tl;dr: Meta released Muse Spark Open, an 816B-parameter (42B active) multimodal MoE model with a 1M-token context, optimized for coding and agentic workflows. Notably, it can run locally on two Apple M5 Ultra Mac Studios via MLX, leveraging their unified memory to hold the full model. Weights are available on Hugging Face under a limited commercial license, with hosted inference through Together AI, Fireworks, Groq, and others.