While Cursor always sends your rules to the model and has had some significant work put into ensuring the model respects the rules you give, the models still may choose to ignore them or only partially follow them, especially depending on the contents of the rules.
If anyone doesn’t think their rules are being included / followed, we can investigate this with a non-privacy mode request ID, as this will enable me and the team to see what the model was sent and what it’s output was!