Meta releases Muse Spark Open with downloadable weights
Meta's open-weight model can be downloaded and run on your own hardware.
Meta has released the weights of Muse Spark Open, which it calls the most capable US open-weight model to date. It is natively multimodal, has 816 billion parameters with 42 billion active at a time, and a context window of 1 million tokens. Meta built it for coding and long, multi-step agent tasks.
Open weights let organizations run and adapt the model themselves instead of only renting access. Meta says it is the first model in its class to run on a desktop, using two Apple Mac Studios with M5 Ultra chips. The license has limited commercial terms, so check it before building a product on the model.
Muse Spark Open is available through API providers including Groq, Together AI and OpenRouter, and for download from Hugging Face, Amazon SageMaker AI, Google Cloud Model Garden and Microsoft Foundry. It runs on common inference engines such as vLLM, llama.cpp and Apple MLX.