OpenAI MCP Server

A Model Context Protocol (MCP) server that enables AI assistants to interact with OpenAI's ChatGPT API.

Features

• Chat Completion: Generate text using OpenAI's latest language models (GPT-4.1, GPT-4.1-mini, GPT-4.1-nano, GPT-4o, o1, o1-pro, o3, o4-mini)
• List Models: Retrieve available OpenAI models
• Configurable Parameters: Control temperature, max tokens, and other generation settings

Prerequisites

• Node.js 18 or higher
• OpenAI API key

Installation

# Clone the repository
git clone https://github.com/akiojin/openai-mcp-server.git
cd openai-mcp-server

# Install dependencies
npm install

# Build the project
npm run build

Configuration

1. Create a .env file in the project root:

cp .env.example .env

1. Add your OpenAI API key to the .env file:

OPENAI_API_KEY=your_api_key_here

Usage

使用例

このMCPサーバーは、Claude CodeなどのAIアシスタントから呼び出して使用することを想定しています：

• 出力結果の検証: Claude Codeの出力結果をChatGPTに検証させることができます
• 画像生成: Claude Codeでは直接画像生成ができませんが、このMCPサーバー経由でChatGPTのgpt-image-1モデルを使用した画像生成が可能です
• 異なるモデルの活用: 用途に応じて様々なOpenAIモデル（GPT-4.1、o1、o3など）を使い分けることができます

As an MCP Server

Add the server to your MCP client configuration:

{
  "servers": {
    "openai": {
      "command": "node",
      "args": ["path/to/openai-mcp-server/dist/index.js"]
    }
  }
}

Available Tools

chat_completion

Generate text using ChatGPT.

Parameters:

• model (string, optional): Model to use (default: "gpt-4.1")
• messages (array, required): Chat history with role and content
• temperature (number, optional): Sampling temperature 0-2 (default: 0.7)
  • Note: GPT-5 models only support temperature=1
• max_tokens (number, optional): Maximum tokens to generate
  • For GPT-4 models: defaults to 1000
  • For GPT-5 models: optional - if not specified, model automatically allocates necessary tokens
• reasoning_effort (string, optional): GPT-5 only - Controls reasoning depth
  • minimal: Fast responses, no reasoning tokens
  • low: Light reasoning
  • medium: Standard reasoning (default)
  • high: Deep reasoning for complex analysis
• verbosity (string, optional): GPT-5 only - Response length (low/medium/high)

list_models

List all available OpenAI models.

generate_image

Generate images using gpt-image-1 model. Returns file paths for generated images saved in temporary directory.

Parameters:

• prompt (string, required): Text description of the desired image(s). Maximum 1000 characters.
• model (string, optional): Model to use (default: "gpt-image-1")
• n (number, optional): Number of images to generate 1-10 (default: 1)
• size (string, optional): Size of images - "1024x1024", "1024x1536", "1536x1024", or "auto" (default: "1024x1024")
• quality (string, optional): Quality - "low", "medium", "high", or "auto" (default: "auto")
• background (string, optional): Background type - "opaque" or "transparent" (default: "opaque")

Note: Generated images are saved as temporary files to minimize token usage. The response includes file paths instead of base64 data.

Example:

{
  "prompt": "A beautiful sunset over mountains",
  "size": "1024x1024",
  "quality": "high",
  "background": "opaque"
}

Development

# Run in development mode with hot reload
npm run dev

# Build for production
npm run build

# Watch mode for development
npm run watch

Project Structure

openai-mcp-server/
├── src/
│   └── index.ts       # Main server implementation
├── dist/              # Compiled JavaScript (generated)
├── .env               # Environment variables (create from .env.example)
├── .env.example       # Example environment configuration
├── package.json       # Project dependencies and scripts
├── tsconfig.json      # TypeScript configuration
└── README.md          # This file

License

MIT License - see LICENSE file for details

Release Process

This project uses semantic-release for automated versioning and publishing.

Commit Message Format

Follow Conventional Commits format:

<type>(<scope>): <description>

[optional body]

[optional footer(s)]

Commit Types

• feat: new feature (minor version bump)
• fix: bug fix (patch version bump)
• BREAKING CHANGE: breaking change (major version bump)
• docs: documentation changes (patch version bump)
• style: formatting changes (patch version bump)
• refactor: code refactoring (patch version bump)
• test: adding tests (patch version bump)
• chore: maintenance tasks (patch version bump)

Examples

# New feature (0.1.0 → 0.2.0)
feat: add streaming support for chat completion

# Bug fix (0.1.0 → 0.1.1)
fix: handle connection timeout properly

# Breaking change (0.1.0 → 1.0.0)
feat: redesign API interface

BREAKING CHANGE: The chat_completion tool now requires a different parameter structure

Helper Scripts

# Interactive commit with commitizen
npm run commit

# Test release without publishing
npm run release:dry-run

# Manual release (usually handled by CI)
npm run release

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Follow conventional commit format for your commits
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Support

For issues and feature requests, please use the GitHub issue tracker.