NPC Behavior -- Design Translation Patterns

Prerequisite skills: unity-physics-queries (perception raycasts, NonAlloc query patterns), unity-state-machines (decision FSM/BT architecture), unity-game-architecture (event bus, Service Locator, component composition)

Claude's default NPC is a single MonoBehaviour with an Update() that raycasts, decides, and moves all in one method. This is untestable and unextensible -- changing perception logic requires touching decision logic, adding a new sense means rewriting the entire method, and squad coordination is impossible when each NPC is a self-contained island. These patterns decompose NPC behavior into pluggable layers that designers can configure without programmer intervention.

PATTERN: Perception System Architecture

DESIGN INTENT: NPCs sense the world through sight, hearing, and proximity. Different NPC types have different senses -- a guard has long-range sight but poor hearing; a dog has short sight but exceptional hearing. Senses are mix-and-match components that feed a unified target list.