SpaceXAI launches Grok 4.5 AI model; Elon Musk says it's 'Opus-class' but faster

Elon Musk-owned SpaceXAI has launched Grok 4.5, dubbed as the company’s “most intelligent model”. In the official announcement, popular AI coding agent Cursor said that the Grok 4.5 can handle difficult, long-running tasks that require creatively using tools to solve problems, whether in software engineering, data science, finance, legal work, or anything else you do on a computer.

“Grok 4.5 is a mixture-of-experts model that we trained jointly with SpaceXAI,” it said adding “Training included trillions of tokens of Cursor data which capture a wide-range of user interactions with codebases and software tools”. This dataset lets the model learn both from existing software as well as developer-agent interactions, capturing how developers work and how agents interact with their environments."It is an Opus-class model, but faster, more token-efficient and lower cost," SpaceX CEO Elon ‌Musk ⁠said in a post on X (formerly Twitter). “Grok 4.5 is built for real-world engineering. It excels in large codebases and handles long-running tasks that span multiple repositories, hundreds of skills, and a variety of tools,” reads an X post by SpaceXAI.SpaceXAI said that Grok 4.5 was trained across tens of thousands of NVIDIA GB300 GPUs, with training and stability techniques designed for large-scale runs.

“Beyond raw token volume, we invested heavily in data filtering and curation: deduplication, quality scoring, and domain-focused selection so that the data mixture stayed high-coverage and high-signal”.The company claims that Grok 4.5 is “incredibly capable at coding”, from challenging Rust and C/C++ tasks to end-to-end app building from prompt to production.

Grok 4.5: Price and availability

Grok 4.5 is available today in Cursor across desktop, web, iOS, CLI, and our SDK. The base model is priced at $2/million input tokens and $6/M output tokens. There is also a fast variant at $4/million input tokens and $18/million output tokens.Individual and team plans include significant usage of the model as part of our first-party model pool. The company is doubling usage for the first week. Grok 4.5 isn't available in the EU yet. EU availability is expected later this month.