Comment by dudeinhawaii

I'm curious how you're prompting. I've performed this sort of dramatic update in both one-shot (Gemini 2.5/o3) and Leader/Agent (ask 2.5/o3 for a detailed roadmap) and then provide that to Claude to execute as an agent.

I find the key is being able to submit your entire codebase to the API as the context. I've only had one situation where the input tokens were beyond o3's limit. In most projects that I work with, a given module and all relevant modules clocks in around 50-100k tokens.

When calling via API, it also means you want to provide the full documentation for the task if it's a new API, etc. This is where the recent o3 price decrease is a godsend.