{
  "$comment": "A2A (Agent-to-Agent protocol) agent card. SendFax.sh is not a conversational A2A agent; this card advertises its single skill — sending a fax — and points at the paid HTTP API and OpenAPI spec that back it. Authentication is per-request payment (x402/MPP), not a token scheme.",
  "protocolVersion": "0.3.0",
  "name": "SendFax.sh",
  "description": "Send real faxes over HTTP. Pay per page with x402 or MPP (USDC) — no account, no API key.",
  "url": "https://sendfax.sh",
  "preferredTransport": "HTTP+JSON",
  "provider": {
    "organization": "SendFax.sh",
    "url": "https://sendfax.sh"
  },
  "version": "1.0.0",
  "documentationUrl": "https://sendfax.sh/llms.txt",
  "iconUrl": "https://sendfax.sh/favicon.ico",
  "capabilities": {
    "streaming": false,
    "pushNotifications": false,
    "stateTransitionHistory": true
  },
  "defaultInputModes": ["application/pdf", "application/json"],
  "defaultOutputModes": ["application/json"],
  "securitySchemes": {
    "x402": {
      "type": "http",
      "scheme": "PAYMENT",
      "description": "Per-request payment via x402 (USDC). Pay on 402 and retry with X-PAYMENT."
    },
    "mpp": {
      "type": "http",
      "scheme": "Payment",
      "description": "Per-request payment via MPP (USDC). Pay on 402 (WWW-Authenticate: Payment) and retry with PAYMENT."
    }
  },
  "security": [{ "x402": [] }, { "mpp": [] }],
  "skills": [
    {
      "id": "send-fax",
      "name": "Send a fax",
      "description": "Send a PDF to an E.164 fax number, paid per page ($0.05/page, USDC) via x402 or MPP. Returns a status URL you can poll until the fax is delivered or failed.",
      "tags": ["fax", "telephony", "x402", "mpp", "usdc", "payments"],
      "examples": [
        "Fax invoice.pdf to +14155550123",
        "Send this PDF as a fax to +442071838750 and tell me when it's delivered"
      ],
      "inputModes": ["application/pdf"],
      "outputModes": ["application/json"]
    }
  ],
  "additionalInterfaces": [
    { "transport": "HTTP+JSON", "url": "https://sendfax.sh/api/v1" }
  ]
}