compose

name

compose

description

Compose expert skill for UI development. Guides state management decisions (@Composable, remember, mutableStateOf, derivedStateOf, State hoisting), view composition and structure, Modifier chains, lazy lists, navigation, animation, side effects, theming, accessibility, and performance optimization. Backed by actual androidx source code analysis. Use this skill whenever the user mentions Compose, @Composable, remember, LaunchedEffect, Scaffold, NavHost, MaterialTheme, LazyColumn, Modifier, recomposition, Style, styleable, MutableStyleState, or any Jetpack Compose API. Also trigger when the user says "Android UI", "Kotlin UI", "compose layout", "compose navigation", "compose animation", "material3", "compose styles", "styles api", or asks about modern Android development patterns. Even casual mentions like "my compose screen is slow" or "how do I pass data between screens" should trigger this skill.

Jetpack Compose Expert Skill

Non-opinionated, practical guidance for writing correct, performant Jetpack Compose code. Focuses on real pitfalls developers encounter daily, backed by analysis of the actual androidx/androidx source code (branch: androidx-main).

Workflow

When helping with Compose code, follow this checklist:

1. Understand the request

• What Compose layer is involved? (Runtime, UI, Foundation, Material3, Navigation)
• Is this a state problem, layout problem, performance problem, or architecture question?

2. Consult the right reference

Read the relevant reference file(s) from references/ before answering:

Topic	Reference File
@State, remember, mutableStateOf, state hoisting, derivedStateOf, snapshotFlow	references/state-management.md
Structuring composables, slots, extraction, preview	references/view-composition.md
Modifier ordering, custom modifiers, Modifier.Node	references/modifiers.md
LaunchedEffect, DisposableEffect, SideEffect, rememberCoroutineScope	references/side-effects.md
LazyColumn, LazyRow, LazyGrid, Pager, keys, content types	references/lists-scrolling.md
NavHost, type-safe routes, deep links, shared element transitions	references/navigation.md
Recomposition skipping, stability, baseline profiles, benchmarking	references/performance.md
Semantics, content descriptions, traversal order, testing	references/accessibility.md

3. Apply and verify

• Write code that follows the patterns in the reference
• Flag any anti-patterns you see in the user's existing code
• Suggest the minimal correct solution — don't over-engineer

Key Principles

1. Compose thinks in three phases: Composition → Layout → Drawing. State reads in each phase only trigger work for that phase and later ones.

2. Recomposition is frequent and cheap — but only if you help the compiler skip unchanged scopes. Use stable types, avoid allocations in composable bodies.

3. Modifier order matters. Modifier.padding(16.dp).background(Color.Red) is visually different from Modifier.background(Color.Red).padding(16.dp).

4. State should live as low as possible and be hoisted only as high as needed. Don't put everything in a ViewModel just because you can.

5. Side effects exist to bridge Compose's declarative world with imperative APIs. Use the right one for the job — misusing them causes bugs that are hard to trace.