When tools break, there's a handy alert to let you know. If there is a functional Tinkertool in inventory, could this alert also ask if you want to repair the broken tool now? "You done broke your $tool! Repair it now? [yes/no]" That would save me a few clicks of hunting through my inventory for the broken tool so that I can repair it.
If there's no functional tinkertool in inventory, maybe the alert could just say "You done broke your $tool! You'll need a working Tinkertool to repair it"
ETA: there should probably be some info about how much energy/time the repair will take in there, too.