There is another aspect to this, IMO.
If someone were to borrow, or even rent, your tool entirely for their own use, on their own project, entirely for their own profit, then I can see them paying out 100% of the value of the lost tool.
But if your employee, who never had even the possibility of ownership of the tool themselves to begin with, should, in the performance for a wage on one of your jobs, for your profit, through neglect or otherwise lose your tool on that job, then I don't think they should be forced to pay 100% of its value for your continued ownership of the tool.
It's a cost of doing business.
If someone were to borrow, or even rent, your tool entirely for their own use, on their own project, entirely for their own profit, then I can see them paying out 100% of the value of the lost tool.
But if your employee, who never had even the possibility of ownership of the tool themselves to begin with, should, in the performance for a wage on one of your jobs, for your profit, through neglect or otherwise lose your tool on that job, then I don't think they should be forced to pay 100% of its value for your continued ownership of the tool.
It's a cost of doing business.