@daedelConfused about tools in game. Is it necessary to have proficiency in any of them to use them? nope – you can still use them, just without the proficiency bonus
— Mike Mearls (@mikemearls) August 26, 2014
@daedel but what about thieves tools? do you require prof to pick locks and disarm traps? No info in the sourcebook about this. nope, anyone can try. you might need the tools to attempt it, or you might attempt at disadvantage if the DM so rules
— Mike Mearls (@mikemearls) August 26, 2014