lords-of-ash/.claude/skills/asset-gen/SKILL.md

name, description

name

description

asset-gen

Generate themed visual assets for the Lords of Ash CK3 total conversion mod using the generate_image MCP tool (Nano Banana / Gemini 2.5 Flash Image). Use when generating any mod art: trait icons, modifier icons, decision illustrations, event backgrounds, loading screens, bookmark art, coat of arms emblems, religion icons, building icons, MaA icons, lifestyle assets, scheme icons, focus icons, activity assets, workshop thumbnail, or frontend art. Also use when the user asks about visual identity, art direction, asset pipeline, or DDS conversion. Triggers on: "generate icons", "make trait art", "create loading screen", "asset pipeline", "convert to DDS", "art style", "generate assets", "batch generate".

Asset Generation — Lords of Ash

Generate visually consistent, CK3-native art assets using the generate_image MCP tool.

Asset descriptions, filenames, resolutions, and directory paths are documented in docs/REQUIRED_ASSETS.md. This skill provides the visual identity, prompt system, and workflow.

Prompt Assembly

Every generate_image call uses three parts:

[STYLE PREFIX] + [CATEGORY TEMPLATE] + [ASSET DESCRIPTION from docs/REQUIRED_ASSETS.md]

Never call generate_image with just the asset description. Always prepend the style prefix and matching category template.

• Style prefix and color palette: Read references/style-guide.md
• Category templates: Read references/category-templates.md and match by asset type (trait icon, modifier icon, decision illustration, etc.)
• Asset description: Look up the specific asset in docs/REQUIRED_ASSETS.md

Aspect Ratio Mapping

Asset Type	Pixel Size	aspect_ratio
All square icons	various	1:1
Decision illustrations	1100x440	5:2 (fallback: 16:9 + crop)
Event backgrounds	1592x848	16:9
Loading screens	3840x2160	16:9
Bookmark art	1920x1080	16:9
Frontend art	3840x2160	16:9
Activity headers	1100x440	5:2 (fallback: 16:9 + crop)
Lifestyle strips	480x160	3:1 (fallback: 16:9 + crop)
Perk tree backgrounds	348x812	9:16 + crop
Lifestyle sidebars	608x1552	9:16 + crop

If the tool doesn't support an exact ratio, generate at the nearest standard ratio and resize/crop with ImageMagick.

Single Asset Workflow

1. Find the asset in docs/REQUIRED_ASSETS.md — note filename, resolution, directory, DDS format, and description.
2. Read references/style-guide.md for the style prefix.
3. Read references/category-templates.md for the matching template.
4. Assemble the full prompt and call generate_image with correct aspect_ratio.
5. Save the PNG to lords_of_ash/ at the correct gfx/ path.
6. Report what was generated.

Batch Workflow

When generating multiple assets of the same type:

1. Read the style prefix and category template once.
2. Iterate through assets in docs/REQUIRED_ASSETS.md for that category.
3. Use the same style prefix and template for every asset.
4. Call generate_image in batches of no more than 3 parallel calls at a time. Wait for each batch to complete before starting the next. This avoids overwhelming the image generation API.
5. Save PNGs to correct paths after each batch.
6. Report summary: count generated, failures, paths written.

Modifier Coin Base

All modifier icons use a shared hammered-metal coin base for visual cohesion. Pass it as inputImagePath when generating modifier icons:

~/Pictures/mcp-images/icons/modifiers/modifier_base_coin.png

Use the stronger prompt pattern to keep the model on the coin base:

On a weathered dark steel-silver coin with rough beveled edges and warm gold-amber rim glow, against a dark navy-charcoal swirled background. CK3 game modifier icon, painterly style. Embossed relief on the coin surface of [MOTIF]. The motif is engraved into the smooth grey coin face as a bas-relief.

If the model drifts (different edge style, wrong background), regenerate — the coin base consistency is critical for the set to look cohesive at 60x60.

PNG Output Directory Structure

Generated PNGs are saved under ~/Pictures/mcp-images/. Mirror the mod's gfx/ directory structure so source PNGs are organized the same way as the final DDS files:

~/Pictures/mcp-images/
  icons/modifiers/          → modifier icons (60x60)
  icons/traits/             → trait icons (120x120)
  icons/faith/              → faith icons (100x100)
  icons/buildings/          → building icons (60x60)
  icons/maa/                → MaA regiment icons (60x60)
  icons/focuses/            → focus icons (140x140)
  icons/schemes/            → scheme icons (120x120)
  icons/casus_belli/        → casus belli icons (60x60)
  illustrations/decisions/  → decision illustrations (1100x440)
  event_backgrounds/        → event scene backgrounds (1592x848)
  loading_screens/          → loading screens (3840x2160)
  bookmarks/                → bookmark art (1920x1080)
  frontend/                 → frontend/menu art (3840x2160)
  coat_of_arms/             → CoA emblems (128x128)
  lifestyles/               → lifestyle strips, sidebars, perk trees

Use the fileName parameter with the subdirectory path (e.g., icons/modifiers/modifier_foo.png) to save directly into the right location. Do not save PNGs loose in the root mcp-images/ directory.

When regenerating an asset, overwrite the existing file — do not create versioned copies (_v2, _v3, etc.).

DDS Conversion

CK3 requires DDS format. After generating PNGs, convert using the format mapping and commands in references/dds-conversion.md.

All output paths are under lords_of_ash/gfx/. The full directory structure is documented at the end of docs/REQUIRED_ASSETS.md.

Critical Rules

• Always prepend the style prefix — without it, images drift in style.
• Icons need dark/near-black backgrounds — light backgrounds break CK3 UI.
• Trait icons are 120x120, NOT 60x60. Modifier icons are 60x60.
• Trait icons MUST be uncompressed ARGB in DDS, not DXT5.
• CoA emblems MUST be uncompressed ARGB for the color mask system.
• Modifier icons need mipmaps; trait icons do not.
• Decision illustrations: weight composition right (left side has UI overlay).
• Filenames are case-sensitive on Linux — match mod code exactly.
• Append "absolutely no text, no letters, no words, no labels, no titles, no captions, no watermarks" to icon prompts — the model tends to add text despite weaker phrasing.
• Never use circular medallion/coin framing for icons — the model defaults to round compositions which leave white/light corners on a square canvas. Enforce "flat square, dark background edge-to-edge" in the prompt.
• Icons must be symbolic motifs only, not scenes or landscapes. If the model generates an environment instead of an icon, the prompt needs stronger "this is an icon, not a scene" language.
• Enforce painterly style explicitly — the model sometimes drifts to vector/flat graphic/mobile game art. Add "painterly style only — NOT vector art, NOT flat graphic design, NOT mobile game art" when this happens.
• For trait families that form a progression (e.g. weak/strong/savant), describe the same base motif in each prompt and only vary the intensity/effects. Specify orientation ("horizontal", "not tilted") to keep compositions consistent.
• Allomantic energy uses cyan-blue, never green or purple.

Quality Checklist

After generating, verify:

• Colors match the palette (no oversaturated neons, no pastels)
• Composition matches the category template
• No unwanted text, labels, or signatures
• Dark/near-black background for icons
• Resolution correct (or needs crop/resize)
• Visually distinguishable from similar assets in same category
• Ash, mist, or metallic elements present where appropriate