Elon Musk announced Grok 4.5's private beta, asserting its performance rivals or surpasses Anthropic's Opus, with ongoing reinforcement learning enhancements.

xAI's Grok 4.5, a 1.5 trillion parameter model built on V9 with Cursor data, enters private beta at SpaceX and Tesla with performance rivaling Anthropic's

Musk said reinforcement learning is continuing to improve the model and that "Grok Build," xAI's coding-agent harness, is being refined daily. He framed the SpaceX and Tesla…