Elon Musk just announced that Grok 4.5, xAI’s newest artificial intelligence model, has entered private beta testing at Tesla and SpaceX. It is a big moment for xAI, since they are moving from training their models to actually using them inside Musk’s two tech giants. Right now, only internal teams can use Grok 4.5, but the news gives a peek at what xAI’s next generation AI can do and shows they are serious about matching up with the industry’s best.
Musk says the model runs on a much larger, more advanced architecture and has gone through extra training to sharpen its coding skills and technical reasoning. Musk even claims Grok 4.5 ranks close to Anthropic’s Claude Opus in internal tests. But since the public hasn’t seen the model yet, nobody outside xAI has verified how well it really performs.
Grok 4.5 Officially Enters Private Beta Testing Exclusively for Tesla and SpaceX Workflow
Musk says Grok 4.5 runs on xAI’s V9 foundation model, boasting a huge 1.5 trillion parameters. They have also added training with Cursor data to make the AI better at coding and handling complex technical tasks. By rolling Grok 4.5 out internally at Tesla and SpaceX, engineers get to try it out in real world situations before xAI launches it more broadly. Instead of relying on benchmark tests alone, the private beta lets teams actually use Grok 4.5 on live engineering problems, so xAI can catch bugs, see how reliable it is, and fine tune its performance.
Musk also talked about Grok Build, xAI’s coding harness. It is designed to streamline developer workflows, and he says it is getting daily updates as engineers continually improve both the AI model and the tools that support it.
This internal rollout is part of a bigger strategy of bringing AI into enterprise settings early in development. With Tesla and SpaceX as testbeds, xAI gets a controlled environment, letting them push the model on tough engineering tasks without the headaches of a public release. Even though Grok 4.5 is still in private beta, xAI’s move signals they are gearing up to launch the model to more users, once they finish internal testing and polish it further.
Elon Musk Claims New Grok 4.5 Matches Claude Opus
Musk’s comparison between Grok 4.5 and Anthropic’s Claude Opus has gained attention. He says xAI’s evaluations show Grok 4.5 performs “close to, perhaps exceeding Claude Opus,” putting xAI’s offering right up there among top AI systems specializing in reasoning and coding. But these claims only come from xAI’s own tests; no third party experts have gotten their hands on Grok 4.5 yet, so we won’t really know how it stacks up against competitors until outsiders give it a try.
Musk also laid out an ambitious plan for xAI’s future. He said the company aims to roll out brand new models, trained from scratch, every month for the rest of the year. If they pull this off, xAI would have one of the fastest development cycles in the field.
All this comes as competition heats up in the AI world. Companies are investing resources into bigger foundation models, smarter reasoning, and smarter coding tools. Software engineering performance matters more than ever, since businesses want to weave AI into programming, automation, and important technical decisions.
For xAI, Grok 4.5’s private beta isn’t just a product milestone, it is a chance to prove their technology handles demanding enterprise tasks before they launch commercially.
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. Early evals show performance close to, perhaps exceeding Opus.
— Elon Musk (@elonmusk) June 28, 2026
RL is continuing to significantly improve the model, and the Grok Build…
The announcement shows xAI believes strongly in its model. With plans to release new, freshly trained models every month this year, xAI is chasing rapid innovation as competition among top AI players ramps up.
