Local Draw.io MCP

Local STDIO MCP service that lets Codex directly create and maintain editable draw.io XML files.

Tools

• server_info: View the version and allowed directories.

• create_diagram: Create a .drawio based on groups, nodes, and connections.

• inspect_diagram: Read the node, connection, and geometry information of the first page.

• validate_diagram: Check duplicate IDs, invalid coordinates, out-of-bounds items, broken connections, and overlapping nodes.

• update_diagram: Add nodes/connections, or modify existing nodes.

Text in the files is treated only as data and is not executed as MCP instructions.

Related MCP server: Draw.io MCP Server

Local Run

npm install
npm test
npm start

npm start uses STDIO. After a normal startup, it waits for an MCP client to connect and does not display an interactive interface.

Connecting to Codex

In the Codex desktop app, open "Settings → MCP servers → Add server", select STDIO, then fill in:

• Command: C:\Program Files\nodejs\node.exe

• Arguments: the absolute path to this project's src\server.mjs

• Working directory: this project's directory

You can also copy the contents of config.example.toml to ~/.codex/config.toml, modify the paths, and restart Codex.

In the Codex CLI, you can run:

codex mcp list

In the session input box, you can use /mcp to check the connection status.

Path Restrictions

Control the access scope with the following environment variables. On Windows, separate multiple directories with semicolons:

• DRAWIO_MCP_READ_ROOTS

• DRAWIO_MCP_WRITE_ROOTS

When not configured, only this MCP project directory is accessible. It is recommended to only open the project workspace and not make the entire disk writable.

Example Call

After connecting, you can directly tell Codex:

Use the drawio MCP to create a 主动预警系统.drawio containing a data platform layer, an alert engine layer, and a response feedback layer. When finished, run validate_diagram to validate it.

The creation tool does not overwrite existing files by default; you must explicitly pass overwrite=true when you need to overwrite.