Long-term agent memory can preserve goals and lessons across months without storing a complete behavioral diary, if products separate commitments from raw life logs.
AI NPC memory can turn repeated encounters into meaningful relationships, but only when the system remembers the right events, forgets safely, and lets players understand what persists.
Persistent AI characters need more than a persona prompt. They need stable identity constraints, evolving episodic state, contradiction handling, and regression tests that survive months of interaction.