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MCP discovery validation

MCP Server Card validator

Check that your Model Context Protocol server is discoverable at/.well-known/mcp.jsonand meets the SEP-1649 specification.

What is an MCP Server Card?

The MCP Server Card is a JSON document at /.well-known/mcp.json that lets agents discover your Model Context Protocol server without prior configuration. It advertises the server’s transport, endpoint, capabilities, and auth requirements so clients like Claude Desktop, Cursor, or Cline can connect automatically.

Why adopt it

If you run an MCP server, Claude Desktop, Cursor, and Cline can’t auto-connect without a Server Card. Without one, users hand-configure transport endpoints and auth; with one, it’s a single-click install. The spec ratified on 2025-11-25 and is quickly becoming table stakes for anyone publishing tools to agents.

What we check

  • C1 - Exists. Server Card is served at /.well-known/mcp.json with HTTP 200.
  • C2 - Fields. Required fields per SEP-1649 (name, transport, endpoint) or SEP-2127 (registry listing format) are present and valid.
  • C3 - OAuth metadata. If auth is required, the RFC 9728 resource metadata at /.well-known/oauth-protected-resource is reachable.

Minimal valid example (SEP-1649)

{
  "protocolVersion": "2025-11-25",
  "serverInfo": {
    "name": "acme-weather",
    "version": "1.0.0"
  },
  "transport": {
    "type": "http",
    "endpoint": "https://api.acme.dev/mcp"
  },
  "capabilities": {},
  "authentication": { "required": false }
}

Served at /.well-known/mcp.json with Content-Type: application/json. If authentication.required is true, also publish /.well-known/oauth-protected-resource.

Specifications

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