an open-source mcp server for excalidraw

Give your agent a whiteboard.

Get AI to draw hand-drawn diagrams while it explains something, on a canvas you can keep editing.

Install in a minute Star on GitHub
$claude mcp add --scope user sketchdex -- npx -y sketchdex
Claude drew this in one tool call
The sketchdex editor with Excalidraw's toolbar across the top and the event loop scene on the canvas: call stack, Web APIs, callback queue and event loop with numbered arrows, and a gold note reading 'the 0 ms is a minimum, not a promise'.
why a sketch

Some things are easier drawn.

Ask an agent how something works and you get a wall of text. Ask it to draw it and you get a drawing you understand, on a canvas you can keep editing.

Without sketchdex

A request for the feed starts in the browser and is routed to the nearest CDN edge, which checks its cache. Roughly 80% of requests are served from there and go no further. On a miss, the edge forwards the request to the API tier, which currently runs as three Node pods behind the load balancer. The API performs read-only queries against Postgres directly for anything that doesn't mutate state. Writes take a different path: the API publishes a job onto the queue and returns immediately, and a pool of workers consumes the queue and performs the actual writes, which is where most of the latency accumulates under load, and is also why adding API pods has had little effect on…

A hand-drawn gold scribble spiral next to the words 'i ain't reading allat' and, smaller, 'blah blah blah blah blah'.
A hand-drawn system diagram: browser to CDN edge cache to API to queue to worker to postgres, with notes about cache hits and where the slow part is.
ok, this one i get
A hand-drawn Eisenhower matrix with four coloured quadrants labelled do, schedule, delegate and drop, and sticky notes placed in each.
it put my actual list on the matrix
A hand-drawn hot-air balloon in red, gold and blue next to the words 'v1 plan: ship the balloon first, worry about the wind once it is in the air'.
it can draw things too, not just diagrams
the interface

The real Excalidraw, with a library.

The editor is the official Excalidraw package, so every tool and shortcut is one you know.

The sketchdex library: a grid of four scene cards with hand-drawn previews, a search box, sort controls and a New scene button.
A close crop of the sketchdex editor: the Web APIs box the agent drew is selected, with Excalidraw's resize handles around it and the properties panel beside it showing stroke, background, fill, stroke width, sloppiness and font controls.

everything the agent draws is a normal element that you can grab and change

Run npx sketchdex app to open the interface. There is no account needed and everything runs locally.

how it works

You + AI on one canvas.

Panel one, you ask: a hand-drawn speech bubble reading 'explain jwt auth to me', an arrow down to a small app to api to token diagram, and the note 'it draws the explanation, in one tool call'. Panel two, you draw on it: the same diagram with a gold hand-drawn circle around the token and 'expiry??' scribbled, the agent's reply '15 min, then a refresh token' written beside it, and the note 'it sees your mark and answers on the canvas'. Panel three, or you write: a hand-written launch plan with three lines and a small sketched rocket drawn next to it, with the note 'and it adds the illustration'.
A hand-drawn gold hammer next to the words '18+ tools included'.
install

Install on any client.

Needs Node 20 or newer, and Chrome, Edge or Brave on the machine for rendering.

  • Appnpx sketchdex app opens the library: search, history, live reload while the agent draws.
  • VaultScenes save to ~/Documents/sketchdex. Add --vault to point it anywhere, iCloud and Dropbox included.
  • LicenceMIT, built on the official Excalidraw package.

one command, registers it for every project

claude mcp add --scope user sketchdex -- npx -y sketchdex

one command, or the same block in ~/.codex/config.toml

codex mcp add sketchdex -- npx -y sketchdex
Add to Cursor one click, then Install in the dialog

or in ~/.cursor/mcp.json (global) or .cursor/mcp.json (this project)

{
  "mcpServers": {
    "sketchdex": {
      "command": "npx",
      "args": ["-y", "sketchdex"]
    }
  }
}
Install in VS Code one click, for Copilot's agent mode

or from a terminal

code --add-mcp '{"name":"sketchdex","command":"npx","args":["-y","sketchdex"]}'

Claude Desktop, Windsurf, Gemini CLI and the rest: the mcpServers block in the client's config

{
  "mcpServers": {
    "sketchdex": {
      "command": "npx",
      "args": ["-y", "sketchdex"]
    }
  }
}

npx -y sketchdex docs install has the exact file and path for each one.

or let your agent do it

install the sketchdex mcp server for me. run npx -y sketchdex docs install for the steps.