PlantUML MCP Server

A Model Context Protocol (MCP) server that provides PlantUML diagram generation capabilities for Claude Desktop and Claude Code.

Available Tools

1. generate_plantuml_diagram - Generate diagrams and get embeddable URLs (SVG/PNG)
2. encode_plantuml - Encode PlantUML code for URL sharing
3. decode_plantuml - Decode PlantUML from encoded strings

Quick Setup

For Claude Code

# Using default PlantUML server
claude mcp add plantuml --scope user --env PLANTUML_SERVER_URL=https://www.plantuml.com/plantuml -- npx plantuml-mcp-server

For Claude Desktop

Add this to your Claude Desktop MCP configuration (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "plantuml": {
      "command": "npx",
      "args": ["plantuml-mcp-server"],
      "env": {
        "PLANTUML_SERVER_URL": "https://www.plantuml.com/plantuml"
      }
    }
  }
}

To use your own PlantUML server, change the PLANTUML_SERVER_URL environment variable.

Then restart Claude Desktop/Code to activate the MCP server.

What You Can Do

After setup, you can ask Claude to:

• Generate PlantUML diagrams and get embeddable SVG/PNG URLs
• Create sequence diagrams, class diagrams, architecture diagrams
• Use advanced PlantUML features like !include directives and external libraries
• Encode/decode PlantUML for URL sharing

Examples

C4 diagram for plantuml-mcp-server

> add c4 diagram for this project in readme 'C4 diagram for plantuml-mcp-server' section

Sequence diagram for plantuml-mcp-server

> add sequence diagram in readme in architecture section

OAuth2 Authorization Code Flow Diagram

> show me basic oauth2 flow png, open it in browser

Development Setup

Prerequisites

• Node.js 18+
• npm

Local Installation

# Clone and setup
git clone https://github.com/mzagar/plantuml-mcp-server.git
cd plantuml-mcp-server
make setup

Testing & Development

# Test the server
make test-mcp

# Development commands
make install      # Install dependencies
make build        # Build TypeScript to JavaScript  
make run          # Build and run the server
make dev          # Run in development mode (watch)
make help         # Show all available commands

License

MIT License - see LICENSE file for details.