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Muse-Spark-Open-816B-A42B

Change history

  1. 15 Oct 2026
    Meta releases Muse Spark Open, an 816B-parameter open-weight multimodal MoE model
    ParameterBeforeNow
    ArchitectureMuse Glimmer: dense feed-forward network per layerMuse Spark Open: Mixture-of-Experts, 256 experts per layer, 8 selected per token
    Model sizeNot specified~816B total parameters, ~42B active per token
    Context windowNot specifiedUp to 1,000,000 tokens
    InputsNot specified (Muse Glimmer: no audio encoder)Text, images, audio, and video
    OutputNot specifiedText
    Checkpoint formatsNot specifiedBF16 and NVFP4 (4-bit, for NVIDIA Blackwell GPUs)
    Tool callingNot specifiedSupported, text-only and multimodal

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Models· Important· 🧪 Worth Testing

Meta releases Muse Spark Open, an 816B-parameter open-weight multimodal MoE model

Meta published Muse Spark Open, an open-weight mixture-of-experts model with about 816 billion total parameters and 42 billion active per token. It accepts text, images, audio and video as input and generates text, with a context window of up to 1 million tokens. Meta positions it as a coding-optimized, agentic model built on top of the smaller Muse Glimmer architecture, calling it the most capable US open-weights model released so far.

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Muse-Spark-Open-816B-A42B · TENESYS AI NEWS