Similarity Rs
Use when you suspect duplicate or near-duplicate Rust code — writing a utility function that might already exist, copy-paste-modifying a function, creating near-duplicate structs or enums, or running `similarity-rs 0.5` with flags like `--threshold`, `--cross-file`, or `--min-lines`. Also triggers on `cargo install similarity-rs`, reviewing CI duplication gates, or tuning false-positive threshold…
Bevy Migration 0 18 To 0 19
Use when upgrading from Bevy 0.18 to Bevy 0.19, when `TextLayout::new_with_justify` or `TextFont { font_size: 24.0, font: handle }` stops compiling (now `TextLayout::justify`, `FontSize::Px`, `FontSource`), when `bevy_scene`/`DynamicScene` serialization moved to `bevy_world_serialization` (`WorldAsset`/`DynamicWorld`), when a `#[derive(Resource)]` type now also matches `&T` component queries, or…
Bevy Pbr Materials
Use when spawning a mesh with `StandardMaterial`, writing a custom `Material` with `AsBindGroup` and a required `label()` (new in 0.18), wiring `MaterialPlugin<M>` whose `prepass_enabled`/`shadows_enabled` config moved to trait methods, or chasing visual shifts caused by the 0.18 PBR shading fix. Covers Bevy 0.18 PBR materials.
Bevy Animation
Use when wiring `AnimationPlayer` + `AnimationGraphHandle`, building an `AnimationGraph` from glTF clips, blending state-driven animations with `AnimationTransitions::play`, isolating body parts with `AnimationMask`, firing gameplay sync via `#[derive(AnimationEvent)]` + `On<E>` observers, tweening with `AnimatableCurve` / `EaseFunction` / `CubicSegment::new_bezier_easing`, or applying the 12 Bas…
Bevy Wasm Webgpu
Use when targeting `wasm32-unknown-unknown`, picking between the `webgl2` and `webgpu` Bevy features, configuring `wasm-bindgen` glue, sizing down the bundle via `default-features = false`, or hitting "asset 404" errors caused by relative path handling in the browser. Covers Bevy 0.18 WASM build pipeline.
Bevy Ecs Components
Use when defining `#[derive(Component)]`, declaring required components with `#[require(...)]`, writing observers with `On<E>` (NOT `Trigger<E>` — renamed in 0.17), choosing between Table and SparseSet storage, or registering `on_add`/`on_remove` hooks in Bevy 0.18.
Bevy Porting
Use when porting a game project to Bevy 0.18 from another engine — Unity (Prefab, MonoBehaviour, Animator, UGUI), Unreal, Godot, Cocos, vanilla JavaScript / Phaser, Flash/SWF, Defold, Roblox, or GameMaker — and need a mapping of each engine's primitives to Bevy equivalents, plus inventory/extraction scripts to pull assets out of the source project.
Bevy Ecs Systems
Use when deriving `SystemParam`, grouping with `SystemSet`, gating execution with `.run_if(on_message::<M>())` / `in_state(...)` / `resource_exists::<R>`, ordering with `.before`/`.after`/`.chain()`, or removing systems at runtime with `remove_systems_in_set` (new in 0.18). Covers Bevy 0.18 system params, sets, and run conditions.
Bevy Ecs Queries
Use when writing `Query<D, F>` with filters like `With`/`Without`/`Or`, detecting changes with `Changed<T>`/`Added<T>`, parallelising with `par_iter`/`par_iter_mut`, building a query lens with `transmute_lens`, or hitting the new 0.18 `ArchetypeQueryData` bound. Covers Bevy 0.18 query patterns.
Bevy Cameras
Use when spawning `Camera3d` or `Camera2d`, choosing a `Projection`, rendering to an image with the new 0.18 `RenderTarget` component (no longer a `Camera` field), wiring up `FreeCamera`/`PanCamera` from `bevy::camera_controller::*`, or setting a per-camera `AmbientLight` override. Covers Bevy 0.18 camera spawning, render targets, and built-in controllers.
Bevy Custom Assets
Use when implementing `AssetLoader` for a custom file format, depending on other assets via `LoadContext::loader().with_settings(..).load(..)`, hitting the 0.18 requirement to `#[derive(TypePath)]` on the loader, or using `reader.read_to_end(..)` / `seekable()` async access. Covers Bevy 0.18 custom asset loaders.
Bevy Ui
Use when building UI with `Node`, `Button`, `children![]`, `TextFont`, `InputFocus`, `BackgroundColor`, `BorderColor`, or `BorderRadius` in Bevy 0.18. Covers layout, text styling, interaction handling, colors, palettes, accessibility, and the frame-0 `Changed<Interaction>` invariant.
Bevy Voxel Pipeline
Use when meshing voxel chunks with `block-mesh-rs` (`greedy_quads` / `visible_block_faces`), translating a `GreedyQuadsBuffer` into a Bevy 0.18 `Mesh` via `try_insert_attribute`, choosing between greedy and simple meshing, or scheduling chunk meshing on `AsyncComputeTaskPool` so the main thread doesn't stall. Covers Bevy 0.18 voxel meshing.
Bevy Capture
Use when adding `CapturePlugin` to record a `Camera3d` or `Camera2d` to video, spawning `CaptureBundle` on a camera entity, calling `Capture::start` with `Mp4Openh264Encoder` for in-process MP4 encoding, using `Mp4FfmpegCliEncoder` or `Mp4FfmpegCliPipeEncoder` for ffmpeg-backed output, or writing per-frame PNGs with `FramesEncoder` in Bevy 0.18.
Bevy Voxel Data
Use when defining voxel blocks in RON (`name`, `textures`, `flags`), building a runtime palette mapping `BlockId -> BlockDef`, baking per-block textures into a KTX2 atlas, or binding the atlas as `StandardMaterial.base_color_texture` so meshed quads sample by face index. Generic Bevy 0.18 voxel-data patterns — no game-specific data baked in.
Bevy
Use when starting any Bevy task, choosing between Update and FixedUpdate, picking Cargo feature flags, or recalling which sibling skill covers ECS, assets, rendering, or migration. Routes to the right Bevy 0.18 skill and pins the engine version for downstream snippets.
Bevy Migration 0 17 To 0 18
Use when upgrading from Bevy 0.17 to Bevy 0.18, when an LLM writes `EventReader`/`EventWriter`/`Trigger<E>` instead of `MessageReader`/`MessageWriter`/`On<E>`, when `mesh.insert_attribute` fails to compile, when `AmbientLight` no longer works as a resource, or when `Camera { target: ... }` errors on the `target` field. Index of every breaking 0.17→0.18 change.
Bevy Cargo Features
Use when picking Bevy Cargo features for a project — high-level `2d`/`3d`/`ui`, mid-level `2d_api`/`3d_api`/`ui_api` for custom renderers, opting in to `mouse`/`keyboard`/`gamepad`/`touch`/`gestures` with `default-features = false`, or hitting renamed features (`gltf_animation`, `ui_picking`, `mesh_picking`, `reflect_documentation`). Critical for WASM client size in Bevy 0.18.
Bevy Assets
Use when loading anything with `AssetServer`, holding a `Handle<T>`, indexing `Assets<T>`, enabling hot-reload via `AssetPlugin { watch_for_changes_override: Some(true), .. }`, or chasing the 0.18 `LoadContext::path -> AssetPath` and `SeekableReader` changes. Covers Bevy 0.18 asset loading.
Bevy Vfx
Use when adding GPU particles via `bevy_hanabi 0.18.0` (`HanabiPlugin`, `EffectAsset`, `ParticleEffect`, `Module` + `ExprWriter`, modifiers like `SetPositionSphereModifier` / `ColorOverLifetimeModifier`), rendering Gaussian splats via `bevy_spark 0.2.0` for photoreal scene captures, picking between hanabi and lighter sprite-sheet flipbooks, writing custom `Material` + WGSL shaders for fire/water/…
Bevy Core Concepts
Use when wiring up an `App`, writing a `Plugin`, choosing between `Update` and `FixedUpdate`, ordering `Startup`/`PreUpdate`/`PostUpdate`, or writing an exclusive system (`fn(&mut World)`) in Bevy 0.18. Covers the schedule graph, run order, and the `SimpleExecutor` removal.
Bevy Fluent
Use when adding localization to a Bevy 0.18 app with `es-fluent-manager-bevy`, defining typed messages with `#[derive(EsFluent)]`, wrapping UI text in `FluentText<T>`, auto-registering locale updates with `#[derive(BevyFluentText)]`, or reacting to locale switches via `LocaleChangeEvent`. Covers `I18nPlugin`, `RequestedLanguageId`, `i18n.toml` config, and hot-reload of `.ftl` assets.