If it has no access to your filesystem or network services that's better, but you're still giving input from an unknown party to an interpreter, with the extra bonus of that interpreter being non-deterministic by design.
But then again people today will also pipe curl to bash, so I may have lost this battle a while ago...
> "Hey Claude, summarize, this document I downloaded from the Internet"
I think you've created confusion with this example due to its ambiguity. Let's be clear about the difference between a chatbot and an agent: Asking a chatbot (e.g. vanilla Claude) to summarize an unknown document is not risky, since all it can do is generate text. Asking an agent (e.g. Claude Code) to summarize an unknown document could indeed be risky for the reason you state.
But then again people today will also pipe curl to bash, so I may have lost this battle a while ago...