mcp-lint

If you're building MCP servers that need to work across Claude, Cursor, Gemini, VS Code Copilot, and other clients, this is your schema validator. It checks tool definitions against client-specific quirks before they break in production. Run it as a CLI to catch issues like required: false (invalid JSON Schema), missing additionalProperties (breaks OpenAI strict mode), or nested objects that confuse Gemini. The compat command shows a cross-client matrix so you know exactly which tools work where. It auto-fixes safe issues, runs as a watch process during development, and can lint live servers over stdio or SSE. Think of it as a linter for the JSON Schema layer between your MCP server and the eight different clients trying to parse it.