UML-MCP: A Diagram Generation Server with MCP Interface

UML-MCP is a powerful diagram generation server that implements the Model Context Protocol (MCP), enabling seamless diagram creation directly from AI assistants and other applications.

🌟 Features

• Multiple Diagram Types: Support for UML diagrams (Class, Sequence, Activity, etc.), Mermaid, D2, and more
• MCP Integration: Seamless integration with LLM assistants supporting the Model Context Protocol
• Playground Links: Direct links to online editors for each diagram type
• Multiple Output Formats: SVG, PNG, PDF, and other format options
• Easy Configuration: Works with local and remote diagram rendering services

📋 Supported Diagram Types

UML-MCP supports a wide variety of diagram types:

Category	Diagram Types
UML	Class, Sequence, Activity, Use Case, State, Component, Deployment, Object
Other	Mermaid, D2, Graphviz, ERD, BlockDiag, BPMN, C4 with PlantUML

🚀 Getting Started

Prerequisites

• Python 3.10 or higher
• pip (Python package installer)

Installation

1. Clone the repository:

git clone https://github.com/yourusername/uml-mcp.git
cd uml-mcp

2. Install the dependencies:

pip install -r requirements.txt

3. For development environments:

pip install -r requirements-dev.txt

Running the Server

Start the MCP server:

python mcp_server.py

This will start the server using stdio for communication with MCP clients.

🔧 Configuration

Editor Integration

Cursor

To integrate with Cursor:

python mcp/install_to_cursor.py

Or manually configure in Cursor settings:

"mcpServers": {
  "UML-MCP-Server": {
    "command": "python",
    "args": ["/path/to/uml-mcp/mcp_server.py"],
    "output_dir": "/path/to/output"
  }
}

Environment Variables

• MCP_OUTPUT_DIR - Directory to save generated diagrams (default: ./output)
• KROKI_SERVER - URL of the Kroki server (default: https://kroki.io)
• PLANTUML_SERVER - URL of the PlantUML server (default: http://plantuml-server:8080)
• USE_LOCAL_KROKI - Use local Kroki server (true/false)
• USE_LOCAL_PLANTUML - Use local PlantUML server (true/false)

📚 Documentation

For detailed documentation, visit the docs directory or our documentation site.

🧩 Architecture

UML-MCP is built with a modular architecture:

• MCP Server Core: Handles MCP protocol communication
• Diagram Generators: Supporting different diagram types
• Tools: Expose diagram generation functionality through MCP
• Resources: Provide templates and examples for various diagram types

🛠️ Local Development

For local development:

1. Set up local PlantUML and/or Kroki servers:

# PlantUML
docker run -d -p 8080:8080 plantuml/plantuml-server

# Kroki
docker run -d -p 8000:8000 yuzutech/kroki

2. Configure environment variables:

export USE_LOCAL_PLANTUML=true
export PLANTUML_SERVER=http://localhost:8080
export USE_LOCAL_KROKI=true  
export KROKI_SERVER=http://localhost:8000

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

📄 License

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

👏 Acknowledgements

• PlantUML - UML diagram generation
• Kroki - Unified diagram generation service
• Mermaid - Generation of diagrams from text
• D2 - Modern diagram scripting language

UML-MCP Server

An MCP Server that provides UML diagram generation capabilities through various diagram rendering engines.

Components

Resources

The server provides several resources via the uml:// URI scheme:

• uml://types: List of available UML diagram types
• uml://templates: Templates for creating UML diagrams
• uml://examples: Example UML diagrams for reference
• uml://formats: Supported output formats for diagrams
• uml://server-info: Information about the UML-MCP server

Tools

The server implements multiple diagram generation tools:

Universal UML Generator

• generate_uml: Generate any UML diagram
  • Parameters: diagram_type, code, output_dir

Specific UML Diagram Tools

• generate_class_diagram: Generate UML class diagrams
  • Parameters: code, output_dir
• generate_sequence_diagram: Generate UML sequence diagrams
  • Parameters: code, output_dir
• generate_activity_diagram: Generate UML activity diagrams
  • Parameters: code, output_dir
• generate_usecase_diagram: Generate UML use case diagrams
  • Parameters: code, output_dir
• generate_state_diagram: Generate UML state diagrams
  • Parameters: code, output_dir
• generate_component_diagram: Generate UML component diagrams
  • Parameters: code, output_dir
• generate_deployment_diagram: Generate UML deployment diagrams
  • Parameters: code, output_dir
• generate_object_diagram: Generate UML object diagrams
  • Parameters: code, output_dir

Other Diagram Formats

• generate_mermaid_diagram: Generate diagrams using Mermaid syntax
  • Parameters: code, output_dir
• generate_d2_diagram: Generate diagrams using D2 syntax
  • Parameters: code, output_dir
• generate_graphviz_diagram: Generate diagrams using Graphviz DOT syntax
  • Parameters: code, output_dir
• generate_erd_diagram: Generate Entity-Relationship diagrams
  • Parameters: code, output_dir

Prompts

The server provides prompts to help create UML diagrams:

• class_diagram: Create a UML class diagram showing classes, attributes, methods, and relationships
• sequence_diagram: Create a UML sequence diagram showing interactions between objects over time
• activity_diagram: Create a UML activity diagram showing workflows and business processes

Configuration

Install

Claude Desktop

On MacOS: ~/Library/Application\ Support/Claude/claude_desktop_config.json
On Windows: %APPDATA%/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "uml_diagram_generator": {
      "command": "python",
      "args": [
        "/path/to/uml-mcp/mcp_server.py"
      ]
    }
  }
}

Cursor Integration

The UML-MCP Server can also be integrated with Cursor:

{
  "mcpServers": {
    "uml_diagram_generator": {
      "command": "python",
      "args": [
        "/path/to/uml-mcp/mcp_server.py"
      ]
    }
  }
}

Usage

Command Line Arguments

usage: mcp_server.py [-h] [--debug] [--host HOST] [--port PORT] [--transport {stdio,http}] [--list-tools]

UML-MCP Diagram Generation Server

options:
  -h, --help            show this help message and exit
  --debug               Enable debug logging
  --host HOST           Server host (default: 127.0.0.1)
  --port PORT           Server port (default: 8000)
  --transport {stdio,http}
                        Transport protocol (default: stdio)
  --list-tools          List available tools and exit

Environment Variables

• LOG_LEVEL: Set logging level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
• UML_MCP_OUTPUT_DIR: Directory to store generated diagram files
• KROKI_SERVER: Kroki server URL for diagram rendering
• PLANTUML_SERVER: PlantUML server URL for diagram rendering
• LIST_TOOLS: Set to "true" to display tools and exit

Example: Generating a Class Diagram

result = tool.call("generate_class_diagram", {
    "code": """
        @startuml
        class User {
          -id: int
          -name: string
          +login(): boolean
        }
        class Order {
          -id: int
          +addItem(item: string): void
        }
        User "1" -- "many" Order
        @enduml
    """,
    "output_dir": "/path/to/output"
})

Development

Building and Running

# Clone the repository
git clone https://github.com/your-username/uml-mcp.git
cd uml-mcp

# Install dependencies
pip install -r requirements.txt

# Run the server
python mcp_server.py

Debugging

For debugging, you can run the server with:

python mcp_server.py --debug

Debug logs will be stored in the logs/ directory.

Running Tests

# Run all tests
pytest

# Run specific tests
pytest tests/test_diagram_tools.py