Meta released the weights to a new AI model on Thursday, and a massive one at that — over 800 billion parameters model. Muse Spark Open, which Meta describes as its most capable open-weight model built in the U.S. to date, can also run entirely on a desktop setup built from Apple’s Mac Studio computers, the result of a direct collaboration between two companies that have spent years keeping their distance from each other.
The model itself is a serious release on paper. Muse Spark Open carries 816 billion total parameters with 42 billion active, a 1 million token context window, and native multimodal support across text, image, video and audio, and Meta has built it specifically for coding and agentic work — long-horizon tasks, multi-step reasoning, and the kind of software engineering that used to require a closed frontier model to handle well. Developers can download the weights and modify the model freely under Meta’s license.
What makes it usable outside a data center is the Apple side of the deal.
Customers can pair two to four Mac Studio computers, running Apple’s M5 Ultra chip, to hold and run the model locally rather than through the cloud — a setup Apple says adds a layer of security and cuts down on the cost of renting cloud compute for every query. That capability isn’t cheap: a single 256GB Mac Studio starts at $10,799, a 512GB version is due later this month, and a four-machine configuration can run past $40,000. Frontier-scale AI now fits on a desk. It just costs about as much as a car to get there.
Apple and Meta have avoided public collaborations for years, and the relationship soured badly after Apple’s 2021 privacy changes restricted the kind of ad tracking Meta’s business depended on — a shift Meta estimated cost it $10 billion in revenue the following year. Neither company would say whether Thursday’s announcement is the start of something bigger. But Mark Zuckerberg posted on X that the new model’s weights were live and running well on the new Mac Studios, and Apple CEO John Ternus replied publicly, calling it a strong showcase for on-device AI performance. Two companies that spent years sniping at each other now have a reason to be seen cooperating, and they took it.
Muse Spark Open — weights releasing today — runs great on new Mac Studios thanks to work with @johnternus and Apple. https://t.co/U2wJNrKBOg
— Mark Zuckerberg (@finkd) October 15, 2026
Muse Spark Open arrives days after Meta debuted Muse Wonder, a more advanced model built for personal and professional AI agents that the company has described as its strongest system yet, trained at a new gigawatt-scale data center and built with what Meta calls its toughest safeguards to date against cyber and CBRN misuse. Meta ties decisions about what gets released openly, and when, to an internal risk-assessment process — the Advanced AI Scaling Framework — that evaluates a model against catastrophic-risk thresholds before it ever reaches the public, open or closed. Muse Spark Open cleared that process for an open release; Wonder, as the newer and more capable system, is still only available through Meta’s own API.
For Apple, every demonstration that serious AI work can run on Mac hardware instead of a data center full of Nvidia chips is a point in favor of the silicon it sells. For Meta, open-sourcing a model that already has a compelling way to run it locally, on hardware people already associate with reliability, makes for a stronger developer pitch than a download link on its own ever would.