Codex skills for Android and Kotlin
Android work with these skills follows the official layered architecture: ViewModels expose one StateFlow of UI state, Room is the single source of truth and Hilt is wired with KSP. Compose screens split into a route and a stateless screen, coroutines never swallow cancellation, and Play releases ship as signed App Bundles checked for 16 KB page-size alignment.
Start with these 3
- Android Jetpack Compose Stateless screens, keyed effects, stable lists Codex splits each Compose screen into a route that talks to the ViewModel and a stateless screen that previews and tests cleanly. It picks remember, rememberSaveable or derivedStateOf from a decision table, keys every LaunchedEffect on what should restart it, gives lazy lists stable keys, and routes colours and spacing through MaterialTheme and CompositionLocals.
- Android Architecture ViewModel, Hilt and Room wired the testable way Codex builds Android features along the official layered architecture: ViewModels expose one StateFlow of immutable UI state, repositories make Room the single source of truth and refresh it from the network, and Hilt wires it all with KSP. Every Room version gets an exported schema and a migration test, and ViewModels are tested with fakes and Turbine instead of mocks.
- Android Play Release Bundles that pass Play checks on first upload Codex builds a signed App Bundle with secrets kept out of the repo, runs a bundled script that checks every native library for 16 KB page-size alignment, and installs the bundle with bundletool before anything reaches Play. Releases move from internal testing to a staged production rollout tied to crash and ANR thresholds, and every upload, promotion and policy submission waits for your confirmation.
11 more Android and Kotlin skills
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Kotlin Idioms
Kotlin that stops reading like Java -
Maven and Gradle Builds
Reproducible JVM builds with explained versions -
Kotlin Coroutines
Structured concurrency that cancels cleanly -
Kotlin Multiplatform
Share the logic, keep the platforms honest -
Ktor Server
Kotlin APIs with plugins that tests can swap -
Mobile Deep Links
Links that open the app, not the browser -
Mobile Push Notifications
Pushes that arrive, tokens that stay clean -
Capacitor Apps
Ship the web app natively without forking it -
Mobile App Security
Treat the app binary as attacker-owned -
JUnit 5 with AssertJ and Mockito
Jupiter tests that are discovered, strict and fluent -
Mobile UI Patterns
Thumb-first screens that respect the platform
General skills with Android and Kotlin guidance
Not built around Android and Kotlin, but they include steps or tools for it. Not part of the install-all command.
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Dependency Upgrades
One major at a time, changelog read first -
Codemods
Change 500 files with code you can rerun -
React Native Expo
Native apps you can regenerate from config -
React Native Performance
Measured fixes for jank and slow starts -
Flutter Apps
Small widgets, one theme, typed native calls -
Mobile Accessibility
Every core task, eyes closed, text at 200% -
Tauri Apps
Small binaries, smallest possible permissions -
Mobile CI with fastlane
Signed builds from a clean runner, every time -
Mobile App Architecture
Structure sized to the app, enforced by the build -
Mutation Testing
Find the bugs your green test suite would ship -
Test Data Factories
Valid by default, special only where it matters -
Mobile E2E Testing
Few journeys, stable ids, green on every run
Every Android and Kotlin skill in one command
Installs these 14 into ~/.agents/skills/. Add --project after -- to install into the current repository instead.
The installer is a 104-line POSIX shell script. It fetches the skills you name from codexskills.dev and unpacks each into its own folder in your skills directory. No sudo, no telemetry, and every skill page shows the full SKILL.md first. Read install.sh
curl -fsSL codexskills.dev/install.sh | sh -s -- android-jetpack-compose android-architecture android-play-release kotlin-idioms maven-gradle-builds kotlin-coroutines kotlin-multiplatform ktor-server mobile-deep-links mobile-push-notifications capacitor-apps mobile-app-security junit-5 mobile-ui-patterns Android and Kotlin FAQ
Is there a Codex skill for Jetpack Compose state and recomposition?
Android Jetpack Compose splits each screen into a route that talks to the ViewModel and a stateless composable that previews and tests cleanly, choosing remember, rememberSaveable or derivedStateOf from a decision table. It uses the Kotlin 2.x Compose Compiler Gradle plugin, where strong skipping is on by default, and the Compose BOM to keep UI libraries aligned. Lazy lists get stable keys and every LaunchedEffect is keyed on what should restart it.
Can Codex prepare an Android app for a Google Play release?
Android Play Release builds a signed App Bundle with ./gradlew bundleRelease and an upload key kept out of the repo, then runs a bundled check_16kb_alignment.py script, since from 1 November 2025 apps targeting Android 15+ need 16 KB-compatible native libraries. It installs the bundle with bundletool, moves from internal testing to a staged production rollout, and asks for confirmation before each upload, promotion or policy submission.
Do these skills cover Kotlin coroutines and Flow testing?
Kotlin Coroutines gives every coroutine an owner, injects dispatchers so suspend functions stay main-safe, and rewrites catch blocks and runCatching calls that swallow cancellation. Flows are shared with stateIn or shareIn instead of restarting per collector, one-off events stop riding on StateFlow, and tests run on virtual time with runTest and Turbine.
How do I install all 14 Android and Kotlin skills at once?
Pass every name to the installer in one command: curl -fsSL https://codexskills.dev/install.sh | sh -s -- android-jetpack-compose android-architecture android-play-release kotlin-idioms maven-gradle-builds kotlin-coroutines kotlin-multiplatform ktor-server mobile-deep-links mobile-push-notifications capacitor-apps mobile-app-security junit-5 mobile-ui-patterns. Add --project right after -- to put them in the current repository's .agents/skills/ so your team gets them too.
Which Android and Kotlin skill should I try first?
Android Jetpack Compose is the closest fit for most Android and Kotlin work. Mention it with $android-jetpack-compose in a prompt to load it on purpose; after that, Codex picks it up on its own whenever a task matches.