Her husband wanted to use ChatGPT to create sustainable housing. Then it took over his life.

On 7 August, Kate Fox received a phone call that upended her life. A medical examiner said that her husband, Joe Ceccanti – who had been missing for several hours – had jumped from a railway overpass and died. He was 48.

Fox couldn’t believe it. Ceccanti had no history of depression, she said, nor was he suicidal – he was the “most hopeful person” she had ever known. In fact, according to the witness accounts shared with Fox later, just before Ceccanti jumped, he smiled and yelled: “I’m great!” to the rail yard attendants below when they asked him if he was OK.

But Ceccanti had been unravelling. In the days before his death, he was picked up from a stranger’s yard for acting erratically and taken to a crisis center. He had been telling anyone who would listen that he could hear and feel a painful “atmospheric electricity”.

He had also recently stopped using ChatGPT.