Musk says xAI will release Grok 4.5 to public Thursday

Elon Musk announced that xAI's Grok 4.5 will become publicly available Thursday, calling it an "Opus-class" model that is faster and more cost-efficient.x+1
The model, built on xAI's V9 foundation, has been in private beta at SpaceX and Tesla since June 28, trained partly on data from AI coding tool Cursor.AIWire+1
The release coincides with OpenAI's planned GPT-5.6 launch the same day, intensifying the frontier AI competition between the two rivals.beincrypto

Elon Musk announced on Tuesday that SpaceXAI will make Grok 4.5 available to the public on Thursday, July 9, marking the first major AI model to emerge from SpaceX's pending $60 billion acquisition of Cursor-maker Anysphere. Musk described the 1.5-trillion-parameter model as "Opus-class" but "faster, more token-efficient and lower cost" in a post on X.x+1

The release places SpaceXAI in direct competition with OpenAI, which said the same day that its GPT-5.6 family of models — Sol, Terra, and Luna — will also launch publicly on Thursday.beincrypto

From Private Beta to Public Launch

Grok 4.5 is built on xAI's V9 foundation model, which completed training on May 25, and incorporates supplemental training data from Cursor, the AI coding assistant used by roughly four million developers. The model entered private beta at SpaceX and Tesla on June 28, when Musk first claimed its performance was "close to, perhaps exceeding Opus".digg+2

Musk said positive feedback from beta customers drove the accelerated timeline to a public release. No independent benchmarks or a system card have been published, and the performance claims rest on internal evaluations.AIWire+1

The Cursor Connection

The model's coding capabilities are tied to SpaceX's June 16 agreement to acquire Anysphere, the company behind Cursor, in a $60 billion all-stock deal — the largest acquisition of a venture-backed startup on record. The transaction, expected to close in the third quarter of 2026, gives xAI access to Cursor's developer workflow data and an installed base of millions of professional coders.reuters+3

SpaceX and Anysphere had been jointly training a model for several months prior to the acquisition announcement, with the resulting technology slated for integration into both Cursor and Grok Build, xAI's coding agent. The deal followed SpaceX's acquisition of xAI in February and its record $75 billion IPO on the Nasdaq .Forbes+3

A Competitive Landscape

The simultaneous launches from SpaceXAI and OpenAI underscore the intensifying race in frontier AI. Cursor was once considered the leader in AI-assisted coding, but Anthropic's Claude Code and OpenAI's Codex have since emerged as strong competitors. With Grok 4.5, Musk is betting that Cursor's data advantage and SpaceX's computing infrastructure — including the Colossus supercomputer — can close that gap.X (formerly Twitter)+2

Sources (29)