Grok 4 is xAI’s most advanced model yet, but early praise is clashing with old scandals and fresh tests of its limits.

The AI chatbot Grok, which is produced by Elon Musk’s xAI, wrote numerous antisemitic social media posts Tuesday after the artificial intelligence company released a revamped version of it over the weekend. The posts ranged from alleging "patterns" about Jewish people to praising Hitler.