MCP Runner

A CLI tool that generates a Model Context Protocol (MCP) server from a Swagger/OpenAPI document.

Features

• 🚀 Generate a fully functional MCP server from a Swagger/OpenAPI JSON document
• 📝 Automatically create TypeScript API types from schemas
• 🔧 Support for all HTTP methods and parameter types (query, path, header, body)
• 📡 Built-in stdio transport for MCP communication
• 🎯 Each API endpoint becomes an MCP tool with proper descriptions and input schemas
• 📦 Generates complete project structure with build configuration

Installation

# Install dependencies
npm install

# Build the project
npm run build

# Link globally (optional)
npm link

Usage

Basic Usage

node dist/cli.js --doc <swagger-json-path-or-url> [--output <output-directory>]

Examples

# Generate MCP server from a local Swagger document
node dist/cli.js --doc api-spec.json --output my-api-server

# Generate from a remote URL
node dist/cli.js --doc https://petstore.swagger.io/v2/swagger.json --output petstore-server

# Use default output directory (./generated-mcp-server)
node dist/cli.js --doc api-spec.json

Options

• --doc <path>: Path or URL to Swagger/OpenAPI JSON document (required)
• --output <path>: Output directory for generated MCP server (default: ./generated-mcp-server)
• --help: Display help information
• --version: Display version information

Generated MCP Server

The generated MCP server includes:

• src/index.ts: Main MCP server implementation with tools for each API endpoint
• src/types.ts: TypeScript types generated from Swagger schemas
• package.json: Node.js package configuration with dependencies
• tsconfig.json: TypeScript compilation configuration
• README.md: Documentation for the generated server

Running the Generated Server

cd <output-directory>
npm install
npm run build
npm start

The server runs on stdio transport and can be used with any MCP-compatible client.

How It Works

1. Parse Swagger: Reads and validates the provided Swagger/OpenAPI document
2. Extract Endpoints: Identifies all API endpoints with their methods, parameters, and schemas
3. Generate Types: Creates TypeScript interfaces and types from Swagger schemas
4. Create Tools: Maps each API endpoint to an MCP tool with proper input validation
5. Build Server: Generates a complete MCP server with stdio transport
6. Package Project: Creates a buildable Node.js project with all necessary files

API Endpoint Mapping

Each API endpoint in your Swagger document becomes an MCP tool:

• Tool Name: Uses the operationId from Swagger, or generates one from method + path
• Description: Uses the summary or description from the endpoint
• Input Schema: Combines query parameters, path parameters, headers, and request body
• HTTP Handling: Properly constructs HTTP requests with all parameters and headers

Parameter Support

• Query Parameters: Added to the request URL
• Path Parameters: Substituted in the URL path
• Header Parameters: Added to request headers
• Request Body: Sent as JSON in the request body
• Response Handling: Returns the full HTTP response including status, headers, and data

Examples

Input Swagger Document

{
  "openapi": "3.0.0",
  "info": {
    "title": "User API",
    "version": "1.0.0"
  },
  "paths": {
    "/users/{id}": {
      "get": {
        "operationId": "getUserById",
        "summary": "Get user by ID",
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": { "type": "string" }
          }
        ]
      }
    }
  }
}

Generated MCP Tool

The above endpoint becomes an MCP tool named getUserById with:

• Description: "Get user by ID"
• Input schema requiring an id string parameter
• HTTP GET request to /users/{id} with path parameter substitution

Development

Project Structure

mcpr/
├── src/
│   ├── cli.ts           # CLI entry point
│   ├── parser.ts        # Swagger document parser
│   ├── generator.ts     # MCP server generator
│   ├── type-generator.ts # TypeScript type generator
│   └── templates.ts     # Code templates
├── dist/                # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Scripts

• npm run build: Compile TypeScript to JavaScript
• npm run dev: Run CLI in development mode with tsx
• npm run lint: Run ESLint
• npm run typecheck: Run TypeScript type checking

Requirements

• Node.js 18+
• TypeScript 5+
• Swagger/OpenAPI 3.0+ documents

TODO

• Add optional parameter for initializing a git repository at the output directory
• Add optional parameter for specifying the transport type (stdio, http, etc.)
• Add tests for the CLI
• Add support for authentication (e.g. API keys, OAuth)