What is Brooks's law?

Example: You built a morning planning agent, then an evening review agent, then a weekly reflection agent, then a reading curation agent, then a health tracking agent, then a relationship maintenance agent, then a financial review agent. Each one seemed worthwhile when you created it. But now you spend forty minutes a day just running the agents — checking outputs, feeding inputs between them, resolving conflicts when the health agent says to sleep early and the reading agent has queued three articles for tonight. The agents are not failing individually. The system they form is failing collectively, because the overhead of coordinating seven agents exceeds the value any three of them produce.

This concept is part of Agent Lifecycle in the How to Think curriculum.