Meta releases Muse Spark Open, an 816B open-weight model, and partners with Apple to run it on Mac Studio
Per Meta's own announcement, Muse Spark Open is a mixture-of-experts model excelling at long-horizon tasks, complex software engineering and multi-step reasoning, available today via API platforms (Baseten, Fireworks AI, Groq, Modal, Nebius, OpenRouter, Together AI) and as downloadable weights (Hugging Face, Amazon SageMaker AI, Google Cloud Model Garden, Microsoft Foundry). It ships three days after Meta's closed, frontier-class Muse Wonder — suggesting Meta is running a fast release cadence to cover both the proprietary and open-weight ends of the market at once. NVIDIA noted the model was trained on its GB300 NVL72 systems.
Signal: Meta calls it "the most capable US open-weight model to date" — 816B total parameters (42B active), a 1M-token context window, natively multimodal, and trained specifically for agentic coding. The real hook is the Apple tie-in: it's the first model in its class built to run locally on two M5 Ultra Mac Studios via MLX, with Apple CEO John Ternus publicly congratulating the team — a notable thaw between two companies that have clashed for years.