SpaceXAI releases Grok 4.5 publicly: 1.5 trillion parameters, Opus-class claims Musk

What happened

SpaceXAI (rebranded xAI after the $60B Anysphere acquisition in June 2026) released Grok 4.5 on July 9, 2026. The model is available to SuperGrok Heavy subscribers ($99-149/month), X Premium+ subscribers, and xAI API. Elon Musk described it as 'Opus-class' though independent benchmarks were not yet available.

Context and impact

Grok 4.5 is the first model from SpaceXAI since the company went public. The model was trained on Cursor IDE data thanks to the Anysphere acquisition. This marks a historic moment — the first time three frontier labs simultaneously had publicly accessible models on the same day.

Details

• Built on V9 foundation model with 1.5 trillion parameters
• Training includes Cursor IDE data (from $60B Anysphere acquisition)
• SpaceXAI rebrand following Anysphere acquisition in February 2026
• Available via SuperGrok Heavy, X Premium+, and xAI API
• Per-token pricing unconfirmed at launch
• Company claims 'twice the token efficiency' vs. competitors