Kotlin Expert

This is a solid reference for modern Kotlin development, covering the fundamentals through coroutines, Flow, and Android Jetpack Compose. The code examples are current and practical, showing real patterns like StateFlow for state management, suspend functions with proper dispatchers, and Hilt for dependency injection. The Kotlin Multiplatform section gets cut off but the Android coverage is comprehensive. Use this when you need quick syntax reminders or want to see how pieces fit together in a real codebase. It assumes you already know what you're building and just need the Kotlin-specific implementation details rather than architectural guidance.

skills.sh installs: 201
GitHub stars: 44
last updated: Aug 21, 2026

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$ npx -y skills add personamanagmentlayer/pcl --skill kotlin-expert --agent claude-code

Installs into .claude/skills of the current project.

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Kotlin Expert

Expert guidance for Kotlin development, Android, coroutines, Kotlin Multiplatform, and modern JVM development.

Core Concepts

Kotlin Fundamentals

Null safety
Extension functions
Data classes
Sealed classes
Coroutines and Flow
Higher-order functions

Android Development

Jetpack Compose
ViewModel and LiveData
Room database
Retrofit networking
Dependency injection (Hilt)
Android lifecycle

Kotlin Multiplatform

Shared business logic
Platform-specific implementations
iOS and Android targets
Common module architecture

Modern Kotlin Syntax

// Data classes
data class User(
    val id: String,
    val name: String,
    val email: String,
    val createdAt: LocalDateTime = LocalDateTime.now()
)

// Sealed classes for type-safe states
sealed class Result<out T> {
    data class Success<T>(val data: T) : Result<T>()
    data class Error(val exception: Exception) : Result<Nothing>()
    object Loading : Result<Nothing>()
}

// Extension functions
fun String.isValidEmail(): Boolean {
    return this.contains("@") && this.contains(".")
}

SKILL.md on GitHub