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MUST read this skill BEFORE developing VR/MR/browser-first 3D applications using IWSDK (Immersive Web SDK). Covers project scaffolding, headless browser setup, CLI tools, reference system, ECS debugging, XR emulation, verification workflows, deployment, and known issues.

Test audio system (AudioSource loading, playback state, stop, spatial audio) against the audio example using the iwsdk CLI.

Test ECS core functionality (system registration, components, Transform sync, pause/step/resume, system toggle, entity discovery, snapshots) against the poke example using the iwsdk CLI.

Test environment system (DomeGradient, IBLGradient, default lighting, component schemas) against the poke example using the iwsdk CLI.

Test grab system (distance grab, one-hand grab, two-hand grab) against the grab example using the iwsdk CLI.

Test XR interactions (ray, poke/touch, dual-mode, audio, UI panel) against the poke example using the iwsdk CLI.

Test level system (LevelRoot, LevelTag, default lighting, scene hierarchy) against the poke example using the iwsdk CLI.

Test locomotion system (slide, snap turn, teleport, jump) against the locomotion example using the iwsdk CLI.

Stream, video frames, photo capture, resolution/frame rate configuration

Swift patterns, async/await, naming conventions, key types for DAT SDK iOS development

Common issues, Developer Mode, version compatibility, state machine diagnosis

Display capability setup, display-capable device selection, UI DSL, icons, buttons, images, and video playback

SDK setup, Swift Package Manager integration, Info.plist configuration, and first connection to Meta glasses

MockDeviceKit for testing without physical glasses hardware

App registration with Meta AI, camera permission flows

Building a complete DAT app with camera streaming and photo capture

Session and Stream capability setup, video frames, photo capture, resolution and frame rate configuration

Kotlin patterns, DatResult, session and capability conventions for DAT SDK Android development

Common issues, Developer Mode, version compatibility, and session and stream diagnosis

Display capability setup, display-capable device selection, UI DSL, icons, buttons, images, and video playback

SDK setup, Gradle integration, AndroidManifest configuration, and first connection to Meta glasses

MockDeviceKit for testing without physical glasses hardware

App registration with Meta AI and device permission flows

Building a complete DAT app with session creation, camera streaming, and photo capture

Use when adding new error messages to React, or seeing "unknown error code" warnings.

Use when feature flag tests fail, flags need updating, understanding @gate pragmas, debugging channel-specific test failures, or adding new flags to React.

Use when you have lint errors, formatting issues, or before committing code to ensure it passes CI.

Use when you need to check feature flag states, compare channels, or debug why a feature behaves differently across release channels.

Use when you need to run Flow type checking, or when seeing Flow type errors in React code.

Use when you need to run tests for React core. Supports source, www, stable, and experimental channels.

Use when you want to validate changes before committing, or when you need to check all React contribution requirements.

Rules for writing and reviewing GC-safe C++ code in the Hermes VM runtime. Use when writing, modifying, or reviewing C++ runtime VM code that uses internal Hermes VM APIs (as opposed to code using JSI). This includes working with GC-managed types (HermesValue, Handle, PinnedValue, JSObject, StringPrimitive, etc.), Locals, GCScope, PseudoHandle, CallResult, or any function with _RJS suffix. Typically in lib/VM/, include/hermes/VM/, API/hermes/, or API/napi/.

Guide for adding new JSI functionality to the JavaScript Interface (JSI) layer. Use when the user asks to add, create, or implement new methods or features in the JSI Runtime interface. Covers all required files across JSI core, Hermes implementation, and SynthTrace replay support.

This skill should be used when the user wants to analyze hermesvm binary size changes across a range of commits. Use when the user mentions "binary size", "size analysis", "size regression", "size increase", or asks to measure how commits affect the hermesvm library size.

Use when needing to reorder, split, drop, or amend git commits that are not the top commit, without interactive editor access. Covers programmatic rebase via GIT_SEQUENCE_EDITOR, commit splitting with automated hunk selection, and metadata changes (author, message, dates) on any commit in a range.

Guide for adding a new IR instruction to the Hermes compiler. Use when the user asks to add, create, or define a new IR instruction (Inst/Instruction) in the Hermes intermediate representation. Covers all required files and the patterns for each.

Use when you need to understand the Pyre or Pysa codebase architecture, find where specific functionality is implemented, or navigate the source directory structure. Use when working on OCaml code, debugging type checking or taint analysis issues, or exploring the codebase.

Use when creating commits or diffs to apply the correct title prefix, reviewer, and test plan based on the area of the codebase being changed.

Use when debugging a Pysa false negative (missing taint issue), comparing two Pysa output directories, or finding where taint flow is lost.

Use when running, debugging, updating, or creating Pysa end-to-end integration tests. Use when taint analysis tests fail, when expected output files need updating, or when working with .models, .cg, .hofcg, .overrides files under `source/interprocedural_analyses/taint/test/integration`.

Use when reading, writing, or debugging Pysa JSON model output (.models files). Use when working with taint models that describe sources, sinks, TITO, sanitizers, or issues in JSON format.

Design documentation for the OpenZL component registry located under tests/registry. **USE AUTOMATICALLY** whenever editing files under tests/registry/.

Design patterns and requirements for OpenZL codecs (located under `src/openzl/codecs/`). **USE AUOMATICALLY** when creating, modifying, or reviewing codecs in OpenZL.

Use when creating benchmark scenarios for new openzl codec nodes in unitBench - adding kernel-level encode/decode benchmarks or graph-level compress/decompress benchmarks for codecs like bitsplit, delta, transpose, entropy, etc.

Best practices for writing idiomatic Relay code. ALWAYS use this skill when writing or modifying React components that use Relay for data fetching. Covers fragments, queries, mutations, pagination, and common anti-patterns. Use when you see `useFragment`, `useLazyLoadQuery`, `usePreloadedQuery`, `useMutation`, `usePaginationFragment`, `graphql` template literals, `react-relay` imports, or `__generated__/*.graphql` files. Also use when asked to explain Relay concepts, debug Relay issues, or review Relay code.

Write and run markdown-driven e2e tests for Relay. Covers fixture format, server/client code patterns, interaction DSL, snapshots, and running tests.

Reorder Rust file declarations to match OCaml source order. Use when porting OCaml to Rust and declarations are out of order, or when asked to fix ordering to match OCaml.

Load FIRST before searching code in eden/. Contains component-to-file maps, key type names, and architecture diagrams for EdenFS, Sapling, and Mononoke. Tells you exactly which files to read for any task. References contain per-component quick reference tables.

Port a PyTorch model to use pyrefly's tensor shape type system (Tensor[B, C, H, W], Dim[T]). Use this skill whenever the user wants to add shape annotations to a PyTorch model, type a model with tensor dimensions, port a model to use shape tracking, or annotate model forward methods with tensor shapes. Also use when the user mentions tensor shape ports, Dim types for PyTorch, or pyrefly shape checking on a model file. Invoke BEFORE starting any model port — the skill's gated workflow prevents common failure modes.

Guide users through writing their first Buck2 rule to learn fundamental concepts including rules, actions, targets, configurations, analysis, and select(). Use this skill when users want to learn Buck2 basics hands-on or need help understanding rule writing.