But another thing I have found is that I get significantly better results from the LLM by treating it like an intelligent independent agent. All of the "you are a senior dev ..." or "your starving kids depend on the correctness of this answer ..." kind of prompting has been mostly useless. In general, I find being honest and clear to be the best strategy.

You can't "pretend" to be a senior software engineer. If I can root you out of an interview process then you aren't going to fool the LLM. But if you clearly state your level of expertise and your desired outcome, then the LLM does a very good job of meeting you where you are.

There is also a strange ephemeral attitude I get from agents sometimes, like they don't like to be called out for being wrong. But in the same way that human's show this trait, they also seem to warm up over time as they gain trust. It is almost like social positioning, once they realize they aren't actually expert they morph into a support role stance pretty seamlessly. That is also why they can still feel sycophantic, because once they realize they aren't actually driving the discussion they can actually feel like enthusiastic passengers, wanting to see where the conversation leads as much as the prompter.