Should an AI agent be allowed to say “I don’t know”?

Say an agent runs a shell command. We can see that Bash executed, but that doesn’t necessarily tell us what actually happened. It could have read a file, changed code, deleted something, touched infrastructure, or done several of those things at once. If the runtime can’t confidently determine the effect, should the governance layer still be forced to label it safe, unsafe, destructive, etc.? I’m increasingly thinking unknown is a perfectly valid answer. I’d rather have the system say “I don’t have enough evidence” than manufacture certainty. Curious how people here handle this. Do you preserve unknown as a real state, or force everything into a classification?