Excalidraw MCP server for AI agents

MCP Excalidraw Server combines Excalidraw's drawing capabilities with Model Context Protocol (MCP) integration, allowing AI agents to create and manipulate diagrams in real-time on a live canvas. This server enables both human users and AI systems to collaborate on visual diagrams with real-time synchronization.

Installation

Recommended: Local Development Setup

1. Clone the Repository

git clone https://github.com/yctimlin/mcp_excalidraw.git
cd mcp_excalidraw
npm install

2. Build the Frontend

npm run build

3. Start the System

Option A: Production Mode (Recommended)

# Start canvas server (serves frontend + API)
npm run canvas

Option B: Development Mode

# Start both canvas server and Vite dev server
npm run dev

4. Access the Canvas

Open your browser and navigate to:

http://localhost:3000

Alternative Installation Methods (In Development)

NPM Package (Beta)

# Currently debugging tool registration
npm install -g mcp-excalidraw-server
npx mcp-excalidraw-server

Docker Version (Coming Soon)

# Canvas sync improvements in progress
docker run -p 3000:3000 mcp-excalidraw-server

Usage Guide

For End Users

Open the canvas at http://localhost:3000
Check connection status (should show "Connected")
AI agents can now create diagrams that appear in real-time
Use "Clear Canvas" to remove all elements

For AI Agents (via MCP)

The MCP server provides these tools for creating visual diagrams:

Basic Element Creation

// Create a rectangle
{
  "type": "rectangle",
  "x": 100,
  "y": 100, 
  "width": 200,
  "height": 100,
  "backgroundColor": "#e3f2fd",
  "strokeColor": "#1976d2",
  "strokeWidth": 2
}

Create Text Elements

{
  "type": "text",
  "x": 150,
  "y": 125,
  "text": "Process Step",
  "fontSize": 16,
  "strokeColor": "#333333"
}

Create Arrows & Lines

{
  "type": "arrow",
  "x": 300,
  "y": 130,
  "width": 100,
  "height": 0,
  "strokeColor": "#666666",
  "strokeWidth": 2
}

Batch Creation for Complex Diagrams

{
  "elements": [
    {
      "type": "rectangle",
      "x": 100,
      "y": 100,
      "width": 120,
      "height": 60,
      "backgroundColor": "#fff3e0",
      "strokeColor": "#ff9800"
    },
    {
      "type": "text", 
      "x": 130,
      "y": 125,
      "text": "Start",
      "fontSize": 16
    }
  ]
}

Integration with Claude Desktop

Recommended: Using Local Installation

For the local development version (most stable), add this configuration to your claude_desktop_config.json:

{
  "mcpServers": {
    "excalidraw": {
      "command": "node",
      "args": ["/absolute/path/to/mcp_excalidraw/dist/index.js"]
    }
  }
}

Important: Replace /absolute/path/to/mcp_excalidraw with the actual absolute path to your cloned repository.

Alternative Configurations (Beta)

NPM Package (Beta Testing)

{
  "mcpServers": {
    "excalidraw": {
      "command": "npx",
      "args": ["-y", "mcp-excalidraw-server"]
    }
  }
}

Docker Version (Coming Soon)

{
  "mcpServers": {
    "excalidraw": {
      "command": "docker",
      "args": ["run", "-i", "--rm", "mcp-excalidraw-server"]
    }
  }
}

Integration with Other Tools

Cursor IDE

Add to your .cursor/mcp.json:

{
  "mcpServers": {
    "excalidraw": {
      "command": "node",
      "args": ["/absolute/path/to/mcp_excalidraw/dist/index.js"]
    }
  }
}

VS Code MCP Extension

For VS Code MCP extension, add to your settings:

{
  "mcp": {
    "servers": {
      "excalidraw": {
        "command": "node",
        "args": ["/absolute/path/to/mcp_excalidraw/dist/index.js"]
      }
    }
  }
}

Environment Variables

Variable	Default	Description
`EXPRESS_SERVER_URL`	`http://localhost:3000`	Canvas server URL for MCP sync
`ENABLE_CANVAS_SYNC`	`true`	Enable/disable canvas synchronization
`DEBUG`	`false`	Enable debug logging
`PORT`	`3000`	Canvas server port
`HOST`	`localhost`	Canvas server host

Available MCP Tools

Element Management

create_element - Create any type of Excalidraw element
update_element - Modify existing elements
delete_element - Remove elements
query_elements - Search elements with filters

Batch Operations

batch_create_elements - Create complex diagrams in one call

Element Organization

group_elements - Group multiple elements
ungroup_elements - Ungroup element groups
align_elements - Align elements (left, center, right, top, middle, bottom)
distribute_elements - Distribute elements evenly
lock_elements / unlock_elements - Lock/unlock elements

Resource Access

get_resource - Access scene, library, theme, or elements data

Troubleshooting

NPM Package Issues

Symptoms: MCP tools not registering properly
Solution: Use local development setup
Status: Actively debugging

Docker Version Notes

Symptoms: Elements may not sync to canvas immediately
Solution: Use local development setup
Status: Improving synchronization reliability

Canvas Not Loading

Ensure npm run build completed successfully
Check that dist/index.html exists
Verify canvas server is running on port 3000

Elements Not Syncing

Confirm MCP server is running (npm start)
Check ENABLE_CANVAS_SYNC=true in environment
Verify canvas server is accessible at EXPRESS_SERVER_URL

WebSocket Connection Issues

Check browser console for WebSocket errors
Ensure no firewall blocking WebSocket connections
Try refreshing the browser page

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "mcp_excalidraw" '{"command":"npx","args":["-y","excalidraw-mcp"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "mcp_excalidraw": {
            "command": "npx",
            "args": [
                "-y",
                "excalidraw-mcp"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json
Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "mcp_excalidraw": {
            "command": "npx",
            "args": [
                "-y",
                "excalidraw-mcp"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect