compose-performance-skills

Use this skill to explain why the Compose compiler classified a class or composable parameter as stable, runtime, unknown, or unstable. Covers the 12-phase inference algorithm, the five compiler-level stability types (Certain / Runtime / Unknown / Parameter / Combined), the generic bitmask encoding (Pair=0b11, ImmutableList=0b1), the Known Stable Constructs registry, and the runtime `$stable: Int` field generated by `@StabilityInferred`. Use when the developer asks "why is X classified as Y?", when a stability report shows a surprising `runtime stable`, `unknown`, or `unstable` verdict, when generics, inheritance, cycles, interfaces, or cross-module classes are involved, or when the user mentions `$stable`, `@StabilityInferred`, separate compilation, or "the compiler thinks my class is unstable but it looks fine".

Use this skill to drive the active investigation features of the `skydoves/compose-stability-analyzer` IntelliJ / Android Studio plugin: the static Recomposition Cascade visualizer that walks the call graph from a root `@Composable`, and the live Recomposition Heatmap that streams `D/Recomposition` events from a connected device's logcat into block inlays above each instrumented composable. Covers the `Compose Stability Analyzer` tool window's three tabs (Explorer, Cascade, Heatmap), the cascade analyzer's static PSI walk with depth cap and cycle detection, the ADB logcat command the heatmap consumes, and the toggle/clear actions. Use when the user asks "what gets dragged in if I change this composable", "how many times did this recompose during that scroll", "what is the blast radius of this state change", or mentions the cascade tab, the heatmap tab, the recomposition inlays, or `Toggle Recomposition Heatmap`.

Use this skill to run an end-to-end Jetpack Compose performance audit when the symptom is broad ("the app feels sluggish", "scroll is rough everywhere", "we're starting a perf sprint", "what should we fix first?"). Orchestrates the four-phase Measure → Diagnose → Fix → Verify loop by sequencing the 25 focused skills (release-mode setup, R8, Baseline Profiles, Compose Compiler reports, stability inference, Layout Inspector, `@TraceRecomposition`, stabilization, strong skipping, phase-deferral, derivedStateOf, lazy layouts, lazy prefetch, Modifier.Node, modifier ordering, flow collection, effects, CI gates, hot-reload) and produces a written audit report with Before/After Macrobenchmark numbers. Use when the developer wants a perf sprint kickoff, a pre-release perf gate, onboarding to a perf-troubled codebase, or a written deliverable. Use when the user mentions "audit", "perf review", "perf sprint", "where do I start", or has no specific symptom yet.

Use this skill to configure R8 correctly for a Jetpack Compose application — full mode by default, `proguard-android-optimize.txt`, resource shrinking on, and minimal keep rules because Compose ships consumer ProGuard rules. Covers AGP 8.0+ R8 full mode default, R8's Compose-aware optimizations (lambda grouping, `sourceInformation()` stripping, composable arg constant-folding, `ComposerImpl` devirtualization), legitimate keep needs (`@Serializable`, Hilt entry points, reflective `Saver`s), and the AGP 8.x missing-rule reporter / R8 retrace. Cited gain is roughly 75 percent startup and 60 percent frame-render improvement debug-to-release. Use when setting up a new Compose app, when a PR adds an over-broad keep like `-keep class androidx.compose.** { *; }`, when a release build crashes after enabling minification, when APK size needs reduction, or when first enabling minification.

Use this skill to drive Compose HotSwan from an AI agent (Claude Code, Cursor, any MCP client) so the agent can edit a Kotlin file, trigger a hot reload, capture a device screenshot, evaluate the result against a design intent, and iterate without a human in the loop. Covers the seven HotSwan MCP tools (hotswan_get_status, hotswan_reload, hotswan_take_screenshot, hotswan_start_snapshot, hotswan_stop_snapshot, hotswan_select_variant, hotswan_build_and_install), the canonical edit-reload-screenshot loop, snapshot-based rollback, and when to fall back to a full install for schema changes. Use when the developer says "get the AI to tune this screen until it matches a mock", asks "can the AI see what changed?" or "can the AI screenshot the device?", sets up a Claude Code or Cursor workflow that needs MCP tool access, or wants AI-driven UI iteration.

Use this skill to keep Jetpack Compose state alive across HotSwan hot reloads by understanding the three escalating tiers Compose HotSwan uses (tier 1 targeted recomposition, tier 2 composition reset, tier 3 Activity.recreate) and choosing edits and state holders that stay inside tier 1 where scroll position, lazy items, dialog state, and per-composable remember values all survive. Explains which edits force escalation, which state holders survive each tier, and how to hoist transient UI state when the iteration loop must escalate. Use when the developer says "scroll jumped to top after a hot reload", "lost dialog state", "lazy column re-fetched", "tab selection reset", asks why HotSwan reload escalated to tier 2 or 3, plans a refactor and needs to know which scope it touches, or wants to know which state holders survive composition reset.

Use this skill to install and verify Compose HotSwan end to end so a developer goes from zero to working sub-second hot reload on a real device or emulator in one session. Covers the JetBrains IDE plugin install, the `com.github.skydoves.compose.hotswan.compiler` Gradle plugin wiring, the canonical `hotSwanCompiler { enabled = true; debugOnly = true }` DSL block, the HotSwan tool window flow, and the first save-to-reload verification. Trigger when the user mentions HotSwan, Compose hot reload, instant UI update, "save and see", "no rebuild", live edit on device, fast Compose iteration, or already has the JetBrains plugin installed and asks how to apply the Gradle compiler plugin.

Use this skill to teach Claude exactly which Kotlin and Compose changes hot-reload under Compose HotSwan and which trigger a full incremental rebuild fallback. Root cause is Android Runtime (ART) class schema immutability; only method bodies are mutable at runtime, so any change to fields, signatures, constructors, interfaces, inline functions, or new resource ids forces a rebuild. Covers the supported-changes table, the rebuild-forcing list, the diff-then-batch workflow that keeps a hot-reload session inside the fast path, and the inline-function and new-resource-id pitfalls. Trigger when the user asks "why did this rebuild?", "why isn't this hot reloading?", wants to learn HotSwan's boundaries before adopting it, or when reviewing a refactor that risks pushing a hot-reload session into a full rebuild.

Use this skill to tune Jetpack Compose lazy-layout prefetch with LazyLayoutCacheWindow (Compose Foundation 1.9+, @ExperimentalFoundationApi) and pausable composition in prefetch (Compose Foundation 1.10+, default on). Covers configurable Dp-based ahead/behind cache windows plumbed through rememberLazyListState(cacheWindow = ...), NestedPrefetchScope for items containing inner lazy layouts (HorizontalPager inside a LazyColumn row), version requirements, and the trade-off between memory pressure and idle-frame work. Use when the developer mentions dropped frames at high scroll velocity, prefetch window, ahead/behind extents, LazyLayoutCacheWindow, NestedPrefetchScope, pausable composition for prefetch, or wants composition retained for items briefly scrolled past. Item-level fixes (keys, contentType) live in a sibling skill.

Use this skill to fix scroll jank, lost item state, and broken animateItem() animations in LazyColumn, LazyRow, LazyVerticalGrid, and LazyHorizontalGrid. Covers stable item keys, contentType for mixed-type feeds, Modifier.animateItem() requirements, hoisting modifier chains and painters out of the items lambda, and validating item composable stability. Use when the developer mentions LazyColumn jank, dropped frames while scrolling, items losing scroll state on insert/remove/reorder, mixed feeds of cards/headers/ads feeling sluggish, animateItem() not animating, RecyclerView view-type analog, key parameter, or contentType parameter. The prefetch-window tuning lives in a sibling skill.

Use this skill to generate and measure Jetpack Compose Baseline Profiles end-to-end with the AGP 8.2+ Baseline Profile Generator module and the Macrobenchmark harness. Covers writing the `BaselineProfileRule` journey for cold startup plus first-scroll, generating `baseline-prof.txt`, verifying it shipped at `assets/dexopt/baseline.prof`, measuring with `MacrobenchmarkRule` under `CompilationMode.Partial(BaselineProfileMode.Require)`, and emitting accurate time-to-fully-drawn via `ReportDrawn` / `ReportDrawnWhen` / `ReportDrawnAfter` from `androidx.activity.compose`. Compose ships unbundled, so every Compose UI app benefits — cited gains around 30% faster startup and 40% smoother first-scroll. Use when the user mentions "baseline profile", "macrobenchmark", "slow cold startup", "first-scroll jank", "StartupTimingMetric", "FrameTimingMetric", "ReportDrawn", "TTFD", or preparing a release build for performance measurement.

Use this skill to ensure Jetpack Compose performance numbers reflect production reality by measuring against a release variant with R8 enabled, Live Literals disabled, and Compose Compiler reports read from the release output directory. Covers why debug builds lie (interpreted Compose runtime, JIT warmup, Live Literals constant-getters), how to set up a release-with-symbols measurement build, and how to wire Macrobenchmark, Compose Compiler reports, Layout Inspector, simpleperf, and Android Studio Profiler against it. Cited result is roughly 75 percent startup gain and 60 percent frame-render gain debug to release. Use when the developer reports "slow startup", "jank", "dropped frames", "high recomposition count", or quotes timings from `assembleDebug`, Layout Inspector, or `CompilationMode.None`. Use when reviewing a perf bug, setting up a CI perf gate, or before filing a perf regression.

Use this skill to instrument a Jetpack Compose composable with `@TraceRecomposition` from `skydoves/compose-stability-analyzer` so per-recomposition diffs (which state or parameter changed, what value transition) print to logcat under the `Recomposition` tag. Works in release-with-debug-symbols builds where Android Studio Layout Inspector cannot reach, and feeds the IntelliJ / Android Studio plugin's live recomposition heatmap (green under 10, yellow 10–50, red 50+). Covers the Gradle plugin setup, the `ComposeStabilityAnalyzer.setEnabled(BuildConfig.DEBUG)` runtime gate that keeps the instrumentation out of production, and the handoff to debug-time Layout Inspector and CI `stabilityCheck`. Use when the user mentions `@TraceRecomposition`, "trace recomposition", "compose-stability-analyzer", "recomposition logcat", "recomposition heatmap", "release-mode recomposition counts", or needs to confirm a stability fix in a release-like build.

Use this skill to author new custom Jetpack Compose modifiers and migrate legacy ones from Modifier.composed { } to Modifier.Node + ModifierNodeElement<T>. Covers the persistent-node lifecycle (onAttach, onDetach, onReset, coroutineScope), the specialized node interfaces (DrawModifierNode, LayoutModifierNode, SemanticsModifierNode, PointerInputModifierNode, CompositionLocalConsumerModifierNode, LayoutAwareModifierNode, GlobalPositionAwareModifierNode, ObserverModifierNode, DelegatingNode, TraversableNode), why ModifierNodeElement MUST be a data class for diffing, and the manual-invalidation knobs (invalidateDraw, invalidateMeasurement, invalidatePlacement, shouldAutoInvalidate). Use when the developer mentions Modifier.composed, custom modifier, ModifierNodeElement, Modifier.Node, "rewriting our drawBehind helper", node lifecycle, or sees Modifier.composed { } in a code review.

Use this skill to diagnose and fix Jetpack Compose Modifier ordering bugs — wrong paint region for background, wrong click area for clickable, wrong clipping for clip, wrong measurement for padding/size, surprising graphicsLayer scope. Covers the wrap-the-next-modifier mental model, the canonical pitfalls (padding vs background, clickable placement, clip before background, graphicsLayer placement), and why hoisting an entire Modifier chain via remember { Modifier.… } is rarely a real perf win because Compose already interns identical chains. Use when the developer asks "why does the click area extend past the visible button", "why is my background painted in the wrong place", "does Modifier order matter", "should I cache my Modifier chain", or reviews a diff that reorders modifiers.

Use this skill when a Compose tree uses SubcomposeLayout, BoxWithConstraints, or Scaffold and the developer reports extra measure passes, slow first frame, or layout passes running content composition repeatedly. Covers why SubcomposeLayout composes its slots during the measure phase, why BoxWithConstraints forces a subcomposition for every new Constraints value, why nesting Scaffold or BoxWithConstraints multiplies the cost, when a custom Layout or Modifier.layout { } replaces SubcomposeLayout, and how to use SubcomposeLayoutState's slot reuse policy and precompose APIs when SubcomposeLayout is genuinely required. Use when the developer mentions BoxWithConstraints, SubcomposeLayout, Scaffold, "extra measure pass", "double measurement", "first frame slow", "subcompose", or notices that wrapping content in BoxWithConstraints regresses scroll perf inside a LazyColumn.

Use this skill to decide when Jetpack Compose derivedStateOf is the right tool and when it is pure overhead. Covers the "input frequency must exceed output frequency" rule, the mandatory remember { derivedStateOf { } } wrapper, the canonical pitfall of capturing non-state variables by initial value (and the remember(key) fix), and the snapshotFlow alternative for fire-and-forget side effects on derived values. Use when the developer mentions derivedStateOf, scroll-position-driven booleans, threshold checks, firstVisibleItemIndex, "show FAB on scroll", recomposition counts that don't drop after wrapping a value, or asks whether a computed string concatenation should use derivedStateOf.

Use this skill to find which Jetpack Compose composables are recomposing and why, using Android Studio Layout Inspector recomposition counts and skip counts, the per-parameter Argument Change Reasons (Changed / Unchanged / Uncertain / Static / Unknown) introduced in Android Studio Hedgehog and later, and runtime `@TraceRecomposition` from `compose-stability-analyzer` for production-like measurement. Walks through enabling counts, mapping each Argument Change Reason to a fix, and confirming the result in a release build. Use when the developer says "this should be skipping but isn't", "I want to see recomposition counts", asks what "Uncertain" or "Unknown" means in the inspector, or needs to confirm a stability or strong-skipping fix actually worked end-to-end.

Use this skill to push frequently-changing Jetpack Compose state reads (scroll position, animation values, drag offsets) out of the Composition phase and down into Layout or Draw using lambda-based modifiers like Modifier.offset { }, Modifier.layout { }, Modifier.graphicsLayer { }, Modifier.drawBehind { }, and Modifier.drawWithCache { }. Covers the three-phase model (Composition, Layout, Draw), why a state read at phase N invalidates phase N and every phase below, the modifier-phase cheat sheet, and lambda providers (() -> T) for hoisting hot values across composables. Use when the developer mentions every-frame work, scroll jank, animation jank, dropped frames, animated alpha or offset, "the whole subtree recomposes on scroll", Modifier.alpha(state.value), Modifier.offset(x.dp), or graphicsLayer.

Use this skill to reason about Jetpack Compose's Strong Skipping Mode — the default since Kotlin 2.0.20 — including what it changes about skippability, when it does and does not auto-`remember` lambdas, and which escape hatches (`@DontMemoize`, `@NonSkippableComposable`, `@NonRestartableComposable`, `@ReadOnlyComposable`) apply where. Covers verifying the mode is active, auditing lambda capture sites, and the gaps where strong skipping does not memoize (`LazyListScope.items {}`, `Modifier.pointerInput {}`, object expressions, non-@Composable scopes). Use when the developer asks "do I still need @Stable?", "does this composable skip?", "why does this still recompose despite strong skipping", "when do I need @DontMemoize or @NonSkippableComposable?", is migrating from older Compose, or sees auto-remembered lambdas in compiler output.

Use this skill to migrate Compose UI from `collectAsState()` to `collectAsStateWithLifecycle()`, hoist `Flow<T>` parameters out of composables, and apply `.conflate()` / `.distinctUntilChanged()` / `snapshotFlow` so background CPU and battery stop draining and chatty flows stop invalidating the UI per emission. Covers ViewModel `StateFlow`/`SharedFlow` consumers, sensor and location streams, and the "Flow as composable parameter" antipattern. Trigger when the user mentions `collectAsState`, `collectAsStateWithLifecycle`, lifecycle-aware flow collection, `Lifecycle.State.STARTED`, background battery drain from a Compose screen, `snapshotFlow`, `Flow` parameter on a composable, conflate, or distinctUntilChanged.

Use this skill to choose the cheapest correct effect API in Jetpack Compose — `LaunchedEffect`, `DisposableEffect`, `SideEffect`, `rememberUpdatedState`, and skydoves/compose-effects' `RememberedEffect` and `ViewModelStoreScope`. Covers stale-callback bugs in long-lived `LaunchedEffect`, setup/teardown for non-coroutine subscribers, avoiding a coroutine scope just to react to a key change, and per-row ViewModels in a `LazyColumn`. Trigger when the user mentions LaunchedEffect, DisposableEffect, RememberedEffect, SideEffect, rememberUpdatedState, ViewModelStoreScope, effect restarts unexpectedly, leaked listener, or per-item ViewModel.

Use this skill to diagnose Jetpack Compose stability problems by enabling and reading the Compose Compiler Reports (classes.txt, composables.txt, composables.csv, module.json). Covers the Gradle DSL, the release-only build requirement, and how to interpret per-class and per-composable stability annotations including stable, unstable, runtime, restartable, skippable, readonly, @static, and @dynamic markers. Use when the developer asks "why does this recompose", reports jank, dropped frames, slow scroll, high recomposition count, suspects an unstable parameter, mentions Compose Compiler Reports, classes.txt, composables.txt, module.json, or wants to know which composables are non-skippable. The fix lives in a sibling skill — this one only diagnoses.

Use this skill to set up a CI gate that fails the build when Compose stability silently regresses, using the `skydoves/compose-stability-analyzer` Gradle plugin (primary) or the `j-roskopf/ComposeGuard` plugin (alternative for non-Android multiplatform). Covers applying `com.github.skydoves.compose.stability.analyzer`, configuring the `composeStabilityAnalyzer { stabilityValidation { ... } }` DSL, generating a `.stability` baseline with `:stabilityDump`, committing it to version control, and wiring `:stabilityCheck` into a GitHub Actions or other CI job. Use when the team wants a stability SLO, when an unstable parameter slipped into a shared data class and went unnoticed until jank was reported, when migrating a large app to strong skipping, or when the user mentions stabilityCheck, stabilityDump, baseline drift, ComposeGuard, or "fail the build on stability regression".

Use this skill to fix unstable Jetpack Compose types once a stability diagnosis has identified them. Covers the three-tier strategy — make the type truly stable with val plus immutable fields, mark with @Immutable or @Stable when the source is owned, and use stabilityConfigurationFiles for third-party or Java types. Explains the compiler-level difference between @Immutable and @Stable (static expression promotion), kotlinx.collections.immutable for List/Set/Map parameters, and the StableHolder wrapper escape hatch. Use when the developer asks how to stabilize a User class, a List parameter, java.time.LocalDateTime, a Flow parameter, or when the compiler report shows unstable params and the developer wants the fix. The diagnostic step lives in a sibling skill.

Use this skill to install and operate the `skydoves/compose-stability-analyzer` IntelliJ / Android Studio plugin so the developer sees Compose stability feedback live in the editor instead of waiting for a Gradle build. Covers installing the plugin from disk, configuring the `Settings → Tools → Compose Stability Analyzer` panel, reading the four gutter colors (green stable, red unstable, yellow runtime, gray no-params), the per-parameter hover documentation, the inline parameter hint badges, and the `UnstableComposable` weak-warning inspection with its `@Suppress("NonSkippableComposable")` and `@Suppress("ParamsComparedByRef")` quick fixes. Use when the user mentions gutter icons, inline hints, the stability inspection, the IDEA plugin, real-time stability feedback while editing, or asks why a composable is flagged as non-skippable in the editor.