The agent should ask whether it's allowed to read/write particular files, rather than whether it's allowed to run particular commands. It would be much easier to review. Then wrap each command invocation in bwrap (+http proxy) accordingly.
Look at how SELinux is structured, or AppArmor. Neither one is enough. I.e. you need both: file access permissions and permissions to run commands and more... Trying to restrict to only one security feature will make the system either too restrictive or too fragile or useless.
I’ve even had plenty of situations where the command was so long that it gets truncated. Maybe my screen wasn’t big enough but as far as I could tell it wasn’t possible to read the whole thing. “Send it, claude!!”