Meta releases open-weight Muse Spark Open model, says it worked with Apple

Meta released an open-weight version of its Muse Spark artificial intelligence model on Thursday, 15 October 2026. The Verge and Reuters each reported the release.

Meta CEO Mark Zuckerberg announced the release in a post on X. The Verge quoted him as writing: "Muse Spark Open -- weights releasing today -- runs great on new Mac Studios thanks to work with @johnternus and Apple."

Apple CEO John Ternus replied to the post. The Verge quoted his reply: "Congrats to the team! Amazing to run a model of Muse Spark Open’s caliber and scale this efficiently, right from your desk. Mac Studio keeps pushing the boundaries of on-device AI!" The Verge describes Ternus as Apple's new CEO.

About the model

According to The Verge, Meta says Muse Spark Open is a "natively multimodal model" with 816 billion total parameters. According to Reuters, the model is aimed at coding and AI agents. Reuters reported that it expands developers' ability to download and adapt the technology.

According to The Verge, Apple published a new technical post about MLX. The Verge describes MLX as an "array framework" for machine-learning tasks on Apple Silicon. The post covers Muse Spark Open and two other open models. The reports reviewed by Vocemundi do not identify those two models.

The Meta-Apple collaboration

According to The Verge, Axios reported that Meta and Apple have been collaborating for several months. The Verge also reported that Meta chief AI officer Alexandr Wang told Axios: "We’re excited for mommy and daddy to be playing nice again." Vocemundi did not review the Axios report directly.

What each side says

• Meta, according to The Verge, calls Muse Spark Open the "most capable US open-weight model to date." Meta says it is "the first model in its class" able to "run on your desktop using two Apple M5 Ultra Mac Studios with the latest MLX framework." Meta also says the model "excels at long-horizon tasks, complex software engineering, and multi-step reasoning."
• Mark Zuckerberg says the model runs well on new Mac Studios because of work with Ternus and Apple.
• John Ternus says the model runs efficiently on a desktop and that Mac Studio continues to advance on-device AI.

What the reports do not include

The reports reviewed by Vocemundi do not include independent benchmarks or third-party checks of Meta's capability claims. They do not describe the license terms for the weights or where to download them. They do not describe any financial or contractual terms of the Meta-Apple collaboration. They do not give speed or memory figures for running the model on two M5 Ultra Mac Studios. Only a short summary of the Reuters report was reviewed.

Analysis

If Meta's claims hold, a model of this size running on two desktop computers could widen who can test and adapt large AI systems locally, rather than only through cloud services. Independent benchmarks will be important. They could confirm Meta's ranking claim, qualify it, or contradict it. The license terms, not yet described in the reports reviewed, may shape how freely developers and companies can use the weights. The public exchange between the two CEOs points to closer technical cooperation. Its scope and any lasting effect on the companies' wider relationship remain unclear from the available reporting.

Produced by the Vocemundi newsroom with AI assistance.