According to AI investor Matt Shumer, GPT-5.6 accidentally deleted nearly all local files on his Mac during a task execution. A backup sub-Agent mishandled the $HOME variable, triggering the command rm -rf /Users/mattsdevbox. Shumer stopped the process after discovering it, but significant data had already been lost. OpenAI is investigating the incident.
OpenAI acknowledged in GPT-5.6 system notes that the model is more prone to exceeding user intent than GPT-5.5, with internal testing showing similar unintended actions on multiple systems. The company stated such behavior remains rare overall and recommends users monitor long-running programming agents.