Not even SotA models are good enough to generate code (beyond functions or small, very simple modules) that I'd be happy shipping, so I've decided to just not have them do that. And given this, it has basically turned out that what's left is information gathering + analysis + design overview stuff.

I've just recently started trying out DeepSeek 4 Flash and I was very skeptical at first because I've had some really good experiences with GPT-5.{4,5}, and couldn't possibly believe that this model they charge nothing for could give me similar results, but it absolutely shreds through things and ends up giving me very good answers in almost no time. I also like that it doesn't really seem to have much personality, it's given me mostly just facts and data so far without any additions to the prompt by me.

In my own agent I also specifically prompt to remove flowery language, snark, etc., but I haven't tried it with models like GPT-5.x which I've found has too much personality and tries to make it seem like I'm talking to a human too much.