A better way to phrase the sentence is like this:
- I would like you to keep quiet about me leaving until I tell the boss.
This sentence means that you are leaving your current job but that you haven’t told your boss yet. You are asking your friend or colleague to keep quiet or to keep it a secret until you tell your boss.
I wouldn’t use the present perfect simple I have told as it is used to refer to an a completed action in the past.
