Source Claim Proof

{
  "protocolVersion": "1.0",
  "name": "Source Claim Proof",
  "description": "Verify whether a supplied public source page currently supports one atomic factual claim. Returns supported, contradicted, or insufficient-evidence plus source snippets, or explicit blocked/unreachable/unsupported states. Not a general fact checker or web search.",
  "url": "https://source-claim-proof.mattskowronis.workers.dev/a2a",
  "preferredTransport": "JSONRPC",
  "additionalInterfaces": [
    {
      "url": "https://source-claim-proof.mattskowronis.workers.dev/a2a",
      "transport": "JSONRPC"
    },
    {
      "url": "https://source-claim-proof.mattskowronis.workers.dev/v1/verify",
      "transport": "HTTP+JSON"
    }
  ],
  "provider": {
    "organization": "Matthew Skowron",
    "url": "https://source-claim-proof.mattskowronis.workers.dev"
  },
  "version": "1.0.0",
  "documentationUrl": "https://source-claim-proof.mattskowronis.workers.dev/openapi.json",
  "defaultInputModes": [
    "application/json"
  ],
  "defaultOutputModes": [
    "application/json"
  ],
  "skills": [
    {
      "id": "verify_source_claim",
      "name": "Verify Source Claim",
      "description": "Check whether a supplied public source currently supports one atomic factual claim. Returns supported, contradicted, or insufficient-evidence plus source snippets.",
      "tags": [
        "claim-verification",
        "source-evidence",
        "citation-check",
        "research-preflight"
      ],
      "examples": [
        "Does this page say admission costs $45?",
        "Confirm the event starts at 7:00 PM on this source.",
        "Check whether this documentation still states a three-year warranty."
      ]
    }
  ],
  "securitySchemes": {
    "x402": {
      "type": "apiKey",
      "in": "header",
      "name": "PAYMENT-SIGNATURE",
      "description": "x402 exact scheme, $0.01 USDC on eip155:8453"
    }
  },
  "security": [
    {
      "x402": []
    }
  ],
  "protocol": "x402",
  "x402Version": 2,
  "environment": "production",
  "payment": {
    "method": "POST",
    "path": "/v1/verify",
    "scheme": "exact",
    "price": "$0.01",
    "network": "eip155:8453",
    "asset": "USDC",
    "payTo": "0x22B3D4485C8Dcd8FC4840a7570664747c9055530"
  },
  "input_schema": {
    "type": "object",
    "additionalProperties": false,
    "required": [
      "url",
      "claim"
    ],
    "properties": {
      "url": {
        "type": "string",
        "maxLength": 2048,
        "description": "Public HTTP or HTTPS source page URL to inspect."
      },
      "claim": {
        "type": "string",
        "minLength": 3,
        "maxLength": 500,
        "description": "One atomic factual assertion to check against that source only."
      }
    }
  },
  "output_schema": {
    "type": "object",
    "additionalProperties": false,
    "required": [
      "verdict",
      "claim",
      "source_url",
      "final_url",
      "source_status",
      "evidence",
      "reasoning_summary",
      "retrieval_method",
      "retrieved_at",
      "content_hash",
      "service_version"
    ],
    "properties": {
      "verdict": {
        "type": "string",
        "enum": [
          "supported",
          "contradicted",
          "insufficient_evidence"
        ],
        "description": "supported, contradicted, or insufficient_evidence."
      },
      "claim": {
        "type": "string",
        "description": "The claim that was checked."
      },
      "source_url": {
        "type": "string",
        "description": "Requested source URL."
      },
      "final_url": {
        "type": "string",
        "description": "Final URL after redirects."
      },
      "source_status": {
        "type": "string",
        "enum": [
          "verified",
          "blocked",
          "unreachable",
          "unsupported",
          "insufficient_evidence"
        ],
        "description": "verified, blocked, unreachable, unsupported, or insufficient_evidence."
      },
      "evidence": {
        "type": "array",
        "maxItems": 3,
        "description": "Compact source snippets used for the verdict.",
        "items": {
          "type": "object",
          "additionalProperties": false,
          "required": [
            "text",
            "location",
            "evidence_type",
            "polarity"
          ],
          "properties": {
            "text": {
              "type": "string",
              "maxLength": 240,
              "description": "Source snippet that supports or contradicts the claim."
            },
            "location": {
              "type": [
                "string",
                "null"
              ],
              "description": "Page location of the snippet, or null if unknown."
            },
            "evidence_type": {
              "type": "string",
              "enum": [
                "visible_text",
                "heading",
                "json_ld",
                "meta",
                "status"
              ],
              "description": "Where the snippet came from on the source page."
            },
            "polarity": {
              "type": "string",
              "enum": [
                "supports",
                "contradicts",
                "neutral"
              ],
              "description": "Whether the snippet supports, contradicts, or is neutral."
            }
          }
        }
      },
      "reasoning_summary": {
        "type": "string",
        "maxLength": 400,
        "description": "Short machine-readable reason for the verdict."
      },
      "retrieval_method": {
        "type": "string",
        "enum": [
          "direct_http",
          "browser_run",
          "official_api",
          "unsupported"
        ],
        "description": "How the source page was fetched."
      },
      "retrieved_at": {
        "type": "string",
        "description": "UTC timestamp of the check."
      },
      "content_hash": {
        "type": "string",
        "description": "Hash of retrieved source content."
      },
      "service_version": {
        "type": "string",
        "description": "Source Claim Proof service version."
      }
    }
  },
  "input_example": {
    "url": "https://example.com/event",
    "claim": "The event begins at 7:00 PM."
  },
  "output_example": {
    "verdict": "supported",
    "claim": "The event begins at 7:00 PM.",
    "source_url": "https://example.com/event",
    "final_url": "https://example.com/event",
    "source_status": "verified",
    "evidence": [
      {
        "text": "Doors 6:30 PM. Program begins at 7:00 PM.",
        "location": "Schedule",
        "evidence_type": "visible_text",
        "polarity": "supports"
      }
    ],
    "reasoning_summary": "Visible schedule text states the program begins at 7:00 PM.",
    "retrieval_method": "direct_http",
    "retrieved_at": "2026-08-18T22:00:00.000Z",
    "content_hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "service_version": "1.0.0"
  },
  "network": "eip155:8453",
  "listed_price": "$0.01"
}