1. Yes. I've spent several late nights nudging Cline and Claude (and other systems) to the right answers. And being able to use AWS Bedrock to do this has been great (note: I work at Amazon).
2. I've had good fortunes keeping the agents to constrained areas, working on functions, or objects, with clearly defined (by me) boundaries. If the measure of a junior engineer is that you correct them once a day, an engineer once a week, a senior once a month, a principal once a quarter... Treat these agents like hyper-energetic interns. Nudge frequently.
3. Standard org management coding practices apply. Force the agents to show work, plan, unit test, investigate.
And, basically, I've described that we're becoming Software Development Managers with teams of on-demand low-quality interns. That's an incredibly powerful tool, but don't expect hyper-elegant and compact code from them. Keep that for the senior engineering staff (humans) for now.
(Note: The AlphaEvolve announcement makes me wonder if I'm going to have hyper-energetic applied science interns next...)