Meta Open-Sources Muse Spark Open Weights, Partners With Apple for Local Runs

The Decoder reports that Meta released Muse Spark Open, an 816B-parameter open-weight model that handles text, images, video and audio with up to 1M tokens of context. It is said to perform roughly on par with the strongest Chinese open-weight models on benchmarks and is optimized to run locally on Apple's M5 Ultra.

The Verge reports that Meta announced Muse Spark Open, calling it the most capable US open-weight model to date. Meta also says it is the first model in its class able to run on a desktop, specifically on two Apple M5 Ultra Mac Studios using the latest MLX framework.

Meta released Muse Spark Open, an open-weight model with 816 billion parameters and a 1M-token context window aimed at coding and agent tasks; developers can download the weights and run or customize them on compatible hardware and inference frameworks. The more capable Muse Wonder series remains closed.

Meta has published the weights for Muse Spark Open, a coding and agent model it says is less capable than its frontier Muse Wonder model launched Monday. Chief AI officer Alexandr Wang said Meta will generally not open-source its most powerful models for safety and capability reasons, while still releasing good open models. Bloomberg reported the weights are on Hugging Face, Amazon SageMaker AI and Google Cloud Model Garden.

Meta has launched Muse Spark Open, a coding-optimized 816B mixture-of-experts model with 42B active parameters and a 1M token context window that can hold an entire project. Trained on NVIDIA GB300 NVL72 for agentic coding workflows, it ships with Meta-generated NVFP4 checkpoints tuned for Blackwell Ultra to shrink the memory footprint of all 816B parameters and lower cost per token.

Meta is releasing the weights for Muse Spark Open, which it calls the most capable US open-weights model to date, available today on Hugging Face under the Muse Model License. The announcement was published on the official PyTorch blog.

Together AI says Meta's Muse Spark Open is now available through its serverless inference offering, giving developers a high-throughput, managed production path for agentic coding and multimodal workloads. Developers can start building on it directly through the platform.

Together AI describes Muse Spark Open as 'agentic from the ground up': it browses the web, spawns and coordinates subagents, and uses computer-use capabilities across desktop, mobile and browser. The model states its intent before acting so users can see what it is doing and why.

Together AI lists what Muse Spark Open brings: it handles multi-file refactors, debugging and long-running tasks, holds entire projects in a 1M context window including dependencies and legacy code, and accepts audio, audio-video, image and document input. These are vendor claims that have not been independently verified.

Together AI says Muse Spark Open is now live on its platform and that it is a Day 0 launch partner for the model from Meta. Together describes it as the most capable US open-weights model to date, built for long-running agentic coding workflows that keep entire codebases in context.

Apple and Meta are collaborating to make the Muse Spark Open model easier to run locally on clustered Mac Studio systems, CNBC reports. Both companies confirmed the work, but no timeline, supported hardware list, or performance figures were given. The collaboration would let teams run the model on Apple hardware instead of cloud infrastructure.

TestingCatalog reports that Meta's open-weight Muse Spark Open (Muse-Spark-Open-816B-A42B) is now available on Hugging Face. The mixture-of-experts model has 42B active and 816B total parameters with a 1M-token context window, and is built for agentic and coding workflows.

Baseten has made Muse Spark Open available on its platform: an 816B open-weight omnimodal model built for coding agent workflows with a 1M token context. Developers can run coding and agent tasks on it directly through Baseten.

Meta says it worked with Apple to make Muse Spark Open run locally on M5 Ultra Mac Studios, with users able to pair two to four of the machines for coding or agentic work, per CNBC. CNBC notes the longtime rivals are finding common ground in AI as John Ternus takes the reins at Apple.

Meta AI Research released Muse Spark Open, which it calls the most capable US open-weight model, with 816B total and 42B active parameters and a 1M-token context window. The model is available today and brings leading agentic capabilities to the desktop for the first time on Apple M5 Ultra Mac Studios.

A post on r/LocalLLaMA announces Muse Spark Open, described by its makers as the most capable US open-weight model to date and built for coding and agentic work. The stated specs are 816B total parameters with 42B active, a 1M-token context window, and text, image, video, and audio input, plus extra safety post-training run under Meta's Superintelligence Scaling Framework. The capability and ranking claims come from the release post itself.

Meta Platforms has released one of its new AI models for developers to download and modify, according to Bloomberg, while keeping its most advanced technology closed. The move is described as an effort to convert the company's AI investments into revenue.