MCP Excalidraw is an open-source MCP server, CLI and agent skill that gives AI coding agents a live Excalidraw canvas to draw on, inspect and refine. It has around 2,600 GitHub stars and is under active development.
The server exposes 26 tools over the Model Context Protocol, so agents in clients like Claude Code, Cursor and Claude Desktop can create architecture diagrams and flowcharts programmatically instead of describing them in text. Unusually, the agent can screenshot its own canvas, spot layout problems and fix them before saving, with real-time sync to the canvas open in your browser. Because diagrams land as native Excalidraw files, anything the agent draws stays fully editable by hand afterwards. Finished diagrams export to .excalidraw files you can commit next to your code, as well as SVG and PNG. There are three ways to drive it — an agent skill with a CLI, the MCP server over stdio, or a REST API — and it ships as an npm package and Docker image.
MCP Excalidraw is free and open source under the MIT license. All 26 tools are included and there is no pro version; install it from npm or Docker at no cost — you only need an MCP-capable AI client to use it.
Developers and technical writers who want their AI assistant to produce real, editable diagrams instead of ASCII art or Mermaid-only output, and teams documenting systems with AI help.