moai-lang-kotlin

name	moai-lang-kotlin
description	Kotlin 2.0+ development specialist covering Ktor, coroutines, Compose Multiplatform, and Kotlin-idiomatic patterns. Use when building Kotlin server apps, Android apps, or multiplatform projects.
license	Apache-2.0
compatibility	Designed for Claude Code
user-invocable	false
metadata	{"version":"1.1.0","category":"language","status":"active","updated":"2026-01-11","modularized":"false","tags":"kotlin, ktor, coroutines, compose, android, multiplatform","context7-libraries":"/ktorio/ktor, /jetbrains/compose-multiplatform, /jetbrains/exposed","related-skills":"moai-lang-java, moai-lang-swift"}
progressive_disclosure	{"enabled":true,"level1_tokens":100,"level2_tokens":5000}
triggers	{"keywords":["Kotlin","Ktor","coroutine","Flow","Compose","Android",".kt",".kts","build.gradle.kts"],"languages":["kotlin"]}

Quick Reference (30 seconds)

Kotlin 2.0+ Expert - K2 compiler, coroutines, Ktor, Compose Multiplatform with Context7 integration.

Auto-Triggers: Kotlin files (.kt, .kts), Gradle Kotlin DSL (build.gradle.kts, settings.gradle.kts)

Core Capabilities:

• Kotlin 2.0: K2 compiler, coroutines, Flow, sealed classes, value classes
• Ktor 3.0: Async HTTP server/client, WebSocket, JWT authentication
• Exposed 0.55: Kotlin SQL framework with coroutines support
• Spring Boot (Kotlin): Kotlin-idiomatic Spring with WebFlux
• Compose Multiplatform: Desktop, iOS, Web, Android UI
• Testing: JUnit 5, MockK, Kotest, Turbine for Flow testing

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Implementation Guide (5 minutes)

Kotlin 2.0 Features

Coroutines and Flow: Use coroutineScope with async for parallel operations. Create deferred values with async, then call await on each to get results. Combine results into data classes. For reactive streams, create flow blocks with emit calls inside while loops. Use delay for intervals and flowOn to specify dispatcher.

Sealed Classes and Value Classes: Define sealed interface with generic type parameter. Create data class implementations for success and data object for stateless cases like Loading. Use @JvmInline annotation with value class wrapping a primitive. Add init blocks with require for validation.

Ktor 3.0 Server

Application Setup: Call embeddedServer with Netty, port, and host parameters. Inside the lambda, call configuration functions for Koin, security, routing, and content negotiation. Call start with wait equals true.

For Koin configuration, install Koin plugin and define modules with single declarations for singletons. For security, install Authentication plugin and configure JWT with realm, verifier, and validate callback. For content negotiation, install ContentNegotiation with json configuration.

Routing with Authentication: Define routing function on Application. Inside routing block, use route for path prefixes. Create unauthenticated endpoints with post and call.receive for request body. Use authenticate block with verifier name for protected routes. Inside route blocks, define get endpoints with call.parameters for path/query params. Use call.respond with status code and response body.

Exposed SQL Framework

Table and Entity: Define object extending LongIdTable with table name. Declare columns with varchar, enumerationByName, and timestamp functions. Use uniqueIndex() and defaultExpression for defaults.

Create entity class extending LongEntity with companion object extending LongEntityClass. Declare properties with by syntax using table column references. Create toModel function to map entity to domain model.