Prosecutors and rehab officials are warning Chris Brown: Don't eff this up!

Breezy was given permission to leave his live-in anger management rehab to attend a three-hour charity toy drive event tomorrow (Dec. 22) because his rehab facility thought it'd be a good experience for him and for his treatment. But if he pulls any punches, he's in deep doodoo.

TMZ reports that Brown will be on a very tight leash with his Malibu rehab facility for the excursion. The facility is giving him only just enough time to get to and from the three-hour toy drive, leaving him no opportunities to hang with pals or get into trouble (well, hopefully) in the meantime.

What's more, the rehab facility let Brown know that if he's late coming back after the event, he's out for good. Breezy was already kicked out of rehab once, and if it happened again, he's pretty likely to end up behind bars -- because rehab is the only thing keeping him out of jail. Brown's probation was revoked, which could have landed him in prison, but he was allowed to stay in in-patient anger management because his judge thought he was progressing well.

Another tidbit? Breezy will be drug tested upon his return, so no funny business can go down! Here's hoping Brown behaves himself.