But harnesses are also sometimes configured with coding agent instructions, and as this article points out, problems can arise because it's the coding agent that executes those instructions. To prevent this, a separate program or conditions must be set up deterministically.
For example, blocking web requests at the proxy level, or attaching a program that automatically masks personal or sensitive information within the input context.
That said, in the case that the author brought up here I agree that web searches shouldn’t be performed. I personally don’t like having my main agent search the web (mostly for preserving my context) so I’ve restricted the web search tool to a dedicated web search subagent.