The law is a hundreds of billions of dollar annual industry, just in the US. It was worth 367 billion just in 2022. An AI that flawlessly checks over a legal brief would probally be worth billions/year because that means it could also write them flawlessly. Since its so easy, you should probally whip it up and make your billions.

Hell, you seem to have a way to solve chatbots persistent error rate that trillion dollar companies can't fix, so you might actually have a trillion dollar answer. Why stop at just law if "its so easy to make a LLM not lie?"