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

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.

Tools:

• create_diagram — Renders draw.io XML as an interactive diagram inline in chat
• search_shapes — Searches 10,000+ shapes across all draw.io libraries (AWS, Azure, GCP, P&ID, electrical, Cisco, Kubernetes, UML, BPMN, etc.) by keyword. Returns exact style strings that can be used directly in XML. Use this to find the correct shape before calling create_diagram.

Full documentation →

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

Full documentation →

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.

Full documentation →

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.

Full documentation →

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:

shared/xml-reference.md

All four approaches above use this file as their single source of truth for LLM prompts:

When updating XML generation guidance, edit only shared/xml-reference.md — changes propagate to all consumers automatically.

Shape Search Index

The search_shapes tool is powered by a pre-built index of all draw.io shapes. The index is generated from the draw.io client source code (app.min.js) by running all sidebar palette initializations in Node.js via jsdom and capturing the shape data.

# Generate the shape search index (requires ../drawio-dev checkout)
cd shape-search
npm install
DRAWIO_DEV_PATH=../../drawio-dev node generate-index.js

# Rebuild the MCP App Server worker to embed the updated index
cd ../mcp-app-server
npm run build:worker

When to regenerate: Re-run generate-index.js after updating drawio-dev (new shapes, renamed stencils, updated style strings). The script loads app.min.js and all sidebar palettes, so it captures any changes to the shape libraries automatically.

The generated search-index.json is committed to the repository so that the MCP App Server can be built and deployed without a local drawio-dev checkout.

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