create-mascot-pack

name: create-mascot-pack description: > Create or modify pixel-art mascot packs for claude-code-mascot-statusline plugin. Use when: creating a new character pack from scratch, modifying existing pack sprites, fixing visual issues in half-block rendering, iterating on sprite design, or adding new states to a pack. Triggers: "create pack", "new mascot", "pixel art", "make character", "edit sprite", "fix sprite", "パック作成", "キャラ作成", "スプライト編集", "new pack", "mascot pack", "インベーダー", "キャラクター"

Create Mascot Pack

Interactive assistant for creating and modifying pixel-art mascot packs for the claude-code-mascot-statusline plugin.

Workflow Decision

Determine the task type:

Creating a new pack? → Follow "New Pack Workflow" below Modifying an existing pack? → Follow "Existing Pack Workflow" below

New Pack Workflow

Phase 1: Requirements

Ask the user:

1. Character concept (animal, robot, invader, object, etc.)
2. Grid size — recommend 16x16 for half-block, 8x8 for simpler characters
3. Render mode — half-block (recommended for faces/characters) or bg-space (simpler)
4. Pack name (lowercase, hyphens, e.g. space-invader)
5. Install location:
   • Project-local: <project>/.claude/mascot-packs/<name>/
   • User-global: ~/.claude/plugins/claude-code-mascot-statusline/packs/<name>/

Phase 2: Palette Design

Design the color palette. Rules:

• Index 0 = null (transparent) — always required
• Index 1 = outline / dark color — defines the silhouette
• Index 2 = main body color — this is the heat target (shifts toward #ff4444 when context window usage reaches 60-85%). Choose a warm or neutral color that looks good interpolating toward red.
• Index 3+ = accent colors (eyes, mouth, effects, highlights)
• Recommend 5-10 colors total

Read references/pixel-buddy-anatomy.md for palette reference (10-color example).

Phase 3: Idle Sprite Design

The idle frame is the baseline for all other states. Get this right first.

Design approach:

1. Sketch the silhouette first — all non-zero cells form the shape
2. Place outline (index 1) at edges for clear contour
3. Fill body with index 2
4. Add face features: eyes, mouth, ears, etc.
5. Ensure left-right symmetry unless intentionally asymmetric

Critical: Half-block awareness (see "Half-Block Rendering" section below).

Write the frame as a 2D integer array in pack.yaml (preferred) or pack.json.

Phase 4: Validate and Preview

After creating the idle frame, immediately validate and preview:

# Validate pack structure
node dist/cli/validate-pack.js <pack-dir>

# Preview idle state
node dist/cli/preview-pack.js --dir <pack-dir> --state idle --color always

# Check visual metrics
node dist/cli/storybook.js --dir <pack-dir> --states idle --metrics --color always

Review visual lint warnings:

• overall center offset should be near 0 (±0.35 acceptable)
• mirror mismatch should be < 0.18 (unless intentionally asymmetric)
• top/bottom band offsets should be < ±0.5

Iterate with the user until the idle frame looks good.

Phase 5: State Variants

Read references/state-design-guide.md for the full guide on all 10 states.

Start with a minimum viable pack (4 states + fallback):

1. idle — baseline (1-2 frames)
2. thinking — active animation (2-3 frames)
3. tool_success — positive feedback (1 frame)
4. done — completion (1-2 frames)

Set fallbacks.unknown: idle_1 to cover missing states.

For each new state:

1. Copy the idle frame as starting point
2. Modify only what's needed for the expression/animation
3. Run the vertical collision check (see below)
4. Preview with node dist/cli/preview-pack.js --dir <pack-dir> --state <state> --color always

Phase 6: Full Validation

node dist/cli/storybook.js --dir <pack-dir> --color always --metrics

Review every state. Fix visual lint warnings.

Phase 7: Timing and Fallbacks

Set required fallbacks and optional timing in the pack file:

fallbacks:
  unknown: idle_1    # REQUIRED
  narrow: idle_1     # optional
timing:              # optional — defaults are sensible
  idleFramePeriodMs: 500
  thinkingFramePeriodMs: 300

Phase 8: Activate

Tell the user how to activate:

# Environment variable (temporary)
export CLAUDE_MASCOT_PACK=<pack-name>

# Project config (.claude/mascot.json)
{"pack": "<pack-name>"}

# User config (~/.claude/plugins/claude-code-mascot-statusline/config.json)
{"pack": "<pack-name>"}

Existing Pack Workflow

1. Find the pack: search packs/, ~/.claude/plugins/claude-code-mascot-statusline/packs/, .claude/mascot-packs/
2. Read the current pack manifest
3. Show current sprites: node dist/cli/storybook.js --dir <pack-dir> --color always --metrics
4. Make targeted edits to specific frames
5. Re-validate after each change
6. Run storybook for final review

Half-Block Rendering

This is the most critical knowledge for sprite editing. Read this before modifying any half-block pack.

Row Pairing

In half-block mode, consecutive row pairs render as one display line:

Row 0 + Row 1  → Display line 0  (Row 0 = upper ▀, Row 1 = lower ▄)
Row 2 + Row 3  → Display line 1
Row 4 + Row 5  → Display line 2
...

A 16-pixel-tall sprite produces 8 display lines. When editing a pixel, think about which display line it affects.

Cell Rendering

For each column in a row pair (top pixel, bottom pixel):

Vertical Collision Rule

When the same column has dark/outline colors in adjacent row pairs, they create an unwanted continuous vertical line.

Example from pixel-buddy tool_success:

• Row 4, col 4 = outline(1) — closed eye
• Row 6, col 4 = outline(1) — whisker dot
• Display lines 2 and 3 both show dark in col 4 → eyes visually connect to whiskers

Fix: Change one of the colliding cells to body color (index 2) to break the dark continuity.

Verification Procedure

After any sprite edit:

1. For each modified column, list the palette indices vertically
2. Group into row pairs: (0,1), (2,3), (4,5), ...
3. Check: does the same column have outline/dark color in consecutive display lines?
4. If yes → change one cell to body color or another lighter color
5. Preview to confirm: node dist/cli/preview-pack.js --dir <pack-dir> --state <state> --color always

Common Traps

• Closing eyes: Open eyes have white(4) that interrupts dark lines. Closed eyes remove this interruption → check for new vertical collisions at eye columns
• Widening mouth outline: May align with whisker or eye outlines in the same column
• Adding effects at sprite edges: May create unintended dark borders if outline color is used

References

• references/pack-spec-quick.md — Pack spec v2 fields, validation rules, and minimal template
• references/pixel-buddy-anatomy.md — Detailed analysis of pixel-buddy's structure, palette roles, and row layout
• references/state-design-guide.md — All 10 states with design guidelines, effect placement rules, and differentiation checklist

Read packs/pixel-buddy/pack.json in the plugin directory as a full working 16x16 reference.