What Would You Ask an AI to Do in Every Prompt?

I'm referring to the way some AI agents let you add a rule that applies to every conversation, and the AI will follow that rule every time you interact with it. Is it necessary to set up such rules in agents?

I used to add a rule that reminds the AI to commit code every time it modifies code or documentation, following a set of git commit conventions. The second rule I often add tells the AI to update AGENTS.md whenever it changes any functionality in the overall project.