> Most important of all, everything must be setup so the agent can iterate, test and validate it's changes.

This was the biggest unlock for me. When I received a bug report I have the LLM tell me where it thinks the source of the bug is located, write a test that triggers the bug/fails, design a fix, finally implement the fix and repeat. I'm routinely surprised how good it is at doing this, and the speed with which it works. So even if I have to manually tweak a few things, I've moved much faster than without the LLM.