However, I think producing detailed enough specification requires same or even larger amount of work than writing code. We write rough specification and clarify these during the process of coding. I think there are minimal effort required to produce these specification, AI will not help you speed up these effort.
This is sort of a fundamental problem with all AI. If you tell a robot assistant to "make a cup of tea", how's it supposed to know that that implies "don't break the priceless vase in the kitchen" and "don't step on the cat's tail", et cetera. You're never going to align it well enough with "human values" to be safe. Even just defining in human-understandable terms what those values are is a deep existential question of philosophy, let alone specifying it for a machine that's capable of acting in the world independently.