Muse Spark Open

Muse Spark Open is Meta’s open-weight model, which Meta calls the most capable US open-weight model to date. It is natively multimodal, with 816B total parameters, 42B active, and a 1M-token context window, built for coding and agentic work. Meta says it runs on a desktop with two Apple M5 Ultra Mac Studios. Weights are on Hugging Face under the Muse Model License, which has limited commercial terms.