SpaceXAI, the company formerly known as xAI, released its newest flagship model, Grok 4.5, to the public on July 9, becoming the first AI system trained on data from Cursor, the coding assistant that SpaceX agreed to acquire for $60 billion in June.
Grok 4.5 is built on a roughly 1.5-trillion-parameter foundation model the company calls V9 internally, according to its launch page. Unlike earlier Grok releases, it draws on trillions of tokens captured from Cursor’s developer traces, extending beyond pure coding into research, finance and other knowledge work, Cursor said in its own announcement of the release.
Priced well below rivals
The model costs $2 per million input tokens and $6 per million output tokens in its base configuration, with a faster variant priced at $4 and $18. That undercuts Anthropic’s Claude Opus 4.8, which lists at $5 and $25 per million tokens for input and output respectively — roughly a quarter of the cost for comparable use. Elon Musk, who now runs the merged company following xAI’s rebrand to SpaceXAI on July 6, called Grok 4.5 an “Opus-class model, but faster, more token-efficient and lower cost.”
Self-reported, unverified benchmarks
The company’s own figures tell a more mixed story. On four benchmarks SpaceXAI chose to publish, Grok 4.5 beat Opus 4.8 on two — Terminal-Bench 2.1 and DeepSWE 1.0 — and lost on the other two, including SWE-Bench Pro, where it scored 64.7% against Opus 4.8’s 69.2%. Anthropic’s separate Claude Fable 5 model led all four benchmarks in the comparison. None of the figures have yet been confirmed by independent evaluators such as Artificial Analysis or LMSYS Arena, which have not tested Grok 4.5.
Grok 4.5 is available immediately through Grok Build, the SpaceXAI console, and inside Cursor on all subscription tiers, where new users get double their usual model quota for the first week. The model is not yet available in the European Union; SpaceXAI has said access there is expected by mid-July.
The launch is the first tangible product of SpaceX’s pending acquisition of Cursor, a deal that valued the coding startup — used daily by roughly 7 million developers — at $60 billion in stock when it was announced in June. The acquisition is expected to close in the third quarter of 2026.