Mobile App Development Skills
Browse 79 curated mobile app development skills for AI coding agents. License-verified, MCP-ready, free to start.
Android Design Guidelines
Material Design 3 and Android platform guidelines. Use when building Android apps with Jetpack Compose or XML layouts, implementing Material You, navigation, or accessibility. Triggers on tasks involving Android UI, Compose components, dynamic color, or Material Design compliance.
Android Kotlin
Android Kotlin development with Coroutines, Jetpack Compose, Hilt, and MockK testing
Appium Skill
Generates production-grade Appium mobile automation scripts for Android and iOS in Java, Python, or JavaScript. Supports real device and emulator testing locally and on TestMu AI cloud with 100+ real devices. Use when the user asks to automate mobile apps, test on Android/iOS, write Appium tests, or mentions "Appium", "mobile testing", "real device", "app automation". Triggers on: "Appium", "mobile test", "Android test", "iOS test", "real device", "app automation", "UiAutomator", "XCUITest driver", "TestMu", "LambdaTest".
Apple Appstore Reviewer
Serves as a reviewer of the codebase with instructions on looking for Apple App Store optimizations or rejection reasons.
App Rejection Recovery
When the user's app or update was rejected by Apple App Review or Google Play Review and they need to diagnose why, fix it, and resubmit fast. Use when the user mentions "app rejected", "App Review rejection", "guideline violation", "Apple rejected my app", "Google Play rejected", "Play policy violation", "Resolution Center", "metadata rejection", "binary rejection", "guideline 2.1", "guideline 4.3", "guideline 5.1.1", "Sign in with Apple required", "Apple ID rejection", "Play Store suspension", "appeal", "I need to respond to App Review", or "expedited review". For pre-submission listing health, see aso-audit. For metadata-only fixes, see metadata-optimization.
App Store Preflight Skills
Scan an iOS/macOS Xcode project for common App Store rejection patterns before submission. Use when preparing an app for App Store review, after receiving a rejection from Apple, or when auditing metadata, subscriptions, privacy manifests, entitlements, or design compliance. Integrates with the asc CLI for metadata inspection.
Asc App Create UI
Create a new App Store Connect app record via browser automation. Use when there is no public API for app creation and you need an agent to drive the New App form.
Asc Aso Audit
Run an offline ASO audit on canonical App Store metadata under `./metadata` and surface keyword gaps using Astro MCP. Use after pulling metadata with `asc metadata pull`.
Asc CLI Usage
Guidance for using asc cli in this repo (flags, output formats, pagination, auth, and discovery). Use when asked to run or design asc commands or interact with App Store Connect via the CLI.
Asc Localize Metadata
Automatically translate and sync App Store metadata (description, keywords, what's new, subtitle) to multiple languages using LLM translation and asc CLI. Use when asked to localize an app's App Store listing, translate app descriptions, or add new languages to App Store Connect.
Asc Metadata Sync
Sync, validate, and apply App Store metadata with the current asc canonical metadata workflow. Use when updating metadata, localizations, keywords, or migrating legacy fastlane metadata.
Asc Ppp Pricing
Set territory-specific pricing for subscriptions and in-app purchases using current asc setup, pricing summary, price import, and price schedule commands. Use when adjusting prices by country or implementing localized PPP strategies.
Asc Release Flow
Determine whether an app is ready to submit, then drive the current App Store release flow with asc, including validation, staging, review submission, first-time availability, subscriptions, IAP, Game Center, and App Privacy checks.
Asc Revenuecat Catalog Sync
Reconcile App Store Connect subscriptions and in-app purchases with RevenueCat products, entitlements, offerings, and packages using asc and RevenueCat MCP. Use when setting up or syncing subscription catalogs across ASC and RevenueCat.
Asc Screenshot Resize
Resize and validate App Store screenshots with current asc screenshot-size data and macOS sips. Use when preparing or fixing screenshots for App Store Connect submission.
Asc Shots Pipeline
Orchestrate iOS screenshot automation with xcodebuild/simctl for build-run, AXe for UI actions, JSON settings and plan files, Koubou-based framing (`asc screenshots frame`), and screenshot upload (`asc screenshots upload`). Use when users ask for automated screenshot capture, AXe-driven simulator flows, frame composition, or screenshot-to-upload pipelines.
Asc Signing Setup
Set up bundle IDs, capabilities, signing certificates, provisioning profiles, and encrypted signing sync with the asc cli. Use when onboarding a new app, rotating signing assets, or sharing them across a team.
Asc Submission Health
Validate App Store submission readiness, submit prepared versions, and monitor review status with current asc commands. Use when shipping or troubleshooting review submissions.
Avoiding Subcomposition Pitfalls
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.
Building Native UI
Complete guide for building beautiful apps with Expo Router. Covers fundamentals, styling, components, navigation, animations, patterns, and native tabs.
Choosing Derivedstateof
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.
Collecting Flows Safely
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.
Configuring Lazy Prefetch
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.
Crash Analytics
When the user wants to monitor, triage, or reduce their app's crash rate — including setting up Crashlytics, prioritizing which crashes to fix first, interpreting crash data, and understanding how crashes affect App Store ranking. Use when the user mentions "crash", "crashlytics", "crash rate", "ANR", "app not responding", "crash-free sessions", "crash-free users", "symbolication", "stability", "firebase crashes", "app crashing", or "crash report". For overall analytics setup, see app-analytics.
Debugging Recompositions
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.
Deferring State Reads
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.
Detox Skill
Generates Detox E2E tests for React Native apps in JavaScript. Gray-box testing framework with automatic synchronization. Supports local simulators/emulators and TestMu AI cloud. Use when user mentions "Detox", "React Native test", "element(by.id())", "device.launchApp". Triggers on: "Detox", "React Native E2E", "React Native test", "element(by.id)", "device.launchApp".
Developing iOS Apps
Develops iOS/macOS apps with XcodeGen, SwiftUI, and SPM, including Apple Developer signing, notarization, and CI/CD pipelines. Use when building iOS/macOS apps, fixing Xcode build failures, deploying to real devices, or configuring CI/CD signing. Triggers on XcodeGen project.yml, SPM dependency issues, code signing errors (Error -25294, keychain mismatch, adhoc fallback, EMFILE, notarization credential conflict), "Library not loaded @rpath", Electron @electron/osx-sign / @electron/notarize, notarytool, or certificate/provisioning problems.
Diagnosing Compose Stability
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.
Display Glasses With Jetpack Compose Glimmer
Provides guidelines for developing projected Android XR apps for display glasses using the Jetpack Compose Glimmer UI toolkit. This skill covers foundational Glimmer design principles, workflows for implementing Jetpack Compose Glimmer, and interaction models for the glasses form factor. Use this skill to build an Android XR Augmented Experience app with Jetpack Compose Glimmer that adheres to the Glimmer design system for optimized glasses styling.
Eas Update Insights
Check the health of published EAS Updates: crash rates, install/launch counts, unique users, payload size, and the split between embedded and OTA users per channel. Use when the user asks how an update is performing, whether a rollout is healthy, how many users are on the embedded build vs OTA, or wants to gate CI on update health.
Edge To Edge
Use this skill to migrate your Jetpack Compose app to add adaptive edge-to-edge support and troubleshoot common issues. Use this skill to fix UI components (like buttons or lists) that are obscured by or overlapping with the navigation bar or status bar, fix IME insets, and fix system bar legibility.
Enforcing Stability In CI
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".
Espresso Skill
Generates Espresso UI tests for Android apps in Kotlin or Java. Espresso runs inside the app process for fast, reliable UI testing. Supports local and TestMu AI cloud real devices. Use when user mentions "Espresso", "onView", "ViewMatchers", "Android UI test", or "instrumentation test". Triggers on: "Espresso", "onView", "ViewMatchers", "Android UI test", "instrumentation", "TestMu".
Expo Dev Client
Build and distribute Expo development clients locally or via TestFlight
Expo Module
Guide for creating and writing Expo native modules and views using the Expo Modules API (Swift, Kotlin, TypeScript). Covers module definition DSL, native views, shared objects, config plugins, lifecycle hooks, autolinking, and type system. Use when building or modifying native modules for Expo.
Expo Tailwind Setup
Set up Tailwind CSS v4 in Expo with react-native-css and NativeWind v5 for universal styling
Flutter
Flutter development with Riverpod state management, Freezed, go_router, and mocktail testing
Flutter Expert
Use when building cross-platform applications with Flutter 3+ and Dart. Invoke for widget development, Riverpod/Bloc state management, GoRouter navigation, platform-specific implementations, performance optimization.
Flutter Testing Skill
Generates Flutter widget tests, integration tests, and golden tests in Dart. Supports local execution and TestMu AI cloud for real device testing. Use when user mentions "Flutter", "widget test", "WidgetTester", "testWidgets", "flutter_test", "integration_test". Triggers on: "Flutter", "widget test", "Dart test", "testWidgets", "WidgetTester", "golden test".
Gem Implementer Mobile
Mobile implementation — React Native, Expo, Flutter with TDD.
Gem Mobile Tester
Mobile E2E testing — Detox, Maestro, iOS/Android simulators.
Generating Baseline Profiles
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.
iOS Design Guidelines
Apple Human Interface Guidelines for iPhone. Use when building, reviewing, or refactoring SwiftUI/UIKit interfaces for iOS. Triggers on tasks involving iPhone UI, iOS components, accessibility, Dynamic Type, Dark Mode, or HIG compliance.
iOS Simulator Skill
29 production-ready scripts for iOS app testing, building, and automation. Provides semantic UI navigation, build automation, accessibility testing, and simulator lifecycle management. Optimized for AI agents with minimal token output.
Iterating With AI And MCP
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.
MAUI Expert
Support development of .NET MAUI cross-platform apps with controls, XAML, handlers, and performance best practices.
Migrate XML Views To Jetpack Compose
Provides a structured workflow for migrating an Android XML View to Jetpack Compose. This skill details the step-by-step process, from planning and dependency setup, to theming and layout migration, validation and XML cleanup. Use this skill when you need to migrate an XML View to Jetpack Compose in an Android project. It solves the problem of converting the UI of a legacy XML View into modern, declarative Compose components while maintaining interoperability.
Migrating To Modifier Node
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.
Mobile Android Design
Master Material Design 3 and Jetpack Compose patterns for building native Android apps. Use when designing Android interfaces, implementing Compose UI, or following Google's Material Design guidelines.
Mobile iOS Design
Master iOS Human Interface Guidelines and SwiftUI patterns for building native iOS apps. Use when designing iOS interfaces, implementing SwiftUI views, or ensuring apps follow Apple's design principles.
Native Data Fetching
Use when implementing or debugging ANY network request, API call, or data fetching. Covers fetch API, React Query, SWR, error handling, caching, offline support, and Expo Router data loaders (`useLoaderData`).
.NET MAUI
.NET MAUI component and application patterns
Optimizing Lazy Layouts
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.
Ordering Modifier Chains
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.
Play Billing Library Version Upgrade
Use this skill when upgrading or migrating an Android project from any legacy Google Play Billing Library (PBL) version to the latest stable version of PBL.
Port
Designing web-to-iOS/Android porting strategies. Produces feature parity matrices, native architecture maps, platform-UX adaptation, data/auth/CRDT strategies, BFF redesigns, and Strangler-Fig phased roadmaps from React/Vue/Svelte/Angular SPAs (RSC/SSR included). Optionally proposes a hybrid path (pure-native UI + KMP shared logic). 2026 spec aware (Swift 6.3 / Compose 1.11 / Privacy Manifest / 16KB / Passkey / DMA / EAA). Use when designing web-to-native ports. Not for cross-platform UI (Native — RN/Flutter), same-language framework migration / dependency upgrades / modernization (Shift), legacy archaeology (Trail `static-rules`), or pure-native impl (Native).
Preserving State Across Reloads
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.
React Native
React Native patterns for mobile app development with Expo and bare workflow. Trigger: When building mobile apps, working with React Native components, using Expo, React Navigation, or NativeWind.
React Native
React Native mobile patterns, platform-specific code
React Native Best Practices
Provides React Native performance optimization guidelines for FPS, TTI, bundle size, memory leaks, re-renders, and animations. Applies to tasks involving Hermes optimization, JS thread blocking, bridge overhead, FlashList, native modules, or debugging jank and frame drops.
React Native Brownfield Migration
Provides an incremental adoption strategy to migrate native iOS or Android apps to React Native or Expo using @callstack/react-native-brownfield for initial setup. Use when planning migration steps, packaging XCFramework/AAR artifacts, and integrating them into host apps.
React Native Expert
Builds, optimizes, and debugs cross-platform mobile applications with React Native and Expo. Implements navigation hierarchies (tabs, stacks, drawers), configures native modules, optimizes FlatList rendering with memo and useCallback, and handles platform-specific code for iOS and Android. Use when building a React Native or Expo mobile app, setting up navigation, integrating native modules, improving scroll performance, handling SafeArea or keyboard input, or configuring Expo SDK projects.
Setting Up Compose Hotswan
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.
Swift Expert
Builds iOS/macOS/watchOS/tvOS applications, implements SwiftUI views and state management, designs protocol-oriented architectures, handles async/await concurrency, implements actors for thread safety, and debugs Swift-specific issues. Use when building iOS/macOS applications with Swift 5.9+, SwiftUI, or async/await concurrency. Invoke for protocol-oriented programming, SwiftUI state management, actors, server-side Swift, UIKit integration, Combine, or Vapor.
Swift Patterns
Review, refactor, or build SwiftUI features with correct state management, modern API usage, optimal view composition, navigation patterns, performance optimization, and testing best practices.
Testing Compose In Release Mode
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.
Tracing Recompositions At Runtime
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.
UI Mobile
Mobile UI patterns - React Native, iOS/Android, touch targets
Understanding Hot Reload Limits
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.
Upgrading Expo
Guidelines for upgrading Expo SDK versions and fixing dependency issues
Upgrading from .NET MAUI 9 to .NET MAUI 10
Instructions for upgrading .NET MAUI applications from version 9 to version 10, including breaking changes, deprecated APIs, and migration strategies for ListView to CollectionView.
Upgrading React Native
Upgrades React Native apps to newer versions by applying rn-diff-purge template diffs, updating package.json dependencies, migrating native iOS and Android configuration, resolving CocoaPods and Gradle changes, and handling breaking API updates. Use when upgrading React Native, bumping RN version, updating from RN 0.x to 0.y, or migrating Expo SDK alongside a React Native upgrade.
Use Dom
Use Expo DOM components to run web code in a webview on native and as-is on web. Migrate web code to native incrementally.
Using Efficient Effects
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.
Using Strong Skipping Correctly
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.
Vercel React Native Skills
React Native and Expo best practices for building performant mobile apps. Use when building React Native components, optimizing list performance, implementing animations, or working with native modules. Triggers on tasks involving React Native, Expo, mobile performance, or native platform APIs.
Watchos Design Guidelines
Apple Human Interface Guidelines for Apple Watch. Use when building watchOS apps, complications, or workout features. Triggers on tasks involving Watch UI, Digital Crown, glanceable interfaces, or wrist-based interactions.
Xcuitest Skill
Generates XCUITest UI tests for iOS/iPadOS apps in Swift. Apple's native testing framework for reliable, fast UI automation. Supports local simulators and TestMu AI cloud real devices. Use when user mentions "XCUITest", "XCTest", "iOS UI test", "Swift test", "XCUIApplication". Triggers on: "XCUITest", "XCTest UI", "iOS UI test", "Swift UI test", "XCUIApplication", "TestMu".