Games Skill | Agent Skills

Games

You MUST use this skill for ANY game development, SpriteKit, SceneKit, RealityKit, touch controls, game controller, or interactive simulation work.

Quick Reference

| Symptom / Task | Reference | |----------------|-----------| | Building a SpriteKit game | See skills/spritekit.md | | Adding touch controls to a game (TouchController) | See skills/game-input.md | | Game controller input (GCController, polling vs handlers) | See skills/game-input.md | | Controller Home button settings, spatial accessories OS27 | See skills/game-input.md | | SpriteKit API lookup | See skills/spritekit-ref.md | | Physics contacts not firing | See skills/spritekit-diag.md | | Frame rate drops (SpriteKit) | See skills/spritekit-diag.md | | Touches not registering | See skills/spritekit-diag.md | | Memory spikes in gameplay | See skills/spritekit-diag.md | | Coordinate confusion | See skills/spritekit-diag.md | | Scene transition crashes | See skills/spritekit-diag.md | | Objects tunneling through walls | See skills/spritekit-diag.md | | SpriteKit node/action reference | See skills/spritekit-ref.md | | SceneKit maintenance/migration | See axiom-graphics (skills/scenekit.md) | | SceneKit API / migration mapping | See axiom-graphics (skills/scenekit-ref.md) | | RealityKit (3D, ECS, AR) | See axiom-graphics (skills/realitykit.md) | | RealityKit API reference | See axiom-graphics (skills/realitykit-ref.md) | | RealityKit diagnostics | See axiom-graphics (skills/realitykit-diag.md) | | RealityKit 27 game features (navmesh, LOD, splats) | See axiom-graphics (skills/realitykit-ref.md Part 10) | | Long-session game performance tracing (metalperftrace) | See axiom-graphics (skills/display-performance.md Part 12) | | Porting a Mac/Windows game to Metal | See axiom-graphics (skills/metal-migration.md) | | In-game content, asset packs, IAP | See axiom-integration (skills/background-assets.md, skills/in-app-purchases.md) |

External Routes

These topics are part of the broader games/3D domain but live in separate skill suites:

SceneKit (3D — soft-deprecated iOS 26):

Maintenance and migration planning → See axiom-graphics (skills/scenekit.md)
API reference and migration mapping → See axiom-graphics (skills/scenekit-ref.md)

RealityKit (3D — modern):

ECS architecture, AR, SwiftUI integration → See axiom-graphics (skills/realitykit.md)
API reference → See axiom-graphics (skills/realitykit-ref.md)
Troubleshooting → See axiom-graphics (skills/realitykit-diag.md)
27-cycle game-engine layer: navigation mesh + pathfinding, behavior trees, animation graphs, LOD, Gaussian splats → See axiom-graphics (skills/realitykit-ref.md Part 10)

Game performance and porting:

Long-session game traces, metalperftrace CLI, Game Performance Overview template → See axiom-graphics (skills/display-performance.md Part 12)
Metal migration, shader conversion → See axiom-graphics (skills/metal-migration.md)

In-game content and monetization:

Apple-Hosted Background Assets, asset packs, Steam depot conversion → See axiom-integration (skills/background-assets.md)
In-app purchase, StoreKit views → See axiom-integration (skills/in-app-purchases.md)

Decision Tree

digraph games {
    start [label="Game development" shape=ellipse];
    what [label="Which framework?" shape=diamond];
    sprite_what [label="SpriteKit need?" shape=diamond];

    start -> what;
    what -> sprite_what [label="SpriteKit (2D)"];
    what -> "skills/game-input.md" [label="touch controls / game controllers"];
    what -> "axiom-graphics/scenekit" [label="SceneKit (3D legacy)"];
    what -> "axiom-graphics/realitykit" [label="RealityKit (3D modern)"];
    what -> "axiom-graphics/metal-migration" [label="porting (Metal)"];

    sprite_what -> "skills/spritekit.md" [label="architecture/patterns"];
    sprite_what -> "skills/spritekit-ref.md" [label="API lookup"];
    sprite_what -> "skills/spritekit-diag.md" [label="broken/slow"];
}

Building/designing a 2D SpriteKit game? → skills/spritekit.md
How to use a specific SpriteKit API? → skills/spritekit-ref.md
SpriteKit broken or performing badly? → skills/spritekit-diag.md
Adding touch controls, or handling game controller input? → skills/game-input.md
Maintaining existing SceneKit code? → See axiom-graphics (skills/scenekit.md)
SceneKit API reference or migration mapping? → See axiom-graphics (skills/scenekit-ref.md)
Building new 3D game or experience? → See axiom-graphics (skills/realitykit.md)
How to use a specific RealityKit API? → See axiom-graphics (skills/realitykit-ref.md)
RealityKit entity not visible, gestures broken, performance? → See axiom-graphics (skills/realitykit-diag.md)
Migrating SceneKit to RealityKit? → See axiom-graphics (skills/scenekit.md) (migration tree) + See axiom-graphics (skills/scenekit-ref.md) (mapping table)
Building AR game? → See axiom-graphics (skills/realitykit.md)
Porting a Mac/Windows game to Apple platforms? → See axiom-graphics (skills/metal-migration.md)
Unlocking in-game content (asset packs, IAP)? → See axiom-integration (skills/background-assets.md, skills/in-app-purchases.md)
Want automated SpriteKit code scan? → spritekit-auditor agent

Automated Scanning

SpriteKit audit → Launch spritekit-auditor agent or /axiom:audit spritekit

Detects anti-patterns AND architectural gaps:

Physics bitmask issues (default 0xFFFFFFFF, missing contactTestBitMask, magic numbers)
Draw call waste (SKShapeNode in gameplay, missing texture atlases)
Node accumulation and runaway spawn-in-update() without cleanup
Action memory leaks (strong self, .repeatForever without withKey:)
Coordinate confusion (touch.location(in: self.view) instead of in: self)
Silent input dead zones (custom touchesBegan without isUserInteractionEnabled)
Missing object pooling for hot spawns
Missing/ungated debug overlays
Leaked scenes (transition without removeAllActions() and child cleanup)
Missing time-step clamping → spiral-of-death teleports bodies through walls
HUD attached to scene root instead of camera (drifts with scrolling)
Fast bodies without usesPreciseCollisionDetection (tunneling)

Scores: PERFORMANT / DEGRADED / UNPLAYABLE

Critical Patterns

SpriteKit (skills/spritekit.md):

PhysicsCategory struct with explicit bitmasks (default 0xFFFFFFFF causes phantom collisions)
Camera node pattern for viewport + HUD separation
SKShapeNode pre-render-to-texture conversion
[weak self] in all SKAction.run closures
Delta time with spiral-of-death clamping

SpriteKit diagnostics (skills/spritekit-diag.md):

5-step bitmask checklist (2 min vs 30-120 min guessing)
Debug overlays as mandatory first diagnostic step
Tunneling prevention flowchart
Memory growth diagnosis via showsNodeCount trending

Game input (skills/game-input.md):

One GCController pipeline — touch controls surface as a GCController, existing logic unchanged
TCTouchController.isSupported gate + connect/render/touch-routing setup
Half-screen collider shapes for movement and camera (never small circles)
Safe-area-adjusted anchor offsets for fullscreen games
Controller Home button settings + visionOS spatial accessories OS27

Anti-Rationalization

| Thought | Reality | |---------|---------| | "SpriteKit is simple, I don't need a skill" | Physics bitmasks default to 0xFFFFFFFF and cause phantom collisions. The bitmask checklist catches this in 2 min. | | "I'll just use SKShapeNode, it's quick" | Each SKShapeNode is a separate draw call. 50 of them = 50 draw calls. spritekit.md has the pre-render-to-texture pattern. | | "I can figure out the coordinate system" | SpriteKit uses bottom-left origin (opposite of UIKit). Anchor points add another layer. spritekit-diag.md Symptom 6 resolves in 5 min. | | "Physics is straightforward" | Three different bitmask properties, modification rules inside callbacks, and tunneling edge cases. spritekit.md Section 3 covers all gotchas. | | "The performance is fine on my device" | Performance varies dramatically across devices. spritekit.md Section 6 has the debug overlay checklist. | | "SceneKit is fine for our new project" | SceneKit is soft-deprecated iOS 26. No new features, only security patches. axiom-graphics (skills/scenekit.md) has the migration decision tree. | | "ECS is overkill for a simple 3D app" | You're already using ECS — Entity + ModelComponent. axiom-graphics (skills/realitykit.md) shows how to scale from simple to complex. | | "I don't need collision shapes for taps" | RealityKit gestures require CollisionComponent. axiom-graphics (skills/realitykit-diag.md) diagnoses this in 2 min vs 30 min guessing. | | "I'll overlay UIButtons for touch controls" | TouchController renders in your Metal pass and surfaces as a GCController — existing controller logic just works. UIButton overlays mean a second input path and per-frame UIKit cost. game-input.md Section 2. | | "Touch controls = put every controller button on screen" | A 1:1 mapping clutters the play area and demands 3+ fingers. game-input.md Section 5 has the redesign patterns (context icons, hide unused, collapse combos). |

Example Invocations

User: "I'm building a SpriteKit game" → See skills/spritekit.md

User: "My physics contacts aren't firing" → See skills/spritekit-diag.md

User: "How do I create a physics body from a texture?" → See skills/spritekit-ref.md

User: "Frame rate is dropping in my game" → See skills/spritekit-diag.md

User: "What action types are available?" → See skills/spritekit-ref.md

User: "Objects pass through walls" → See skills/spritekit-diag.md

User: "I'm porting my controller game to iPhone and need touch controls" → See skills/game-input.md

User: "How do I handle game controller input?" → See skills/game-input.md

User: "How do I read spatial accessory input on visionOS?" → See skills/game-input.md

User: "I need to build a 3D game" → Invoke: See axiom-graphics (skills/realitykit.md)

User: "I'm migrating from SceneKit to RealityKit" → Invoke: See axiom-graphics (skills/scenekit.md) + See axiom-graphics (skills/scenekit-ref.md)

User: "Can you scan my SpriteKit code for common issues?" → Launch spritekit-auditor agent

Agent Skills: Games

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