Conciseness

The body is lean — terse imperative workflow steps, one-line core decisions, and tight DON'T/DO code fixes with no explanations of concepts Claude already knows. Minor trimmable tokens remain: the intro pins time-sensitive versions ('iOS 26+ using SpriteKit and Swift 6.3') outside any deprecated section, and the self-referential Contents list adds modest padding. Not 5 because of those few non-earning tokens; not 3 because everything else is efficient.

Actionability

Guidance is copy-paste ready and covers the common failure cases: the @State scene vs. per-render GameScene(size:) contrast, 'player.physicsBody?.contactTestBitMask = PhysicsCategory.enemy', and the SKAction.sequence([moveBy, removeFromParent]) pattern are all executable Swift, and even the prose mistakes give exact directives ('Set physicsWorld.contactDelegate = self in didMove(to:)').

Workflow Clarity

The five-step workflow is clearly sequenced with an explicit verification step ('Verify frame-rate behavior, contact delivery, pause/resume, resizing, and scene teardown') and a 17-item Review Checklist. Not 5 because the steps are high-level directives without executable commands and there is no feedback loop telling Claude how to recover when a checklist item fails; not 3 because checkpoints are present and explicit.

Progressive Disclosure

The body is a genuine overview with details appropriately split into two real, one-level-deep bundle files, each clearly signaled with its contents ('Read [core implementation details]... for scene setup, sprites, actions, physics...' / 'Read [extended SpriteKit patterns]... for tile maps, atlases, shaders...'), and the References section aids navigation. Verified that both referenced files exist and contain no nested references.

Specificity

The description lists multiple concrete, API-named actions — 'creating game scenes with SKScene and SKView, adding sprites with SKSpriteNode, animating with SKAction sequences, simulating physics with SKPhysicsBody and contact detection, creating particle effects with SKEmitterNode, building tile maps, using SKCameraNode' — giving comprehensive coverage of the skill's domain.

Completeness

It explicitly answers both questions: 'Build 2D games and animations using SpriteKit' states what the skill does, and 'Use when creating game scenes..., adding sprites..., animating..., simulating physics..., or integrating SpriteKit scenes in SwiftUI with SpriteView' gives concrete trigger phrases for when to use it.

Trigger Term Quality

Natural phrases users would say ('2D games', 'animations', 'sprites', 'physics', 'particle effects', 'tile maps') appear alongside the trigger clause, but the list leans on technical class names (SKScene, SKView, SKCameraNode) and omits common variations like 'iOS game' or 'Swift game development'. Not 3 because several genuinely natural terms are present; not 5 because natural-synonym coverage is incomplete.

Distinctiveness Conflict Risk

SpriteKit-specific class names and tasks ('SKPhysicsBody and contact detection', 'building tile maps', 'SKEmitterNode') carve out a clear niche with distinct triggers; only trivial overlap risk with a general SwiftUI skill, which the 'SpriteView' trigger already disambiguates.