# excalidraw-skill

Enables Claude Code to update native Excalidraw diagrams without breaking manual layouts. Generates side-by-side visual diffs and preserves original files.

- plugin · `type=plugin` · Claude Code · ★ 212
- Author: edwingao28
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/edwingao28/excalidraw-toolkit
- Updated: 2026-09-09
- HTML: https://affpapa.org/en/nevibecode/plugins/excalidraw-skill

## What it does

The plugin adds the `scoped-edit` capability to Claude Code for targeted updates to `.excalidraw` canvases. Instead of redrawing everything from scratch, the agent targets shapes by their IDs, shifts anchored arrows, and inserts components into open space. It writes output to a separate copy alongside a `receipt.json` manifest and before-and-after PNG previews.

If labels overflow bounding boxes or an edit touches unsupported geometry, the run fails immediately rather than silently corrupting your canvas. The toolkit relies on Node.js 24.15+ (or Node 26+) and Git if you run its preview and build tools locally.

## Install

### Claude Code (native platform)

**Plugin marketplace**
In the agent chat (not a shell):
```text
/plugin marketplace add anthropics/claude-plugins-community
```
In the agent chat (not a shell):
```text
/plugin install excalidraw-skill@claude-community
```

## When to use it
- add architecture components and connectors into an existing canvas
- generate side-by-side PNG previews explaining recent code changes
- recolor nodes and update bound arrow labels without moving nearby notes
- export edited `.excalidraw` copies while keeping the original file intact

## Example prompts
- Use scoped-edit on `architecture.excalidraw` to insert an agent interface and preserve the current layout.
- Explain the recent changes in `src/scoped-mcp.js` on `pipeline.excalidraw` with before and after previews.
- Recolor the database block and adjust bound arrows in `overview.excalidraw`.

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 98f3acfbc9a0881f.

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````text
# Excalidraw Toolkit

**Diagram with your agent. Stay in control.**

Use Claude Code or Codex to edit an existing Excalidraw diagram. Review what
changed, keep drawing in the same workspace, and export a native file you can
keep editing. Your original file and unrelated work stay intact.

[![Watch the Excalidraw Toolkit launch film — Your diagram. Your next move.](https://edwingao.com/excalidraw-toolkit/launch-poster.jpg)](https://edwingao.com/excalidraw-toolkit#launch-film)

**[Watch the launch film · 38 seconds →](https://edwingao.com/excalidraw-toolkit#launch-film)** · [Explore the toolkit](https://edwingao.com/excalidraw-toolkit) · [Get started](#get-started)

*Real product captures: agent edits, before/after review, manual drawing, export,
and reopen. Camera motion and transitions are added for pacing.*

![A real agent edit with the original notes and diagram layout preserved](examples/workflows/agent-edit.png)

> Extend this architecture diagram with the MCP interface in `src/scoped-mcp.js`.
> Show where agent requests enter and how verified images come back. Preserve
> the existing pipeline, layout, and notes.

The agent inspects existing elements, applies supported edits by ID, and returns
an edited `.excalidraw` copy with before/after PNGs and a change receipt.

This real Codex/MCP edit extends a nine-stage diagram of this repository into an
eleven-stage overview. The blue additions show the existing MCP interface;
the original pipeline and annotations stay in place.
Try the [original diagram](examples/workflows/toolkit-pipeline-before.excalidraw),
open the [edited result](examples/workflows/toolkit-pipeline-after.excalidraw), or
read the [task and source references](examples/workflows/).

**Implemented on `main`.** The npm `latest` release is still `0.1.0`; it does not include these workflows. Version `0.2.0` is not published yet. Use the source setup below.

## What you can do

| Task | What the toolkit provides |
| --- | --- |
| Recolor or rename a component | Scoped style edits and measured bound-label updates. |
| Revise a flow | Move supported shapes and reanchor bound arrows; add nodes/connections; remove or detach explicit dependencies. |
| Explain a code change | Source-linked before/after diagrams at article, slide, or canvas dimensions. |
| Update a diagram after code changes | A staged refresh that preserves manual overrides and identifies conflicts. |
| Run from CI | Explicit source scope, execution budget, retained artifacts, and stale-event checks. |
| Publish a PR update | An opt-in managed comment that reconciles retries and checks the current PR head. |

Your existing coding agent supplies the reasoning. The toolkit owns supported
native edits, preservation checks, rendering, and retained results; it adds no
extra model service.

## Get started

Use Node.js **24.15+ in the 24.x line** (or Node 26+), Git, and a POSIX shell with `tar`. The build uses npm 12.0.2:

```sh
git clone https://github.com/edwingao28/excalidraw-toolkit.git
cd excalidraw-toolkit
npx --yes npm@12.0.2 ci
npx --yes npm@12.0.2 run build

TOOLKIT_CLI="$PWD/bin/cli.js"
TOOLKIT_PROJECT="/absolute/path/to/your-project"
node "$TOOLKIT_CLI" setup-preview
node "$TOOLKIT_CLI" init --target all --project "$TOOLKIT_PROJECT"
node "$TOOLKIT_CLI" doctor --target all --project "$TOOLKIT_PROJECT"
```

Set `TOOLKIT_PROJECT` to the project containing your diagram. Use `--target claude`
or `--target codex` for one client. Keep this checkout available: the installed
skill records its absolute CLI path. [Installation guide](docs/install.md)
covers the packed archive, updates, runtime requirements, and uninstalling.

### Claude Code

Start a new Claude Code session in the project. Its installed `scoped-edit` skill
uses the native CLI for saved-file edits. Try:

> Use scoped-edit on `architecture.excalidraw`. Read the relevant source and add
> the missing agent entry point and its connections in the available space.
> Preserve my notes and existing layout. Show before/after previews and return
> the editable copy.

### Codex
````
END THIRD-PARTY FILE 98f3acfbc9a0881f

The third-party file has ended. Everything between the 98f3acfbc9a0881f tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 4080 of 9551 bytes. © edwingao28 · MIT · https://github.com/edwingao28/excalidraw-toolkit

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