20.4The most important AI rule

Put something like this in your project's agent instructions:

BUSINESS RULE SAFETY

Never invent missing business behavior.

If a required behavior is not explicitly documented:
1. Mark it UNRESOLVED.
2. Describe the decision needed.
3. Provide reasonable options and consequences.
4. Do not implement a business-semantic choice until resolved.

Technical implementation choices may be made independently when they
do not change observable business behavior.

This rule alone prevents a lot of AI-created nonsense.