It is hard to do any leather project without tools of some kind. At least you will need a knife to cut the leather, but you do not need a special round knife or half-moon knife. Nor a fancy-schmancy Vergez Blanchard, even though they look nice!

I quite like this one below: a Presch folding knife with easily exchangeable blades. It is sharp and is nice to use.
But I have also used the traditional scalpel for many years.