/retrodiffusion

name: retrodiffusion
description: Generate true pixel art sprites, tilesets, and animations with the Retro Diffusion API — the best dedicated pixel art model. Use when the user says "generate pixel art", "make a sprite with AI", "use Retro Diffusion", "rdpk", or wants high-quality pixel art faster than hand-coded sprite arrays. Requires a Retro Diffusion account and RETRODIFFUSION_API_KEY (paid credits). Great for quick prototyping of 2D Phaser games.
argument-hint: "[prompt]"
license: MIT
compatibility: Requires a Retro Diffusion account, RETRODIFFUSION_API_KEY environment variable, and internet access for API calls. Each generation consumes paid credits from the user's account.
metadata:
  author: OpusGameLabs
  version: 1.0.0
  tags: [game, 2d, pixel-art, retro-diffusion, ai, image-generation, sprites, tilesets, animation]

Retro Diffusion — True Pixel Art Generation

Generate authentic pixel art sprites, tilesets, and animations from text prompts or reference images using the [Retro Diffusion](https://www.retrodiffusion.ai) API. Output is true pixel art (clean integer-pixel grids, limited palettes), not blurry diffusion-model output downscaled into pixels — making it the best AI option for shippable 2D game art and fast prototyping.

> **Paid service.** Retro Diffusion requires an account at https://www.retrodiffusion.ai and an API key with credits. **Always tell the user this requires a paid Retro Diffusion account before generating anything**, and confirm they understand each call deducts from their balance.

Reference Files

| File | Description | |------|-------------| | [api-reference.md](./api-reference.md) | Full API endpoints, models, prompt_style values, response shape, pricing, and error codes |

When to Use

• **Quick prototypes** — generate dozens of unique sprites in a minute instead of hand-coding 16×16 arrays
• **Polish pass on a working game** — replace placeholder shapes with cohesive pixel art that already matches a chosen style
• **Tilesets** — wang-style ground/wall sets without manually drawing every transition tile
• **Sprite animations** — walk cycles, idle bobs, attacks delivered as transparent GIFs or spritesheets

**Choose this over `add-assets` (code-only pixel art) when:** the user wants AI-generated art, has a Retro Diffusion key, or the game needs more visual variety than hand-coded matrices can deliver in a reasonable time. The two skills compose well — Retro Diffusion for hero sprites/tilesets, code-only matrices as a free fallback for quick filler.

**Do NOT use this for:** 3D models (use `meshyai`), 3D worlds (use `worldlabs`), audio (use `game-audio`), or when the user explicitly wants the all-code procedural pixel art approach (use `add-assets`).

Authentication

Before prompting the user, check if the key already exists:

test -f .env && grep -q '^RETRODIFFUSION_API_KEY=.' .env && echo "found"

If found, export it with `set -a; . .env; set +a` and skip the prompt.

If the key is **not** set, **ask the user immediately and explain the cost model**:

> I'll generate true pixel art with Retro Diffusion — the best dedicated pixel art model for shippable game sprites. > > **Heads up: this is a paid service.** You'll need a Retro Diffusion account with credits. Each image typically costs between $0.015 (RD_FAST) and $0.18 (RD_PRO). Get a key in 60 seconds: > > 1. Sign up at https://www.retrodiffusion.ai > 2. Buy credits (smallest pack is fine for prototyping) > 3. Account → API → Generate API key > > Paste your key like: `RETRODIFFUSION_API_KEY=rdpk-...` > (It will be saved to `.env` and redacted from this conversation.) > > Or type "skip" to fall back to free hand-coded pixel art via `/add-assets`.

If the user provides a key, save it to `.env` and use it via `set -a; . .env; set +a && node scripts/retrodiffusion-generate.mjs ...`.

If the user skips, **stop and hand off to `/add-assets`** — do not silently degrade to a different art style without telling them.

CLI Script — `scripts/retrodiffusion-generate.mjs`

Zero-dependency Node.js script. Handles all six modes: generate, img2img, animate, tileset, edit, and balance.

Generate (text-to-pixel-art)

# Single 64×64 sprite, RD_FAST (cheapest)
RETRODIFFUSION_API_KEY=<key> node scripts/retrodiffusion-generate.mjs \
  --mode generate \
  --prompt "a cute green slime with big eyes" \
  --model RD_FAST --style retro \
  --width 64 --height 64 \
  --output public/assets/sprites/ --slug slime

# Higher quality with RD_PRO (flat $0.18, supports up to 256×256)
RETRODIFFUSION_API_KEY=<key> node scripts/retrodiffusion-generate.mjs \
  --mode generate \
  --prompt "a heroic knight, full body, side view" \
  --model RD_PRO --style fantasy \
  --width 128 --height 128 \
  --output public/assets/sprites/ --slug knight

# Transparent background for game sprites
RETRODIFFUSION_API_KEY=<key> node scripts/retrodiffusion-generate.mjs \
  --mode generate --prompt "a treasure chest, closed" \
  --model RD_FAST --style game-asset \
  --width 64 --height 64 --remove-bg \
  --output public/assets/sprites/ --slug chest

# Seamless tiling texture (e.g., grass, water)
RETRODIFFUSION_API_KEY=<key> node scripts/retrodiffusion-generate.mjs \
  --mode generate --prompt "lush grass texture, top down" \
  --model RD_PLUS --style top-down \
  --width 64 --height 64 --tile-x --tile-y \
  --output public/assets/tiles/ --slug grass

# Estimate cost before paying for it
RETRODIFFUSION_API_KEY=<key> node scripts/retrodiffusion-generate.mjs \
  --mode generate --prompt "..." --check-cost

Image-to-Image (refine a reference)

RETRODIFFUSION_API_KEY=<key> node scripts/retrodiffusion-generate.mjs \
  --mode img2img \
  --image ./concept-art/hero-sketch.png \
  --prompt "a heroic knight in shining armor" \
  --model RD_FAST --style retro \
  --width 64 --height 64 --strength 0.75 \
  --output public/assets/sprites/ --slug hero

`--strength` controls how much the AI deviates from the