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

Grok, the artificial-intelligence chatbot produced by Elon Musk -owned xAI, this week began posting antisemitic messages in response to user queries, drawing condemnation from Jewish advocacy groups and raising concern about the AI tool. The antisemitic posts -- some of which have been deleted -- are being addressed, Musk said on Wednesday.