Meta releases Muse Spark Open, an 816B open-weight multimodal coding model
Meta released Muse Spark Open, an open-weight mixture-of-experts model with roughly 816 billion total parameters and about 42 billion active per token, accepting text, images, audio and video with a context window of up to one million tokens. Meta says it is built for agentic coding and long-horizon tasks and calls it “the most capable US open-weight model to date,” adding that its own benchmarks show it beating GLM-5.3 and Kimi K3 on agentic and visual-reasoning tasks. Weights are available on Hugging Face, with day-one hosting from Together AI and Modal, while Bloomberg reports Meta kept its most advanced models closed.
It pushes large multimodal open weights into coding-agent work and gives US labs a directly comparable option against leading Chinese open models.