Gmail Send Skill - MCP Server

🚀 AI-Powered Email Sending Skill with Model Context Protocol (MCP) support

Send emails via Gmail using App Password authentication with Markdown content support, specifically designed for AI agents and MCP-compatible applications.

✨ Features

📧 Core Email Functionality

• Gmail SMTP Integration - Send emails through Gmail's secure SMTP server (Port 587, TLS)

• App Password Authentication - Secure authentication using Gmail App Passwords

• Rich Error Reporting - Detailed success/failure feedback with error types

• Input Validation - Comprehensive email and parameter validation

📝 Enhanced Markdown Support (v1.1.0+)

• Advanced Markdown Conversion - Full markdown library support with extensions (BSD license)

• Professional Email Styling - Email-safe CSS with responsive design

• Graceful Fallback System - Basic Markdown converter when external library unavailable

• Commercial License Compliance - BSD-licensed dependencies for commercial use

• Email Client Compatibility - Optimized HTML for major email clients

🤖 AI Integration

• MCP Compatible - Full Model Context Protocol support for AI agents

• OpenAI Function Calling - Compatible with OpenAI Function Calling standard

• Skill Framework - Standalone and integrated execution modes

Related MCP server: Gmail MCP Pro

🚀 Quick Start

1. Installation

# Clone the repository
git clone <repository-url>
cd mcp-server-gmail-send

# Run automated installation
chmod +x install.sh
./install.sh

2. Gmail Setup

1. Enable 2-Factor Authentication in your Gmail account

2. Generate App Password:

   • Go to Google Account → Security → 2-Step Verification → App Passwords

   • Select "Mail" and generate password

   • Save the 16-character password (e.g., abcd efgh ijkl mnop)

3. Claude Desktop Integration

# Copy configuration to Claude Desktop
cp claude_desktop_config.json ~/Library/Application\ Support/Claude/claude_desktop_config.json

# Restart Claude Desktop

4. Test the Setup

# Test the MCP server
python3 mcp_server.py --test

# Run comprehensive tests
python3 test_gmail_skill.py

📧 Usage Example

Enhanced Markdown to HTML Conversion (v1.1.0+)

The skill now supports advanced Markdown conversion with professional email styling:

Supported Markdown Features

• Headers (H1-H6) with proper hierarchy

• Text Formatting - Bold, italic, strikethrough

• Lists - Ordered and unordered with nesting

• Links - Automatic link formatting

• Code Blocks - Syntax highlighting and inline code

• Blockquotes - Professional quote styling

• Tables - Responsive table design (with markdown library)

Email Styling Features

• 📱 Responsive Design - Adapts to desktop and mobile email clients

• 🎨 Professional CSS - Clean, modern email appearance

• 📧 Email Client Compatibility - Works with Gmail, Outlook, Apple Mail, etc.

• 🔧 Graceful Fallback - Basic conversion when advanced features unavailable

Markdown Content Example

# Project Status Report

## Executive Summary
The project is **on track** with key milestones achieved:

### Completed Tasks ✅
1. User authentication system
2. Database schema design
3. API endpoints implementation

### In Progress 🚧
- Front-end development
- Integration testing
- Performance optimization

> **Note**: All deliverables are meeting quality standards.

For technical details, see: [Project Documentation](https://example.com/docs)

```python
def get_project_status():
    return "Active"

This Markdown will be converted to professional HTML email format automatically.

### Basic Email Sending

```python
from gmail_send_skill import GmailSendSkill
from skill_compat import ExecutionContext

# Initialize
skill = GmailSendSkill()
ctx = ExecutionContext()

# Send email
result = skill.execute(ctx,
    username="your.email@gmail.com",
    app_password="abcd efgh ijkl mnop", 
    content="# Hello World!\n\nThis is a **test** email with *markdown*.",
    to_email="recipient@example.com",
    subject="Test Email from Skill"
)

print(f"Success: {result['success']}")

Via AI Agent (Claude Desktop)

Simply ask Claude:

Can you send an email using the gmail_send function? I need to send:
- From: my.email@gmail.com  
- To: colleague@company.com
- Subject: Project Update
- Content: A markdown report about our progress

I'll provide my app password when prompted.

📊 Function Schema

OpenAI Function Calling Format

{
  "name": "gmail_send",
  "description": "Send email via Gmail using App Password authentication with Markdown support",
  "parameters": {
    "type": "object", 
    "properties": {
      "username": {
        "type": "string",
        "description": "Gmail address for authentication"
      },
      "app_password": {
        "type": "string", 
        "description": "16-character Gmail App Password"
      },
      "content": {
        "type": "string",
        "description": "Email content in Markdown format"
      },
      "to_email": {
        "type": "string",
        "description": "Recipient email address"
      },
      "subject": {
        "type": "string",
        "description": "Email subject line",
        "default": "Email from Gmail Send Skill"
      },
      "from_name": {
        "type": "string", 
        "description": "Display name for sender",
        "default": null
      }
    },
    "required": ["username", "app_password", "content", "to_email"]
  }
}

📋 Project Structure

mcp-server-gmail-send/
├── 📄 gmail_send_skill.py      # Main skill implementation
├── 🔧 skill_compat.py          # Framework compatibility layer  
├── 🖥️  mcp_server.py           # MCP server with stdio transport
├── 📊 version.py               # Version management
├── 🧪 test_gmail_skill.py      # Comprehensive test suite
├── ⚙️  mcp_config.json         # MCP client configuration
├── 🔌 claude_desktop_config.json # Claude Desktop integration
├── 📦 requirements.txt         # Python dependencies
├── 🛠️ install.sh               # Automated installation script
├── 📖 GMAIL_SEND_USAGE.md      # Detailed usage guide
├── 🚀 MCP_DEPLOYMENT.md        # MCP deployment instructions
└── 📝 README.md                # This file

🔧 Configuration

MCP Server Configuration

Update paths in mcp_config.json:

{
  "mcpServers": {
    "gmail-send": {
      "command": "python",
      "args": ["/absolute/path/to/mcp_server.py"],
      "env": {
        "PYTHONPATH": "/absolute/path/to/project"
      }
    }
  }
}

Claude Desktop Configuration

Update claude_desktop_config.json with your installation path and copy to:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Linux: ~/.config/claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

🧪 Testing

Automated Testing

# Run all tests
python3 test_gmail_skill.py

# Test specific components
python3 test_gmail_skill.py --test TestGmailSendSkill

# Verbose output
python3 test_gmail_skill.py --verbose

Manual Testing

# Test skill directly
python3 gmail_send_skill.py

# Test MCP server
python3 mcp_server.py --test

# Check version and info
python3 version.py --info

⚙️ Technical Details

Dependencies and Licensing

Core Dependencies (Built-in Python)

• smtplib - SMTP email sending

• email.mime - Email composition

• ssl - TLS encryption

• json - Configuration handling

• re - Regular expressions for fallback conversion

Optional Enhancement (Commercial-Friendly)

• markdown library (BSD 3-Clause License)

  • ✅ Commercial use allowed

  • ✅ Distribution allowed

  • ✅ Modification allowed

  • 🔧 Graceful fallback when unavailable

System Requirements

• Python 3.7+ (tested up to 3.12)

• Internet connection for Gmail SMTP

• Gmail account with 2FA enabled

Architecture

Gmail Send Skill Architecture
├── gmail_send_skill.py      # Core skill implementation
├── skill_compat.py          # Framework compatibility layer
├── mcp_server.py           # MCP Protocol server
└── version.py              # Version management

HTML Conversion Pipeline:
Markdown Content → Advanced/Basic Converter → CSS Styling → Email HTML

Conversion System Details

Advanced Mode (with markdown library)

• Full CommonMark specification support

• Extensions: tables, strikethrough, task lists

• Professional syntax highlighting

• Advanced table rendering

Fallback Mode (built-in)

• Regex-based Markdown parsing

• Core element support (headers, lists, formatting)

• Email-safe HTML generation

• Professional CSS styling maintained

📚 Documentation

• 📖 Usage Guide - Comprehensive usage instructions and examples

• 🚀 MCP Deployment - Complete MCP integration guide

• 🔧 Installation Script - Automated setup and configuration

• 🧪 Test Suite - Comprehensive testing framework

🔒 Security

Best Practices

• ✅ Use App Passwords - Never use regular Gmail passwords

• ✅ Enable 2FA - Required for App Password generation

• ✅ Secure Storage - Never commit credentials to version control

• ✅ Input Validation - All parameters are validated before use

• ✅ Error Handling - Sensitive information is not exposed in errors

Supported Authentication

• Gmail App Passwords (recommended)

• G Suite/Workspace accounts with App Passwords

• 2-Factor Authentication required

📊 Response Format

Success Response

{
  "success": true,
  "function_name": "gmail_send",
  "result": {
    "message": "Email sent successfully to recipient@example.com",
    "timestamp": "2026-02-14T10:30:00",
    "from": "sender@gmail.com",
    "to": "recipient@example.com",
    "subject": "Email Subject"
  }
}

Error Response

{
  "success": false,
  "function_name": "gmail_send", 
  "error": {
    "message": "Authentication failed. Please check your credentials.",
    "type": "authentication_error",
    "details": "SMTP Authentication Error: (535, 'Incorrect password')"
  }
}

🔄 Version Information

Current Version: 1.0.0 (2026-02-14)

# Check version
python3 version.py --version

# Full version info  
python3 version.py --info

# View changelog
python3 version.py --changelog

🛠️ Requirements

System Requirements

• Python 3.7+ (required)

• Internet connection for SMTP access

• Gmail account with 2FA enabled

Dependencies

• Built-in Python libraries: smtplib, email, json, logging

• Optional: markdown>=3.4.0 (for rich formatting)

Compatibility

• ✅ MCP Protocol 2024-11-05

• ✅ OpenAI Function Calling compatible

• ✅ Claude Desktop integration

• ✅ Cross-platform (macOS, Linux, Windows)

🆘 Troubleshooting

Common Issues

Authentication Errors

# Verify App Password format (16 characters)
# Check 2FA is enabled
# Generate new App Password

Module Import Errors

# Check Python path
export PYTHONPATH=/path/to/mcp-server-gmail-send

# Verify file permissions
chmod 644 gmail_send_skill.py

MCP Connection Issues

# Test MCP server
python3 mcp_server.py --test

# Check Claude Desktop logs
tail -f ~/Library/Logs/Claude/claude-desktop.log

Support Resources

• 📋 Usage Guide - Detailed troubleshooting

• 🔧 Deployment Guide - MCP-specific issues

• 🧪 Test Suite - python3 test_gmail_skill.py

• 📊 Logs - Check gmail_send_mcp.log

🤝 Contributing

1. Fork the repository

2. Create feature branch: git checkout -b feature/amazing-feature

3. Commit changes: git commit -m 'Add amazing feature'

4. Push to branch: git push origin feature/amazing-feature

5. Open Pull Request

Development Setup

# Clone for development
git clone <repository-url>
cd mcp-server-gmail-send

# Install development dependencies
pip3 install -r requirements.txt
pip3 install pytest pytest-asyncio  # For testing

# Run tests
python3 test_gmail_skill.py

# Check code style
python3 -m flake8 gmail_send_skill.py

� Version History

v1.1.0 (2024-12-19) - Enhanced Markdown Support

• ✨ Advanced Markdown Conversion - Full markdown library support with extensions

• 🎨 Professional Email Styling - Responsive CSS for email clients

• 🔧 Graceful Fallback System - Basic converter when external library unavailable

• ⚖️ Commercial License Compliance - BSD-licensed dependencies

• 📧 Email Client Optimization - Improved compatibility across platforms

• 🧪 Enhanced Testing - Comprehensive conversion and styling tests

v1.0.0 (2024-12-19) - Initial Release

• 📧 Gmail SMTP Integration - Secure email sending via Gmail

• 🔐 App Password Authentication - Secure credential handling

• 🤖 MCP Protocol Support - Full Model Context Protocol implementation

• 📝 Basic Markdown Support - Simple markdown to HTML conversion

• ✅ Comprehensive Testing - 18 unit tests with edge case coverage

• 🛠️ Local Development Tools - Configuration templates and testing utilities

�📄 License

This project is licensed under the terms specified in the LICENSE file.

Third-Party License Compliance

• markdown library (Optional) - BSD 3-Clause License - Commercial use allowed

• Python Standard Library - Python Software Foundation License

🙏 Acknowledgments

• Model Context Protocol - For the standardized AI agent integration

• OpenAI Function Calling - For the function schema standard

• Gmail SMTP - For reliable email delivery infrastructure

• Python Community - For the excellent libraries and tools

• Markdown Community - For the BSD-licensed markdown processing library

Built for AI-Powered Applications 🤖 | MCP Compatible 🔌 | Production Ready 🚀

Gmail Send Skill v1.1.0 - Enhanced Markdown conversion with professional email styling Send mail through gmail.