Believable AI should not react to information it could not know. A perception layer turns events into observations; a belief layer decides what the agent currently thinks is true.
Sight is more than a raycast
Use distance, field of view, occlusion and update frequency deliberately. Peripheral detection can accumulate slowly. Stagger expensive checks across agents.
Sound needs semantics
Carry location, strength, age and category. Footsteps, gunfire and a warning should not be interchangeable. Zones can approximate walls and floors without full acoustics.
Memory creates fair uncertainty
Store last-known position and observation time. Confidence should decay or be invalidated by evidence. Epic documents perception update events and ageing; projects still need game-specific belief rules.
Expose knowledge
Debug views should show stimuli, affiliation, age, confidence and the belief used by decision logic. Player-facing cues make changes legible. Feed results into a readable decision layer.