Umlout MCP Server

Let your AI assistant draw on a real whiteboard.

Umlout exposes a hosted Model Context Protocol server, so Claude, Cursor, VS Code Copilot and any other MCP client can create and edit diagrams in your Umlout workspace — UML class and sequence diagrams, flowcharts, activity diagrams, wireframes and domain models.

Nothing to install and nothing to run: the server is hosted at https://www.umlout.com/mcp/sse. You only need an API key.

Quick start

1. Get an API key. Sign in at umlout.com, open Profile → MCP API Keys, and create a key.

2. Add the server to your client.

claude mcp add --transport sse umlout https://www.umlout.com/mcp/sse --header "Authorization: Bearer YOUR_API_KEY"

More options, including project scope: examples/claude-code.md.

~/.cursor/mcp.json:

{
  "mcpServers": {
    "umlout": {
      "url": "https://www.umlout.com/mcp/sse",
      "headers": { "Authorization": "Bearer YOUR_API_KEY" }
    }
  }
}

For VS Code Copilot use examples/vscode.json — it prompts for the key and keeps it in VS Code's secret storage instead of a committed file.

Claude Desktop's config file does not take a remote URL directly, so route it through mcp-remote (needs Node.js). Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "umlout": {
      "command": "npx",
      "args": [
        "-y", "mcp-remote", "https://www.umlout.com/mcp/sse",
        "--header", "Authorization: Bearer YOUR_API_KEY"
      ]
    }
  }
}

Then quit Claude Desktop completely and reopen it — closing the window is not enough.

3. Ask for a diagram:

Draw a UML sequence diagram of an OAuth2 authorization code flow on a new board called "Auth".

Verify your setup at any time:

python3 scripts/check_connection.py --api-key YOUR_API_KEY

Related MCP server: fcp-drawio

What it can do

37 tools across four areas, plus 4 read-only resources. Full reference with every argument: docs/tools.md and docs/resources.md.

The shape vocabulary covers 70 types — basic geometry, UML class/interface/package, sequence (actor, lifeline, activation, fragment), activity (action, decision, fork/join, swimlanes), and a full wireframe kit (screens, buttons, inputs, navbars, tables, cards).

Things worth asking for

• "Turn this OpenAPI spec into a component diagram."

• "Sketch the mobile onboarding flow as wireframes — three screens."

• "Read the board 'Checkout' and tell me which states have no outgoing transitions."

• "Build a domain model from these requirements: orders, invoices, customers."

Authentication and limits

Every request carries your key in Authorization: Bearer <key> (or X-API-Key). Keys are scoped to your account — the assistant sees exactly the diagrams you can see, and nothing else.

Details, key rotation and revocation: docs/authentication.md. Something not working? docs/troubleshooting.md.

About this repository

This repo is the public home of the Umlout MCP connector: documentation, client configs, the registry manifest (server.json) and a connection checker. The server itself is a hosted service — there is no local installation, so there is no server source here.

Issues and questions about the MCP integration are welcome in Issues.

License

MIT — documentation and examples.