anvil-ui-stitch

name	anvil-ui-stitch
description	Semantic Design System Skill for Google Stitch. Generates agent-friendly DESIGN.md files that enforce premium, anti-generic UI standards — strict typography, calibrated color, asymmetric layouts, perpetual micro-motion, and hardware-accelerated performance.

Stitch Design Taste — Semantic Design System Skill

Overview

This skill generates DESIGN.md files optimized for Google Stitch screen generation. It translates the battle-tested anti-slop frontend engineering directives into Stitch's native semantic design language — descriptive, natural-language rules paired with precise values that Stitch's AI agent can interpret to produce premium, non-generic interfaces.

The generated DESIGN.md serves as the single source of truth for prompting Stitch to generate new screens that align with a curated, high-agency design language. Stitch interprets design through "Visual Descriptions" supported by specific color values, typography specs, and component behaviors.

Prerequisites

• Access to Google Stitch via labs.google/stitch
• Optionally: Stitch MCP Server for programmatic integration with Cursor, Antigravity, or Gemini CLI

The Goal

Generate a DESIGN.md file that encodes:

1. Visual atmosphere — the mood, density, and design philosophy
2. Color calibration — neutrals, accents, and banned patterns with hex codes
3. Typographic architecture — font stacks, scale hierarchy, and anti-patterns
4. Component behaviors — buttons, cards, inputs with interaction states
5. Layout principles — grid systems, spacing philosophy, responsive strategy
6. Motion philosophy — animation engine specs, spring physics, perpetual micro-interactions
7. Anti-patterns — explicit list of banned AI design clichés

Analysis & Synthesis Instructions

1. Define the Atmosphere

Evaluate the target project's intent. Use evocative adjectives from the taste spectrum:

• Density: "Art Gallery Airy" (1–3) → "Daily App Balanced" (4–7) → "Cockpit Dense" (8–10)
• Variance: "Predictable Symmetric" (1–3) → "Offset Asymmetric" (4–7) → "Artsy Chaotic" (8–10)
• Motion: "Static Restrained" (1–3) → "Fluid CSS" (4–7) → "Cinematic Choreography" (8–10)

Default baseline: Variance 8, Motion 6, Density 4. Adapt dynamically based on user's vibe description.

2. Map the Color Palette

For each color provide: Descriptive Name + Hex Code + Functional Role.

Mandatory constraints:

• Maximum 1 accent color. Saturation below 80%
• The "AI Purple/Blue Neon" aesthetic is strictly BANNED — no purple button glows, no neon gradients
• Use absolute neutral bases (Zinc/Slate) with high-contrast singular accents
• Stick to one palette for the entire output — no warm/cool gray fluctuation
• Never use pure black (#000000) — use Off-Black, Zinc-950, or Charcoal

3. Establish Typography Rules

• Display/Headlines: Track-tight, controlled scale. Not screaming. Hierarchy through weight and color, not just massive size
• Body: Relaxed leading, max 65 characters per line
• Font Selection: Inter is BANNED for premium/creative contexts. Force unique character: Geist, Outfit, Cabinet Grotesk, or Satoshi
• Serif Ban: Generic serif fonts (Times New Roman, Georgia, Garamond, Palatino) are BANNED. If serif is needed for editorial/creative contexts, use only distinctive modern serifs: Fraunces, Gambarino, Editorial New, or Instrument Serif. Serif is always BANNED in dashboards or software UIs
• Dashboard Constraint: Use Sans-Serif pairings exclusively (Geist + Geist Mono or Satoshi + JetBrains Mono)
• High-Density Override: When density exceeds 7, all numbers must use Monospace

4. Define the Hero Section

The Hero is the first impression and must be creative, striking, and never generic:

• Inline Image Typography: Embed small, contextual photos or visuals directly between words or letters in the headline. Images sit inline at type-height, rounded, acting as visual punctuation. This is the signature creative technique
• No Overlapping: Text must never overlap images or other text. Every element occupies its own clean spatial zone
• No Filler Text: "Scroll to explore", "Swipe down", scroll arrow icons, bouncing chevrons are BANNED. The content should pull users in naturally
• Asymmetric Structure: Centered Hero layouts BANNED when variance exceeds 4
• CTA Restraint: Maximum one primary CTA. No secondary "Learn more" links

5. Describe Component Stylings

For each component type, describe shape, color, shadow depth, and interaction behavior:

• Buttons: Tactile push feedback on active state. No neon outer glows. No custom mouse cursors
• Cards: Use ONLY when elevation communicates hierarchy. Tint shadows to background hue. For high-density layouts, replace cards with border-top dividers or negative space
• Inputs/Forms: Label above input, helper text optional, error text below. Standard gap spacing
• Loading States: Skeletal loaders matching layout dimensions — no generic circular spinners
• Empty States: Composed compositions indicating how to populate data
• Error States: Clear, inline error reporting

6. Define Layout Principles

• No overlapping elements — every element occupies its own clear spatial zone. No absolute-positioned content stacking
• Centered Hero sections are BANNED when variance exceeds 4 — force Split Screen, Left-Aligned, or Asymmetric Whitespace
• The generic "3 equal cards horizontally" feature row is BANNED — use 2-column Zig-Zag, asymmetric grid, or horizontal scroll
• CSS Grid over Flexbox math — never use calc() percentage hacks
• Contain layouts using max-width constraints (e.g., 1400px centered)
• Full-height sections must use min-h-[100dvh] — never h-screen (iOS Safari catastrophic jump)

7. Define Responsive Rules

Every design must work across all viewports:

• Mobile-First Collapse (< 768px): All multi-column layouts collapse to single column. No exceptions
• No Horizontal Scroll: Horizontal overflow on mobile is a critical failure
• Typography Scaling: Headlines scale via clamp(). Body text minimum 1rem/14px
• Touch Targets: All interactive elements minimum 44px tap target
• Image Behavior: Inline typography images (photos between words) stack below headline on mobile
• Navigation: Desktop horizontal nav collapses to clean mobile menu
• Spacing: Vertical section gaps reduce proportionally (clamp(3rem, 8vw, 6rem))

8. Encode Motion Philosophy

• Spring Physics default: stiffness: 100, damping: 20 — premium, weighty feel. No linear easing
• Perpetual Micro-Interactions: Every active component should have an infinite loop state (Pulse, Typewriter, Float, Shimmer)
• Staggered Orchestration: Never mount lists instantly — use cascade delays for waterfall reveals
• Performance: Animate exclusively via transform and opacity. Never animate top, left, width, height. Grain/noise filters on fixed pseudo-elements only

9. List Anti-Patterns (AI Tells)

Encode these as explicit "NEVER DO" rules in the DESIGN.md:

• No emojis anywhere
• No Inter font
• No generic serif fonts (Times New Roman, Georgia, Garamond) — distinctive modern serifs only if needed
• No pure black (#000000)
• No neon/outer glow shadows
• No oversaturated accents
• No excessive gradient text on large headers
• No custom mouse cursors
• No overlapping elements — clean spatial separation always
• No 3-column equal card layouts
• No generic names ("John Doe", "Acme", "Nexus")
• No fake round numbers (99.99%, 50%)
• No AI copywriting clichés ("Elevate", "Seamless", "Unleash", "Next-Gen")
• No filler UI text: "Scroll to explore", "Swipe down", scroll arrows, bouncing chevrons
• No broken Unsplash links — use picsum.photos or SVG avatars
• No centered Hero sections (for high-variance projects)

Output Format (DESIGN.md Structure)

# Design System: [Project Title]

## 1. Visual Theme & Atmosphere
(Evocative description of the mood, density, variance, and motion intensity.
Example: "A restrained, gallery-airy interface with confident asymmetric layouts
and fluid spring-physics motion. The atmosphere is clinical yet warm — like a
well-lit architecture studio.")

## 2. Color Palette & Roles
- **Canvas White** (#F9FAFB) — Primary background surface
- **Pure Surface** (#FFFFFF) — Card and container fill
- **Charcoal Ink** (#18181B) — Primary text, Zinc-950 depth
- **Muted Steel** (#71717A) — Secondary text, descriptions, metadata
- **Whisper Border** (rgba(226,232,240,0.5)) — Card borders, 1px structural lines
- **[Accent Name]** (#XXXXXX) — Single accent for CTAs, active states, focus rings
(Max 1 accent. Saturation < 80%. No purple/neon.)

## 3. Typography Rules
- **Display:** [Font Name] — Track-tight, controlled scale, weight-driven hierarchy
- **Body:** [Font Name] — Relaxed leading, 65ch max-width, neutral secondary color
- **Mono:** [Font Name] — For code, metadata, timestamps, high-density numbers
- **Banned:** Inter, generic system fonts for premium contexts. Serif fonts banned in dashboards.

## 4. Component Stylings
* **Buttons:** Flat, no outer glow. Tactile -1px translate on active. Accent fill for primary, ghost/outline for secondary.
* **Cards:** Generously rounded corners (2.5rem). Diffused whisper shadow. Used only when elevation serves hierarchy. High-density: replace with border-top dividers.
* **Inputs:** Label above, error below. Focus ring in accent color. No floating labels.
* **Loaders:** Skeletal shimmer matching exact layout dimensions. No circular spinners.
  Composed, illustrated compositions — not just "No data" text.


(Grid-first responsive architecture. Asymmetric splits for Hero sections.
Strict single-column collapse below 768px. Max-width containment.
No flexbox percentage math. Generous internal padding.)


(Spring physics for all interactive elements. Staggered cascade reveals.
Perpetual micro-loops on active dashboard components. Hardware-accelerated
transforms only. Isolated Client Components for CPU-heavy animations.)


(Explicit list of forbidden patterns: no emojis, no Inter, no pure black,
no neon glows, no 3-column equal grids, no AI copywriting clichés,
no generic placeholder names, no broken image links.)

Best Practices

• Be Descriptive: "Deep Charcoal Ink (#18181B)" — not just "dark text"
• Be Functional: Explain what each element is used for
• Be Consistent: Same terminology throughout the document
• Be Precise: Include exact hex codes, rem values, pixel values in parentheses
• Be Opinionated: This is not a neutral template — it enforces a specific, premium aesthetic

Tips for Success

1. Start with the atmosphere — understand the vibe before detailing tokens
2. Look for patterns — identify consistent spacing, sizing, and styling
3. Think semantically — name colors by purpose, not just appearance
4. Consider hierarchy — document how visual weight communicates importance
5. Encode the bans — anti-patterns are as important as the rules themselves

Common Pitfalls to Avoid

• Using technical jargon without translation ("rounded-xl" instead of "generously rounded corners")
• Omitting hex codes or using only descriptive names
• Forgetting functional roles of design elements
• Being too vague in atmosphere descriptions
• Ignoring the anti-pattern list — these are what make the output premium
• Defaulting to generic "safe" designs instead of enforcing the curated aesthetic