Meta releases Muse Spark Open, an open-weight model with 816B parameters
Meta has released the weights for Muse Spark Open, which it calls the most capable US open-weight model to date. The model is natively multimodal, has 816B total parameters (42B active) and a 1M-token context window. Meta says it is built for coding and agentic work, and that it can run on a desktop using two Apple M5 Ultra Mac Studios with the MLX framework. Weights are on Hugging Face, Amazon SageMaker AI, Google Cloud Model Garden and Microsoft Foundry Models, and hosted APIs come from providers including Together AI, Fireworks AI, Groq and OpenRouter. The license is the Muse Model License, which Meta says has limited commercial terms that let many developers use the model for free.