I think I didn't explain myself clearly. I definitely would want to avoid court. But I've heard that many agreements stipulate that one parent has ultimate decision making over education, for example, while perhaps the other has ultimate decision over religious-related things. So, the parties agree to attempt to come to an agreement, but if they can't, there is a default. I'm not sure that running to mediation every time there is an unresolvable conflict is the answer. I don't know.
OK, Claire, I understand better now. And that's something to ask your L about. I have a friend who has been in a knock-down, drag-out D and custody battle for years. Her H is really awful to their 4 kids. At various times over the years, she has had temporary sole decision making, but that has only lasted a few months at a time, even though the XH is a real pig to his kids. And my point is......in this state you would be unlikely to get an agreement of the type you described, I don't know about your state, something to check on.