Gaudenz AlderDraw.io MCP Server
The official draw.io MCP (Model Context Protocol) server that enables LLMs to create and open diagrams in the draw.io editor.
Three Ways to Create Diagrams
This repository offers three approaches for integrating draw.io with AI assistants. Pick the one that fits your setup:
| MCP Tool Server | MCP App Server | Project Instructions | |
|---|---|---|---|
| How it works | Opens diagrams in your browser | Renders diagrams inline in chat | Claude generates draw.io URLs via Python |
| Diagram output | draw.io editor in a new tab | Interactive viewer embedded in conversation | Clickable link to draw.io |
| Requires installation | Yes (npm package) | Yes (Node.js server or CF Worker) | No — just paste instructions |
| Supports XML, CSV, Mermaid | ✅ All three | XML only | ✅ All three |
| Editable in draw.io | ✅ Directly | Via "Open in draw.io" button | Via link |
| Works with | Claude Desktop, any MCP client | Claude.ai, VS Code, any MCP Apps host | Claude.ai (with Projects) |
| Best for | Local desktop workflows | Inline previews in chat | Quick setup, no install needed |
MCP Tool Server
The original MCP server that opens diagrams directly in the draw.io editor. Supports XML, CSV, and Mermaid.js formats with lightbox and dark mode options. Published as @drawio/mcp on npm.
Quick start: npx @drawio/mcp
MCP App Server
The MCP App server renders draw.io diagrams inline in AI chat interfaces using the MCP Apps protocol. Instead of opening a browser tab, diagrams appear directly in the conversation as interactive iframes.
It can run locally via Node.js or be deployed to Cloudflare Workers for a public endpoint without tunnels.
Note: Inline diagram rendering requires an MCP host that supports the MCP Apps extension. In hosts without MCP Apps support, the tool still works but returns the XML as text.
Alternative: Project Instructions (No MCP Required)
An alternative approach that works without installing anything. Add instructions to a Claude Project that teach Claude to generate draw.io URLs using Python code execution. No MCP server, no desktop app — just paste and go.
Development
# MCP Tool Server
cd mcp-tool-server
npm install
npm start
# MCP App Server
cd mcp-app-server
npm install
npm start
Related Resources
- draw.io - Free online diagram editor
- draw.io Desktop - Desktop application
- @drawio/mcp on npm - This package on npm
- drawio-mcp on GitHub - Source code repository
- Mermaid.js Documentation
- MCP Specification
- MCP Apps Extension