OpenAPI to MCP Generator (openapi-mcp-generator)

What is OpenAPI to MCP Generator?

A CLI tool that generates Model Context Protocol (MCP) servers from OpenAPI 3.0+ specifications. It produces proxy servers that let AI agents and MCP clients interact with existing REST APIs.

How to use OpenAPI to MCP Generator?

Install globally via npm (npm install -g openapi-mcp-generator), then run the CLI with --input (path/URL to an OpenAPI spec) and --output (target directory). Optionally specify transport (--transport=stdio|web|streamable-http), port, and other flags. The generated project can be run with npm start (stdio), npm run start:web, or npm run start:http.

Key features of OpenAPI to MCP Generator

• Converts OpenAPI 3.0+ specs into MCP-compatible servers
• Proxies calls to the original REST API with validation and auth
• Supports API key, Bearer, Basic, and OAuth2 authentication
• Generates Zod schemas for runtime input validation
• Outputs a complete, typed TypeScript project with dependencies
• Offers three transport modes: stdio, SSE (web), and StreamableHTTP
• Includes a browser-based test client for web transports

Use cases of OpenAPI to MCP Generator

• Expose an existing REST API as MCP tools for AI assistants
• Quickly scaffold an MCP server from a well-defined OpenAPI spec
• Test and debug MCP interactions locally with stdio transport
• Deploy a multi-client MCP server behind a firewall using HTTP transports