It is not unethical. It is just business.
The other company is a market leader and the idea behind copying this tool is if it works for them it will work for us.
Businesses do this all the time and there is no problem. It is part of how a competitive market functions.
I explained I am concerned about the ethics behind doing this.
My boss got upset and explained that it is neither trademarkable nor copyrightable content -- which I am unsure about but am leaning towards agreeing with,-- and that it's okay to do it.
Your personal ethics don't matter. If there is a legal problem, your company and/or your boss might be responsible, but you wouldn't personally be.
This isn't a generic interface that is used en masse and commonplace known as the best way to do something.
It isn't yet used en masse, but it will be once the competitors catch up, if it is as good as it seems, and not copyrightable, as your boss claims.
Reimplementing the interface might be unethical according to your personal ethics. But not according to "most" people in software, or we wouldn't have software or the web as we do today. Everything is built (and sometimes improved) upon what someone else did, and nobody cares who thought it up first. People care about what is useful.
