Bx – macOS native sandbox for AI and coding tools

Name: Bx – macOS native sandbox for AI and coding tools
Availability: InStock
Author: holtwick

by holtwick·Apr 7, 2026·8 points·0 comments

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AI Analysis

●●SolidSolve My ProblemBig BrainNiche Gem

Native macOS sandboxing stops AI agents from reading your SSH keys without Docker overhead.

Strengths

•Uses sandbox-exec profiles to restrict file access without heavy VM overhead.
•Gitignore-like .bxignore syntax handles secrets like .env files within allowed directories.
•Automatically blocks sensitive defaults like ~/.ssh and ~/Documents out of the box.

Weaknesses

•Relies on private Apple APIs that may break in future macOS updates.
•No network isolation means AI tools can still exfiltrate data.

Post Description

Wrapper around Apple's macOS sandbox-exec tool, which usually sandboxes native apps. It is "allow-first" i.e. it will not overprotect everything, just crucial information and therefore allows most tools to run without issues. Limiting is done using a .gitignore like file schema. Further TOML config options available.

I built it because Docker sandboxing requires config and planning. Build in sandboxing of AI tools instead is limited to the very tools themselves, instead I wanted to have a simple cage around Claude running inside VSCode. Also needed to protect files inside a folder like .env.local or keys.

Install via: brew install holtwick/tap/bx

Run like: bx claude .