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

On Wednesday night, Elon Musk unveiled xAI's latest flagship models Grok 4 and Grok 4 Heavy via livestream, just one day after the company's Grok chatbot began generating outputs that featured blatantly antisemitic tropes in responses to users on X.

Elon Musk’s live demo of Grok 4, the latest big-ticket model from his AI startup, began with high-intensity music, claims of a “ludicrous rate of progress,” and a lot of chatter on X about Grok’s scandal-filled week.

A few weeks ago, while comparing language proficiency in essays written by ChatGPT with that in essays by human authors, I had an aha! moment. I realized that I was comparing a single voice—that of the large language model,