Excalidraw MCP: diagrams an agent can see and refine

Ask an agent for an architecture diagram and you usually get one shot: labels spilling out of boxes, arrows crossing, and the only fix is to regenerate the whole thing. This Excalidraw MCP server gives the agent a live canvas instead. It creates and edits individual elements, takes a screenshot to see how things look, nudges whatever overlaps, and finally exports an .excalidraw file that sits next to your code. The repo, by community developer yctimlin, had about 2.5k stars as of 2026-10-06.

What it does

• Element-level edits: create_element, update_element, delete_element, batch_create_elements and more, so one box’s label can change without a redraw.
• Sees its own work: describe_scene returns a structured description and get_canvas_screenshot an image. Since v2.1 screenshots render server-side, with no browser tab needed.
• Layout tools: align, distribute, group and lock, plus snapshot_scene and restore_snapshot for rollback.
• Import and export: create_from_mermaid turns Mermaid into editable Excalidraw, export_scene saves the file, export_to_image renders it, and export_to_excalidraw_url makes a share link.

Who it’s for

• Developers who want Claude Code or Cursor to draw a service’s architecture from the code and keep the diagram committed and current.
• Engineers writing docs who want to draft flowcharts in Mermaid and then fine-tune them by hand.
• Multi-agent setups, since several agents can draw on the same canvas at once.

Setup

You need Node.js 20+ and no API keys or accounts. In Claude Code:

claude mcp add excalidraw --scope user -- npx -y mcp-excalidraw-server

The server starts a local canvas on launch (default http://127.0.0.1:3000); open it in a browser to watch the agent draw. For coding agents, the README also recommends the bundled skill plus CLI, which uses fewer tokens.

Our take

Excalidraw has an official MCP server too, but it’s a chat widget that renders a diagram from one prompt. This project solves a different problem: a canvas a coding agent can revise, inspect and commit, with 26 tools from drawing to export. Caveats: it’s a community project, not from the Excalidraw team, and the canvas opens a local port. share and share links upload an encrypted scene to excalidraw.com, and the canvas page loads fonts from the esm.sh CDN, which matters on locked-down networks. MIT-licensed.