Musk announces Grok 4.5 coming tomorrow: targeting Opus but faster and cheaper, facing off against GPT-5.6

Elon Musk announced that SpaceXAI will release Grok 4.5 to the public on July 9. The model is built on the 1.5 trillion parameter V9 base model, trained with Cursor IDE interaction data. Musk calls it "Opus-class, but faster, more token-efficient, and lower cost."
(Previous: Grok 4.3 beta opens to Heavy subscribers! Musk: True flagship version initial training complete in 5 days)
(Background: SpaceX officially renamed to SpaceXAI, Musk ties space and AI into one company)

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• 1.5 Trillion Parameter V9 Base Model + Cursor Training Data
• First Visible Result of Cursor Integration
• July 9: "Double Launch Day" in the AI Model War

Musk posted on X platform today (8th) afternoon, announcing that SpaceXAI will release the Grok 4.5 AI model to the public tomorrow. He said that based on positive feedback from customers, Grok 4.5 will be an Opus-class model, but faster, more token-efficient, and lower cost.

Based on strong positive feedback from customers in our beta test program, @SpaceXAI will make Grok 4.5 available to the public tomorrow.

It is an Opus-class model, but faster, more token-efficient and lower cost.

— Elon Musk (@elonmusk) July 8, 2026

1.5 Trillion Parameter V9 Base Model + Cursor Training Data

Grok 4.5 is not a minor 4.x iteration. According to the architecture description in the beta announcement on June 28:

• Base Model: 1.5 trillion parameter V9 base model
• Supplemental Training: Cursor IDE interaction data (real agentic coding sessions, multi-round edits, large codebase context, bug fixes, etc.)
• Beta Environment: SpaceX and Tesla internal engineering systems
• Training Infrastructure: Memphis Colossus cluster (220k+ NVIDIA GPUs)
• Continuous Improvement: Reinforcement learning (RL) through Grok Build training rounds

First Visible Result of Cursor Integration

The upcoming Grok 4.5 is the first model jointly developed by SpaceX and Cursor. In June of this year, SpaceX officially acquired Cursor's parent company, Anysphere, via a wholly owned subsidiary using an all-stock transaction at a $60 billion valuation.

Grok 4.5 is the first tangible result of this integration strategy: combining the model lab, IDE interaction data, and massive computing resources. Whether it will surprise the market, we will soon have a chance to test.

July 9: "Double Launch Day" in the AI Model War

Notably, on the same day, OpenAI's GPT-5.6 Sol will also be released publicly:

• Grok 4.5 (SpaceXAI), Opus-class, faster, cheaper
• GPT-5.6 Sol (OpenAI), flagship GPT-5.6 tier, 91.9% on Terminal-Bench