Comment by bionhoward

> plan mode has always been a prompt — it has never changed the toolset because doing so would break the prompt cache, and so would be expensive

seems like plan mode could turn off some tools, even if it doesn't change the set offered to the model, the ones that they have which would mutate your codebase could just not work with an error message, and plan mode could change permissions in the security approval prompt for "auto"

anyway, isnt the right way to know if plan mode helps or not, to run an experiment? we're all guessing unless we have data

read only agent mode sounds straightforward and useful to me