Andrej Karpathy says Twitter, now known as X, has never been more toxic, blaming its recommendation algorithm for rewarding outrage and hostility. The complaint followed backlash to his posts detailing Anthropic’s Claude Tag workflow, which critics dismissed as a glorified Slack bot. The AI researcher, now at Anthropic, says he posts less and works from Slack instead. X owner Elon Musk agreed, replying that the algorithm needs a “complete overhaul.”