Palette Enforcer — Visual Coherence

Applies color palette constraints to all generated PNG assets so every sprite, tile, and background shares the same enumerated color set. Without this, GPT Image 2 returns arbitrary colors and assets from the same game look like they came from different games.

When to use

After all art generation (sprite-artist, tile-artist, bg-artist) and before codesmith. Also run if the user says "make the art more cohesive" or "unify the palette."

Palettes available

Output contract

• All PNGs in public/assets/ are overwritten in-place with palette-quantized versions.
• game-state.json gains state.style.palette with the chosen palette ID.
• Transparent pixels (alpha < 128) are preserved; only opaque pixels are quantized.
• The magenta chroma-key background (#FF00FF) is kept as-is — it's stripped later at runtime.

// game-state.json after running
{
  "style": {
    "palette": "sweetie-16"
  }
}

Process

1. Choose palette: use --palette <id> arg, or auto-select based on genre:
   • platformer / action-platformer → pico8
   • top-down-rpg / dungeon-crawler → endesga-32
   • shoot-em-up → pico8
   • default → sweetie-16
2. Run scripts/enforce_palette.mjs <project-dir> [--palette <id>]
3. Script processes all PNGs found in public/assets/ and writes them back.
4. Writes state.style.palette to game-state.json.

Scripts

• scripts/enforce_palette.mjs <project-dir> [--palette <id>] — quantize all assets.

References

• references/palettes.json — all palette definitions with hex color arrays.