Pixelbolt

<img src="https://raw.githubusercontent.com/skulitom/Pixelbolt/main/showcase/gallery/library.gif" width="100%" alt="A library drawn with Pixelbolt: books circle the chandelier, a lectern book turns its page and a grey tabby sleeps on a shelf">

<img src="https://skulitom.github.io/Pixelbolt/gallery/montage.gif" alt="Eight looping effects made with Pixelbolt: a campfire, a torch, a steam vent, a bubbling potion, pouring honey, a drip, a plasma globe and a boiling pot">

The gallery: 66 pixel art effects, sprites and scenes from Pixelbolt 0.11.0, all playing, each one click from its recipe in the playground.

Give Claude Code the pixel art skill in one line (Node.js 20 or newer):

npx -y pixelbolt@latest skill install

For Codex, Cursor and the other agents the open skills CLI supports: npx skills add skulitom/Pixelbolt. It copies the skill file alone, which then runs Pixelbolt through npx. The CLI reports installs to the skills.sh leaderboard unless DISABLE_TELEMETRY=1 is set. The skills CLI needs Node.js 22.20 or newer.

Pixel art and sprite animation that your AI agent can make, check and fix. Pixelbolt turns an editable JSON recipe into sprites, tiles, icons, effects and short animations, and exports them as PNG sprite sheets, texture atlases, animated PNGs, GIFs and frames for a video editor. Agents drive it through a local MCP server or the command line; you can open, play and edit the same recipe in a local browser studio.

Try it in your browser: render, export and share recipes with nothing installed.

Poke the pixels: blow on a live pixel-art campfire, pour honey and slime, then save a GIF or share a link that replays exactly what you did.

Effect guides: fire, explosions, smoke and steam, water, slime and honey, and magic, each with recipes that open in the playground.

Neon Voyage: a free browser game made with Pixelbolt. Every sprite, effect and letter is a recipe, and the rocket's exhaust is a live fluid simulation that bends as you steer.

English · 简体中文 · 日本語 · 한국어 · Español

Fire, smoke, steam, explosions, magic, water, honey, slime and sand come from a real fluid simulation that runs on your own CPU in well under a second and bakes every frame into palette pixels you can edit, with seamless loops (fluid effects).

• Who it's for: game developers, game-jam teams and web or video makers who want an agent such as Claude, Codex or Cursor to draw and revise their pixel art, and people building agents that need exact, repeatable images.
• Use it when you want small 2D game assets that stay editable as text: the agent reads every pixel back, fixes one pixel or one frame without redrawing the rest, and the same recipe renders the same image every time.
• Don't use it for painted or photographic images, large animations (an animation frame is at most 256 × 256 pixels, and a project at most 256 frames and 4,194,304 pixels in all; a single still, such as a 1920 × 1080 backdrop or mural, may be up to 4096 pixels a side within that total), generating art with an image model, or editing GIFs and Aseprite files (it imports PNG only, at up to 8 bits per channel).
• Compared with aseprite-mcp, pixel-mcp, pixscii, pixelart-mcp, pixelforge-mcp and SpriteCook, with Pixelbolt's measured runs, the others read from their code and docs, and when to choose each one instead: Pixel art and sprite MCP servers for AI agents: 7 compared (checked 17 October 2026; refreshed 29 October). For fire, smoke, explosion, water and spell effects, with Pixel FX Designer, SpriteMancer, Fluid FX, Pixel Composer, PHOSPHOR, BlastFX and Pixel VFX Forge: Pixel FX Designer alternatives: 8 tools compared (checked 19 October 2026; Pixel VFX Forge added 27 October). Measured with and without Pixelbolt on Claude Haiku, Sonnet and Opus 5.5, in a benchmark we planned in advance: Does a pixel-art MCP server help Claude? (run 23 October to 3 November 2026; on 0.11.0, 32 of 36 runs passed every check with Pixelbolt and 31 without, blind pairs 18 to 13 with one by default, p = 0.47, at 1.47 times the cost, short of our rule for saying it helps; animations and effects, which 0.11.0 was built for, 9 of 15 pairs, p = 0.61, and a same-day repeat would have failed that bar).

Try it. You need Node.js 20 or newer; there is nothing else to install, no API key and no network service:

git clone https://github.com/skulitom/Pixelbolt.git
cd Pixelbolt
node bin/pixelbolt.js preview --open

Give it to your agent. For Claude Code, one line installs the pixel art skill, with nothing to clone and no MCP server (Pixelbolt 0.9.2 or later):

npx -y pixelbolt@latest skill install

It writes ~/.claude/skills/pixelbolt-pixel-art/ (--project writes the current folder's .claude/skills/ instead, --dir any skills folder), runs every command it names through npx -y pixelbolt@<that version>, and never replaces a copy you have changed unless you add --force. For Pixelbolt's MCP tools too, install the Claude Code plugin instead: it brings the server and the same skill together. In Claude Desktop, download pixelbolt.mcpb from the latest release and open it (or install it from file under Settings → Extensions), choose a workspace folder for recipes and artwork, then ask the agent to call pixel_help. For Codex, Cursor and other MCP clients, see Connect an agent through MCP. Pixelbolt is in the official MCP Registry as io.github.skulitom/pixelbolt.

Pixelbolt was called PixelForge until 0.8.0. The pixelforge command still works as an alias, and recipe files keep their pixelforge-* format tags, so existing files and agent setups keep working.

Gallery · Fluid effects · Quick start · Agent setup · MCP server · Portable builds · Recipe reference · Contributing · Sibling tools

How it works

Write a JSON recipe with palettes, text grids, reusable symbols and drawing operations. Get transparent PNGs, sprite sheets, animated PNGs, GIFs for sharing, numbered frames for video editors, and the metadata and player needed to use them. Inspect and edit the recipe in a local browser studio.

Zero runtime dependencies. No build step, API key, image model, network service or native graphics library. Requires Node.js 20 or newer. Works from a checkout on Windows, macOS and Linux.

Figures in motion

Author limbs as bones, bodies as masses, and faces or props as grids. Relative joints and two-bone reach keep attachments together; idle, walk, run, jump, attack and hurt templates expand into editable poses. Review planted feet, ground contact and loop joins in the CLI, MCP or studio. The output uses the existing sprite player.

node bin/pixelbolt.js preview character.poses.json
node bin/pixelbolt.js compile character.poses.json --expand --out character-edit.poses.json
node bin/pixelbolt.js inspect character.poses.json --motion run --speed 48

Pose and motion reference

Baked wave effects

Looping interference and portal interiors combine waves before colouring them, leaving cancellation gaps between bright bands. Two editable presets bake to ordinary sprite frames and appear in the studio's sample list. The game only plays the exported animation.

node bin/pixelbolt.js preview examples/portal.wave.json --open
node bin/pixelbolt.js compile examples/portal.wave.json --out output/portal.json
node bin/pixelbolt.js render output/portal.json --out output/portal-assets

Wave controls and limits · Scene comparison and review. Loops only; masks shape the artwork without simulating reflection or collision.

Gallery

An AI agent drew these with Pixelbolt. Its scripts write the recipes, particle sources and scenes; Pixelbolt renders every sprite to a transparent sheet with an atlas, plays each 240×135 room as a scene and writes the GIFs. They are shown at 3×.

Two more rooms and how these were made

Fluid effects

A pixelforge-fluid source runs a small, deterministic fluid simulation and compiles it into an ordinary recipe of palette grids: gases with buoyancy, swirling vorticity, cooling and dissipation, and liquids as FLIP particles on the same grid, thin as water, thick as honey (a stream that never breaks, a mound that slowly sinks) or firm as slime (a blob that squashes, springs back and holds its shape). Look layers map density, temperature, speed and depth onto your palette ramps through ordered dither, so no colour outside the palette can appear, and looping effects close their seam. Each preset below compiles in well under a second on a laptop CPU, with no GPU and no model calls. Shown at 4×.

![A campfire: flames lick up from crossed lo