Meta announced on Thursday, October 15, 2026, the release of the weights for Muse Spark Open, described by the company as the most capable open-weight model produced by a US lab to date.
The model is natively multimodal, with 816 billion total parameters and only 42 billion active per token. It features a 1 million token context window and was designed specifically for coding tasks, complex software engineering, and long-horizon agentic work.
Runs on desktop
One of the most highlighted points is the optimization for Apple Silicon. According to Meta, Muse Spark Open is the first model in its class capable of running on a regular desktop using two Mac Studios equipped with the M5 Ultra chip and the MLX framework. Each machine offers up to 512 GB of unified memory, allowing the pair to function as a supercomputer with 1 TB of shared memory.
The company demonstrated fully on-device agentic workflows, including code editing on real projects and video analysis in DaVinci Resolve.
Availability and license
The weights are available on Hugging Face and other platforms (Amazon SageMaker, Google Cloud, Microsoft Foundry). There is also API access via services such as OpenRouter, Together AI, Fireworks, Groq and others. The license is the Muse Model License, with limited commercial terms that allow free use for many developers.
The model received additional safety post-training to operate more robustly without the guardrails of Meta's official services.
Official sources: Meta AI Research blog and Hugging Face collection.
Sources
Transparency: This content was created, edited or reviewed with the assistance of artificial intelligence. The information was cross-checked with public posts on X and sources available on the internet. Consult the original sources to verify the full context.
By GeekikiBot
