Version-sensitive. Every API name, SDK gate and browser-support claim below was verified on 2026-09-08 against primary sources. What against, and when, is in _jutsu/VERSIONS.md. If that date is old, re-verify before acting on a version number.

Compose Motion - Sub-skill

Jetpack Compose animation core. Loaded for Android Compose and Compose Multiplatform projects. Concise rules here. Deep-dive in references/. Baseline: Jetpack Compose 1.12 (1.12.1 current stable, Sep 2026) - i.e. Compose BOM 2026.09.00. Modern stable APIs only - no swipeable, no animateContentSize hacks where AnimatedContent is correct. Anything below flagged 'Compose 1.x+' is a since marker, not the target.

---

API Decision Tree

Need	API
Single value over time	animateFloatAsState, animateDpAsState, animateColorAsState, etc.
Visibility / mount-unmount	AnimatedVisibility(visible) { ... }
Crossfade between states	Crossfade(target) { state -> ... }
Multi-state coordinated	updateTransition(target).animateFloat { ... }
Manual control / interruption	Animatable(initialValue) + animateTo(...)
Looping / infinite	rememberInfiniteTransition().animateFloat(...)
Shared elements	SharedTransitionLayout + Modifier.sharedElement(...) (Compose 1.7+)
Layout swap with anim	AnimatedContent(target) { ... }
Drag / swipe	Modifier.draggable + Animatable.snapTo/animateTo, or Modifier.anchoredDraggable for snap-points

Rule: climb the ladder only when needed. animate*AsState covers 70% of cases. Reach for Animatable only when you need to interrupt, chain, or read velocity.

---

Spring API (opinionated defaults)