[suttontom]

Models are not innately backwards-compatible. Both OpenAI and Anthropic encourage running evaluations and comparing the performance of your existing agent workflows against new models before just stepping up to the newest one because you may encounter regressions. I myself have seen lengthy/long-horizon multi-agent workflows begin breaking after moving to a newer model because for some reason the prompt containing an instruction to call a tool that worked 99/100 times before suddenly just stops working and needs to be modified.