Claude tried to clean up after itself and deleted a developer's entire home folder instead.
Sebastien Guillemot asked Claude Fable to write a script that would sandbox and clean up temp files left behind by his AI coding agents, since he was tired of them littering his /tmp directory. Because the script involved permanently deleting data, Anthropic's safety harness flagged it as risky and swapped the model running the job down to Opus 4.8 before letting it perform a safety check meant to confirm the deletion logic wouldn't touch /tmp or the user's home directory. That check correctly identified both paths as dangerous - but the cleanup step for the test itself reused the same variable name as the thing it was testing, so Opus 4.8 deleted Guillemot's actual home directory instead of a scratch copy. About 700 GB of data disappeared, including a week of work, and the /tmp junk that started the whole project survived untouched.
The bug itself is a garden-variety variable collision, the kind of thing a careful code review catches. What's notable is that Anthropic's own safety system may have made the mistake more likely: Fable 5 reportedly outperforms Opus 4.8 at coding, and the downgrade swapped in the weaker model right before the step that needed to catch this exact kind of error. A safeguard against accidental deletion helped cause the accidental deletion.
Guillemot recovered most of his files from git, Nix, and session logs rather than a proper backup - which says less about Claude than about how many developers still treat backups as optional.