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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Model Context Protocol server is discoverable at/.well-known/mcp.jsonand meets SEP-2127, the current Server Card draft (superseded SEP-1649).

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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 should I publish an MCP server card?

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 Server Card convention (SEP-2127, still a Working Group draft) is quickly becoming table stakes for anyone publishing tools to agents.

What does the MCP card validator check?

  • C1 - Exists. Server Card is served at /.well-known/mcp.json with HTTP 200.
  • C2 - Fields. Required fields per the current schema — name, description, version — are present and valid. (SEP-1649's older shape — protocolVersion, serverInfo, transport — was superseded by SEP-2127 and is no longer required.)
  • C3 - OAuth metadata. If auth is required, the RFC 9728 resource metadata at /.well-known/oauth-protected-resource is reachable.

Minimal valid example (SEP-2127)

{
  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-10-17/server.schema.json",
  "name": "acme-weather",
  "description": "Live weather data for AI agents",
  "version": "1.0.0",
  "remotes": [
    { "type": "streamable-http", "url": "https://api.acme.dev/mcp" }
  ]
}

Served at /.well-known/mcp.json with Content-Type: application/json. If your server requires auth, also publish /.well-known/oauth-protected-resource.

Specifications

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