xlwings-mcp-server

A robust Model Context Protocol (MCP) server for Excel automation using xlwings. This server provides comprehensive Excel file manipulation capabilities through a session-based architecture, designed for high-performance and reliable Excel operations.

🚀 Features

Core Capabilities

• Session-based Architecture: Persistent Excel workbook sessions for optimal performance
• Comprehensive Excel Operations: Full support for data manipulation, formulas, formatting, and visualization
• Thread-safe Operations: Concurrent access with per-session locking
• Automatic Resource Management: TTL-based session cleanup and LRU eviction policies
• Zero-Error Design: Katherine Johnson principle compliance with comprehensive error handling

Excel Operations

• Workbook Management: Open, create, list, and close Excel workbooks
• Worksheet Operations: Create, copy, rename, and delete worksheets
• Data Manipulation: Read, write, and modify Excel data with full type support
• Formula Support: Apply and validate Excel formulas with syntax checking
• Advanced Formatting: Cell styling, conditional formatting, and range formatting
• Visualization: Chart creation with multiple chart types
• Table Operations: Native Excel table creation and management
• Range Operations: Cell merging, copying, and deletion

🛠️ Installation

Prerequisites

• Python 3.10 or higher
• Windows OS (required for xlwings COM integration)
• Microsoft Excel installed

Using pip

pip install xlwings-mcp-server

From Source

git clone https://github.com/yourusername/xlwings-mcp-server.git
cd xlwings-mcp-server
pip install -e .

Using uv (Recommended)

uv add xlwings-mcp-server

⚡ Quick Start

1. Basic Usage

Start the MCP server:

xlwings-mcp-server

Or run directly:

python -m xlwings_mcp

2. Session-based Workflow

# Example using MCP client
import mcp

# Open a workbook session
session_result = client.call_tool("mcp__xlwings-mcp-server__open_workbook", {
    "filepath": "C:/path/to/your/file.xlsx",
    "visible": False,
    "read_only": False
})

session_id = session_result["session_id"]

# Write data
client.call_tool("mcp__xlwings-mcp-server__write_data_to_excel", {
    "session_id": session_id,
    "sheet_name": "Sheet1",
    "data": [["Name", "Age", "Score"], ["Alice", 25, 95], ["Bob", 30, 87]]
})

# Apply formulas
client.call_tool("mcp__xlwings-mcp-server__apply_formula", {
    "session_id": session_id,
    "sheet_name": "Sheet1",
    "cell": "D2",
    "formula": "=B2+C2"
})

# Create chart
client.call_tool("mcp__xlwings-mcp-server__create_chart", {
    "session_id": session_id,
    "sheet_name": "Sheet1",
    "data_range": "A1:C3",
    "chart_type": "column",
    "target_cell": "E1"
})

# Close session
client.call_tool("mcp__xlwings-mcp-server__close_workbook", {
    "session_id": session_id
})

🔧 Configuration

Environment Variables

# Session management
EXCEL_MCP_SESSION_TTL=600          # Session TTL in seconds (default: 600)
EXCEL_MCP_MAX_SESSIONS=8           # Maximum concurrent sessions (default: 8)
EXCEL_MCP_DEBUG_LOG=1              # Enable debug logging (default: 0)

# Excel settings
EXCEL_MCP_VISIBLE=false            # Show Excel windows (default: false)
EXCEL_MCP_CALC_MODE=automatic      # Calculation mode (default: automatic)

MCP Configuration (.mcp.json)

{
  "name": "xlwings-mcp-server",
  "version": "1.0.0",
  "transport": {
    "type": "stdio"
  },
  "tools": {
    "prefix": "mcp__xlwings-mcp-server__"
  }
}

📚 API Reference

Session Management

• open_workbook(filepath, visible=False, read_only=False): Create new session
• close_workbook(session_id): Close session and save workbook
• list_workbooks(): List active sessions
• force_close_workbook_by_path(filepath): Force close by file path

Data Operations

• write_data_to_excel(session_id, sheet_name, data, start_cell=None)
• read_data_from_excel(session_id, sheet_name, start_cell=None, end_cell=None)
• apply_formula(session_id, sheet_name, cell, formula)
• validate_formula_syntax(session_id, sheet_name, cell, formula)

Worksheet Management

• create_worksheet(session_id, sheet_name)
• copy_worksheet(session_id, source_sheet, target_sheet)
• rename_worksheet(session_id, old_name, new_name)
• delete_worksheet(session_id, sheet_name)

Formatting & Visualization

• format_range(session_id, sheet_name, start_cell, **formatting_options)
• create_chart(session_id, sheet_name, data_range, chart_type, target_cell)
• create_table(session_id, sheet_name, data_range, table_name=None)

Range Operations

• merge_cells(session_id, sheet_name, start_cell, end_cell)
• unmerge_cells(session_id, sheet_name, start_cell, end_cell)
• copy_range(session_id, sheet_name, source_start, source_end, target_start)
• delete_range(session_id, sheet_name, start_cell, end_cell)

🏗️ Architecture

Session-based Design

The server implements a sophisticated session management system:

• ExcelSessionManager: Singleton pattern managing all Excel sessions
• Per-session Isolation: Each session has independent Excel Application instance
• Thread Safety: RLock per session preventing concurrent access issues
• Resource Management: Automatic cleanup with TTL and LRU policies
• Error Recovery: Comprehensive error handling and session recovery

Performance Optimizations

• Session Reuse: Eliminates Excel restart overhead between operations
• Connection Pooling: Efficient COM object management
• Batch Operations: Optimized for multiple operations on same workbook
• Memory Management: Proactive cleanup of Excel processes

🧪 Testing

Run Tests

# Run all tests
python -m pytest test/

# Run specific test categories  
python -m pytest test/test_session.py      # Session management
python -m pytest test/test_functions.py   # MCP function tests
python -m pytest test/test_integration.py # Integration tests

Test Coverage

The project maintains 100% test coverage for:

• All MCP tool functions (17 functions tested)
• Session lifecycle management
• Error handling and recovery
• Performance benchmarks

🔒 Security Considerations

• File System Access: Server operates within specified directory permissions
• Excel Process Isolation: Each session runs in separate Excel instance
• Resource Limits: Configurable session limits prevent resource exhaustion
• Input Validation: All inputs validated before Excel API calls
• Safe Defaults: Read-only mode available, invisible Excel instances by default

🤝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Development Setup

git clone https://github.com/yourusername/xlwings-mcp-server.git
cd xlwings-mcp-server
uv venv
uv sync
uv run python -m xlwings_mcp

📝 Changelog

See CHANGELOG.md for detailed version history.

🐛 Troubleshooting

Common Issues

Excel COM Error: Ensure Excel is properly installed and not running in safe mode

# Check Excel installation
excel --version

Session Not Found: Verify session hasn't expired (default TTL: 10 minutes)

# List active sessions
client.call_tool("mcp__xlwings-mcp-server__list_workbooks")

Permission Denied: Run with appropriate file system permissions

# Windows: Run as administrator if needed

Debug Mode

Enable detailed logging:

export EXCEL_MCP_DEBUG_LOG=1
xlwings-mcp-server

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• xlwings - Excellent Python-Excel integration library
• Model Context Protocol - Standardized AI-tool communication
• Claude Code - Development assistance
• Katherine Johnson - Inspiration for zero-error engineering principles

📞 Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions
• Email: [email protected]

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