Organic personality development through self-observation. Teaches agents to notice their own behavioral patterns, develop authentic character traits, and grow a genuine identity over time. Use when (1) setting up a new agent that should develop personality, (2) the agent wants to reflect on its own behavior, (3) reviewing or updating the agent's self-model, (4) running periodic self-reflection during heartbeats. Works alongside SOUL.md (who you are) by adding SELF.md (who you're becoming). No forced introspection — only genuine observations.