I also do that and it works quite well to iterate on spec md files first. When every step is detailed and clear and all md files linked to a master plan that Claude code reads and updates at every step it helps a lot to keep it on guard rails. Claude code only works well on small increments because context switching makes it mix and invent stuff. So working by increments makes it really easy to commit a clean session and I ask it to give me the next prompt from the specs before I clear context. It always go sideways at some point but having a nice structure helps even myself to do clean reviews and avoid 2h sessions that I have to throw away. Really easier to adjust only what’s wrong at each step. It works surprisingly well