Excalidraw MCP Server & Agent Skill

Let your AI agent run a live Excalidraw canvas and draw diagrams. This repo provides:

• MCP Server: Connect via Model Context Protocol (Claude Desktop, Cursor, Claude Code, etc.)
• Agent Skill: Portable skill for OpenClaw agents and other skill-enabled agents

Built on top of mcp_excalidraw by @yctimlin. Added shareable links, image export, agent skill, and a hosted API.

Demo

<p align="center"> <img src="assets/demo-telegram.gif" alt="Demo — OpenClaw agent draws a diagram and sends it to Telegram" width="600" /> </p>

Hosted Instance

A public instance is running at https://excalidraw-mcp.up.railway.app — no setup needed.

{
  "mcpServers": {
    "excalidraw": {
      "url": "https://excalidraw-mcp.up.railway.app/mcp"
    }
  }
}

Self-Hosting

Local

git clone https://github.com/0xArtex/excalidraw-mcp.git
cd excalidraw-mcp
npm install
npm run build
npm run canvas

Server starts at http://localhost:3000.

Docker

docker build -f Dockerfile.canvas -t excalidraw-mcp .
docker run -p 3000:3000 -e PUBLIC_URL=https://your-domain.com excalidraw-mcp

Environment Variables

Variable	Default	Description
PORT	3000	Server port
PUBLIC_URL	auto-detected	Public URL for edit links
CANVAS_BASE_URL	http://localhost:3000	Internal URL for renderer (auto-resolved)
RATE_LIMIT_RPM	10	Rate limit per IP per minute
MAX_ELEMENTS	2000	Max elements per render request
RENDER_TIMEOUT_MS	300000	Render timeout (5 min)

Configure MCP Clients

The MCP server can be connected via Streamable HTTP (hosted) or stdio (local).

Claude Desktop

Hosted:

{
  "mcpServers": {
    "excalidraw": {
      "url": "https://excalidraw-mcp.up.railway.app/mcp"
    }
  }
}

Local (node):

{
  "mcpServers": {
    "excalidraw": {
      "command": "node",
      "args": ["/path/to/excalidraw-mcp/dist/index.js"],
      "env": {
        "EXPRESS_SERVER_URL": "http://localhost:3000"
      }
    }
  }
}

Claude Code

claude mcp add excalidraw --scope user \
  -e EXPRESS_SERVER_URL=http://localhost:3000 \
  -- node /path/to/excalidraw-mcp/dist/index.js

Cursor

Config location: .cursor/mcp.json

{
  "mcpServers": {
    "excalidraw": {
      "url": "https://excalidraw-mcp.up.railway.app/mcp"
    }
  }
}

Agent Skill

For OpenClaw and other skill-enabled agents, install the skill to render diagrams with a single API call — no MCP client needed.

The skill is available at skills/excalidraw-canvas/ or can be installed from ClawhHub.

See SKILL.md for usage — it's a single curl call.

MCP Tools

Tool	Description
start_diagram	Start a new diagram session, returns live canvas URL
create_element	Create a shape (rectangle, ellipse, diamond, arrow, text, line)
batch_create_elements	Create multiple elements at once
delete_element	Remove an element
finish_diagram	Finalize and get shareable link with image

Development

npm run dev        # Watch + hot reload
npm run build      # Build everything
npm run type-check # TypeScript check

License

MIT

Acknowledgments

• @yctimlin - Original mcp_excalidraw project
• Excalidraw - The drawing library
• Model Context Protocol - The MCP specification