watchos-design

What this skill does

# watchOS Design Guidelines

Apple Watch is a personal, glanceable device worn on the wrist. Interactions are measured in seconds, not minutes. Every design decision must prioritize speed of comprehension and brevity of interaction.

---

## 1. Glanceable Design (CRITICAL)

The defining constraint of watchOS. If a user cannot extract the key information within 2 seconds of raising their wrist, the design has failed.

### Rules

- **W-GL-01**: Primary information must be visible without scrolling. The first screen is the only guaranteed screen.
- **W-GL-02**: Target interaction sessions of 5 seconds or less. Design for raise-glance-lower.
- **W-GL-03**: Use large, high-contrast text. Minimum effective body text is 16pt (system font). Titles should be 18pt or larger.
- **W-GL-04**: Limit text to essential content. Truncate or abbreviate aggressively. Use SF Symbols instead of text labels where meaning is unambiguous.
- **W-GL-05**: Respect wrist-down time. When the wrist lowers, the app enters an inactive state. Do not assume continuous user attention.
- **W-GL-06**: Prioritize a single piece of information per screen. If showing multiple data points, establish clear visual hierarchy with size, weight, and color.

### Screen Dimensions Reference

| Device | Screen Width | Screen Height | Corner Radius |
|--------|-------------|---------------|---------------|
| 41mm (Series 9) | 176px | 215px | 36px |
| 45mm (Series 9) | 198px | 242px | 39px |
| 42mm (Series 10) | 180px | 220px | 37px |
| 46mm (Series 10) | 205px | 251px | 40px |
| 49mm (Ultra 2) | 205px | 251px | 40px |

### Anti-Patterns

- Walls of text requiring scroll to understand context
- Small, dense data tables
- Requiring multiple taps before showing useful information
- Replicating an iPhone screen layout on Watch

---

## 2. Digital Crown (HIGH)

The Digital Crown is the primary physical input for scrolling and precise value selection. It provides haptic feedback and should feel purposeful.

### Rules

- **W-DC-01**: Use the Digital Crown as the primary scroll mechanism for vertical content. Do not rely solely on swipe gestures for scrolling.
- **W-DC-02**: For value pickers (time, quantity, sliders), bind the Crown to precise adjustments with haptic detents at each discrete value.
- **W-DC-03**: Do not override or conflict with system Crown behaviors. The system uses the Crown for volume control during media playback, scrolling in system UI, and Time Travel in complications.
- **W-DC-04**: Provide visual feedback synchronized with Crown rotation. The UI must respond frame-by-frame to Crown input with no perceptible lag.
- **W-DC-05**: Update on each Crown increment. Values, selection, and highlight states should move with each detent. Do not debounce Crown input until the gesture ends.

**Correct — Crown binding with haptic detents:**
```swift
struct VolumePickerView: View {
    @State private var volume: Double = 0.5

    var body: some View {
        VStack {
            Text("\(Int(volume * 100))%")
                .font(.title.bold())
            Image(systemName: "speaker.wave.3")
        }
        .focusable()
        .digitalCrownRotation(
            $volume,
            from: 0.0,
            through: 1.0,
            by: 0.05,
            sensitivity: .medium,
            isContinuous: false,
            isHapticFeedbackEnabled: true
        )
    }
}
```

**Incorrect — ignoring the Crown and forcing touch-only interaction:**
```swift
struct VolumePickerView: View {
    @State private var volume: Double = 0.5

    var body: some View {
        Slider(value: $volume)
        // No .digitalCrownRotation — Crown input is ignored
        // Users must use touch-only, which is imprecise and frustrating on Watch
    }
}
```

### Anti-Patterns

- Ignoring the Crown and forcing all interaction through touch
- Custom Crown behaviors that conflict with system expectations
- Missing haptic feedback on discrete value changes
- Laggy or batched responses to Crown rotation

---

## 3. Navigation (HIGH)

Watch navigation must be shallow and predictable. Users should never feel lost or unable to return to a known state.

### Rules

- **W-NV-01**: Use vertical page scrolling as the default content navigation pattern. Pages scroll top-to-bottom with the Digital Crown.
- **W-NV-02**: Use `TabView` for top-level sections (max 5 tabs). Swipe horizontally between tabs. Each tab is a distinct functional area.
- **W-NV-03**: Use `NavigationStack` for hierarchical drill-down. Limit hierarchy to 2-3 levels maximum. Every pushed view must have a back button (provided automatically by the system).
- **W-NV-04**: Avoid modal sheets for primary flows. Modals should be reserved for focused, single-purpose tasks (e.g., confirmation, quick input).
- **W-NV-05**: The app's most important action should be reachable within 1 tap from launch. Do not bury primary functionality behind menus or navigation.

### Navigation Pattern Reference

| Pattern | Use Case | Gesture |
|---------|----------|---------|
| Vertical scroll | Long-form content within a single view | Digital Crown / swipe up-down |
| TabView (horizontal pages) | Top-level app sections | Swipe left-right |
| NavigationStack (push/pop) | Hierarchical drill-down | Tap to push, swipe right or back button to pop |
| Modal sheet | Confirmation, focused input | Presented programmatically, dismiss via button or swipe down |

### Anti-Patterns

- Deep navigation hierarchies (4+ levels)
- Hamburger menus or hidden navigation drawers
- Tab bars with more than 5 items
- Forcing users to scroll through long lists to find key actions

---

## 4. Complications (HIGH)

Complications are the most visible surface of a Watch app. They live on the watch face and provide at-a-glance data without launching the app.

### Rules

- **W-CP-01**: Support multiple complication families to maximize watch face compatibility. At minimum support `accessoryCircular`, `accessoryCorner`, and `accessoryRectangular` (WidgetKit, watchOS 9+).
- **W-CP-02**: Provide both tinted (single-color) and full-color variants. Tinted complications must remain legible when the system applies a single tint color.
- **W-CP-03**: Update complications via `TimelineProvider`. Provide future timeline entries when data is predictable (e.g., next calendar event, weather forecast). Keep data fresh -- stale complications erode trust.
- **W-CP-04**: Complication content must be meaningful without context. A user glancing at their watch face should immediately understand the data (e.g., "72F" not "72").
- **W-CP-05**: Tapping a complication must launch the app to a relevant context, not just the app's root view.

**Correct — WidgetKit TimelineProvider for an accessoryCircular complication:**
```swift
struct StepCountProvider: TimelineProvider {
    func placeholder(in context: Context) -> StepEntry {
        StepEntry(date: Date(), steps: 5000)
    }

    func getSnapshot(in context: Context, completion: @escaping (StepEntry) -> Void) {
        completion(StepEntry(date: Date(), steps: HealthStore.shared.todaySteps))
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<StepEntry>) -> Void) {
        let entry = StepEntry(date: Date(), steps: HealthStore.shared.todaySteps)
        // Refresh in 15 minutes
        let nextUpdate = Calendar.current.date(byAdding: .minute, value: 15, to: Date())!
        completion(Timeline(entries: [entry], policy: .after(nextUpdate)))
    }
}

struct StepCountComplicationView: View {
    let entry: StepEntry

    var body: some View {
        Gauge(value: Double(entry.steps), in: 0...10000) {
            Image(systemName: "figure.walk")
        } currentValueLabel: {
            Text("\(entry.steps / 1000)k")
        }
        .gaugeStyle(.accessoryCircular)
    }
}
```

### Complication Family Reference

Use `WidgetFamily` values:

| Family | Shape | Typical Content |
|--------|-------|-----------------|
| `accessoryCircular` | Small circle | Single va