Can I customize Unity editor to add button to copy files?

I have a bunch of assets in an /art directory which I would like to copy to my Unity project’s /Assets directory after I’ve edited them. It would be nice if I could add a button or a menu command or something to the Unity Editor UI to run a script to copy the files. Is there a way to customize Unity to do this?

Okay, I’ve found the editor API. I should be able to use this.