Meta releases 816B-parameter Muse Spark Open

Meta released Muse Spark Open on October 15, making the model’s weights available for developers to download and adapt. The company says the multimodal model has 816 billion total parameters, 42 billion active parameters and a one-million-token context window, and is designed for coding and agentic tasks. ^[1][3]

Meta says the model can run locally across two Apple M5 Ultra Mac Studios using its MLX framework; TechCrunch notes that local use requires substantial memory. ^[1][2] The weights are released under Meta’s Muse Model License, which includes limited commercial terms. ^[1] Meta describes the model as its most capable US open-weight release to date, but the reported capabilities and evaluations are largely company claims; they do not by themselves establish performance across independent real-world use. ^[1][2]