Gaudenz Alder
3366c8e7b3
Move the draw.io XML generation reference to shared/xml-reference.md and wire all four consumers to use it instead of duplicating the content. Add layers, tags, and metadata/placeholders documentation. - MCP app server: reads at startup (Node.js) or pre-builds into generated-html.js (Workers) via build-html.js - MCP tool server: reads at startup with fallback to local copy; prepack script bundles the file before npm publish - Skill: references the GitHub raw URL so it works after install - Project instructions: tells users to copy from GitHub Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
5.1 KiB
Draw.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.
Four Ways to Create Diagrams
This repository offers four approaches for integrating draw.io with AI assistants. Pick the one that fits your setup:
| MCP App Server | MCP Tool Server | Skill + CLI | Project Instructions | |
|---|---|---|---|---|
| How it works | Renders diagrams inline in chat | Opens diagrams in your browser | Generates .drawio files, optional PNG/SVG/PDF export |
Claude generates draw.io URLs via Python |
| Diagram output | Interactive viewer embedded in conversation | draw.io editor in a new tab | .drawio or .drawio.png / .svg / .pdf |
Clickable link to draw.io |
| Requires installation | No (hosted at mcp.draw.io) |
Yes (npm package) | Copy skill file + draw.io Desktop | No — just paste instructions |
| Supports XML, CSV, Mermaid | XML only | ✅ All three | XML only (native format) | ✅ All three |
| Editable in draw.io | Via "Open in draw.io" button | ✅ Directly | ✅ Directly | Via link |
| Works with | Claude.ai, VS Code, any MCP Apps host | Claude Desktop, any MCP client | Claude Code | Claude.ai (with Projects) |
| Best for | Inline previews in chat | Local desktop workflows | Local development workflows | Quick setup, no install needed |
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.
The official hosted endpoint is available at:
https://mcp.draw.io/mcp
Add this URL as a remote MCP server in Claude.ai or any MCP Apps-compatible host — no installation required.
You can also run the server locally via Node.js or deploy your own instance to Cloudflare Workers.
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.
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
Skill + CLI
A Claude Code skill that generates native .drawio files, with optional export to PNG, SVG, or PDF (with embedded XML so the exported file remains editable in draw.io). No MCP setup required — just copy a skill file.
By default, the skill writes a .drawio file and opens it in draw.io. Mention a format in your request (/drawio png ...) to export using the draw.io desktop CLI with --embed-diagram.
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.
XML Reference (Single Source of Truth)
The draw.io XML generation reference — covering edge routing, containers, layers, tags, metadata, dark mode, style properties, and XML well-formedness — lives in a single canonical file:
All four approaches above use this file as their single source of truth for LLM prompts:
| Approach | How it accesses the reference |
|---|---|
| MCP App Server | Reads the file at startup / build time and includes it in the tool description |
| MCP Tool Server | Reads the file at startup (from repo or bundled copy via prepack) |
| Skill + CLI | References the GitHub raw URL |
| Project Instructions | Users copy its contents into their Claude Project |
When updating XML generation guidance, edit only shared/xml-reference.md — changes propagate to all consumers automatically.
Development
# MCP App Server
cd mcp-app-server
npm install
npm start
# MCP Tool Server
cd mcp-tool-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