People tested it, teased it, challenged it, praised it, feared it, and shared screenshots. Three and a half years later, the novelty has become infrastructure. AI now sits inside search engines, office software, customer-service platforms, coding environments, writing tools, and corporate workflows. That shift has created a new managerial problem: agency decay. Agency decay is the gradual erosion of a person’s ability and willingness to observe carefully, think independently, choose deliberately, and act responsibly. It does not arise because AI is inherently harmful. It arises when convenience becomes the default setting for cognition. A tool that first helps us think can begin to think around us, then for us, then without us noticing what has been weakened.