What is Openapi Mcpserver Generator

openapi-mcpserver-generator is a command-line tool that generates Model Context Protocol (MCP) server code from OpenAPI specifications, facilitating the creation of an MCP server that connects Large Language Models (LLMs) with APIs.

Use cases

Use cases include generating MCP servers for AI applications, creating bridges between APIs and LLMs, and automating the setup of server infrastructure based on OpenAPI specifications.

How to use

To use openapi-mcpserver-generator, install it globally via npm, yarn, or pnpm. Then, run the command openapi-mcpserver-generator --openapi path/to/openapi.json --output /Path/to/output to generate an MCP server from your OpenAPI specification.

Key features

Key features include automatic tool generation for API endpoints, support for nested $ref in OpenAPI specifications, generation of MCP server configuration, easy environment-based configuration, and logging capabilities.

Where to use

openapi-mcpserver-generator can be used in software development environments where there is a need to integrate APIs with Large Language Models, particularly in applications involving AI and machine learning.

OpenAPI to MCP server 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.

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At the beginning

This repo is originally forked from openapi-mcp-generator, and add some additional features:

• Support nested $ref in openapi specifications
• Besides source code, generate MCP server configuration
• Allow client to set log level and send log message to client as notification
• When hit error, send message to stderr
• Support build docker image and guide client to run in docker container (2025/5/8 updated)

Features

• Automatic Tool Generation: Converts each API endpoint in your OpenAPI spec into an MCP tool
• Transport Options: Only supports stdio, for sse you can leveral mcp-proxy
• Complete Project Setup: Generates all necessary files to run an MCP server
• Easy Configuration: Simple environment-based configuration for the generated server

Installation

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

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

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

Usage

Generate an MCP server from an OpenAPI specification:

openapi-mcpserver-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
--help	-h	Show help information

Examples

Generate from a local OpenAPI file:

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

Generate from a remote OpenAPI URL:

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

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
• Dockerfile - Dockerfile
• .dockerignore - Docker ignore file

Using the Generated Server

After generating your MCP server:

1. Navigate to the generated directory:

   cd my-mcp-server
   

2. Install dependencies:

   npm install
   

3. Create an environment file:

   cp .env.example .env
   

4. 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
   

5. Start the server:

   npm start
   

Requirements

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

E2E example

Suggest use mcpclihost as MCP host to take a try.
This tool(mcpclihost) could support both Azure Openai and deepseek

You can add generated MCP server congiguration like this:

{
  "mcpServers": {
    "petstore-mcp": {
      "command": "/usr/local/bin/node",
      "args": [
        "/Users/lipeng/workspaces/github.com/vincent-pli/openapi-mcpserver-generator/petstore-mcp/server.js",
        "run"
      ]
    }
  }
}

to the ~/.mcp.json(default mcp server configuration path of mcpclihost), then take a try

Security Schemes in Openapi

Openapi 3.0 support 4 security types:

• apiKey:
  for example:

        "securitySchemes": {
            "my_api_key": {
                "type": "apiKey",
                "name": "api_key",
                "in": "header"
            }
        }

Expect a env param named upper cased MY_API_KEY_{securitySchemes.my_api_key.name}, in this case, it should be: MY_API_KEY_API_KEY defined in .env

• http:

        "securitySchemes": {
            basicAuth: {
               type: "http",
               scheme: "basic"
            }
        }

it try to find BASICAUTH_USERNAME and BASICAUTH_PASSWORD in .env

        "securitySchemes": {
            basicAuth: {
               type: "http",
               scheme: "bearer"
            }
        }

it try to find BASICAUTH_BEARERTOKEN in .env

• oauth2:
  Because of the complexity of oauth2, cannot handle it automaticly, we suggest manually get the access token, then set it to .env as this:

API_HEADERS=Authorization:Bearer your-access-token-here

• openIdConnect
  Not support yet

License

Apache 2.0