git:20260911.b4df358 to git:20261010.4ade947

12 added, 31 removed. Audit A to A.

---

name: create-asset-sheet

description: "Generate a pack of 2D game assets from one prompt — tile sheet, UI kit, character pack, or biome set — sliced, classified, and saved as one pack ArtAsset."

license: MIT

compatibility: [Cursor, Claude Code, Windsurf, Codex]

category: 2d-assets

user-invocable: true

allowed-tools: Read Grep Glob Write Edit summer_get_studio_workflow summer_generate_image summer_slice_asset_sheet summer_search_assets summer_import_asset_by_id summer_import_from_url

paths: ["assets/**", "art/**", "sprites/**"]

---

# create-asset-sheet — Generate a coherent pack of 2D assets

- This skill turns a single prompt into a categorized pack of isolated, named 2D assets ready to drop into a game. It exists because the alternative — generating each asset one-by-one, then losing visual coherence between them, then manually matting backgrounds in Photoshop — is the most-cited pain point from indie devs working with image models in 2026.

+ This skill turns a single prompt into a categorized pack of isolated, named 2D assets ready to drop into a game. Generating assets one by one loses visual coherence between them and leaves you matting backgrounds by hand; one sheet keeps the pack consistent.

**Pipeline:**

1. **Generate a sheet** of N isolated assets in one image-gen call.

- 2. **Remove background** (fal/bria) so each asset can stand on its own.

- 3. **Detect + name + classify** each asset in one vision call (Gemini 3 Pro outputs bbox + snake_case name + category per region).

- 4. **Crop** each region with sharp.

- 5. **Optionally upscale** any small slice via fal flux-2/edit i2i, preserving aspect.

+ 2. **Remove the background** so each asset can stand on its own.

+ 3. **Detect, name and classify** each asset in one vision pass (bounding box + snake_case name + category per region).

+ 4. **Crop** each region.

+ 5. **Optionally upscale** any small slice, preserving aspect.

6. **Save** as a single pack ArtAsset with `packFiles: [{url, name, type}]` and `metadata.sliceBboxes`.

Categories the classifier outputs (used to route into downstream pipelines):

## When to use

- "Make me a Japanese village tileset."

- "Generate a sci-fi UI kit — buttons, panels, icons."

- "I need 12 fantasy props for a dungeon — chest, torch, skeleton, gold, etc."

- "Give me a character pack: 6 cute monsters."

- "Build a forest biome — trees, rocks, plants, ground tiles."

## When NOT to use

- The user wants a **single** asset → `pixel-art` or `character-portrait`.

- The user wants character **animation** (walk cycle, attack frames) → `sprite-sheet`.

- The user wants **3D models** of a planned pack → not yet supported in one shot; loop `concept-art` → image-to-3D per item, or use `asset-strategy` to pick the right path.

- The user wants **terrain tiles that connect seamlessly** (auto-tiling / Wang tiles) → `tileable-texture` is the right home for edge logic; this skill produces standalone tiles, not edge variants.

## The cleanest path: the studio wizard

- The fastest, most reliable way to invoke this flow today is the **Create Asset Sheet** wizard in the Summer studio:

- ```

- https://summerengine.com/studio/create-tileset

- ```

- Direct the user there if they're working in the browser. The wizard:

+ The most reliable way to run this flow is the **Create Asset Sheet** wizard in Summer Studio's guided workflows. Open it for the user with `summer open workflows` (or `summer_open`) if they're working in the browser. The wizard:

- Offers a 2D / 3D mode toggle (2D is the slice flow described here; 3D is a soft pointer to `concept-art` + per-asset image-to-3D for now)

- Surfaces six prompt templates (tile sheet, UI kit, menu, character pack, biome, freeform)

- Lets the user upload an existing sheet if they have one (skip generation)

- Shows variants in a grid with full-screen lightbox + arrow-key toggling

- Runs the full slice pipeline on click

- Has per-slice HD upscale + bulk "Upscale all"

- Saves as a pack ArtAsset visible in the user's library

If the user is in a chat / agent context, use the programmatic path below. It

- now calls the same server-side slicer as the Studio wizard.

+ calls the same server-side slicer as the Studio wizard.

## Programmatic path (chat / agent driving the engine)

1. **Load the exact current recipe.** Call

`summer_get_studio_workflow({workflowId: "asset-pack"})`. Follow its ordered

steps and report any `manual` handoff instead of pretending it ran.

2. **Generate the sheet.** Call `summer_generate_image` with a prompt like:

```

<theme> asset sheet: <comma-separated list of items>. Each item isolated with empty space around it, transparent or neutral background.

```

- Pick model by style: pixel art → `grok-imagine`, painterly / illustrative / structured grids → `gpt-image-2`.

- 1024x1024 is the sweet spot. Larger sheets fragment in the slicer when individual assets get below ~64px.

- Keep the asset list to 6–20 items per sheet. Past 20, model attention degrades and slices get muddy.

3. **Slice, remove background, detect, name, classify, crop, and save.** Pass

the returned image asset id to:

```

summer_slice_asset_sheet({ assetId: "<generated asset id>" })

```

This is the same cloud slicing pipeline used by the Studio flow. Keep the

returned slice ids/names/categories; do not reimplement the vision boxes

locally.

- 4. **Optional upscale.** For any crop where longest side < 256px, send through fal flux-2/edit i2i with prompt:

+ 4. **Optional upscale.** The Studio wizard has per-slice HD upscale. Over MCP, for any crop where the longest side is under 256px, call `summer_generate_image` with the slice as `referenceImageUrl` and this prompt:

```

Recreate this exact <name> at high resolution. Preserve every detail, the exact pose, the exact style. Sharper edges, more detail. Transparent background. Single isolated asset, no scene.

```

- - Scale longest side to 1024, preserve aspect ratio (FLUX requires multiples of 32).

- - Don't blindly upscale everything — high-res slices get diminishing returns and you spend $0.04/slice.

+ - Don't upscale everything: each upscale is a paid generation, and large slices gain little.

5. **Import what the game needs.** Use the returned asset ids with

`summer_import_asset_by_id`. Keep the source pack in My Assets so the agent

and the human Studio session see the same result.

## Prompt patterns that work

**Tile sheet (terrain + props + buildings):**

```

<setting> tile sheet: <terrain tiles>, <props>, <buildings>. Each item isolated with empty space around it.

```

**UI kit:**

```

<theme> game UI kit: round button, square button, panel background, slider, toggle switch, progress bar, icon set, banner header.

```

**Menu screen:**

```

<theme> main menu UI: title banner, Start Game button, Settings button, Quit button, <background style>, ornate frame, decorative element.

```

**Character pack:**

```

<theme> character pack, single front-facing frame each: <character 1>, <character 2>, ... <character N>. Each isolated.

```

**Biome:**

```

<biome name> biome assets: <flora>, <terrain features>, <rocks/water/sky elements>. Each item isolated.

```

## Common failure modes

| Symptom | Cause | Fix |

|---|---|---|

| Slicer returns 1 giant bbox covering the whole sheet | Items overlap / no gaps in the source | Re-prompt with "each item fully isolated, empty space around each item". Re-generate. |

| Slicer misses items | Items too small in the source, classifier dropped them as noise | Generate at higher resolution (2048) or with fewer items per sheet |

| Two items merge into one slice | Items touching in the source | Re-prompt with more isolation. Or accept and let the user split manually in step 2's review. |

- | Slice has a sliver of neighbor in it | Vision bbox is off by 5–15px | Expected. The slicer pads but doesn't snap-to-content yet. Live with it or upscale the slice (FLUX often cleans the edge) |

+ | Slice has a sliver of neighbor in it | Vision bbox is off by 5–15px | Expected. The slicer pads but doesn't snap-to-content yet. Live with it or upscale the slice (upscaling often cleans the edge) |

| Upscaled slice looks invented | Source was too small / too ambiguous | Don't upscale slices below ~32×32. Or accept the hallucination and edit |

| Detection returns wrong category | Model misjudged context | User can override in the review step; not a blocker |

## What this skill does NOT do (yet)

- - Per-asset planning + individual generation (the Codex-style flow where each asset is generated separately at full resolution). The planner endpoint exists (`POST /api/art/plan-asset-pack`) but the per-asset gen loop is not wired into the wizard yet.

+ - Per-asset planning and individual generation, where each asset is generated separately at full resolution.

- 3D pack assembly. The 3D mode in the wizard is a placeholder pointer to `concept-art` + image-to-3D for now.

- - Character animation routing. Once a slice is classified as `character`, the next step (sprite-sheet generation) is a separate skill that the user has to invoke manually. Auto-routing is on the roadmap.

+ - Character animation routing. Once a slice is classified as `character`, the next step (sprite-sheet generation) is a separate skill that the user has to invoke manually.

- Terrain auto-tiling / Wang-tile generation. Use `tileable-texture` for that.

- Level composition / scene assembly. Use `design-level`.

- ## Honest cost estimate

- Per 12-asset sheet, end to end through the wizard:

- - Generate sheet: $0.04–0.10 (varies by model)

- - Background removal: $0.05

- - Vision detect + classify: $0.02–0.03

- - Save pack: free

- - Optional bulk upscale: ~$0.04 per slice ($0.48 for 12)

- **Without upscale:** ~$0.12. **With full upscale:** ~$0.60. About a third of what a Photoshop hour would cost.