Meta Launches Muse Spark Open, 816 Billion Parameter AI for Macs
Meta's Muse Spark Open packs 816 billion parameters, a 1 million token window and local Mac support, but requires at least 1 terabyte of RAM to run on-device.
Summary
On Thursday, October 15, 2026, Meta launched Muse Spark Open, which it calls the most capable open-weight model in the United States. The natively multimodal model uses 816 billion parameters and a 1 million token context window, targeting complex coding and agentic work. Meta’s evaluations claim stronger performance than popular open-weight rivals. Local Mac operation requires at least 1 terabyte of RAM and works best on a Mac Studio with Apple’s M5 Ultra chip.
Paired with Meta’s Muse Code AI terminal, the model fixed bugs, added features and completed a full build for a Mastodon client. It also reviewed and cropped footage in DaVinci Resolve. Open weights can offer lower costs, transparency and flexibility compared with closed proprietary models, but the memory requirement sharply limits local accessibility. Muse Spark Open is available now through several API platforms, which Meta did not specify.
Positives
- 816 billion parameters and a 1 million token context window support complex coding, multimodal tasks and agentic workflows.
- Muse Code used the model to fix bugs, add features and complete a full build for a Mastodon client.
- DaVinci Resolve testing showed Muse Spark Open could review and crop video footage.
- Several API platforms now provide access to Muse Spark Open.
- Open weights can improve cost efficiency, transparency and flexibility compared with closed proprietary models.
Risks & concerns
- At least 1 terabyte of RAM is required to run Muse Spark Open locally, severely restricting compatible Macs.
- Apple’s M5 Ultra Mac Studio provides the best local performance, narrowing practical access to exceptionally powerful hardware.
- Meta’s performance advantage is based on its own evaluations, while independent comparative results remain unavailable.
- Several API platforms offer the model, but Meta did not specify their names or access terms.