FontLab MCP Server

A Model Context Protocol (MCP) server that provides programmatic access to FontLab's PythonQt API, enabling Claude and other AI assistants to interact with FontLab for font design and manipulation.

Overview

This MCP server bridges the Model Context Protocol with FontLab's powerful font editing capabilities, allowing you to:

• Query font metadata and glyph information

• Create and modify glyphs programmatically

• Apply transformations (scale, rotate, translate)

• Export fonts to various formats

• Automate font design workflows

Architecture

┌─────────────────┐
│   Claude/MCP    │
│     Client      │
└────────┬────────┘
         │ MCP Protocol (stdio)
         │
┌────────▼────────┐
│  FontLab MCP    │
│     Server      │
│  (Python)       │
└────────┬────────┘
         │ Script Execution
         │
┌────────▼────────┐
│    FontLab      │
│   Application   │
│  (PythonQt API) │
└─────────────────┘

The server uses a bridge pattern to execute Python scripts within FontLab's environment, communicating via temporary files and JSON serialization.

Features

Resources (Read-Only Operations)

• fontlab://font/current - Get current font information

• fontlab://font/current/glyphs - List all glyphs

• fontlab://font/info - Get detailed font metadata

• fontlab://glyph/{name} - Get specific glyph details

Tools (Write Operations)

• create_glyph - Create new glyphs with custom parameters

• modify_glyph_width - Adjust glyph widths

• transform_glyph - Apply scale, rotation, and translation

• update_font_info - Modify font metadata

• export_font - Export to OTF, TTF, WOFF, WOFF2, UFO

• delete_glyph - Remove glyphs from font

Installation

Prerequisites

• Python 3.10 or higher

• FontLab 7 or 8 installed

• pip package manager

Setup

1. Clone this repository:

   git clone https://github.com/dithilli/fontlab-mcp-server.git
   cd fontlab-mcp-server

2. Create a virtual environment (recommended):

   python3 -m venv venv
   source venv/bin/activate  # On Windows: venv\Scripts\activate

3. Install dependencies:

   pip install -r requirements.txt

4. Install the package:

   pip install -e .

Configuration

The server automatically detects FontLab installations in standard locations:

• macOS: /Applications/FontLab 8.app or /Applications/FontLab 7.app

• Custom paths can be configured in the bridge initialization

Usage

Running the Server

Start the server using stdio transport:

python -m src.server

Or use the installed command:

fontlab-mcp-server

Claude Desktop Configuration

Add to your Claude Desktop config file (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "fontlab": {
      "command": "/path/to/venv/bin/python",
      "args": ["-m", "src.server"],
      "cwd": "/path/to/fontlab-mcp-server"
    }
  }
}

Example Usage with Claude

Once configured, you can ask Claude to:

Query font information:

"What fonts are currently open in FontLab?"

Create glyphs:

"Create a new glyph called 'customA' with a width of 650"

Modify glyphs:

"Scale the 'A' glyph by 1.2x horizontally"

Export fonts:

"Export the current font as an OTF to ~/Desktop/myfont.otf"

API Reference

Resources

Get Current Font

URI: fontlab://font/current
Returns: JSON with font metadata

List Glyphs

URI: fontlab://font/current/glyphs
Returns: Array of glyph objects with names, unicodes, and widths

Get Glyph Details

URI: fontlab://glyph/{name}
Parameters:
  - name: Glyph name (e.g., "A", "space", "Agrave")
Returns: Detailed glyph information including bounds and contours

Tools

create_glyph

{
  "name": "glyph_name",
  "unicode": 65,  // optional
  "width": 600    // optional, default 600
}

modify_glyph_width

{
  "name": "glyph_name",
  "width": 650
}

transform_glyph

{
  "name": "glyph_name",
  "scale_x": 1.2,      // optional, default 1.0
  "scale_y": 1.0,      // optional, default 1.0
  "rotate": 45,        // optional, default 0 (degrees)
  "translate_x": 10,   // optional, default 0
  "translate_y": 0     // optional, default 0
}

update_font_info

{
  "family_name": "My Font Family",  // optional
  "style_name": "Bold",             // optional
  "version": "1.0",                 // optional
  "copyright": "Copyright 2025"     // optional
}

export_font

{
  "path": "/path/to/output.otf",
  "format": "otf"  // optional: otf, ttf, woff, woff2, ufo
}

delete_glyph

{
  "name": "glyph_name"
}

Development

Project Structure

fontlab-mcp-server/
├── src/
│   ├── __init__.py           # Package initialization
│   ├── server.py             # Main MCP server
│   ├── fontlab_bridge.py     # FontLab communication bridge
│   ├── resources.py          # Resource handlers
│   ├── tools.py              # Tool handlers
│   └── utils/                # Utility functions
├── scripts/                  # FontLab executor scripts
├── tests/                    # Unit tests
├── pyproject.toml            # Package configuration
├── requirements.txt          # Python dependencies
└── README.md                 # This file

Testing

Run tests:

pytest tests/

Contributing

Contributions are welcome! Please:

1. Fork the repository

2. Create a feature branch

3. Make your changes

4. Add tests if applicable

5. Submit a pull request

Limitations & Notes

• FontLab must be running for the server to function

• Script execution uses subprocess communication, which may have latency

• Some FontLab features may require specific versions (7 or 8)

• The bridge assumes FontLab CLI accepts -script flag (may need adjustment)

Roadmap

Future enhancements:

• Support for component manipulation

• Kerning table operations

• OpenType feature editing

• Batch glyph operations

• Real-time event streaming

• Better error handling and validation

• Support for multiple open fonts

• Undo/redo functionality

License

MIT License - See LICENSE file for details

Acknowledgments

• Built on Anthropic's Model Context Protocol

• Integrates with FontLab's Python API

Support

For issues, questions, or contributions, please visit:

• GitHub: https://github.com/dithilli/fontlab-mcp-server

• FontLab API Docs: https://fontlabcom.github.io/fontlab-python-docs/

Version: 0.1.0 Author: David Szarzynski Status: Alpha - MVP Implementation