Strangely, I found that LLMs responds better to philosophical explanations alongside instructions when writing code than simple imperative tasks of "do this". For example, if you tell a frontier model "This is the feature I'm trying to implement, and this is the problem I intend to solve with it and the reasoning behind it.", you usually get a lot more reliable results that both pass tests as well as function as you intended, even if your spec isn't as detailed overall.