Skill Claude CodeCodex
Use when a task asks for a model, a score, a forecast or a prediction-driven feature — pin down the decision, target, unit, prediction time, metric and baseline before writing any modelling code.
Skill Claude CodeCodex
Use when writing tests for data or ML code — what to test at each layer (transforms, schemas, properties, pipeline smoke, model-quality thresholds, determinism and parity), how to build small synthetic fixtures, and what not to test.
Skill Claude CodeCodex
Use when a model is served online (FastAPI, BentoML) or scored in batch, when changing how a model artifact is loaded or versioned, or when adding drift, quality or prediction monitoring and a rollout plan for a new model.
Skill Claude CodeCodex
Use when training, tuning, comparing or evaluating a model — choosing the cross-validation scheme, baselines, tuning inside CV, thresholds and calibration, per-slice metrics, feature importance and error analysis.
Skill Claude CodeCodex
Use when writing or changing analytical SQL or a dbt model — CTE structure, window functions, grain and join correctness, dbt data tests, unit tests, contracts and incremental models, and how to run them.
Skill Claude CodeCodex
Use when designing or analysing an A/B test, computing power or sample size, testing whether a difference is real, or writing any statistical claim — effect sizes with intervals, SRM checks, multiple comparisons and causal caveats.
Skill Claude CodeCodex
Use when writing Bevy (Rust ECS) game code - pin and respect the repo's minor version, plugins/systems/queries/resources, schedules with FixedUpdate and Time, states and run conditions, messages vs observers across versions, required components, testing systems with App::update and a manual time strategy, compile-time…
Skill Claude CodeCodex
Use when adding or changing tuning values, items, enemies, abilities or levels - put them in the engine's data assets (ScriptableObject, Resource, DataAsset/DataTable, JSON/RON) with validation and stable IDs, keep runtime state out of shared data, inject services instead of singletons, and test data invariants.
Skill Claude CodeCodex
Use when adding, importing, moving or loading textures, models, audio or scenes - per-platform compression, atlases, LODs, async loading per engine, engine metadata files (.meta, .import, .uid, .uasset), Git LFS, and asset validation tests.
Skill Claude CodeCodex
Use when a game task could run on more than one engine or the repository has no engine yet - read the repo's engine and pinned version, and only for a brand-new game pick one from platforms, 2D/3D, team language, scale and licensing.
Skill Claude CodeCodex
Use when an editor MCP server (unity, godot, unreal, blender) or the browser MCP shows up in your tool list - what each one can observe or change, how to check it is attached to YOUR task workspace, why the repo's tests still decide, the Blender code-execution caution, and the headless fallback when none is connected.
Skill Claude CodeCodex
Use when adding controls, menus, HUD, subtitles or effects - input through named actions with rebinding and controller support per engine, input buffering, and the accessibility floor (remapping, colour-blind safe cues, subtitles, text scale, reduced motion and flashes).
Skill Claude CodeCodex
Use when writing anything that moves, animates, counts down or simulates - per-frame vs fixed-step callbacks per engine, the accumulator loop with interpolation, delta-scaled smoothing, pause and time scale, and determinism.
Skill Claude CodeCodex
Use when touching multiplayer code - authoritative server, client prediction and reconciliation, interpolation, lockstep and rollback, server-side validation of every RPC per engine (Netcode, Unreal replication, Godot multiplayer, Colyseus, Bevy crates), bandwidth and versioned messages.
Skill Claude CodeCodex
Use when touching anything that runs per frame, adding entities/effects at scale, or answering a stutter/frame-drop report - frame budgets per target FPS, per-system split, the profiler per engine, before/after numbers, and threshold tests.
Skill Claude CodeCodex
Use when adding or changing save games, settings or progression storage - a versioned save format with a tested migration chain, atomic writes with backup and checksum, per-engine storage locations, safe serializers, and the round-trip/migration/corruption tests.
Skill Claude CodeCodex
Use when adding character/enemy/game-flow states or NPC behaviour - explicit transition tables instead of flag soup, hierarchical and pushdown machines, behaviour trees per engine, navmesh pathfinding, AI tick budgets, and table-driven tests.
Skill Claude CodeCodex
Use when you are about to hand off a change a player can see - the exact steps to look at it running (web game in the browser at two viewports plus a seeded Playwright smoke run for input and console errors; engine games through a headless frame capture), the checklist, and how to report what could not be observed.
Skill Claude CodeCodex
Use when a Godot project uses or considers C# (.NET) or native code - when C# is the right call and its export limits (no web export), C# node patterns with generated SignalName/StringName caching, plain C# rule libraries tested with dotnet test, and GDExtension (godot-cpp, godot-rust) pinning and build hygiene.
Skill Claude CodeCodex
Use when writing Godot 4 GDScript - static typing everywhere, scene composition with component nodes, call down/signal up, @onready caching, Resources as data duplicated per instance, autoloads only for services, state machines, pooling, physics in physicsprocess, and threaded loading.
Skill Claude CodeCodex
Use when writing or running Godot tests - gdUnit4 or GUT (whichever the repo has), unit tests on typed GDScript classes, scene runners for frames, physics, input and signals, headless CLI with --import first, reports and exit codes, and C# tests via gdUnit4Net or plain dotnet test.
Skill Claude CodeCodex
Use when the repository is Defold, MonoGame, pygame/pygame-ce, Excalibur or KAPLAY (or melonJS, Stride, Python arcade, macroquad/ggez) - each engine's lifecycle and delta, where logic goes, the test runner, the headless build/run command, and how to capture a frame.
Skill Claude CodeCodex
Use when building a 2D web game with Phaser (3.x/4.x) or PixiJS 8 in TypeScript - framework vs renderer, Phaser scenes/game objects/arcade physics/groups as pools/scale manager/loader, scene shutdown cleanup, PixiJS 8 async init, Assets bundles, ticker units and destroy, and keeping rules in plain TS modules.
Skill Claude CodeCodex
Use when working in a Unity project that uses Entities (DOTS) or when a task needs thousands of simulated objects - when ECS is worth it, components/bakers/ISystem with IJobEntity and Burst, entity command buffers for structural changes, native memory rules, and testing systems in a test World.
At most 3 mods per repository are shown here, and a mod shipped inside a plugin is left to that plugin's page — the rest are on their repository pages: