android-skills

Skills are invoked automatically based on context — working on Compose code activates the compose skill, a coroutine bug pulls in kotlin-coroutines, and so on. Each SKILL.md is plain, self-contained markdown, so the collection also works outside the plugin format.

Contents

• Installation
• Skills
• Companion tools
• Related projects
• Attribution
• License

Installation

Claude Code (plugin)

/plugin marketplace add rcosteira79/android-skills
/plugin install android-skills@android-skills

Updates are picked up automatically when the plugin version is bumped.

Copilot CLI (plugin)

Copilot CLI detects the same plugin format automatically:

copilot plugin install rcosteira79/android-skills

Manual / other agents

Copy the skill directories into your agent's skills folder:

git clone https://github.com/rcosteira79/android-skills.git
cp -r android-skills/plugins/android-skills/skills/* ~/.claude/skills/

The SKILL.md files are plain markdown, so they can be adapted to any editor that supports custom instructions.

Skills

Foundation & architecture

• android-dev — the baseline for Android and KMP work: house defaults (DI, async, JSON, images, networking, module boundaries), routing to the specialised skills, the greenfield MVVM state/effect UI convention, four-bucket UiState modeling, and Channel(BUFFERED) over SharedFlow(replay = 0) for one-shot effects.
• modularization — visibility discipline for multi-module projects: declare everything at the lowest visibility that still compiles (private → internal → public), keep DI-bound implementation classes internal behind public interfaces, and treat widening to public as a decision that requires a real cross-module consumer.
• android-data-layer — data-layer implementation: the layered error-propagation model (repository as the error boundary, sealed DataError, Result placement with and without a domain layer) and KMP Room setup (@ConstructedBy, BundledSQLiteDriver, per-target KSP).

UI — Compose & design

• compose — Jetpack Compose expert guidance: state management (remember, derivedStateOf, hoisting, the unified keying rule, cross-phase back-writing), Modifier chains, lazy lists (LazyLayoutCacheWindow prefetch tuning), navigation (Nav 2 + Nav 3 guardrails), animation, side effects (LifecycleStartEffect/LifecycleResumeEffect), theming, accessibility, performance (Argument Change Reasons, the five compiler stability types, escape-hatch annotations, baseline profiles), focus/key-event navigation (D-pad/TV/ChromeOS, focus restoration, dialog focus traps, predictive-back), and a production-crash playbook with CMP equivalents.
• android-ux — Material Design 3 UX principles: foldable postures (tabletop, book mode), M3 contrast levels (Hct/SchemeContent), motion duration tokens and reduced motion, and an M3 compliance audit scoring screens across 10 categories with grep-based quick checks.
• coil-compose — image loading in Compose and CMP with Coil 3: the KMP specifics (LocalPlatformContext, SingletonImageLoader.setSafe, coil-compose vs coil-compose-core) and two lazy-list performance guardrails (never SubcomposeAsyncImage in lists; rememberAsyncImagePainter needs an explicit size).

Async — Kotlin

• kotlin-coroutines — scope management, structured concurrency, cancellation, and exception handling, centered on scope ownership (prefer suspend fun, let the caller own the scope) and exception discipline that doesn't break cancellation.
• kotlin-flows — Flow traps and semantic edge cases: Channel vs SharedFlow one-shot event semantics, callback bridging (callbackFlow + awaitClose), retry attempt guards, .catch scope and the CancellationException trap, side effects outside transforms, and explicit backing fields (Kotlin 2.4+).

Networking