Art Skill for Claude

Art Skill

Complete visual content system supporting multiple brand aesthetics.

Aesthetic Routing

The art skill supports multiple visual identities. Before generating any visual, determine which aesthetic applies.

How to Select an Aesthetic

• Check if the user specifies a brand/project (e.g., "my-brand icon", "acme newsletter header")
• Check for content-type exceptions (see Content-Type Override Rules below)
• Check if the target output has a site-specific style guide (e.g., HERO-IMAGE-TEMPLATE.md)
• If no brand specified, use the default aesthetic

Content-Type Override Rules

CRITICAL: Some content types intentionally use different aesthetics than their host site.

| Content Type | Detection Pattern | Aesthetic to Use | DO NOT Use |

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

| Satirical/Parody Content | User explicitly says "satire", "parody", "joke product" | Match the satire target's aesthetic (e.g., corporate B2B for business parody) | Host site's aesthetic |

| Easter Eggs | Path contains easter-eggs/, explicitly marked as easter egg | Depends on easter egg theme, ask user if unclear | Host site's default |

Rule: When content-type override detected, DO NOT check host site style guides. The content is intentionally divergent.

Base Prompt Prefix Standard (MANDATORY)

Every aesthetic MUST define a Base Prompt Prefix — a locked consistency block that gets prepended to every image generation prompt for that aesthetic. This ensures visual cohesion across a set of illustrations.

What the prefix locks down:

• Line weight and quality
• Background treatment
• Camera angle / perspective
• Fill ratio (illustration vs. whitespace)
• Color balance percentages
• Shadow intensity and direction
• Text treatment (if applicable)

Where to find each prefix:

• Each aesthetic file (.md) contains a "Base Prompt Prefix" section with the locked values
• Project-specific aesthetics (e.g., lead magnet AESTHETIC.md) inherit from their parent brand and override only what changes
• Always read the aesthetic file and use its prefix before generating — never freestyle prompt parameters that have been locked

When creating new aesthetics via aesthetic-definer: The agent MUST produce a base prompt prefix as part of the output. An aesthetic without a consistency lock is incomplete.

Available Aesthetics

| Brand | Aesthetic File | Style |

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

| Default | ~/.claude/skills/art/aesthetic.md | Hand-drawn sketch, cream backgrounds, teal/orange accents |

To add a new aesthetic: Create a new file at ~/.claude/skills/art/aesthetics/[name].md using the default aesthetic as a template. See aesthetics/README.md for the required format.

Aesthetic Loading Rule

Read the matching aesthetic file BEFORE writing any prompt or generating any image. The aesthetic file is the source of truth for that brand's colors, style parameters, anti-patterns, and prompt integration phrases.

Workflow Routing

| Content Type | Workflow |

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

| Blog headers / Editorial | workflows/workflow.md |

| Adaptive orchestrator | workflows/visualize.md |

| Flowcharts / Sequences | workflows/mermaid.md |

| Architecture diagrams | workflows/technical-diagrams.md |

| Classification grids | workflows/taxonomies.md |

| Chronological | workflows/timelines.md |

| 2x2 matrices | workflows/frameworks.md |

| X vs Y | workflows/comparisons.md |

| Screenshot markup | workflows/annotated-screenshots.md |

| Step-by-step | workflows/recipe-cards.md |

| Sketchnotes / visual notes | workflows/sketchnotes.md |

| Quote cards | workflows/aphorisms.md |

| Idea territories | workflows/maps.md |

| Big numbers | workflows/stats.md |

| Sequential panels | workflows/comics.md |

| Edit existing image | workflows/image-editing.md |

Image Generation

Default model: nano-banana-2 (Gemini 3.1 Flash Image)

bun run ~/.claude/skills/art/tools/generate-image.ts \
  --model nano-banana-2 \
  --prompt "[PROMPT]" \
  --size 2K \
  --aspect-ratio 1:1 \
  --output /path/to/output.png

Alternative Model

| Model | When to Use |

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

| nano-banana-pro | Maximum quality, professional asset production, complex multi-turn editing |

Model Selection Guide

Nano Banana 2 (default):

• Best for: Most image generation tasks, fast iteration
• Strengths: Pro-level quality at Flash speed, reference images, web search grounding, 512px-4K range
• Use when: Default choice for all standard image generation
• API model: gemini-3.1-flash-image-preview

Nano Banana Pro:

• Best for: Professional asset production, maximum reasoning
• Strengths: Advanced reasoning, multi-turn refinement, style transfer
• Use when: Quality matters more than speed, complex compositional tasks
• API model: gemini-3-pro-image-preview

API keys in: ~/.claude/.env

• GOOGLE_API_KEY - Required for both models
• REMOVEBG_API_KEY - Background removal (optional)

Quick Preview Workflow (512px)

Use --size 512px for fast, cheap previews before committing to full resolution:

# 1. Preview at 512px (fast, low cost)
bun run ~/.claude/skills/art/tools/generate-image.ts \
  --prompt "[PROMPT]" --size 512px --output /tmp/preview.png

# 2. Happy? Regenerate at full size
bun run ~/.claude/skills/art/tools/generate-image.ts \
  --prompt "[PROMPT]" --size 2K --output /path/to/final.png

Thinking Flag (Nano Banana 2 only)

Add --thinking to give the model more reasoning time for complex compositions:

bun run ~/.claude/skills/art/tools/generate-image.ts \
  --prompt "Complex multi-element scene..." \
  --thinking high --output /path/to/output.png

| Level | Use When |

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

| minimal | Default — balances quality and latency |

| high | Complex layouts, precise positioning, multi-element scenes |

Only works with nano-banana-2. Thinking is always on (minimal by default). Use high when composition accuracy matters more than speed.

Common Diagram Pitfalls (Avoid These)

Learned from 2026-01-16 portfolio diagram session:

| Pitfall | Problem | Fix |

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

| Hex codes in prompts | #1A8A9B renders as visible text | Use "teal color" not "#1A8A9B" |

| Vague flow direction | Arrows go random directions | Explicitly state "LEFT TO RIGHT" or "TOP TO BOTTOM" |

| Duplicate labels | Text appears both inside and below elements | Specify "SINGLE label BELOW only, not inside" |

| Implicit positioning | Elements placed confusingly | Use "horizontal row" or "vertical column" explicitly |

| Assumed numbering | Numbers placed inconsistently | State "numbered 1-7 in sequence" |

Pre-flight checklist for architecture diagrams:

• [ ] No hex codes - use color names only
• [ ] Flow direction explicitly stated
• [ ] Label position explicitly stated (inside OR below, not both)
• [ ] Layout explicitly stated (horizontal/vertical)
• [ ] Key element highlighting specified

Site-Specific Style Override (CRITICAL)

Before generating images for a specific website, CHECK for style guides:

# Check project root for style documentation
ls HERO-IMAGE-TEMPLATE.md    # Site-specific image style
ls STYLE-GUIDE.md            # Design system

If found, the site's style guide OVERRIDES the default aesthetic.

Default aesthetic.md applies when: No site-specific style guide exists.

Consistent Dimensions for Related Images

When generating multiple images for the same page/section:

• Use identical resize dimensions for all images
• Document the size used: # All diagrams: 800x500
• Prevents distortion when displayed together

Nano Banana Prompting Guide

For detailed prompting techniques: ~/.claude/skills/art/nano-banana-guide.md

Applies to both Nano Banana 2 and Nano Banana Pro — same prompt patterns, same API structure.

Includes:

• Core prompt formula: [Action] the [Subject] by [Specific Change]. The goal is [Desired Outcome].
• Action verb vocabulary (recolor, retouch, style, adjust, enhance, transform, add, remove, replace, blend)
• Mood and atmosphere vocabulary tables
• Color palette phrases
• Aspect ratio selection guide
• Iterative refinement workflow
• Brand integration template

Quick Decision Tree

What does user need?

├─ Unsure which approach? → VISUALIZE (analyzes & orchestrates)
├─ Flowchart/sequence/state diagram? → MERMAID
├─ Abstract metaphor for article? → Editorial (workflow.md)
├─ System/architecture with labels? → Technical Diagram
├─ Categories in grid? → Taxonomy
├─ Change over time? → Timeline
├─ 2x2 matrix or mental model? → Framework
├─ Side-by-side contrast? → Comparison
├─ Markup existing screenshot? → Annotated Screenshot
├─ Step-by-step process? → Recipe Card
├─ Sketchnote or visual meeting notes? → Sketchnote
├─ Quote as social visual? → Aphorism
├─ Idea territories as map? → Conceptual Map
├─ Single striking number? → Stat Card
├─ Multi-panel story? → Comic
└─ Edit/modify/transform existing image? → IMAGE EDITING

Platform Constraints

| Platform | Dimensions | Max Size | Notes |

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

| YouTube thumbnail | 1280x720 (16:9) | 2MB | Use --size 1080p or compress after |

| LinkedIn post | 1200x627 | 5MB | |

| Twitter/X post | 1200x675 (16:9) | 5MB | |

| Newsletter header | 1200x600 | 1MB | Email platform limit |

| Instagram square | 1080x1080 | 8MB | |

If generated image exceeds size limit:

# Compress PNG with pngquant
pngquant --quality=65-80 --force --output compressed.png original.png

# Or convert to optimized JPEG
convert original.png -quality 85 compressed.jpg

Assimilation Note

Source: Personal_AI_Infrastructure Art Skill

Assimilated: 2026-01-04

Adapted: PAI's dark/neon aesthetic → warm/cream aesthetic

For complete visual styling rules, ALWAYS read: ~/.claude/skills/art/aesthetic.md