24th December 2025
Research
OpenAI Codex CLI Sandbox Implementation Analysis
— OpenAI Codex CLI's sandbox employs strong, platform-specific isolation to securely constrain the behavior of AI-driven code agents. On macOS, it uses Apple's Seatbelt sandbox with finely tuned dynamic policies, while on Linux, it combines Landlock for strict filesystem controls and seccomp for syscall-based network blocking—ensuring that agents can only write to user-approved directories and have no outgoing network by default.