We've all been talked into using foil for lots of campfire cooking.
It's all fine and good if you gather your scrap foil, wash it, throw it in your forge, and roll it into sheets again. But most of us don't have time for that sort of thing.
I've found there's plenty of situations where it (or any other utensil) is unnecessary as long as you can maintain a sizeable bed of coals. This is best done by separating the upwind and downwind side of the fire with a large log. The downwind side is for burning wood to make more coals, which you dig out under the log to bring over the upwind sid