Gemini Email Subject Generator MCP

A powerful Model Context Protocol (MCP) server that leverages Google’s Gemini Flash 2 AI model to generate engaging email subjects and detailed thinking processes. This tool integrates seamlessly with Claude Desktop to provide intelligent email subject generation and advanced content creation.

🌟 Features

1. Email Tool with AI Subject Generation (send-email)

• Sends emails with AI-generated subjects using Gemini Flash 2
• Features:
  • Dynamic subject generation based on provided prompt
  • Support for HTML and plain text email content
  • Image attachments with inline display capability
  • Secure authentication using environment variables
  • Error handling and status reporting
  • Fully customizable content with rich formatting options
  • Instant delivery with message tracking

2. Thinking Generation Tool (generate-thinking)

• Generates detailed thinking process text using Gemini’s Flash 2 model
• Supports complex reasoning and analysis
• Saves responses with timestamps
• Customizable output directory
• Ideal for brainstorming, planning, and content creation

🚀 Quick Start

Prerequisites

• Node.js (v16 or higher)
• TypeScript
• Claude Desktop
• Google Gemini API Key
• SMTP Email Account (for email functionality)

Installation

1. Clone and setup:

git clone [your-repo-url]
cd gemini-email-subject-generator
npm install

2. Create .env file:

GEMINI_API_KEY=your_api_key_here
NODEMAILER_EMAIL=your.email@gmail.com
NODEMAILER_PASSWORD=your_app_password_here

3. Build the project:

npm run build

Claude Desktop Configuration

1. Create/Edit %AppData%/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "Gemini Email Generator": {
      "command": "node",
      "args": ["path/to/gemini-email-subject-generator/dist/index.js"],
      "cwd": "path/to/gemini-email-subject-generator",
      "env": {
        "GEMINI_API_KEY": "your_api_key_here",
        "NODEMAILER_EMAIL": "your.email@gmail.com",
        "NODEMAILER_PASSWORD": "your_app_password_here"
      }
    }
  }
}

2. Restart Claude Desktop

📊 Using the Tools

Email Sending with AI Subject Generation

{
  "name": "send-email",
  "arguments": {
    "to": "recipient@example.com",
    "subjectPrompt": "Create a catchy subject line for a marketing email about our new AI-powered analytics platform",
    "text": "Hello! This is the plain text version of our email.",
    "html": "<h1>Hello!</h1><p>This is the <b>HTML</b> version of our email with an inline image: <img src='cid:image0'/></p>",
    "images": [
      {
        "name": "chart.png",
        "data": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAA..."
      }
    ]
  }
}

Important Note About Email Tool: When you use the send-email tool, Claude will display a confirmation message that the email was sent successfully. This confirmation message is NOT the content of the email - it’s just feedback to you that the operation succeeded. The actual email sent to the recipient will contain only the content you specified in the text and html fields, with the subject generated by Gemini based on your prompt.

Thinking Generation

{
  "name": "generate-thinking",
  "arguments": {
    "prompt": "Your complex analysis prompt here",
    "outputDir": "./custom_output"
  }
}

📁 Output Structure

output/
└── thinking/
    └── gemini_thinking_[timestamp].txt

🛠️ Development

Available Scripts

• npm run build: Compile TypeScript to JavaScript
• npm run start: Start the MCP server
• npm run dev: Run in development mode with ts-node

Environment Variables

• GEMINI_API_KEY: Your Google Gemini API key
• NODEMAILER_EMAIL: Your email address for sending emails
• NODEMAILER_PASSWORD: Your email app password (for Gmail, use an app password)

🔒 Security Notes

• Store your API keys securely
• Don’t share your .env file
• For Gmail, use app passwords instead of your main account password
• Be careful with the content of emails sent through the system
• Never include sensitive or personal information in email examples

🐛 Troubleshooting

Common Issues

1. API Key Error

   • Verify .env file exists
   • Check API key validity
   • Ensure proper environment loading

2. Claude Desktop Connection

   • Verify config.json syntax
   • Check file paths in config
   • Restart Claude Desktop

3. Email Sending Issues

   • Check that NODEMAILER_EMAIL and NODEMAILER_PASSWORD are set correctly
   • For Gmail, ensure you’ve created an app password
   • Verify that less secure app access is enabled for non-Gmail providers
   • Check recipient email address format
   • Ensure image data is properly formatted as data URI (data:image/type;base64,)

Debug Mode

Add DEBUG=true to your .env file for verbose logging:

GEMINI_API_KEY=your_key_here
DEBUG=true

📚 API Reference

Email Sending Tool

interface SendEmailParams {
  to: string;              // Recipient email address
  subjectPrompt: string;   // Prompt for generating email subject
  text: string;            // Plain text version of email
  html?: string;           // HTML version of email (optional)
  images?: {               // Optional images to attach
    name: string;          // Image filename
    data: string;          // Base64 encoded image data
  }[];
}

Thinking Generation Tool

interface GenerateThinkingParams {
  prompt: string;           // Analysis prompt
  outputDir?: string;       // Optional output directory
}

🤝 Contributing

1. Fork the repository
2. Create your feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

📄 License

MIT License - See LICENSE file for details