Pixel art

pixel-art — Pixel-Perfect Sprites and Tiles

This skill generates pixel-art assets — sprites, items, tiles, icons, portraits — at a target resolution (32×32, 64×64, 128×128, etc.). Pixel art has hard constraints (grid alignment, limited palette, no anti-aliased edges) that diffusion models violate by default. This skill encodes the prompt patterns and post-processing discipline that makes the output actually look like pixel art and not "blurry small image."

Backing tool: summer_generate_image with an explicit pixel-art prompt.

Two things about that tool you have to know before writing a call, because both silently do nothing:

• There is no "pixel" style preset. style accepts exactly realistic, cartoon, anime, none; anything else is coerced to none. Only cartoon and anime do anything at all (they append a short suffix); realistic and none append nothing. So style: "pixel" is identical to style: "none" — the pixel look has to come entirely from the prompt. Use style: "none" and say so honestly.
• options is not a general passthrough. The MCP tool forwards options to the server, which only recognizes Nano Banana provider keys: seed, outputFormat, safetyTolerance, syncMode, systemPrompt, limitGenerations, thinkingLevel. image_size and negative_prompt are not among them and are dropped without an error. There is no size or aspect-ratio argument on this tool at all — MCP images come back at the server's 1:1 default. Put framing and exclusions in the prompt text instead.

Pixel-perfect output is enforced in Summer Engine with Nearest texture filtering and by downscaling to the target resolution after generation.

When to use

• "Generate a 32×32 sword icon for the inventory."
• "I need a pixel-art portrait of the merchant for the dialogue UI."
• "Make a 64×64 enemy sprite — a slime monster."
• "Generate a tileset for a grass / dirt / stone biome at 16×16 per tile."
• The game has a pixel-art aesthetic and the user wants assets in-style.

When NOT to use

• The user wants a high-resolution painterly portrait → summer:2d-assets/character-portrait.
• The user wants animated frames (walk cycle, attack) → summer:2d-assets/sprite-sheet (pixel art is harder for sprite sheets — read that skill's caveats).
• The user wants a tileable seamless texture (not pixel art) → summer:2d-assets/tileable-texture.
• The game is 3D / non-pixel — verify the user actually wants pixel before generating.

Steps

1. Lock the resolution and palette

Ask the user (or read .summer/GameSoul.md):

• Resolution per asset: 16×16, 32×32, 64×64, 128×128 are standard. Sprites usually 32 or 64; portraits 64 or 128; icons 16 or 32.
• Palette: named retro palette (NES 56-color, Game Boy 4-color green, PICO-8 16-color, Sweetie-16) OR custom hex list OR "no palette restriction."
• Outline: hard black outline, colored outline, or no outline?

Write to .summer/pixel-anchor.md so the rest of the cast/tileset stays consistent:

## Pixel anchor

base resolution: 32x32 per sprite
palette: PICO-8 16-color
outline: hard 1px dark outline (NOT pure black — use the palette's darkest color)
shading: 3-tone (light, mid, shadow), no gradients, no AA

2. Search for existing assets

summer_search_assets(query="<subject> pixel", assetType="2d_image", source="all")

3. Build the prompt

Pattern:

pixel art <subject>, <resolution>, <palette>, <outline rule>, <shading rule>, no anti-aliasing, no blur, sharp pixel edges, transparent background

The model can't actually generate at 32×32 — it generates at 1024×1024 with pixel-art style. You then downscale to the target resolution post-import for crisp pixels.

4. Generate

summer_generate_image(
  prompt="pixel art slime monster, 32x32 sprite, PICO-8 palette, hard 1px outline in palette's darkest color, 3-tone shading, no anti-aliasing, no blur, sharp pixel edges, front-facing. Not blurry, no smooth gradients, no soft edges, not photorealistic, no 3D render.",
  model="nano-banana-2",
  style="none",
  options={ removeBackground: true }
)

Two deliberate choices there:

• The negations live in the prompt. There is no negative_prompt argument — putting one in options is dropped silently. Diffusion models honor in-prompt negations less reliably than a real negative-prompt field, so state them as plain sentences at the end and expect to regenerate more often than you would on a provider UI that exposes the field.
• options.removeBackground: true is real and is the only options key in this skill that does anything: it runs a real background-removal pass after generation and returns a PNG with true alpha. Prefer it over asking for "transparent background" in the prompt, which is what makes models paint a literal checkerboard.

5. Downscale to target resolution

The generated image is 1024×1024 pixel-style. To get true crisp pixels at 32×32:

• Import to the engine, then in the import dock set Filter: Nearest (no smoothing).
• For a true 32×32 atlas/icon, downscale in an external editor (Aseprite, GIMP "nearest neighbor") to 32×32 before importing. Aseprite's "Sprite > Sprite Size" with Nearest gives the cleanest result.
• In Summer Engine, set Project Settings → Rendering → Textures → Default Texture Filter: Nearest if the entire game is pixel art. This disables bilinear smoothing project-wide.

6. Import and wire

summer_import_from_url(url="<fileUrl>", path="res://sprites/slime.png")

For a Sprite2D:

summer_set_prop(
  scenePath="res://main.tscn",
  path="./Slime/Sprite2D",
  key="texture",
  value="res://sprites/slime.png"
)

texture is a property on the node, so it is summer_set_prop. summer_set_resource_property is for reaching inside a resource the node already holds (mesh size, material albedo) and needs all five of scenePath, nodePath, resourceProperty, subProperty, value — there is no two-argument form.

Confirm Filter: Nearest is set in the import dock OR project-wide.

Prompt patterns

Goal	Prompt that works	Why
Item icon (32×32)	pixel art iron sword icon, 32x32, NES palette, hard outline, 3-tone shading, no AA, sharp edges, transparent background, three-quarter view	Three-quarter view reads better than pure side at 32px
Character sprite (64×64)	pixel art knight character sprite, 64x64, PICO-8 palette, hard 1px outline, 3-tone shading, front-facing idle pose, no AA, sharp edges, transparent background	Specifying "idle pose" prevents action poses that don't tile into a sheet
Pixel portrait (128×128)	pixel art portrait of a young witch, 128x128, custom muted fantasy palette, hard outline, 4-tone shading, bust framing, looking forward, no AA, no blur, transparent background	Higher resolution allows 4-tone shading; 32px is too small for that
Tileset (16×16/tile)	pixel art top-down tileset, grass-to-dirt transition, 16x16 per tile, 3x3 grid layout, NES palette, hard outline between tiles, 3-tone shading, no AA, sharp edges	Tilesets render best in a labeled grid layout
Background object (64×64)	pixel art mossy boulder, 64x64, fantasy palette, hard outline, 3-tone shading, no AA, transparent background, three-quarter view	Background props benefit from three-quarter for depth
GB-style asset (Game Boy)	pixel art skeleton enemy, 32x32, Game Boy 4-color green palette (#0f380f, #306230, #8bac0f, #9bbc0f), hard 1px outline, 2-tone shading, no AA	Naming the 4 hex codes locks the palette

Bad prompts (and why)

Bad	Failure mode
8-bit sword	"8-bit" is interpreted loosely. Returns a smooth render of a sword with vague pixel feel. Specify resolution + palette + "no AA" explicitly.
pixel art knight, photorealistic	Conflicting directives. Model averages and gives you neither.
pixel art at 32x32 with no negations	Model adds soft edges and gradient shading. Always spell out "no anti-aliasing, no blur, no smooth gradients" in the prompt itself — there is no negative-prompt argument to fall back on.
pixel sprite walk cycle	Walk cycles need consistent frames — single-prompt sprite sheets fail. Route to summer:2d-assets/sprite-sheet.
cute pixel art	"Cute" without subject is undefined. Specify what.

Anti-patterns

• Skipping the downscale. The model returns a 1024×1024 pixel-style image. If you import that as a 1024 texture, the "pixels" are actually 32-pixel blocks of soft color. Downscale to true target resolution OR set Filter: Nearest so the up-rendering doesn't smooth.
• No Filter: Nearest. The default texture filtering is bilinear. Set Nearest on import or project-wide for pixel art.
• Reaching for negative_prompt or image_size. Neither exists on this tool; both are dropped without an error, so the call looks like it worked and the output is off-style. Negations go in the prompt text; size is fixed.
• Inconsistent palette across the cast. Pick a named palette (PICO-8, NES, custom hex list) and re-use across every asset in the project. Different palettes = the project doesn't read as one game.
• Generating walk-cycle frames as one image. Sprite sheets via single-prompt are unreliable. Route to summer:2d-assets/sprite-sheet.

Edge cases

• User wants animated pixel sprites. Generate base sprite here, then per-frame variants via img2img with the base as referenceImageUrl. For more than 2-3 frames, route to summer:2d-assets/sprite-sheet (and read its caveats).
• User wants the entire game in pixel art. Set Project Settings → Rendering → Textures → Default Texture Filter: Nearest once. Saves you from re-setting it on every import.
• User wants a high-res "pixel art" portrait that's not actually pixelated (faux-pixel-aesthetic at full resolution). That's summer:2d-assets/character-portrait with a "pixel art aesthetic" prompt — not this skill.
• User specifies a palette like "Sweetie-16" or "Endesga-32" and the model ignores it. Name the hex codes explicitly. Palette names alone are unreliable below the top 5-10 famous ones.
• Tilesets need to tile cleanly. Pixel-art tile-edge cleanliness from raw generation is poor. Generate the tile grid, then manually fix edge seams in Aseprite. The AI gets you 80% there.

Fallback (no MCP)

Print the call:

summer_generate_image(
  prompt="<pixel art prompt with full anchor>. Not blurry, no smooth gradients, no anti-aliasing.",
  model="nano-banana-2",
  style="none",
  options={ removeBackground: true }
)

The Summer dashboard does expose size and negative-prompt controls that the MCP tool does not — if the user is running it there, tell them to set square + a real negative prompt.

Tell the user to run via the Summer dashboard, downscale in Aseprite/GIMP to true target resolution with nearest-neighbor, then summer_import_from_url (or drop into res://sprites/) and set Filter: Nearest.

If MCP is offline entirely: open Aseprite or Piskel and hand-author the asset. For pixel art at small resolutions, hand-authoring is often faster than fixing a generation.

Handoff

After the asset is wired:

• More assets in the same style → re-invoke this skill, re-use the pixel anchor.
• Animation frames for the sprite → summer:2d-assets/sprite-sheet with the base sprite as anchor.
• Pixel UI → re-invoke with UI subjects (icons, button frames) at appropriate resolution.
• Tilemap setup → summer:scene-composition for TileMap / TileMapLayer wiring.

See also

• summer:2d-assets/sprite-sheet — animated pixel frames.
• summer:2d-assets/character-portrait — high-res counterpart.
• summer:asset-pipeline/asset-strategy — meta-router.
• ../../../references/mcp-tools-reference.md — summer_generate_image schema.