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MCP Server Cards (SEP-1649)

Publishing Model Context Protocol metadata at /.well-known/mcp/server-card.json for instant agent discovery.

Executive Overview

SEP-1649 specifies how Model Context Protocol (MCP) servers advertise their SSE/WebSocket transport endpoints, capabilities, and tool schemas at /.well-known/mcp/server-card.json.

1. The Server Card Schema

The server card provides all information needed for Claude Code, Cursor, Windsurf, or Antigravity to attach to the MCP server:

  • serverInfo: Name and semantic version.
  • transport: Transport type (sse, websocket, http-post) and URL.
  • capabilities: Supported MCP primitives (tools, resources, prompts, logging).

Frequently Asked Questions

How is an MCP Server Card different from OpenAPI?

OpenAPI describes REST endpoints. An MCP Server Card describes stateful RPC capabilities (tools, dynamic resources, prompts) with live streaming transports.

AI Summary

SEP-1649 specifies how Model Context Protocol (MCP) servers advertise their SSE/WebSocket transport endpoints, capabilities, and tool schemas at /.well-known/mcp/server-card.json.