Welcome Muse Spark Open: open-weight frontier multimodal mixture-of-experts model from Meta
Meta has unveiled Muse Spark Open, an open‑weight multimodal mixture‑of‑experts model with roughly 816 billion parameters (about 42 billion active per token) and a 1‑million‑token context window. The model handles text, images, audio and video, and is optimized for agentic coding tasks such as reading codebases, debugging, and tool use, offering a unified interface for developers. Its MoE architecture enables the massive parameter count while keeping inference speed comparable to a 42 billion‑parameter model, marking the most capable US open‑weight model to date.