Meta Releases Muse Spark Open Open-Weight Model with 1M Context Window

Meta released Muse Spark Open, an 816B total / 42B active MoE model featuring a 1M-token context window, capable of accepting text, image, video, and audio input for coding, long-horizon agents, and multi-step reasoning. This model is licensed under the custom Muse Model License, requiring specific attribution and agreements for large Model-as-a-Service businesses. Independent measurement scores it 39 on its Intelligence Index, ranking it first among US open-weight models.