kotlin-guidelineslisted

# Kotlin Guidelines Shared Kotlin rubric for agents. Prefer repo-local conventions (build setup, coroutine vs Rx, Android vs server) when deliberate; push back on `!!`, platform-type leaks, and gratuitous scope-function nesting. ## Source Of Truth - Kotlin coding conventions (kotlinlang.org) and *Effective Kotlin* (Moskała) - The repo's Gradle (Kotlin DSL) config, `detekt`/`ktlint` rules, and target (JVM/Android/Multiplatform) ## Core Rubric - `val` over `var`; immutable collections (`listOf`, `mapOf`) unless mutation is required; expose read-only types in public APIs. - Null safety: never `!!`. Use `?.`, `?:`, `let`/`also`, and smart casts. Guard platform types coming from Java at the boundary — don't let them propagate untyped. - `data class` for value types; `sealed class`/`sealed interface` for ADTs with exhaustive `when` (no `else` branch when it can be exhaustive). - Prefer expressions (`if`/`when`/`try` as values) and single-expression functions where they read clearly. - Extension functions to extend types you don't own — but keep them discoverable and cohesive, not a junk drawer. - Coroutines: structured concurrency only — no `GlobalScope`; pass a `CoroutineScope`/use `coroutineScope {}`; pick the right `Dispatcher`; make suspend functions main-safe; don't block inside `suspend`. - Scope functions (`let`/`run`/`with`/`apply`/`also`) used for their intent, not stacked into unreadable chains. - Preconditions with `require`/`check`/`error`; results with sealed `Res