Excalidraw Diagram Skill — Development agent for Claude Code

Excalidraw Diagram Skill

A coding agent skill that generates beautiful and practical Excalidraw diagrams from natural language descriptions. Not just boxes-and-arrows - diagrams that **argue visually**.

Compatible with any coding agent that supports skills. For agents that read from `.claude/skills/` (like [Claude Code](https://docs.anthropic.com/en/docs/claude-code) and [OpenCode](https://github.com/nicepkg/OpenCode)), just drop it in and go.

What Makes This Different

• Diagrams that argue, not display. Every shape/group of shapes mirrors the concept it represents — fan-outs for one-to-many, timelines for sequences, convergence for aggregation. No uniform card grids.
• Evidence artifacts. As an example, technical diagrams include real code snippets and actual JSON payloads.
• Built-in visual validation. A Playwright-based render pipeline lets the agent see its own output, catch layout issues (overlapping text, misaligned arrows, unbalanced spacing), and fix them in a loop before delivering.
• Brand-customizable. All colors and brand styles live in a single file (references/color-palette.md). Swap it out and every diagram follows your palette.

Installation

Clone or download this repo, then copy it into your project's `.claude/skills/` directory:

git clone https://github.com/coleam00/excalidraw-diagram-skill.git
cp -r excalidraw-diagram-skill .claude/skills/excalidraw-diagram

Setup

The skill includes a render pipeline that lets the agent visually validate its diagrams. There are two ways to set it up:

**Option A: Ask your coding agent (easiest)**

Just tell your agent: *"Set up the Excalidraw diagram skill renderer by following the instructions in SKILL.md."* It will run the commands for you.

**Option B: Manual**

cd .claude/skills/excalidraw-diagram/references
uv sync
uv run playwright install chromium

Usage

Ask your coding agent to create a diagram:

...