I have gotten a lot of mileage out of giving LLMs narrow focus over the same plan or code change with different objectives. Write a plan, ask the agent to review the plan and consider where code can be consolidated. Consider downstream effects. Consider security risks, consider optimization, consider architectural concerns, etc. Then I generate the code and go through a similar loop. Then I read code and do more loops to clear out any problems or investigate things I'm unclear about.

In this way I spend most of my time building understanding of existing code and understanding the impact of my changes. My company is heavy into AI use and I find I am pushing out more code and much cleaner code than most. The gaps that appear during review are usually product understanding gaps and not code failures, and my LLM spend is somehow less then most.

I find this iterative process is much more inline with building flow than spending 3 hours writing a spec and wait a half hour for it to build a monolith PR.