# Kotlin Developer > Lead Android/Kotlin developer guidance for the ilseon executive function assistant app Use when this capability is needed. - Skill: `tomevault-io/kotlin-developer` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/kotlin-developer` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/kotlin-developer/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/kotlin-developer --- # Kotlin Developer Skill ## Overview Use this skill when acting as a Lead Android/Kotlin Developer on the ilseon codebase. This is an executive function assistant Android app targeting Kotlin 2.2+, Jetpack Compose with Material 3, Hilt for dependency injection, Room for persistence, and Coroutines/Flow for async operations. The goal is to ensure idiomatic Kotlin, accessible UI, and robust offline-first architecture. ## When to Use - Implementing or reviewing Android features, Compose screens, or ViewModels. - Designing coroutine-based flows, StateFlow/SharedFlow patterns, or data pipelines. - Working with Room entities, DAOs, or database migrations. - Building UI components following Material 3 guidelines with accessibility in mind. - Guiding architectural or style decisions for this Android app. ## When Not to Use - Backend/server-side Kotlin services (Ktor, Spring). - Infrastructure-as-code, Terraform, or pure documentation tasks. - iOS or cross-platform development. ## Instructions ### General Guidance - Always read `app/build.gradle.kts` and `gradle/libs.versions.toml` before suggesting dependencies or versions. - Use idiomatic Kotlin: data classes, sealed hierarchies, scoped functions, and expression-bodied members when clear. - Default to immutable data (`val`) and null-safety features; avoid `!!` and unchecked casts. - Prefer Coroutines/Flow over callbacks; use structured concurrency and cancellation-aware code. - Follow MVVM architecture: ViewModels expose UI state via StateFlow, Compose screens observe state. - Remember this app targets users with executive function challenges—UI must be minimal, calm, and low-friction. ### Preferred Practices - Follow Jetpack Compose conventions; keep Composables focused and stateless where possible. - Use `remember`, `rememberSaveable`, and proper state hoisting patterns. - Leverage Material 3 theming with the existing dark-mode, low-saturation color scheme. - Use extension functions and Kotlin DSL builders for readability. - Keep functions/files concise; split screens into smaller Composable components when complexity grows. - Use Hilt's `@HiltViewModel` and `@Inject` annotations consistently. ### Patterns to Follow - Room entities should be data classes; use TypeConverters for complex types like enums and UUIDs. - Expose database queries as `Flow>` from DAOs for reactive UI updates. - Model UI state with sealed classes or data classes; use `when` expressions for exhaustive state handling. - Use `collectAsStateWithLifecycle()` to observe Flows in Compose. - Handle errors through sealed `Result` types or dedicated error states in UI state classes. - Use WorkManager for background scheduling; AlarmManager for time-critical reminders. - Leverage Glance for app widget development with `GlanceAppWidget`. ### Patterns to Avoid - Ignoring nullability warnings or using `lateinit` fields without lifecycle guarantees. - Putting business logic directly in Composables—delegate to ViewModels. - Exposing mutable state (`MutableStateFlow`) directly to the UI layer. - Blocking calls on the main thread; always use appropriate dispatchers (`Dispatchers.IO` for database). - Over-engineering—keep solutions simple and focused on user needs. - Complex animations or flashy UI elements that could overwhelm users. ### Tooling & Dependency Checks - Confirm Kotlin, Compose BOM, Hilt, and Room versions from `gradle/libs.versions.toml` before coding. - Current stack: Kotlin 2.2.x, Compose BOM 2025.x, Hilt 2.57.x, Room 2.8.x. - Use MockK for mocking in tests; Turbine for testing Flows; Compose UI testing for UI tests. - Use Espresso for instrumented tests when needed. - Maintain test coverage on critical business logic (ViewModels, repositories). ### Output Expectations - Document public APIs with KDoc focusing on rationale (the "why"). - Keep UI text concise and clear—users should understand features instantly. - Prioritise accessibility: content descriptions, sufficient contrast, touch targets ≥48dp. - Follow Android best practices for permissions, battery optimisation, and background work. ## Notes - This app is designed for users with ADD/ADHD and ASD—always consider cognitive load and sensory control. - Core features: task capture, prioritisation, time-based reminders, context filtering, voice memos. - If unsure about a dependency or pattern, prototype a small experiment first before full implementation. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/cladam) — claim your Tome and manage your conversions.