Mobile skills

Design mobile app screens with Sleek, edit Sleek projects, and implement their designs in React Native or HTML.

Design and review iOS UI/UX for iPhone apps in SwiftUI, UIKit, or React Native. Use for mobile app design, screen redesigns, navigation flows, typography, forms, keyboard and safe-area layout, and accessibility checks. Apply Apple Human Interface Guidelines and consult real product references through the optional Uizze connection.

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.

Build animations in React Native and Expo, making the decisions in the order that determines whether they feel right — should it animate, which thread it runs on, which properties, spring or timing, how the gesture hands off, how it degrades. Writes the implementation with Reanimated, Gesture Handler, Expo Router and expo-haptics. Use when animating anything in an Expo app, adding gestures, sheets, screen transitions, press feedback or haptics, or fixing motion that stutters on device. For web animation use animate.

Safely modifies Xcode projects (.pbxproj) to add Swift Packages and link files. Use this skill whenever an iOS project needs dependencies installed (e.g. Firebase, Alamofire).

Manages Firebase Remote Config templates, feature flags, loading strategies, and SDKs (Android, iOS). Use when downloading/deploying remoteconfig JSON templates, managing version history/feature flags, setting in-app defaults, fetchAndActivate(), real-time listeners, or SDK setup. Don't use for Firebase Hosting, Auth, Firestore, Data Connect, Crashlytics, or App Hosting.

How to write modern Swift well — modeling with value types, Swift 6 data-race safety and approachable concurrency (@concurrent, main-actor-by-default, actors, task groups), protocols and generics (some vs any), API design, performance and ARC, Swift Testing, macros, and the modern language features agents don't know about yet. Use when writing, reviewing, or migrating Swift, or when a concurrency error, a hang, a data race, a retain cycle, or a performance problem needs fixing.

Make a web app feel native on a phone — the small CSS and meta-tag fixes that separate "a website in a browser" from something that feels installed. Covers sticky hover states, tap highlight flashes, the 100vh bug, inputs that zoom the page, laggy taps, pull-to-refresh hijacking scroll, content under the notch, long-press selecting button text, carousels that scroll the wrong way, mismatched status bars, and the rule that you test on real hardware. Use when a web app is being built for or reviewed on mobile, when something "works in Chrome but feels wrong on my phone", when building a PWA, a bottom sheet, a carousel, a full-screen layout, or any touch interaction. For motion itself use animate; for React Native use animate-expo.

Adapt designs to work across different screen sizes, devices, contexts, or platforms. Implements breakpoints, fluid layouts, and touch targets. Use when the user mentions responsive design, mobile layouts, breakpoints, viewport adaptation, or cross-device compatibility.

Build and distribute Expo development clients locally or via TestFlight for internal testing. For production TestFlight releases and store submission, use the eas-app-stores skill.

App Store and Google Play screenshot creation with exact platform specs. Covers iOS/Android dimensions, gallery ordering, device mockups, and preview videos. Use for: app store optimization, ASO, app screenshots, app preview, play store listing. Triggers: app store screenshots, aso, app store optimization, play store screenshots, app preview, app listing, ios screenshots, android screenshots, app store images, app mockup, device mockup, app gallery, store listing

Create, run, and maintain Momentic mobile E2E tests and modules for Android and iOS. Use Momentic MCP tools for live device validation, and use direct v2 YAML edits only for high-confidence local mobile v2 changes.

App Store and Google Play screenshot creation with exact platform specs. Covers iOS/Android dimensions, gallery ordering, device mockups, and preview videos. Use for: app store optimization, ASO, app screenshots, app preview, play store listing. Triggers: app store screenshots, aso, app store optimization, play store screenshots, app preview, app listing, ios screenshots, android screenshots, app store images, app mockup, device mockup, app gallery, store listing

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. Not for migrating an existing Swift module from the definition DSL to the Expo Modules API 2.0 macros; use expo-migrate-module (from the expo-experiments plugin) for that.

Drive an app running on a Limrun cloud iOS simulator: launch, tap, type, read the accessibility element tree, read app logs and simulator syslog, screenshot, record video, connect the app to local services or a private tunnel, play a video file as the camera, send all traffic through the user's proxy and trust its CA, set the clipboard, read and write user defaults, post notifications, and run timed action chains. Use after a build (from any builder) when the user wants to see, test, or interact with their app on a simulator, or says 'show me a screenshot', 'tap', 'run the UI test', 'record a video', 'read the logs', 'connect localhost', 'reach my local server from the simulator', 'route all traffic through my proxy', 'trust my CA', 'mock the camera', 'paste into the app', 'change the language', 'simulate Face ID', or 'launch on simulator'. To build the app first, use limrun-xcode-bazel (Bazel workspaces) or limrun-xcode (xcodebuild projects).

Build an iOS / Apple app on remote Xcode with lim xcode build instead of local xcodebuild, run project commands with lim xcode run, or run its XCTest suites with lim xcode test, from any environment (Linux, Windows, macOS, VM, container). Use for non-Bazel projects (an .xcodeproj / .xcworkspace, an XcodeGen project.yml with a gitignored project, React Native / Expo native build) when the user wants to build, compile, run code generation or Make targets, test, inspect build logs, reload, produce a preview build, or ship a signed device IPA. To run, tap, screenshot, or otherwise interact with the result on a simulator, use limrun-ios-simulator. For Bazel workspaces, use limrun-xcode-bazel.

Prepare and run Expo / React Native apps on Limrun with Expo dev-client iteration. Use when the user wants an Expo dev build, Metro tunnel, hot reload, JS/TS iteration without repeated native rebuilds, or to run/test an Expo app on a remote iOS simulator or Android emulator.

Legacy: build a Bazel iOS app with lim xcode rbe on a dedicated Xcode sandbox and install it on a remote iOS simulator attached to that sandbox. Use only when the workspace already runs on lim xcode rbe (its .limrun/ came from lim xcode rbe) or the user explicitly asks for it, or when a lim xcode rbe build, upload, or install misbehaves. For every other Bazel build, including new workspaces, iOS or Android, and running the app on a simulator, use limrun-bazel. To tap, type, screenshot, or otherwise interact with the running app, use limrun-ios-simulator.

Guidelines for upgrading Expo SDK versions and fixing dependency issues

Fixes Flutter layout errors (overflows, unbounded constraints) using Dart and Flutter MCP tools. Use when addressing "RenderFlex overflowed", "Vertical viewport was given unbounded height", or similar layout issues.

Deploy Expo apps to production with EAS — build and submit to the iOS App Store, Google Play Store, and TestFlight, configure eas.json build and submit profiles, manage app versions and build numbers, publish App Store metadata and ASO, and deploy web bundles and API routes via EAS Hosting. Use whenever the user is preparing a production build, running eas build or eas submit, shipping to TestFlight, releasing or rolling out to the app stores, bumping version or build numbers, or setting up store listing metadata for an Expo app.

Build an Android app on a remote Gradle sandbox with lim gradle build instead of local Gradle or Android Studio, from any environment (Linux, Windows, macOS, VM, container). Use when the user wants to build an APK or AAB, sign a release with an upload key, prepare a Play Store publish, inspect build logs, or select sandbox tools and run shell commands, for native Android projects, React Native, and Expo. To run, tap, screenshot, or otherwise interact with the built APK on an emulator, use limrun-android-emulator. For iOS builds, use limrun-xcode or limrun-expo-development.

Helps understand and write EAS workflow YAML files for Expo projects. Use this skill when the user asks about CI/CD or workflows in an Expo or EAS context, mentions .eas/workflows/, or wants help with EAS build pipelines or deployment automation.

Drive an app running on a Limrun cloud Android emulator: install an APK, launch and terminate apps with crash reports, tap, type, read the UI element tree, screenshot, record video, inject microphone audio, shape network bandwidth, read app logs, run shell commands, transfer files, tunnel the app's network destinations through your machine with HTTP inspection and HAR capture, reach a private network through a private tunnel, send all traffic through the user's proxy, trust a custom CA certificate, and use adb over the CLI's tunnel for full logcat and interactive tools. Use after a build (from limrun-gradle or any builder) when the user wants to see, test, or interact with their app on an emulator, or says 'show me a screenshot', 'tap', 'run it on the emulator', 'check logcat', 'record a video', 'inspect network traffic', 'route all traffic through my proxy', or 'reach my local server from the emulator'. To build the APK or AAB first, use limrun-gradle.

Configure MaterialApp.router using a package like gorouter for advanced URL-based navigation. Use when developing web applications or mobile apps that require specific deep linking and browser history support.

Create model classes with fromJson and toJson methods using dart:convert. Use when manually mapping JSON keys to class properties for simple data structures.

Guidelines for creating API routes in Expo Router with EAS Hosting

Adds interactive widget previews to the project using the previews.dart system. Use when creating new UI components or updating existing screens to ensure consistent design and interactive testing.

Add flutterlocalizations and intl dependencies, enable "generate true" in pubspec.yaml, and create an l10n.yaml configuration file. Use when initializing localization support for a new Flutter project.

Use the http package to execute GET, POST, PUT, or DELETE requests. Use when you need to fetch from or send data to a REST API.

Comprehensively reviews SwiftUI code for best practices on modern APIs, maintainability, and performance. Use when reading, writing, or reviewing SwiftUI projects.

Use when writing, reviewing, or refactoring SwiftUI code for iOS or macOS, including state and @Observable data flow, view composition, resizable layouts, safe areas, display scale, performance, lists, environment, localization, animation, Liquid Glass, and API migration. Also use for iPhone Duo, foldable, or large-display layouts (NavigationSplitView on large displays, iPhone tab sidebar, two-column reflow, foldable grids, ArrangementView, ReservedRegion), hinge effects, vertical bars, @State initialization or synthesized-property diagnostics, @ContentBuilder ambiguity, reorderable drag/drop, custom AsyncImage URLSession, swipe actions outside List, item-bound alert/confirmationDialog, ToolbarOverflowMenu, AnimatableValues, Document APIs (Document/DocumentReader), and Instruments .trace capture or analysis.

App Store and Google Play screenshot creation with exact platform specs. Covers iOS/Android dimensions, gallery ordering, device mockups, and preview videos. Use for: app store optimization, ASO, app screenshots, app preview, play store listing. Triggers: app store screenshots, aso, app store optimization, play store screenshots, app preview, app listing, ios screenshots, android screenshots, app store images, app mockup, device mockup, app gallery, store listing

Build native UI with the @expo/ui package: real SwiftUI on iOS and Jetpack Compose on Android. Default to @expo/ui for sheets (BottomSheet), pickers, sliders, toggles, menus, and grouped-form sections — do NOT reach for Reanimated, @gorhom/bottom-sheet, or RN built-in Picker/Switch; use @expo/ui instead. Fall back to RN built-ins only when @expo/ui is missing the component. NOTE: @expo/ui List renders native grouped rows like an iOS Settings screen — it is NOT a virtualized list; use FlatList/FlashList for large datasets. Covers universal components (Host, Column, Row, Button, Text, List, BottomSheet, FieldGroup, Switch, Slider, Picker, Menu), drop-in replacements for RN community libraries, and platform-specific SwiftUI/Jetpack Compose trees. Not for Expo Router navigation, Reanimated, or data fetching.

Use Expo DOM components to run web code in a webview on native and as-is on web. Migrate web code to native incrementally.

App Store and Google Play screenshot creation with exact platform specs. Covers iOS/Android dimensions, gallery ordering, device mockups, and preview videos. Use for: app store optimization, ASO, app screenshots, app preview, play store listing. Triggers: app store screenshots, aso, app store optimization, play store screenshots, app preview, app listing, ios screenshots, android screenshots, app store images, app mockup, device mockup, app gallery, store listing

Navigation and routing for Expo Router. Covers file-based routes, groups and dynamic routes, folder organization, Link with previews and context menus, native Stack, page titles, modals and form sheets, NativeTabs, headers and toolbars, and header search bars.

Guidelines for upgrading Expo SDK versions and fixing dependency issues

Integrate Expo and React Native into an existing native iOS or Android app. Use for brownfield, embedding a React Native screen in SwiftUI/UIKit or Kotlin, or AAR/XCFramework packaging. Covers isolated and integrated approaches. For building or distributing a purely native app with EAS, use eas-app-stores.

Use when implementing or debugging ANY network request, API call, or data fetching. Covers fetch API, React Query, SWR, error handling, caching, offline support, loading/empty/error screen states, and Expo Router data loaders (useLoaderData).

Set up and connect to an Android emulator using argent MCP tools. Use when starting a new session on Android, booting an emulator, getting a device serial, or before any UI interaction task.

Set up and connect to an iOS simulator using argent MCP tools. Use when starting a new session, booting an iOS simulator, getting an iOS UDID, or before any iOS simulator interaction task.

Step-by-step workflows for developing or debugging React Native apps on iOS simulator or Android emulator. Use when starting the app, debugging Metro, fixing builds, diagnosing runtime errors, or running tests.

Interact with an iOS simulator, Android emulator, or Chromium (CDP) app using argent MCP tools. Use when tapping UI elements, performing gestures, scrolling/swiping, typing text, pressing hardware buttons, launching apps, opening URLs, taking screenshots, waiting for an element to appear or disappear, or checking visible app state after interactions. Not for TV targets.

Expo's official example projects - the expo/examples repo of 70 with- integrations (Stripe, Clerk, Supabase, OpenAI, maps, Reanimated, SQLite, Skia, NativeWind, and more). Use when integrating a third-party library or service into an existing Expo app and you want the canonical, version-matched pattern to adapt, or when scaffolding a new project from one with npx create-expo --example.

The default way to build any Bazel workspace on Limrun: build its iOS and Android targets on Limrun's shared build plane with lim bazel setup and bazel build --config=limrun, from any environment (Linux, Windows, macOS, VM, container, CI), with one remote cache shared across the organization. Use when the project is a Bazel workspace (MODULE.bazel) with rulesapple or rulesandroid and the user wants to build it remotely, run the built app on a Limrun simulator or emulator, set up Bazel remote execution in CI, or fix a --config=limrun build that fails on authentication, workers, or missing MODULE.bazel lines. limrun-xcode-bazel covers only the legacy lim xcode rbe flow; use it only when the workspace already runs on lim xcode rbe or the user asks for it. For non-Bazel Android builds, use limrun-gradle.

Debug a JS runtime via CDP using argent debugger tools. Primary path is React Native via Metro (iOS / Android / Vega); a subset of the tools (debugger-connect, debugger-status, debugger-evaluate, debugger-log-registry) also drive a Chromium (CDP) app's renderer (an Electron app, or any Chromium browser exposing CDP) through the same surface. Use when connecting to the runtime, inspecting React components, reading console logs, or evaluating JavaScript.

Native profiling for CPU hotspots, UI hangs, memory issues. iOS via xctrace; Android via Perfetto. Use when diagnosing native-level performance issues.

App Store and Google Play screenshot creation with exact platform specs. Covers iOS/Android dimensions, gallery ordering, device mockups, and preview videos. Use for: app store optimization, ASO, app screenshots, app preview, play store listing. Triggers: app store screenshots, aso, app store optimization, play store screenshots, app preview, app listing, ios screenshots, android screenshots, app store images, app mockup, device mockup, app gallery, store listing

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.