The majority of the times I reject a tool call it's because I can tell the agent is about to go off piste. Eg. adding packages to work around some non-problem is a common one.

I guess I could try to actively interrupt it in those moments, but that seems less effective.

More power to those who want to use it like that though, I guess. Perhaps by throwing in extra agentic guardrails, or whatever the idea may be. I don't think it's the best route to a good product or business but let's see.