To me personally, the defining element is some aspect of reasoned thinking and adaptation.

Hermit crabs use shells and beavers build dams because they are evolutionarily predisposed to do those things - so to me that isn’t true tool use.

On the other hand, when we see ravens using sticks to fish things out of small holes, or dropping shells in the road so cars will crush them open, that’s genuine tool-using because, they are applying logic to solve problems in novel ways with what they have available in the environment.