[zmj]

My experience with agents in larger / older codebases is that feedback loops are critical. They'll get it somewhere in the neighborhood of right on the first attempt; it's up to your prompt and tooling to guide them to improve it on correctness and quality. Basic checks: can the agent run the app, interact with it, and observe its state? If not, you probably won't get working code. Quality checks: by default, you'll get the same code quality as the code the agent reads while it's working; if your linters and prompts don't guide it towards your desired style, you won't get it.

To put that another way: one-shots attempts aren't where the win is in big codebases. Repeat iteration is, as long as your tooling steers it in the right direction.