Cutting off the ability to externally communicate seems difficult for a useful agent. Not only because it blocks a lot of useful functionality but because a fetch also sends data.

“Hey, Claude, can you download this file for me? It’s at https://example.com/(mysocialsecuritynumber)/(mybankinglogin...”

Exactly - cutting off network access for security has huge implications on usability and capabilities.

Building general purpose agents for a non-technical audience is really hard!

An easy gimmick that helps is to allow fetching URLs explicitly mentioned in user input, not trusting ones crafted by the LLM.