Elon Musk introduces Grok 4.5 in private beta: xAI's latest AI could rival Claude Opus
Elon Musk has revealed that xAI's Grok 4.5 has entered private beta testing at SpaceX and Tesla. Built on the new 1.5-trillion-parameter V9 foundation model, Grok 4.5 is claimed to deliver performance close to, and possibly better than, Anthropic's Claude Opus, while offering improved coding capabilities.
Published By: Deepti Ratnam | Published: Jun 29, 2026, 08:00 AM (IST) | Edited: Jun 29, 2026, 08:01 AM (IST)
Elon Musk has announced that xAI has started testing its latest artificial intelligence model, Grok 4.5, in private beta. The new AI is being tested in-house at SpaceX and Tesla before it can be made available to the general public.
Grok 4.5 is designed on top of the most recent of xAI's V9 foundation model, and initial internal assessments show it can achieve results that are equal to or superior to Anthropic's Claude Opus in many instances. But the information is based on xAI's own testing and the company has yet to release any independent benchmark results.
Grok 4.5 goes into private beta
The development was announced by Musk in a post on X where he revealed that Grok 4.5 is in private beta with both SpaceX and Tesla.
The model is based on the V9 foundation model developed by xAI, which has 1.5 trillion parameters, and combined with SpaceX's recently announced acquisition of Cursor, an AI coding assistant.
As per Musk, the additional training has enhanced the model's coding capabilities, which have made it more practical for software coding and programming-related tasks.
With the private beta, xAI can test the model in real-world environments before releasing it to the public. SpaceX and Tesla engineers and employees are likely to receive feedback to help find bugs, respond accordingly, and make improvements to the experience.
Grok 4.5 is nearly as good as Claude Opus.
One of the showstoppers of Musk's announcement is that Grok 4.5 performs "close to Anthropic's Claude Opus", which is considered among the most capable AI models on the market.
At the same time, he also said that the new model may even outperform Claude Opus in certain assessments within the company.
In addition, Musk stated that the team is working on reinforcement learning to enhance Grok's capabilities. Reinforcement learning can enable AI models to learn from feedback over time, improving their responses and usefulness.
He also said that "Grok Build", the AI coding platform developed by xAI, is also continuously improving.
Even as they make such claims, xAI has not released benchmark scores or technical reports to enable researchers to independently verify the performance of this model.
The largest foundation model of xAI
The V9 foundation model is the base for Grok 4.5, having about 1.5 trillion parameters.
This is roughly three times the size of the 500 billion parameters model that is currently actively used for Grok at X.
In general, bigger the AI models, the more complex information they can work with, better they can reason, grasp the longer conversations and produce good quality responses. But, the performance in real world will also rely on the quality of training data and optimisation techniques, not only the number of parameters.
The V9 model was trained towards the end of May and is one of the largest AI projects undertaken by xAI.
Cursor is a big portion of Grok 4.5's training
Cursor is an AI-powered coding assistant designed to assist developers with coding, editing, debugging, and code comprehension.
During supplemental training, xAI leveraged developer workflows, multi-file editing sessions, code refactoring examples and iterative debugging data from Cursor, Musk said.
The mission is to build Grok into a more capable coding assistant, capable of holding its own against OpenAI, Anthropic and Google.
With the rise in the use of AI coding assistants by software developers, enhancing programming is a significant priority for top AI companies.
xAI will be releasing new AI models
Musk also announced his company xAI's ambitious plan for the remainder of this year.
He said that the company will be deploying a totally new AI model each month via SpaceX. Each new version will be trained from scratch rather than making some minor tweaks to the existing models.
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