That phrase, “once it was entirely implemented,” is doing a lot of work.

If you go back and read the literature on this stuff, one constant pattern is that technical leaders are repeatedly advocating for iterative development with frequent integration testing, and pushing back against management types’ impulse to favor giant up front over-specified design by committee plans. It’s not a phenomenon that’s unique to software, either.

But managers love meticulous up-front specification because it gives them the illusion of control and predictability. They are always being asked, “How much will it cost? How long will it take?”, and this approach gets you there.

I would argue that that’s the basic instinct behind meticulous up front specification for AI coding projects, too. It makes it easier to believe that, come implementation time, you can reliably one-shot it with an agent and have a working implementation that satisfies all design goals by next morning.