It is made from one's understanding of their weapon's dao. It is like a spirit masters' comprehension or understanding regarding their weapon like thinking the weapon as an extension of yourself and not a separate entity. By merging their conscienceness, entirely new skills similar to soul skills can easily be replicated without the need of a soul ring.
This is not limited to only people with tool spirit either. Though it is more difficult at times, cultivating intent is also possible with any weapon.(including one's own fists)
Weapon intent is a form of energy similar to spiritual intent, and can be injected into targets to apply various effects. It can also be used to enhance the characteristics of one's weapon, in a meta-physical manner. (I.e. swords will become sharper, hammers will become heavier)
Intent can be divided into four stages:
[Weapon Name] Consciousness
[Weapon Name] Soul
[Weapon Name] Spirit
[Weapon Name] God