Muse Spark Open, the Most Capable US Open‑Weight Model to Date
A new open-weight AI model called Muse Spark Open has been released, featuring 816B parameters and a 1M-token context window. It is optimized for high-performance hardware, specifically Apple M5 Ultra Mac Studios, to allow for local, high-end AI development.
Why it matters
This represents a significant shift in AI accessibility, enabling powerful, large-scale model inference on consumer-grade desktop hardware rather than relying solely on cloud infrastructure.
Today, we’re releasing the weights for Muse Spark Open, the most capable US open-weight model to date. Muse Spark Open is a natively multimodal model with 816B total parameters (42B active) and a 1M-token context window. Built for coding and agentic work, it excels at long-horizon tasks, complex software engineering, and multi-step reasoning.
We believe the future is for everyone , and that includes the freedom to run advanced models wherever, including at home. Muse Spark Open is the first model in its class to run on your desktop using two Apple M5 Ultra Mac Studios with the latest MLX framework.
Muse Spark Open is available today through API platforms at Baseten, Fireworks AI, Groq, Modal, Nebius, OpenRouter and Together AI. Model weights are available for download on Amazon SageMaker AI, Google Cloud Model Garden, Hugging Face, and Microsoft Foundry Models.
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