openapi-mcp-generator

What it does

The server reads OpenAPI 3.0+ specifications and generates a complete MCP-compatible TypeScript/Node.js project. It creates MCP tools that proxy calls to your underlying REST API while automatically generating Zod schemas for request validation. Built-in support for multiple authentication methods: API keys, Bearer tokens, Basic auth, and OAuth2. Choose your transport layer: stdio for local use, or web-based transports (Hono/SSE or StreamableHTTP) for remote access. The generated project includes a full Node.js scaffold with tsconfig.json, package.json, and browser-based test clients for web transports.

Who it's for

Backend engineers and API maintainers who want to quickly expose existing REST services to Claude and other MCP clients without manual scaffolding.

Common use cases

• Expose an existing REST API to Claude Code and Claude Chat via MCP
• Generate a typed, validated MCP proxy for a third-party REST API
• Set up a local stdio MCP server for testing API calls in Claude
• Deploy a web-based MCP server with SSE transport for remote AI agent integration
• Create a Node.js project scaffold with authentication and Zod validation pre-configured

Setup pitfalls

• OpenAPI spec must be valid 3.0+ (YAML or JSON); provide via --input (local file or URL)
• If the OpenAPI spec lacks a servers section, you must supply --base-url explicitly
• Authentication is configured via environment variables in .env; the generator creates .env.example but you populate it with actual credentials
• Transport mode is critical: stdio for local use, web or streamable-http for web deployment