SpaceXAI CEO Elon Musk announced on Wednesday that Grok 4.5 will be released publicly on Thursday, posting on X, “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.”“It is an Opus-class model, but faster, more token-efficient and lower cost.”As a surprise to no one, the public launch comes just under two weeks of internal testing at SpaceX and Tesla. With a massive compute boost under the hood, Grok 4.5 runs on xAI’s latest 1.5-trillion-parameter V9 foundation model, which makes Musk’s reference to “Opus-class” especially telling. 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, 2026Cursor deal fuels training dataThe model also reportedly received specialized supplemental training data from Cursor, the AI coding platform that SpaceX is in the midst of acquiring as part of a massive $60 billion deal. That could give Grok 4.5 an advantage on software engineering tasks by exposing it to high-quality coding workflows and developer interactions. Musk also teased that an even larger 2-trillion-parameter V-series model is due for an August release. Grok 4.5’s trillion-parameter engineNot surprisingly, Musk referenced “Opus-class” based on the current success of competitor Anthropic’s Claude Opus, which is currently on version 4.8. This is especially fitting timing given the recent drama surrounding Anthropic’s flagship model, Fable 5. Following a weeks-long standoff in which the federal administration imposed strict export controls on Fable 5 over “jailbreak” national security concerns, Anthropic briefly pulled the model before redeploying it with stricter safety classifiers. However, because Fable 5 now defaults back to Opus 4.8 whenever a security guardrail is tripped — and with access to Fable 5 tightening up — Musk must smell blood in the water.Musk must smell blood in the water.The launch is also an obvious defensive move to stem the bleeding in the user base. Recent Apptopia data shows that the Grok app’s average daily users in the U.S. dropped by 28% since April, with its market share slipping below 9%. Recent Apptopia data shows that the Grok app’s average daily users in the U.S. dropped by 28% since April, with its market share slipping below 9%.Users are already leaving GrokMusk is aiming to steal back momentum with a cheaper, faster “Opus killer” on Thursday. We’ll prepare for a massive, head-to-head tech showdown as OpenAI is heavily rumored to roll out its highly anticipated GPT-5.6 models.The post “Opus-class, but faster”: What Elon Musk says about beating Anthropic appeared first on The New Stack.