By any chance, do you know what Claude Code's sandbox feature uses under the hood and how that relates to your solution ? From what I remember it also uses the native MacOS sandbox framework, but I haven't looked too deep into it and don't trust it fully
Claude Code sandboxing uses the same basic OS primitive but grants read access to the entire filesystem and includes escape hatches (some commands bypass sandboxing). Also, I wanted something solid I can use to limit every agent (OpenCode, Pi, Auggie, etc).