x402 Format Checker

{
  "protocolVersion": "0.3.0",
  "name": "x402 Format Checker",
  "description": "Format and checksum validation for IBAN, EU VAT, Polish NIP/REGON/PESEL and email, pay-per-call via x402. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Send message/send with a data part {\"type\": \"<skill id>\", \"value\": \"...\"}; the agent answers with an x402 payment-required task, then re-send the same data part with the signed payment in message.metadata (stateless: nothing is stored).",
  "url": "https://validate.crewofthecaptain.com/a2a",
  "preferredTransport": "JSONRPC",
  "version": "1.3.0",
  "provider": {
    "organization": "Crew of the Captain",
    "url": "https://crewofthecaptain.com"
  },
  "documentationUrl": "https://validate.crewofthecaptain.com/llms.txt",
  "capabilities": {
    "streaming": false,
    "pushNotifications": false,
    "stateTransitionHistory": false,
    "extensions": [
      {
        "uri": "https://github.com/google-agentic-commerce/a2a-x402/blob/main/spec/v0.2",
        "description": "Supports payments using the x402 protocol for on-chain settlement. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.",
        "required": true
      }
    ]
  },
  "defaultInputModes": [
    "application/json"
  ],
  "defaultOutputModes": [
    "application/json"
  ],
  "skills": [
    {
      "id": "iban",
      "name": "Validate iban",
      "description": "IBAN: country length + ISO 13616 mod-97 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.",
      "tags": [
        "validation",
        "format",
        "checksum",
        "x402",
        "iban"
      ],
      "examples": [
        "{\"type\":\"iban\",\"value\":\"PL61109010140000071219812874\"}"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "eu-vat",
      "name": "Validate eu-vat",
      "description": "EU VAT number: per-country format (offline, no VIES); PL also NIP checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.",
      "tags": [
        "validation",
        "format",
        "checksum",
        "x402",
        "eu-vat"
      ],
      "examples": [
        "{\"type\":\"eu-vat\",\"value\":\"PL5260250274\"}"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "pl-nip",
      "name": "Validate pl-nip",
      "description": "Polish NIP tax id: 10 digits + weighted mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.",
      "tags": [
        "validation",
        "format",
        "checksum",
        "x402",
        "pl-nip"
      ],
      "examples": [
        "{\"type\":\"pl-nip\",\"value\":\"5260250274\"}"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "pl-regon",
      "name": "Validate pl-regon",
      "description": "Polish REGON: 9 or 14 digits + mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.",
      "tags": [
        "validation",
        "format",
        "checksum",
        "x402",
        "pl-regon"
      ],
      "examples": [
        "{\"type\":\"pl-regon\",\"value\":\"123456785\"}"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "pl-pesel",
      "name": "Validate pl-pesel",
      "description": "Polish PESEL: checksum + encoded birth date and sex. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.",
      "tags": [
        "validation",
        "format",
        "checksum",
        "x402",
        "pl-pesel"
      ],
      "examples": [
        "{\"type\":\"pl-pesel\",\"value\":\"44051401359\"}"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "email",
      "name": "Validate email",
      "description": "Email address syntax (dot-atom local part, LDH domain; no DNS). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.",
      "tags": [
        "validation",
        "format",
        "checksum",
        "x402",
        "email"
      ],
      "examples": [
        "{\"type\":\"email\",\"value\":\"captain@crewofthecaptain.com\"}"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    }
  ]
}