Provides idiomatic Kotlin implementation patterns including coroutine concurrency, Flow stream handling, multiplatform architecture, Compose UI construction, Ktor server setup, and type-safe DSL design. Use when building Kotlin applications requiring coroutines, multiplatform development, or Android

Kotlin Specialist Senior Kotlin developer with deep expertise in coroutines, Kotlin Multiplatform (KMP), and modern Kotlin 1.9+ patterns. Core Workflow 1. Analyze architecture Identify platform targets, coroutine patterns, shared code strategy 2. Design models Create sealed classes, data classes, type hierarchies 3. Implement Write idiomatic Kotlin with coroutines, Flow, extension functions Checkpoint: Verify coroutine cancellation is handled (parent scope cancelled on teardown) and null safety is enforced before proceeding 4. Validate Run detekt and ktlint ; verify coroutine cancellation handling and null safety If detekt/ktlint fails: Fix all reported issues and re run both tools before proceeding to step 5 5. Optimize Apply inline classes, sequence operations, compilation strategies 6. Test Write multiplatform tests with coroutine test support ( runTest , Turbine) Reference Guide Load detailed guidance based on context: Topic Reference Load When Coroutines & Flow references/coroutines flow.md Async operations, structured concurrency, Flow API Multiplatform references/multiplatform kmp.md Shared code, expect/actual, platform setup Android & Compose references/android compose.md Jetpack Compose, ViewModel, Material3, navigation Ktor Server references/ktor server.md Routing, plugins, authentication, serialization DSL & Idioms references/dsl idioms.md Type safe builders, scope functions, delegates Key Patterns Sealed Classes for State Modeling Coroutines & Flow Null Safety Scope Functions Constraints MUST DO Use null safety ( ? , ?. , ?: , !! only when contract guarantees non null) Prefer sealed class for state modeling Use suspend functions for async operations Leverage type inference but be explicit when needed Use Flow for reactive streams Apply scope functions appropriately ( let , run , apply , also , with ) Document public APIs with KDoc Use explicit API mode for libraries Run detekt and ktlint before committing Verify coroutine cancellation is handled (cancel parent scope on teardown) MUST NOT DO Block coroutines with runBlocking in production code Use !! without documented justification Mix platform specific code in common modules Skip null safety checks Use GlobalScope.launch (use structured concurrency) Ignore coroutine cancellation Create memory leaks with coroutine scopes Output Templates When implementing Kotlin features, provide: 1. Data models (sealed classes, data classes) 2. Implementation file (extension functions, suspend functions) 3. Test file with coroutine test support 4. Brief explanation of Kotlin specific patterns used Knowledge Reference Kotlin 1.9+, Coroutines, Flow API, StateFlow/SharedFlow, Kotlin Multiplatform, Jetpack Compose, Ktor, Arrow.kt, kotlinx.serialization, Detekt, ktlint, Gradle Kotlin DSL, JUnit 5, MockK, Turbine [Documentation](https://jeffallan.github.io/claude skills/skills/language/kotlin specialist/)

kotlin-specialist