Pixel Art Lab

A local web app for making pixel art in Aseprite using LLMs.

It works by using pixel-mcp to let the model interact with Aseprite through a tool-calling loop — the model draws, renders a preview, looks at it, and iteratively fixes the issues.

OpenRouter is currently the only supported provider.

Requirements

• Node 20+
• Aseprite 1.3.10+, built and working
• pixel-mcp, which needs Go 1.23+ to build
• An OpenRouter API key

You need a working Aseprite executable before any of this does anything — pixel-mcp drives that executable, and this app drives pixel-mcp. Building it yourself from source costs nothing; the prebuilt binaries on Steam and aseprite.org are what you pay for. Either works here, as long as aseprite_path points at it.

Setup

1. pixel-mcp

Clone it into the project root and build it. That is where this app looks by default, and the directory is gitignored, so it stays out of your history:

git clone https://github.com/willibrandon/pixel-mcp.git
cd pixel-mcp && make build && cd ..

Then point it at your Aseprite executable, in ~/.config/pixel-mcp/config.json:

{
  "aseprite_path": "/absolute/path/to/aseprite",
  "timeout": 30
}

aseprite_path must be absolute — pixel-mcp does no discovery and reads no environment variable for it. Confirm the whole chain works before going further:

./pixel-mcp/bin/pixel-mcp --health

Clone it somewhere else if you prefer, and set PIXEL_MCP_BIN in .env to wherever the binary landed.

2. This app

cp .env.example .env

Set OPENROUTER_API_KEY in .env. Everything else there is optional.

npm install
npm run dev        # server on :8787, web on :5273

Open http://localhost:5273. The server listens on localhost only.

Configuration

Environment variables (all optional except the key):