Elon Musk says Grok 4.5 to launch on July 9, calls it 'Opus-class'

Elon Musk announced on X on Wednesday that xAI will release Grok 4.5, its latest large language model (LLM), to the public on July 9.

"It is an Opus-class model, but faster, more token-efficient and lower cost," he wrote.



xAI is speeding up development amid the race for the fastest and cheapest model in the AI space. Grok 4.5 first surfaced in private beta at Tesla and SpaceX in June, with Musk putting its early performance close to, and potentially above, Anthropic's Claude Opus.

None of Musk's performance claims have been independently benchmarked yet; they are based on internal testing at Tesla and SpaceX rather than public evaluations.

Grok 4.5 runs on a new 1.5-trillion-parameter foundation model known as V9, with supplemental training on data from the AI coding platform Cursor to sharpen its technical and coding chops.

SpaceX is in the process of acquiring Cursor in a $60 billion deal.

The release comes under the SpaceXAI banner, the name xAI being adopted after the organisation was folded into SpaceX earlier this year. The latest model would follow Grok 4, launched in July 2025. The company has mapped out a roadmap of monthly model releases through the rest of 2026, Musk had said in June.

The release puts Grok 4.5 on a collision course with OpenAI, which is moving its GPT-5.6 models toward broader availability around the same period. This sets up another head-to-head moment in a race already crowded with players such as Claude, Gemini, and ChatGPT.