It's not exactly a "tool," but put some kind of energy bar in the seat bag in case you need a boost. And the wrapper can serve as an eemergency tire boot.

Also, I generally only carry two tubes if I'm doing > 50 miles. Instead, I carry one extra tube and a patch repair kit. I wrap a little electrical tape around one of my wrenches. You could do the same with duct tape.

Edited to correct type-o: I originally said, "I generally only carry two tubes if I'm doing > 50 mph." I wish.