if you're building an agent or a harness, you need to be an order of magnitude closer to the code than you would be normally
models are VERY bad at building harnesses & agents - not sure if it's lack of training data or smth else
but they have exceptionally bad intuitions about context management and the agent loop and caching and a lot of other components that matter a LOT
it is very high-leverage to design the code yourself - if not typing it by hand, still do the program design yourself