1 entree or combo meal, and one non-alcoholic beverage. No dessert. If you choose to use a credit for breakfast, you are essentially giving up the dessert allotment.
Resort CS, if you prefer, will allow a continental breakfast consisting of one baked good, one piece of fruit, and one non-alcoholic beverage.
Some park CS like Main Street Bakery seem to do their own thing. Not sure they've moved to the 1 baked good, 1 piece of fruit and 1 beverage model.
Cereal plus milk counts as a CS meal. Used to be you could get it as a snack.