You don't. I learned this from it executing commands while in plan mode. It is LLMs all the way down.

if you read the thinking context while in plan mode (I had it shown to me, i think mistakenly, by switching modes while Claude was thinking a week or so ago) plan mode is just a pre-prompt saying “you are now in plan mode, don’t propose edits, read the code and understand how it works.”

it’s not an actual limitation on the harness.