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mcp-compat-check

v0.1.0

Published

Check your own MCP server the way Claude, Cursor and ChatGPT connect to it: protocol version, OAuth discovery, tool schemas.

Vulnerabilities

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Links

Git

Maintainers

franckyofranckyo

Keywords

mcpmodel-context-protocolmcp-serveroauthcompatibilitycheckercli

Readme

MCP Compatibility Check

Check your own MCP server the way Claude, Cursor and ChatGPT connect to it, and get the results in plain language.

npx mcp-compat-check https://mcp.yourcompany.com/mcp

What it checks:

  • Spec 2026-07-28: server/discover, with fallback to the older initialize handshake
  • Protocol negotiation: the version agreed, and whether newer versions are rejected instead of negotiated
  • OAuth sign-in: the discovery documents clients read (WWW-Authenticate, protected-resource metadata and the resource-URL match Cursor enforces, authorization-server metadata, PKCE S256, CIMD / DCR registration)
  • Tools: JSON Schema validity (2020-12), object input schemas, output schemas, names, duplicates
  • Sessions: servers that reject their own Mcp-Session-Id

What it never does: call tools, send credentials, change data, follow redirects, or connect to private/internal addresses (every DNS answer is checked at connect time).

Add --json for machine-readable output (useful in CI). Requires Node.js 20+. Run it only on servers you own or operate.

Page: https://franckyo.github.io/mcp-compat-check/

Want the problems fixed? I fix MCP servers for a fixed price agreed up front (spec upgrades, OAuth for Claude/ChatGPT connectors, broken tools, SDK migrations): [email protected]