Yaccarino announced her departure on X, saying that she is “immensely grateful” to Elon Musk for taking her on in 2023.

The takeaway, at least from a technical standpoint, is that Grok 4 is now firmly in frontier-model territory. That’s a meaningful shift for xAI, which just months ago was primarily known for its integration with X, the rechristened Twitter owned by Musk. xAI is clearly trying to be taken seriously as a legitimate AI research and enterprise company.

The chatbot is giving antisemitic responses and bizarre first-person replies, raising concerns about bias and safety ahead of Grok 4 launch.