"Baseline" is subjective, so I'd recommend just start a global rules file and steer it away from the behaviors you don't like. Don't be afraid of quizzing the agent itself on why it did that thing, and what's a good bit of language to add to the rules file to prevent it from happening.

Also, for specific tasks, skill files are really useful, and LLMs can write the whole thing, based on what you did the hard way in a session. Same thing for triggering a skill file and then ask it if there are any useful improvements to make to the skills file in the future, at the end of the session.