Nix

Claude AI Agent Accidentally Deletes Developer's 700 GB Home Directory

A developer named Sebastien Guillaime instructed an AI agent powered by Claude to create a script that would clean temporary files left by other AI agents. The model was asked to set up isolated sandboxes inside /tmp for each agent and remove them after use. Due to the presence of destructive rm commands, Anthropic's safety system automatically downgraded the model from Fable 5 to Opus 5 and then to Opus 4.8. The weaker model reused a variable that pointed to the user's home directory instead of /tmp, resulting in the deletion of 700 GB of data. Guillaime managed to recover most files from Git repositories, Nix configuration, and session logs, but lost a week of work. He believes the automatic downgrade to a less capable model contributed to the variable conflict going unnoticed.