Claude Fable deletes ~700 GB of a developer's home directory while testing the sandbox meant to protect it

Developer Sebastien Guillemot asked Claude Fable to build per-agent temporary workspaces with cleanup, to stop multiple agents' temp files filling /tmp. During a safety test of the deletion logic, cleanup code reused a variable holding the home-directory path and passed it to rm -rf, deleting about 700 GB before the process was stopped. Tom's Hardware reported the session had been automatically downgraded from Fable 5 to Opus 4.8 before the failure, though the causal chain remains reported, not proven. Guillemot recovered about 90% of uncommitted changes from an old drive and the rest from GitHub.

What this means for youAt home or work, an AI coding helper with delete access can wipe real files by mistake, even while testing safety code. Governments and companies should expect such incidents as agents get more access. Keep backups and run coding agents in a restricted folder or sandbox without access to your home directory.