Could you settle this argument for us, please — if you are proficient in smith's tools, are you able to smith magic items (swords, shields, armour), provided you are at the correct level and have the requisite materials and time?
I’ve read through Xanathar’s Guide to Everything, the DMG, and the Player’s Handbook. Page 129 of Xanathar’s says you need the proficiency, or Arcana.
My interpretation is that you need just one, so you are able to smith magic items as long as you are proficient in smithing and have the requisite materials, but it obviously won’t be able to make anything that has spell effects, like invisibility, since I cannot cast that.
The other party’s interpretation of Xanathar’s is that you need Arcana as well as the tool proficiency.