a confidence score, a short reason, the supporting quote and the source URL. Says insufficient_evidence instead of guessing. Price: $1.00 USDC on Base per call via x402; this MCP call returns payment instructions and the paid HTTP route POST /v1/verify_claim returns the verdict. For a multi-source check use deep_verify. Read-only.","inputSchema":{"type":"object","properties":{"claim":{"type":"string","description":"One factual sentence to check.","minLength":1,"examples":["The Eiffel Tower is in Paris."]},"sources":{"type":"array","maxItems":10,"items":{"type":"object","description":"One source: {url} for a public https page we fetch, or {text, title?, url?} for text you already have.","properties":{"url":{"type":"string","format":"uri","maxLength":2048,"description":"Public https URL. Fetched with a 3.5 s timeout and a 512 KB cap; http, file and other schemes, private / loopback / link-local / metadata addresses, IP-literal hosts, custom ports and URLs with credentials are rejected (HTTP 400, not charged). With text, it is only the citation link."},"text":{"type":"string","minLength":1,"maxLength":20000,"description":"Source text to check the claim against (up to 20,000 characters). When given, no fetch is made."},"title":{"type":"string","maxLength":200,"description":"Optional title shown in citations."}},"anyOf":[{"required":["url"]},{"required":["text"]}],"additionalProperties":false},"description":"Optional. Up to 10 sources of your own, used as extra evidence next to the public sources and cited with provider and source_type \"caller\". The response lists what was used in sources_used."},"sources_only":{"type":"boolean","default":false,"description":"Optional. true = judge the claim only against your sources (no public-source lookups). Needs a non-empty sources array."}},"required":["claim"],"additionalProperties":false},"outputSchema":{"type":"object","properties":{"status":{"type":"string","enum":["payment_required","ok"],"description":"payment_required: pay the HTTP route with x402 to get the result. ok: result is included."},"tool":{"type":"string","description":"Tool name."},"payment":{"type":"object","description":"Payment instructions. MCP tools/call does not charge or run the paid work; call the HTTP route with x402.","properties":{"protocol":{"type":"string","description":"Payment protocol, always x402 (v2)."},"method":{"type":"string","description":"HTTP method for the paid route."},"url":{"type":"string","description":"Paid HTTP route to call."},"price":{"type":"string","description":"Price in USD, paid as USDC."},"amount":{"type":"string","description":"Price in USDC base units (6 decimals)."},"network":{"type":"string","description":"CAIP-2 network id (eip155:8453 = Base mainnet)."},"asset":{"type":"string","description":"USDC contract address on Base."},"pay_to":{"type":"string","description":"Receiving wallet address."},"body":{"type":"object","description":"JSON body to POST (the tool arguments you sent).","additionalProperties":true},"how":{"type":"string","description":"Step-by-step payment flow."}},"required":["protocol","method","url","price","network"]},"result":{"type":"object","description":"Paid result: { mode, claim: { text, verdict, confidence, rationale_short, citations[] }, why, source, receipt }.","properties":{"claim":{"type":"object","properties":{"claim_id":{"type":"string"},"text":{"type":"string"},"verdict":{"type":"string"},"confidence":{"type":"number"},"citations":{"type":"array","description":"Evidence quotes with url, title and source_type (wikipedia, wikidata, news, europepmc, fred, sec_edgar, or caller for your own sources).","items":{"type":"object"}},"next_step":{"type":"object","description":"Present only on unsure or low-confidence claims (check_answer) or unverified high/medium-worthiness factual claims (extract_claims; opinions and predictions skipped; max 3 per response). A ready-to-send request for this claim (optional, paid separately): Quick check ($0.15) from extract_claims, Deep verify from check_answer and quick_check. extract_claims adds alternatives[] with ready-to-send Quick check ($0.15), Deep verify ($0.75) and Verify claim ($1.00) requests.","properties":{"tool":{"type":"string","enum":["quick_check","deep_verify"],"description":"1.5.0: quick_check from extract_claims; deep_verify from check_answer and quick_check."},"why":{"type":"string"},"price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"method":{"type":"string","const":"POST"},"body":{"type":"object","properties":{"claim":{"type":"object","properties":{"text":{"type":"string"}},"required":["text"]}},"required":["claim"]},"alternatives":{"type":"array","description":"1.4.9 (extract_claims): every ready-to-send paid check for this claim. POST body to endpoint with an x402 client.","items":{"type":"object","properties":{"tool":{"type":"string","enum":["quick_check","deep_verify","verify_claim"]},"price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"method":{"type":"string","const":"POST"},"body":{"type":"object"},"when":{"type":"string"}},"required":["tool","price_usd","endpoint","method","body"]}}},"required":["tool","why","price_usd","endpoint","method","body"]}}},"why":{"type":"string"},"source":{"type":["string","null"]},"sources_used":{"type":"array","description":"Present when you sent sources: one entry per source with index, kind, url, title, status (used, fetch_failed, empty), chars and reason.","items":{"type":"object"}}},"additionalProperties":true},"message":{"type":"string","description":"Human-readable summary."}},"required":["status","tool","message"],"additionalProperties":true},"annotations":{"title":"Verify claim","readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}},{"name":"check_answer","title":"Check answer","description":"Fact-check a whole answer: extracts every checkable claim and verifies each against Wikipedia, plus Wikidata structured facts for dates, numbers, quantities, ordinals and records. Returns per-claim verdict, confidence, quote, source URL, sentence span and suggested_correction (quoted only from cited sources when contradicted/outdated), plus an answer-level summary with overall_verdict, counts and problem_sentences. Abstained rather than guessed. Use to audit chatbot or RAG output. Price: $1.00 USDC on Base per call via x402; this MCP call returns payment instructions and POST /v1/check_answer returns the results. Read-only.","inputSchema":{"type":"object","properties":{"answer":{"type":"string","description":"The full answer text to fact-check. Each factual sentence is checked separately.","minLength":1,"examples":["Marie Curie won two Nobel Prizes. She was born in Warsaw."]},"sources":{"type":"array","maxItems":10,"items":{"type":"object","description":"One source: {url} for a public https page we fetch, or {text, title?, url?} for text you already have.","properties":{"url":{"type":"string","format":"uri","maxLength":2048,"description":"Public https URL. Fetched with a 3.5 s timeout and a 512 KB cap; http, file and other schemes, private / loopback / link-local / metadata addresses, IP-literal hosts, custom ports and URLs with credentials are rejected (HTTP 400, not charged). With text, it is only the citation link."},"text":{"type":"string","minLength":1,"maxLength":20000,"description":"Source text to check the claim against (up to 20,000 characters). When given, no fetch is made."},"title":{"type":"string","maxLength":200,"description":"Optional title shown in citations."}},"anyOf":[{"required":["url"]},{"required":["text"]}],"additionalProperties":false},"description":"Optional. Up to 10 sources of your own, used as extra evidence next to the public sources and cited with provider and source_type \"caller\". The response lists what was used in sources_used."},"sources_only":{"type":"boolean","default":false,"description":"Optional. true = judge the claim only against your sources (no public-source lookups). Needs a non-empty sources array."}},"required":["answer"],"additionalProperties":false},"outputSchema":{"type":"object","properties":{"status":{"type":"string","enum":["payment_required","ok"],"description":"payment_required: pay the HTTP route with x402 to get the result. ok: result is included."},"tool":{"type":"string","description":"Tool name."},"payment":{"type":"object","description":"Payment instructions. MCP tools/call does not charge or run the paid work; call the HTTP route with x402.","properties":{"protocol":{"type":"string","description":"Payment protocol, always x402 (v2)."},"method":{"type":"string","description":"HTTP method for the paid route."},"url":{"type":"string","description":"Paid HTTP route to call."},"price":{"type":"string","description":"Price in USD, paid as USDC."},"amount":{"type":"string","description":"Price in USDC base units (6 decimals)."},"network":{"type":"string","description":"CAIP-2 network id (eip155:8453 = Base mainnet)."},"asset":{"type":"string","description":"USDC contract address on Base."},"pay_to":{"type":"string","description":"Receiving wallet address."},"body":{"type":"object","description":"JSON body to POST (the tool arguments you sent).","additionalProperties":true},"how":{"type":"string","description":"Step-by-step payment flow."}},"required":["protocol","method","url","price","network"]},"result":{"type":"object","description":"Paid result: { result_id, version, mode, summary: { overall_verdict, counts, problem_sentences }, claims: [{ text, verdict, confidence, citations[], sentence, suggested_correction, next_step? }], recommended_next_steps, next_actions, receipt }.","properties":{"summary":{"type":"object"},"claims":{"type":"array","items":{"type":"object","properties":{"claim_id":{"type":"string"},"text":{"type":"string"},"verdict":{"type":"string"},"confidence":{"type":"number"},"citations":{"type":"array","description":"Evidence quotes with url, title and source_type (wikipedia, wikidata, news, europepmc, fred, sec_edgar, or caller for your own sources).","items":{"type":"object"}},"next_step":{"type":"object","description":"Present only on unsure or low-confidence claims (check_answer) or unverified high/medium-worthiness factual claims (extract_claims; opinions and predictions skipped; max 3 per response). A ready-to-send request for this claim (optional, paid separately): Quick check ($0.15) from extract_claims, Deep verify from check_answer and quick_check. extract_claims adds alternatives[] with ready-to-send Quick check ($0.15), Deep verify ($0.75) and Verify claim ($1.00) requests.","properties":{"tool":{"type":"string","enum":["quick_check","deep_verify"],"description":"1.5.0: quick_check from extract_claims; deep_verify from check_answer and quick_check."},"why":{"type":"string"},"price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"method":{"type":"string","const":"POST"},"body":{"type":"object","properties":{"claim":{"type":"object","properties":{"text":{"type":"string"}},"required":["text"]}},"required":["claim"]},"alternatives":{"type":"array","description":"1.4.9 (extract_claims): every ready-to-send paid check for this claim. POST body to endpoint with an x402 client.","items":{"type":"object","properties":{"tool":{"type":"string","enum":["quick_check","deep_verify","verify_claim"]},"price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"method":{"type":"string","const":"POST"},"body":{"type":"object"},"when":{"type":"string"}},"required":["tool","price_usd","endpoint","method","body"]}}},"required":["tool","why","price_usd","endpoint","method","body"]}}}},"recommended_next_steps":{"type":"object","description":"1.4.8: summary of claim-level next_step suggestions.","properties":{"tool":{"type":"string"},"count":{"type":"integer","minimum":0},"total_price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"},"options":{"type":"array","description":"1.4.9 (extract_claims): cost to check all suggested claims with each tool.","items":{"type":"object","properties":{"tool":{"type":"string"},"price_usd_each":{"type":"number"},"total_price_usd":{"type":"number"},"endpoint":{"type":"string","format":"uri"}}}},"note":{"type":"string"}},"required":["tool","count","total_price_usd"]},"next_actions":{"type":"array","items":{"type":"object"}},"sources_used":{"type":"array","description":"Present when you sent sources: one entry per source with index, kind, url, title, status (used, fetch_failed, empty), chars and reason.","items":{"type":"object"}}},"additionalProperties":true},"message":{"type":"string","description":"Human-readable summary."}},"required":["status","tool","message"],"additionalProperties":true},"annotations":{"title":"Check answer","readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}},{"name":"deep_verify","title":"Deep verify","description":"Use when a claim is high-stakes, or when check_answer or extract_claims marks it unsure (their next_step gives the exact request). Verifies up to three claims against Wikipedia, Wikidata, Google News, Europe PMC, FRED and SEC EDGAR; returns verdict, confidence, evidence for and against with URLs, and flags contradictions. Async: poll GET /v1/jobs/{job_id} free. $0.75 USDC on Base via x402. Read-only.","inputSchema":{"type":"object","properties":{"answer":{"type":"string","description":"The claim or short text to verify (up to three claims are checked).","minLength":1,"examples":["US unemployment was 3.7% in December 2023."]},"sources":{"type":"array","maxItems":10,"items":{"type":"object","description":"One source: {url} for a public https page we fetch, or {text, title?, url?} for text you already have.","properties":{"url":{"type":"string","format":"uri","maxLength":2048,"description":"Public https URL. Fetched with a 3.5 s timeout and a 512 KB cap; http, file and other schemes, private / loopback / link-local / metadata addresses, IP-literal hosts, custom ports and URLs with credentials are rejected (HTTP 400, not charged). With text, it is only the citation link."},"text":{"type":"string","minLength":1,"maxLength":20000,"description":"Source text to check the claim against (up to 20,000 characters). When given, no fetch is made."},"title":{"type":"string","maxLength":200,"description":"Optional title shown in citations."}},"anyOf":[{"required":["url"]},{"required":["text"]}],"additionalProperties":false},"description":"Optional. Up to 10 sources of your own, used as extra evidence next to the public sources and cited with provider and source_type \"caller\". The response lists what was used in sources_used."},"sources_only":{"type":"boolean","default":false,"description":"Optional. true = judge the claim only against your sources (no public-source lookups). Needs a non-empty sources array."}},"required":["answer"],"additionalProperties":false},"outputSchema":{"type":"object","properties":{"status":{"type":"string","enum":["payment_required","ok"],"description":"payment_required: pay the HTTP route with x402 to get the result. ok: result is included."},"tool":{"type":"string","description":"Tool name."},"payment":{"type":"object","description":"Payment instructions. MCP tools/call does not charge or run the paid work; call the HTTP route with x402.","properties":{"protocol":{"type":"string","description":"Payment protocol, always x402 (v2)."},"method":{"type":"string","description":"HTTP method for the paid route."},"url":{"type":"string","description":"Paid HTTP route to call."},"price":{"type":"string","description":"Price in USD, paid as USDC."},"amount":{"type":"string","description":"Price in USDC base units (6 decimals)."},"network":{"type":"string","description":"CAIP-2 network id (eip155:8453 = Base mainnet)."},"asset":{"type":"string","description":"USDC contract address on Base."},"pay_to":{"type":"string","description":"Receiving wallet address."},"body":{"type":"object","description":"JSON body to POST (the tool arguments you sent).","additionalProperties":true},"how":{"type":"string","description":"Step-by-step payment flow."}},"required":["protocol","method","url","price","network"]},"result":{"type":"object","description":"Paid result: { mode: 'deep', status: 'queued', job_id, receipt }. Poll GET /v1/jobs/{job_id} for { verdict, confidence, contradiction, evidence_for[], evidence_against[], citations[] }.","properties":{"job_id":{"type":"string"},"status":{"type":"string"}},"additionalProperties":true},"message":{"type":"string","description":"Human-readable summary."}},"required":["status","tool","message"],"additionalProperties":true},"annotations":{"title":"Deep verify","readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}}],"prompts":[{"name":"fact_check_answer","title":"Fact-check an answer","description":"Plan a fact-check of an AI answer with Claim Grounding: extract claims, then verify the checkable ones and report verdicts with sources.","arguments":[{"name":"answer","description":"The answer text to fact-check.","required":true}]},{"name":"deep_check_claim","title":"Deep-check one claim","description":"Run a multi-source Deep verify on one claim and summarize agreement or contradiction between sources.","arguments":[{"name":"claim","description":"The single factual claim to check.","required":true}]}],"resources":[{"uri":"claim-grounding://pricing","name":"pricing","title":"Prices and payment","description":"Agent prices per tool and how x402 payment works.","mimeType":"text/markdown"},{"uri":"claim-grounding://verdicts","name":"verdicts","title":"Verdict meanings","description":"What each verdict value means.","mimeType":"text/markdown"}]}