The single-glance contract
Simplicity is a platform requirement.
- W01MUST
One answer per screen
Show one primary value/subject, one short qualifier and one primary action or clear route to it. Use no glass blur, decorative stars, ambient drift, dense map, paragraph card or phone-style bottom dock. Retain Void and the same signal colors in interactive mode; a one-accent screen is valid.
AcceptanceThe compass communicates direction and confidence immediately. The sky communicates the selected body and next event. The geofence communicates target distance/state. Additional facts require a deliberate tap/scroll.
- W02MUST
Round geometry
Design for 192dp and 228dp round viewports plus the minimum supported device. Place critical content inside a safe central area. At vertical offset y from center, available width is 2√(r²−y²) minus at least 12dp each side; avoid generic rectangular edge padding. Bottom commands use the native edge button/scaffold.
AcceptanceNo text, hit region or action is clipped by the circular boundary at the largest supported font. If content does not fit, flow it into a native scaling/transforming scroll list.
Readable and reachable
A small display still deserves full-sized targets.
- W03MUST
Type & controls
Use 32–40sp primary readings, 18–20sp titles, 14–16sp body/control labels and 12–14sp secondary qualifiers. Keep units visible beside the reading. Touch targets are ≥48dp, with nonoverlapping geometry and at least 4dp separation where feasible. Use native Wear typography and components mapped to Cosmos roles.
AcceptanceLargest system text preserves values, units and actions through reflow/scroll. A short label may have an accessible expanded name; truncation cannot hide the primary reading, qualifier or destructive consequence.
- W04MUST
Rotary & assistive input
Use rotary input for native list scrolling and appropriate value adjustment; expose focus/state and a touch alternative. Keep system swipe-back behavior. Long press is optional, never the sole route. TalkBack receives one coherent instrument description with an explicit refresh/read action.
AcceptanceTouch, rotary and TalkBack complete each essential task. Rotary focus is acquired and released with the active screen. Sensor updates do not flood announcements.
A small set of useful tools
Each tool has one recognizable visual structure.
- W05MUST
Home & targets
Home is a short native list of Compass, Sky, Geofence, Plumb bob, Targets and Settings where supported. Use an icon, literal name and useful last-state qualifier; category color is secondary. Targets is a bounded readable list with selected state and a detail route. Empty targets offers a clear phone-sync or add path supported by the product.
AcceptanceNo orbit carousel or icon-only launch grid. The top item is readable immediately on entry and the last item is reachable by touch/rotary. Synced state is honest about connectivity and freshness.
- W06MUST
Compass & plumb bob
Compass uses a simplified dial with no more than four cardinal labels, a clear bearing pointer and one numeric value. Confidence appears as text/icon. Plumb bob uses a stable center/level frame and explicit tilt units. Use no extra precision ticks that compete with the reading.
AcceptanceKnown heading/tilt fixtures render correctly, including wrap-around. Calibrating/unavailable/stale states replace the value with honest status; a tap can expose calibration or target selection.
- W07MUST
Sky & geofence
Sky shows one selected body with next rise/set event and a concise availability state; the full catalog is a separate list. Geofence shows selected target, distance and inside/outside/unknown state. Cyan denotes actual located/live state, not the entire tool theme. Keep the same canonical Cyan; migrate the legacy watch-specific cyan through theme roles.
AcceptanceIndoor/no-fix/offline/stale and revoked permission states cannot resemble a valid lock. The text names the state, and haptic alerts are supplementary, user-controlled and deduplicated.
Ambient is a different composition
When the wrist rests, the interface rests too.
- W08MUST
Always-on state
Provide an explicit ambient layout: pure black background, a sparse muted reading, no filled surfaces/gradient/glow, no seconds, no animation and no touch affordances implying interactivity. Mark the reading time if frozen. Honor low-bit and burn-in requirements and platform-recommended repositioning; ambient is not a dimmed interactive screenshot.
AcceptanceVerify the real ambient lifecycle and supported hardware. UI updates follow platform ambient cadence; no UI frame loop runs. Any background sensing/geofence monitoring is separately justified by the user task and power policy.
- W09MUST
Wake & confidence
On return to interactive mode, display the last value as stale until a fresh valid sample arrives. Restore target and navigation state; never flash a bright intermediate surface. A watch face complication/tile exposes only supported concise public-safe facts and opens the corresponding task.
AcceptanceStale becomes fresh only on new evidence. Interrupted connection and missing phone do not discard the current task. A complication never leaks private target text or exact coordinates without the product authorization.
Battery is part of UX
Remove work that cannot help the person.
- W10MUST
Runtime & energy acceptance
Use no WebView or phone-scale map engine. Cache static dial geometry; stop presentation subscriptions when hidden and never allocate decorative paths per frame. Target <5% janky frames in a named 30-second interactive journey at the device refresh rate. First useful offline reading should appear ≤1s cold on the baseline watch. Use explicit timeouts for acquisition and phone-sync work.
AcceptanceRecord physical watch, OS, refresh rate, build, thermal state and trace. Ambient rendering has zero continuous animation callbacks; retained memory does not grow across repeated tool navigation.
- W11MUST
Power validation
Measure a repeatable 30-minute interactive/ambient scenario with fixed brightness, connectivity and sensor policy. Record total drain, incremental cost versus a same-build task-disabled baseline and the approved product battery budget before release. Do not publish an invented universal mAh or percentage promise.
AcceptanceA named owner approves the observed budget on physical hardware. Low power disables ornament first; stopping a user-owned monitoring task requires an explicit visible reason rather than silent disappearance.
Watch acceptance
Check the smallest device, largest text and resting wrist.
- W12MUST
Wear release matrix
Verify home, compass, sky list/detail, geofence, plumb bob, targets and settings in interactive, ambient, low-bit/burn-in where supported, offline and no-phone states. Include 192/228dp, largest text, Arabic, touch, rotary, TalkBack, permission/sensor failure and low battery.
AcceptancePhysical-device screenshots, lifecycle traces, focused instrumentation and power measurements are required for implementation acceptance. Round emulator screenshots alone do not certify glanceability, comfort or battery behavior.
CONFORMANCE RECORD
From specification to evidence.
Record the product build, applicable rule IDs, owner, fixtures, environment and results. Attach visual, accessibility and performance evidence before calling the implementation production-ready.
Download the release record template ↗