roninforge-kotlin-compose

Cursor plugin for modern Android development with Kotlin 2.x and Jetpack Compose. Teaches the AI to write stateless Screen + stateful Route composables, StateFlow + collectAsStateWithLifecycle, Hilt + hiltViewModel(), type-safe Navigation Compose, KSP, Version Catalogs, and Material 3. Catches 20 legacy regressions LLMs still produce.

The Problem

LLMs trained on Android-View-system + Kotlin 1.x patterns ship code that does not match modern Compose. They produce:

• findViewById<...>(R.id.x) and setContentView(R.layout.x) in projects meant to be Compose-based
• GlobalScope.launch { } (leaks across the process)
• LiveData + observeAsState instead of StateFlow + collectAsStateWithLifecycle
• Public MutableStateFlow exposed from the ViewModel
• Force-unwrap !! everywhere
• Lowercase composable names (@Composable fun userCard())
• LazyColumn { items(list) { ... } } without a key argument
• LaunchedEffect(true) / LaunchedEffect(Unit) as a catch-all
• androidx.compose.material.* (Material 2) imports in a Material 3 project
• Modifier.padding(...).clickable { } (dead zone around the button)
• kotlinCompilerExtensionVersion in composeOptions (removed in Kotlin 2.0+)
• kapt annotation processor instead of KSP
• ViewModel drilled through composition instead of hiltViewModel() at the screen root
• remember { mutableStateOf() } outside a @Composable function
• runBlocking { } on the main thread
• Side effects in composition body without LaunchedEffect / DisposableEffect / SideEffect
• Java-style getX() / setX() accessors instead of Kotlin properties
• Heavy work in the composition body (large map / filter) without remember
• Log.d calls scattered through the codebase
• Hardcoded versions in module build.gradle.kts instead of libs.versions.toml

Install

git clone https://github.com/RoninForge/roninforge-kotlin-compose.git ~/.cursor/plugins/local/roninforge-kotlin-compose

Or copy into your project:

git clone https://github.com/RoninForge/roninforge-kotlin-compose.git
cp -r roninforge-kotlin-compose/rules/* your-project/.cursor/rules/
cp -r roninforge-kotlin-compose/skills/* your-project/.cursor/skills/
cp -r roninforge-kotlin-compose/agents/* your-project/.cursor/agents/

What's Included

Rules (5 files)

Rule	Scope	What it does
compose-core	Always active	Kotlin 2.x + kotlin-compose plugin, Material 3, state hoisting, StateFlow + collectAsStateWithLifecycle, Hilt, type-safe Navigation Compose, KSP, Version Catalogs, BOM
compose-anti-patterns	Always active	20 regressions: findViewById, setContentView, GlobalScope, LiveData, public MutableState, !!, lowercase composables, LazyColumn without key, LaunchedEffect(true), Material 2, modifier order, kotlinCompilerExtensionVersion, kapt, runBlocking, side effects in composition
compose-architecture	**/*.kt	Feature modularization, repository + data source, sealed UI state, ViewModel + stateIn, Ktor + Kotlin Serialization, Room with Flow + KSP, structured concurrency
compose-performance	**/*.kt	Strong-skipping (Kotlin 2.x default), @Stable / @Immutable, remember keys, derivedStateOf, LazyColumn key + contentType, deferred reads
compose-testing	Agent-requested	createComposeRule, semantic matchers, ViewModel tests with runTest + Turbine, fake repositories, Hilt tests, Paparazzi screenshots

Skills (4 commands)

Skill	Command	What it does
New screen	/compose-new-screen	Scaffold stateless Screen + stateful Route + ViewModel + sealed UI state + nav route + previews + test
Migrate Views to Compose	/compose-migrate-views-to-compose	Per-screen migration from XML/Activity to setContent + Route + Screen, with View-to-Compose component mappings
Validate	/compose-validate	Scan codebase for the 20 tracked anti-patterns, report by severity
Modernize build	/compose-modernize-build	Move to Kotlin 2.x: introduce libs.versions.toml, apply kotlin-compose plugin, kapt to KSP, BOM, Material 3, target SDK 36

Agent (1 subagent)

Agent	What it does
compose-reviewer	Reviews Kotlin/Compose code by severity: critical (crashes, build breaks), warnings (regressions), suggestions (style + performance)

What Makes This Different

The existing .cursorrules for Android cover style ("write idiomatic Kotlin"). None of them:

• Force the kotlin-compose plugin and reject kotlinCompilerExtensionVersion (Kotlin 2.0+ requirement)
• Enforce Material 3 imports (every legacy project leaks androidx.compose.material.*)
• Push collectAsStateWithLifecycle() over collectAsState()
• Catch the Modifier.padding(...).clickable { } dead-zone bug
• Teach type-safe Navigation Compose with @Serializable routes
• Bundle a build-modernization skill for the catalog + KSP migration

Fixtures

tests/fixtures/anti-pattern-sample/ is an Activity + XML + LiveData + GlobalScope + Material 2 mess. tests/fixtures/correct-sample/ is the Compose-only + ViewModel + StateFlow + Material 3 + Hilt + Version Catalog equivalent.

License

MIT - see LICENSE

Links

• Jetpack Compose April 2026 release
• Kotlin releases (2.x series, K2 + Compose plugin moved in 2.0)
• Compose Compiler Gradle plugin
• Type-safe Navigation in Compose
• Material 3 Adaptive
• Cursor Plugin Documentation
• RoninForge