Yeah you would make a Mold, but it would be way easier to acquire than what I did in GT6. Once you made something, you can make another of the same kind, though I might make it so you can forget about the Recipe if you dont use it for long enough, so that Books and Paper would become useful.
But first you would need to model the Tool, which is where I meant Clay to model the Shape, so you can put the shape into a blank Mold so you can craft it. Sharpening would require a Grindstone likely. And Flint Tools would just be a sharp Rock you can chop wood with or so.
I want Stuff to be easy to craft in general once you designed it for the first time, or took the Design that someone else shared with you. Maybe I make it so you need to buy Designs from NPCs, or get them from Loot, once you dropped the ones shared by your Friends into a Folder.