Use whenever working with Figma — implementing UI from a Figma URL or design, calling any Figma MCP tool (get_design_context, get_screenshot, get_metadata, get_variable_defs, use_figma), translating designs to code, picking colors/typography/spacing from a design, exporting assets, or verifying a screen against Figma. Covers resolving tokens from the actual node, render-verifying before specing, high-res asset export, and recovering transparent per-layer exports.
Use when modifying existing code — after adding a guard, null-check, error branch, or fix to one handler/function (grep sibling call sites for the same gap before declaring done), and when encountering an empty or TODO/placeholder config value (don't substitute a guessed value). Prevents half-applied fixes and papered-over placeholders.
Use when writing or modifying any @Composable, Compose UI, or state — Modifier chains (size/width/height/padding), LazyColumn/LazyRow/LazyGrid, mutableStateOf, rememberSaveable, rememberCoroutineScope, LaunchedEffect, DisposableEffect, LifecycleResumeEffect/StartEffect/EventEffect, BackHandler, WindowInsets/safeDrawing, Snapshot.withMutableSnapshot, IconButton/Surface touch targets (48dp), @Preview composables, UDF state hoisting, lazy-layout keys, iOS system permission dialogs, navigation route argument types, dismissing a Dialog before presenting a native modal, one-shot preselect effects, and keyed remember caches.
Use whenever adding, editing, or deleting any Compose Multiplatform resource — strings.xml entries, plurals, drawables (WebP/PNG/SVG), ImageVectors, fonts, anything under composeResources/ — or modifying call sites that reference Res.string.*, Res.drawable.*, Res.font.*, stringResource, pluralStringResource, painterResource. Covers image format selection, naming, sizing, apostrophe escaping (don't `\'` in CMP), positional plural specifiers (`%1$d` not `%d`), the per-resource imports CMP requires for every Res.* accessor, brand illustrations vs. ImageVector glyphs, and verifying WebP alpha after encoding.
Use when running git commands that touch a subset of changes — git stash push with a pathspec while the index has staged-added (new) files, or generating/applying patches that include binary files. Prevents stashes that silently capture every staged-add and binary patches that fail to apply.
Use when running or verifying Gradle builds — capturing pass/fail correctly from a gradle invocation (shell pipe exit-code masking), and the Kotlin Multiplatform iOS resource pipeline serving stale composeResources content after a content-only edit. Prevents false "build passed" claims and shipping stale iOS resources.
Use when writing or modifying any Kotlin code — data classes, sealed interfaces/classes, enums (and never relying on `.name` for persistence), value classes, interface delegation, annotations, `Pair` construction, list construction (`List(size) { }` vs `mapIndexed`), explicit backing fields (`-Xexplicit-backing-fields`) vs the `_foo`/`foo` pattern, wildcard or unused imports, `throw` vs `Result<T>` for error handling, `kotlin.time` Duration/Instant APIs, KMP native-SDK wrappers, Kotlin/Native generic type erasure of same-typed parameters at the iOS boundary, file naming, where to put mappers, extension functions on stdlib types, derived members vs. top-level extensions, DI-injected helper classes, code comments that reference other modules, formatter (ktfmt) preferences, and `expect`/`actual` class constructors.
Enforces coroutine safety when writing suspend functions, Flow, runCatching, Dispatchers, coroutineContext, or ensureActive. Prevents CancellationException suppression. Also covers platform implementations owning their own thread dispatch, not re-wrapping suspend functions that are already main-safe, and avoiding async work in constructors/`init` (including ViewModel `init`).