Requirement
One thing the result must do, stated so that someone could check it. "apply ignores an event older than the newest one for that order" is a requirement. "Handle events properly" is a wish.
An agent reads a wish as permission to decide. But plenty of real requirements change nothing either: on payment-events, every vague attempt dropped repeated events without being told. Spend your words on what the model wouldn't have done by itself.
Say it to your agent
“Rewrite these as requirements I can check: each one names the input and the exact result. Flag any line you can't turn into a check and ask me about it. Leave "should be fast" alone until I give you a number.”