Elon Musk says xAI’s latest model, Grok 4.5, has entered private beta testing at SpaceX and Tesla. Musk makes the announcement on X, presenting it as the first confirmed placement of a Grok 4.5-branded version within his companies ahead of any wider release. He says Grok 4.5 is built on xAI’s 1.5-trillion-parameter “V9” foundation model and includes supplemental training using data associated with the AI coding assistant Cursor, after Cursor data is added to improve coding-related performance.
Musk also discusses early performance results, stating that initial evaluations show Grok 4.5’s results are close to, and may exceed, Anthropic’s Claude Opus. He adds that reinforcement learning continues to improve the model and that an internal coding harness (“Grok Build”) is becoming more effective. Both sources report that xAI plans to release new AI models “completely trained from scratch” through SpaceX on a monthly schedule for the remainder of the year, indicating an accelerated development and deployment cycle. No additional technical details or independent verification are provided in the reports.
