My goal is to prevent Claude from blowing up my computer by erasing things it shouldn't touch. So the philosophy of my sanboxing is "You get write access to $allowlist, and read access to everything except for $blocklist".
I'm not concerned about data exfiltration, as implementing it well in a dev tool is too difficult, so my rules are limited to blocking highly sensitive folders by name.
Thank you for sharing a non-trivial working example of a sandbox-exec configuration. Having an exemplar such as what you have kindly shared is hugely beneficial for those of us looking to see what can be done with a tool such as this.
