apple-hig-expert – Design & UI skill for AI agents

Apple HIG Expert

Design and audit apps against the Apple Human Interface Guidelines (HIG, [developer.apple.com/design/human-interface-guidelines](https://developer.apple.com/design/human-interface-guidelines)), including the Liquid Glass design language. HIG content evolves with each OS release — when a claim matters, verify against the live HIG pages cited in references/.

Before Starting

If product-context.md or ios-design-context.md exists, read it before asking questions. Then gather:

1. Platform target: iOS, macOS, watchOS, or visionOS?

2. Current state: new design or auditing an existing mockup/code?

3. App category: utility, productivity, game, social, etc.

Modes

• Mode 1 — Design from scratch: pick the platform navigation paradigm and layout primitives first (see references/platform-specifics.md), then apply typography and semantic color (references/visual-design.md).
• Mode 2 — HIG audit: fill in templates/hig-audit-template.md, run scripts/hig_checker.py on every measurable element, and deliver a scored report (see Worked example below).

The Compliance Tool

scripts/hig_checker.py (stdlib-only) has three subcommands:

# 1. Contrast ratio (WCAG formula; pass >= 4.5:1 for normal text)
python3 scripts/hig_checker.py contrast "#8E8E93" "#FFFFFF"
# -> Contrast Ratio: 3.26 [FAILED]

# 2. Tap-target size (pass >= 44x44 pt per HIG)
python3 scripts/hig_checker.py target 32 32
# -> Tap Target: 32x32 [FAILED]

# 3. Batch audit from JSON -> scorecard (starts at 100, -10 per violation)
python3 scripts/hig_checker.py batch audit.json

Batch input shape:

{
  "checks": [
    {"type": "contrast", "name": "caption-on-card", "fg": "#8E8E93", "bg": "#FFFFFF"},
    {"type": "target", "name": "close-button", "w": 32, "h": 32}
  ]
}

Scorecard rubric: the batch score starts at 100 and subtracts 10 per failed check; violations are listed by element name. 90-100 = ship, 70-80 = fix before release, below 70 = systematic rework. Checks the tool cannot measure (VoiceOver labels, Dynamic Type behavior, Reduce Transparency) are assessed manually via the audit template and tagged with confidence.

Worked example: iOS settings-screen audit

Input: mockup with body text #1C1C1E and captions #8E8E93 on white cards, a 32x32 pt close button, and a 343x50 pt primary CTA.

Run:

python3 scripts/hig_checker.py batch audit.json

Output (real):

{
  "score": 80,
  "violations": [
    "Contrast 3.26 fails for caption-on-card",
    "Target 32x32 small for close-button"
  ]
}

Findings → fixes (bottom line first):

> HIG score 80/100 — two fixes before release.

> 1. Captions fail contrast (3.26 < 4.5). Use .secondaryLabel (semantic color) instead of hardcoded #8E8E93, or darken to ≥ #6E6E73 on white. 🟢 verified by tool.

> 2. Close button is 32x32 pt (< 44x44 minimum). Keep the glyph small but expand the hit region to 44x44 with padding/contentShape. 🟢 verified by tool.

> 3. Manual check: the card uses an ultra-thin material over a photo background — re-test caption contrast against the *busiest* underlying region and with Reduce Transparency on. 🟡 needs device test.

Core Design Principles

1. Liquid Glass — translucent material hierarchy (announced at WWDC25, June 2025; shipped Sept 2025 across iOS 26, iPadOS 26, macOS Tahoe, watchOS 26, tvOS 26, visionOS 26). In SwiftUI, apply it via the glassEffect view modifier; keep hierarchy between content and controls. See references/visual-design.md.

2. Accessibility first — VoiceOver labels on every element, 44x44 pt minimum targets, 4.5:1 contrast for normal text (3:1 large text), Dynamic Type support. See references/accessibility.md.

3. Platform ergonomics — tab bars/thumb reach on iOS, sidebars + menu bar + shortcuts on macOS, ornaments + gaze states on visionOS, glanceable vertical layouts on watchOS. See references/platform-specifics.md.

Proactive Triggers

Surface these WITHOUT being asked: low contrast over translucent layers; interactive elements under 44 pt; icon buttons with no accessibility label; density overload (no breathing room between glass layers).

Communication

• Bottom line first — compliance status before details.
• What + Why + How — "Expand the hit region (What) because 32 pt targets fail the HIG minimum (Why); pad to 44x44 via contentShape (How)."
• Confidence tagging — 🟢 tool-verified / 🟡 needs device test / 🔴 assumed.

Related Skills

• ui-design-system: token-based component systems (not platform HIG rules).
• ux-researcher-designer: persona/research validation (not visual styling).
• landing-page-generator: web marketing pages, not native apps.