Meta releases Muse Spark Open: 816B/42B MoE, 1M context, its most capable open model yet
AIatMeta · x · 2026-10-16
Meta AI released Muse Spark Open, billed as the most capable US open-weight model to date, built for coding and agentic work with strengths in long-horizon tasks, complex software engineering, and multi-step reasoning.
Key specs: 816B total / 42B active parameters, a 1M token context window, and native multimodality across text, image, video, and audio.
It's optimized to run on two Apple M5 Ultra Mac Studios with MLX, and supports SGLang, vLLM, TensorRT-LLM, HF Transformers, llama.cpp, and Unsloth across AMD, Apple, Intel, and NVIDIA silicon. Developers can fine-tune with PyTorch and TorchTitan.
Related event: Meta Open-Sources Muse Spark Open: 816B-Parameter MoE with 1M Context(54 posts)→
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