OpenAPI to MCP Generator

A command-line tool that generates Model Context Protocol (MCP) server code from OpenAPI specifications. This tool helps you quickly create an MCP server that acts as a bridge between LLMs (Large Language Models) and your API.

Features

Automatic Tool Generation: Converts each API endpoint in your OpenAPI spec into an MCP tool
Multiple Transport Options: Supports stdio, WebSocket, and HTTP transport methods
Complete Project Setup: Generates all necessary files to run an MCP server
TypeScript Support: Includes TypeScript definitions and configuration
Easy Configuration: Simple environment-based configuration for the generated server

Installation

# Install globally from npm
npm install -g openapi-mcp-generator

# Or with yarn
yarn global add openapi-mcp-generator

# Or with pnpm
pnpm add -g openapi-mcp-generator

Usage

Generate an MCP server from an OpenAPI specification:

openapi-mcp-generator --openapi path/to/openapi.json --output /Path/to/output

Command Line Options

Option	Alias	Description	Default
`--openapi`	`-o`	Path or URL to OpenAPI specification	(required)
`--output`	`-d`	Output directory for generated files	`./mcp-server`
`--name`	`-n`	Name for the MCP server	`openapi-mcp-server`
`--version`	`-v`	Version for the MCP server	`1.0.0`
`--transport`	`-t`	Transport mechanism (stdio, websocket, http)	`stdio`
`--port`	`-p`	Port for websocket or HTTP server	`3000`
`--help`	`-h`	Show help information

Examples

Generate from a local OpenAPI file:

openapi-mcp-generator --openapi ./specs/petstore.json --output ./petstore-mcp

Generate from a remote OpenAPI URL:

openapi-mcp-generator --openapi https://petstore3.swagger.io/api/v3/openapi.json --output ./petstore-mcp

Specify a WebSocket transport:

openapi-mcp-generator --openapi ./specs/petstore.json --transport websocket --port 8080

Generated Files

The tool generates the following files in the output directory:

server.js - The main MCP server implementation
package.json - Dependencies and scripts
README.md - Documentation for the generated server
.env.example - Template for environment variables
types.d.ts - TypeScript type definitions for the API
tsconfig.json - TypeScript configuration

Using the Generated Server

After generating your MCP server:

Navigate to the generated directory:
```
cd my-mcp-server
```
Install dependencies:
```
npm install
```
Create an environment file:
```
cp .env.example .env
```

Edit .env to set your API base URL and any required headers:

API_BASE_URL=https://api.example.com
API_HEADERS=Authorization:Bearer your-token-here

Start the server:
```
npm start
```

Programmatic Usage

You can also use the package programmatically in your Node.js projects:

const { generateMcpServer } = require('openapi-mcp-generator');

// Using async/await
async function generate() {
  try {
    const result = await generateMcpServer({
      openapi: './specs/petstore.json',
      output: './petstore-mcp',
      transport: 'http',
      port: 3000
    });
    console.log(`MCP server generated at: ${result.outputPath}`);
  } catch (error) {
    console.error('Generation failed:', error);
  }
}

generate();

Requirements

Node.js 16.x or higher
npm 7.x or higher

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Fork the repository
Create your feature branch (git checkout -b feature/amazing-feature)
Commit your changes (git commit -m 'Add some amazing feature')
Push to the branch (git push origin feature/amazing-feature)
Open a Pull Request

License

MIT