One of my players wants to build a forge (see How much gold would the construction of a forge cost?).
I explained to him how the creation of a magic item works (like a +1 weapon, for example), and he asked me how his proficiency with smith's tools was supposed to help him.
Well, the PHB p.154 says the following:
Proficiency with a set of artisan’s tools lets you add your proficiency bonus to any ability checks you make using the tools in your craft.
But crafting a magic item doesn't require any ability check!
So my question is, what is the purpose of having proficiency with artisan's tools? And more specifically with smith's tools?