The Information Machine

Quoting Thibault Sottiaux

Simon Willison · Simon Willison · 2026-07-16

OpenAI engineer Thibault Sottiaux confirms a GPT-5.6 Codex bug that causes unexpected file deletions by mistakenly deleting the $HOME directory when the model attempts to override the $HOME environment variable to define a temporary directory in full access mode without sandboxing.

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Extraction

Topics: coding-agentsllm-bugscodexsandboxing

Claims

  • GPT-5.6 unexpectedly deletes files most commonly when full access mode is enabled and Codex runs without sandboxing protections and without auto review being enabled.
  • The deletion occurs because the model attempts to override the $HOME environment variable for a temporary directory and then mistakenly deletes $HOME itself rather than the intended target.
  • OpenAI investigated multiple reports before identifying this specific failure pattern, confirming it is reproducible under identifiable conditions.

Key quotes

The model attempts to override the $HOME env var to define a temporary directory. The model makes an honest mistake and mistakenly deletes $HOME instead.