Comment by QuercusMax

Part of the value of LLMs and humans is nondeterminism. Pair nondeterministic output with strictly verified results (proper tests) and you can create a useful working system.

Humans can't build a system perfectly, and agents definitely can't. And agents (like humans) will build a different system every time even with the same prompt. Even if it's just trivial differences like array vs linked-list, there are still differences.

The value in having executable code is that it won't change its behavior unless you deliberately modify it. I don't think there are any shortcuts. Models will get smarter and smarter and make fewer mistakes, but you'll still want to produce real source code to execute because it's consistent (you can sell it as a product, set it and forget it, etc.), and most importantly:

running real code is orders of magnitude faster than having an AI either run the process "manually", or have it write the code out multiple times.