On July 28, 2026, Elon Musk announced that Grok 4.5 is now running inside SpaceX and Tesla, having announced the private beta on June 28, 2026. The model is built on a 1.5 trillion-parameter architecture xAI calls “V9.” Musk posted the update on X, stating: “Grok 4.5, based on our 1.5T V9 foundation model, with Cursor data added in supplemental training, is now in private beta at SpaceX & Tesla.” He claimed early evaluations put the new model close to, or perhaps ahead of, Anthropic’s Claude Opus. Musk also promised monthly, from-scratch model releases, a pace no frontier lab has sustained before, and disclosed that “Cursor data” was folded into training without explaining the source or terms. There was no blog post, technical report, or public release date.