Welcome Muse Spark Open: open-weight frontier multimodal mixture-of-experts model from Meta

Meta has released Muse Spark Open, an open-weight multimodal mixture-of-experts model with 816B total parameters and roughly 42B active per token, following the smaller Muse Glimmer. Trained for agentic coding, it accepts text, images, audio, and video, and supports a 1M-token context window. Checkpoints are Muse-Spark-Open-816B-A42B (BF16, ~1.5 TB) and an NVFP4 4-bit variant for NVIDIA Blackwell GPUs. The BF16 version runs across four nodes of eight H200 GPUs.