Muse Spark Open

Meta · open weight · muse-spark-open

Muse Spark Open is Meta Superintelligence Labs' open-weight natively multimodal Mixture-of-Experts model (816B total / 42B active parameters) with a 1,048,576-token context window. The HF model card specifies text, image, video, and audio inputs and text output. It supports configurable reasoning_effort (low/medium/high/xhigh; default xhigh) and is positioned for coding and agentic workflows. Weights are released under the Muse Model License with limited commercial terms and are available on Hugging Face as meta-models/Muse-Spark-Open-816B-A42B (BF16) and an NVFP4 sibling. Hosted inference is offered by third-party providers including Together AI, Fireworks AI, Groq, Modal, Nebius, Baseten, and OpenRouter (slug meta/muse-spark-open).