From my experience, you can't trust the agent to do the entire thing unless you set up very heavy linters, quality control systems (e.g. SonarQube) and a long etc. of things because AI tends to produce pretty bad code: repetition, unused code, lack of structure... basically all the things that we've spent decades learning not to do. And then there is the point where you get a pretty obscure bug that you can only solve if you have a deep understanding of the code which you won't have because you delegated that to an agent.

I like agentic programming, I use it, but I review everything that the agent does and frequently spend a few cycles simply telling the agent to refactor the code because it constantly produces technical debt.