Meta Ships Muse Spark Open: an 816B-Parameter Open-Weight Model Built for Macs
Meta has released Muse Spark Open, an 816-billion-parameter open-weight model designed specifically to run locally on Apple hardware.
Meta launched Muse Spark Open on Thursday, describing it as the "most capable" open-weight model in the United States. The model uses 816 billion parameters and a 1 million token context window. It is natively multimodal and targeted at complex coding tasks and agentic labor. Meta's evaluation results claim superior performance over other popular open-weight models, though the source does not include specific benchmark figures.
The defining design choice is local execution on Macs. Running the model requires at least 1 terabyte of RAM, per Engadget, and Meta indicates the best target is the Mac Studio equipped with the M5 Ultra chip. That hardware requirement puts it beyond most consumer machines, but for practitioners with access to a high-end Mac Studio, it offers a path to running a very large open-weight model without cloud inference costs.
Meta paired Muse Spark Open with Muse Code, its AI coding terminal, and deployed it across agentic workflows. One cited deployment involved coding fixes for a Mastodon client, including "bug fixes, new features, [and] full build." The company also used the model with DaVinci Resolve, where it was capable of reviewing and cropping footage. These are concrete demonstrations of the model operating as an agent across desktop applications rather than as a chat-only assistant.
The model is available now through multiple API platforms. Meta did not specify which platforms in the source text. Open-weight models, Meta notes, offer cost efficiency, transparency, and flexibility advantages over closed proprietary models — a familiar argument, but one that carries more weight when the model in question is positioned for local, on-device deployment.