art-generate

If no argument is provided, read design/assets/asset-manifest.md:

• If it exists: find the first target with any asset at Status: Needed and use question:
  • Prompt: "The next unspecced target is [target]. Generate placeholder art for it?"
  • Options: [A] Yes — generate for [target] / [B] Pick a different target / [C] Stop here
• If no manifest: fail with:

  "No asset manifest found. Run /asset-spec [target] first — I need asset specs to generate art from."

Phase 0: Parse Target

Resolve the target:

1. If argument matches system:<name> → spec at design/assets/specs/[name]-assets.md
2. If argument matches level:<name> → spec at design/assets/specs/[name]-assets.md
3. If argument matches character:<name> → spec at design/assets/specs/[name]-assets.md
4. If argument is a path → read that file directly
5. If argument is a path to a .md file → treat as spec file

Fail if the spec file does not exist:

"No asset spec found at [path]. Run /asset-spec [target] first."

Phase 1: Gather Context

Read all source material before generating anything.

Required reads:

• Asset spec: Read the resolved spec file. Extract all ASSET-NNN entries. For each, extract: Category, Dimensions, Format, Naming, Visual Description.
• Art bible: Read design/art/art-bible.md — fail if missing:

  "No art bible found. Run /art-bible first — I need the palette and shape language to generate art." Extract: Color System (Section 2), Shape Language (Section 3), Asset Standards (Section 8 — dimension tiers).

• Asset manifest: Read design/assets/asset-manifest.md — note which assets already have placeholders. Filter to assets with Status: Needed.

Present context summary:

art-generate: [Target Type] — [Target Name]

• Spec: [path] — [N] assets identified
• Art bible: found — [N] palette colors, shape language: [style]
• Assets to generate: [N] (filtered from [N] total — [N] already have placeholders)
• Output: assets/source/[target]/ and assets/sprites/[target]/

Phase 2: Per-Asset Generation

For each asset with Status: Needed, execute the following pipeline. Process one asset at a time — do NOT batch MCP calls.

Step 2a: Create Canvas

Construct the filename as assets/source/[target]/[naming] (replace .png or similar with .aseprite).

Use the create_canvas MCP tool:

create_canvas(width, height, filename)

Wait for success. If it fails, stop this asset and report.

Step 2b: Apply Palette

Load the art bible palette. If the art bible specifies a named palette resource (e.g., "DB16", "RPG"), use:

load_palette_from_resource(filename, resource_name)

Otherwise extract hex colors from the art bible's Color System section and apply:

set_palette(filename, [hex_colors_array])

Step 2c: Create Layer Structure

Create layers matching the asset category template:

Sprite / 2D Art:

add_layer(filename, "body")
set_layer(filename, "body")
set_layer_label_color(filename, "body", color_hex)
add_layer(filename, "details")
add_layer(filename, "outline")

UI Icon:

add_layer(filename, "icon")

VFX:

add_layer(filename, "core")
set_layer_blend_mode(filename, "core", "normal")
add_layer(filename, "glow")
set_layer_blend_mode(filename, "glow", "add")
add_layer(filename, "sparks")

Environment:

add_layer(filename, "base")
add_layer(filename, "shading")
add_layer(filename, "details")

Character Sprite:

add_layer(filename, "body")
add_layer(filename, "head")
add_layer(filename, "arms")
add_layer(filename, "legs")
add_layer(filename, "outline")

Step 2d: Draw Placeholder Content

Draw shapes on each layer following the art bible's shape language. Use the semantic color from the art bible for the asset's role.

General approach per layer:

1. set_layer(filename, layer_name) — activate the layer
2. set_frame(filename, 1) — draw on frame 1
3. Draw shapes:
   • Body/base: Fill a rectangle/circle/polygon covering ~80% of the canvas at the body center position
   • Details: Smaller shapes offset from center, using secondary/accent colors from the palette
   • Outline: Thin rectangle around the body bounds using a dark color

Use these drawing tools as appropriate:

• draw_rectangle_at(filename, layer, frame, x, y, w, h, color, fill=true) for blocky shapes
• draw_circle_at(filename, layer, frame, cx, cy, r, color, fill=true) for round shapes
• draw_polygon(filename, layer, frame, points, color, fill=true) for angular shapes (character limbs)
• fill_area_at(filename, layer, frame, cx, cy, color) for filled regions
• apply_gradient_rect(filename, layer, frame, x, y, w, h, start, end, horizontal) for gradient fills

Step 2e: Handle Animation

If the spec indicates multiple frames (e.g., "4-frame sprite sheet"):

add_frames(filename, count=3, duration_ms=200)  # frame 1 already exists
set_frame_duration(filename, 1, 200)

For each additional frame, duplicate frame 1 and add minor position offsets for limbs:

copy_frame(filename, source_frame=1, target_frame=N)

Then tag the animation:

set_tag(filename, name="default", from_frame=1, to_frame=N, direction="forward")

If not animated, skip this step.

Step 2f: Export

export_sprite(filename, output_path="assets/sprites/[target]/[naming]")

Step 2g: Verify

Use the quality tools to check the output:

validate_scene(filename, required_layers=[list from step 2c])

Expected: JSON confirming all layers and frames exist.

Also verify the exported file exists:

Test-Path "assets/sprites/[target]/[naming]"

Expected: True

Error Handling

If any MCP tool call fails:

Question: "Tool [tool_name] failed for ASSET-[NNN] ([asset name]): [error]. Options:"
A) Retry this asset
B) Skip this asset, continue with next
C) Stop generation entirely

Phase 3: Update Manifest

After all assets are generated (or after partial completion), update design/assets/asset-manifest.md.

For each generated asset, change its status from Needed to Placeholder Created. Add a Source column if it doesn't exist:

| ASSET-001 | hero-sprite | Sprite | Placeholder Created | design/assets/specs/hero-assets.md | assets/source/hero/ASSET-001-hero-sprite.aseprite |

If the manifest doesn't have a Source column yet, rewrite the header to include it.

Phase 4: Summary Report

Present a completion summary:

art-generate complete for [target]:

• [N]/[M] assets generated successfully
• [N] failed (skipped)
• Output: assets/source/[target]/ (source .aseprite files)
• Output: assets/sprites/[target]/ (exported PNGs)
• Manifest updated: design/assets/asset-manifest.md

Phase 5: Next Steps

Use question:

• Prompt: "Placeholder art generated for [target]. What's next?"
• Options:
  • [A] Generate another target — /art-generate [next-target]
  • [B] Run /asset-audit — validate generated assets against specs
  • [C] Review generated art manually
  • [D] Stop here

Per-Category Drawing Templates

Sprite / 2D Asset (Default)

Canvas: spec dimensions (e.g. 256x256)
Layers: body, details, outline

Frame 1:
  layer=body:   fill_rect(32, 32, 192, 192, body_color)
  layer=details: draw_rect(48, 48, 160, 160, accent_color, fill=false)
  layer=outline: draw_rect(30, 30, 196, 196, outline_color, fill=false)

UI Icon

Canvas: 32x32 or 64x64
Layers: icon

Frame 1:
  layer=icon: fill_rect(4, 4, 24, 24, palette[0])

VFX

Canvas: matching target sprite dimensions
Layers: core, glow, sparks

Frame 1:
  layer=core: circle(center, radius*0.3, core_color, fill=true)
  layer=glow: circle(center, radius, glow_color, fill=true, set opacity=128)

Environment Prop

Canvas: tile dimensions
Layers: base, shading, details

Frame 1:
  layer=base: fill_rect(0, 0, w, h, base_color)
  layer=shading: gradient_rect(0, 0, w, h, shade_top, shade_bottom)

Character Sprite

Canvas: sprite sheet width, frame height
Layers: body, head, arms, legs, outline

Frame 1 (idle pose):
  layer=body:   fill_rect(24, 40, 16, 24, body_color)
  layer=head:   fill_rect(28, 24, 8, 12, skin_color)
  layer=arms:   fill_rect(16, 44, 8, 8, skin_color)
               draw_rect(40, 44, 8, 8, skin_color)
  layer=legs:   fill_rect(24, 64, 6, 12, leg_color)
               fill_rect(34, 64, 6, 12, leg_color)
  layer=outline: draw_rect(22, 22, 20, 54, outline)

Frame 2 (walk frame 1): copy_frame(1, 2)
  layer=legs: offset legs by +2 on x to show stride

Error Recovery

Collaborative Protocol

• Never generate without user confirming the target
• Report each asset's success/failure immediately after processing it
• Write the manifest update only after explicit approval
• If the art bible's palette has changed since the spec was written, ask which to use