Meta releases Muse Spark Open weights
An open-weight multimodal model with 816B total parameters, 42B active, and a 1 million token context window.
Official source (opens in a new tab)
Meta's research post on 15 October 2026 says the weights for Muse Spark Open are available. Meta calls it a natively multimodal model with 816 billion total parameters, 42 billion active, and a 1 million token context window, built for coding and agentic work. Meta says it is the first model in its class to run on a desktop using two Apple M5 Ultra Mac Studios with MLX.
Hosted inference is available through Baseten, Fireworks AI, Groq, Modal, Nebius, OpenRouter, and Together AI. Weights are on Amazon SageMaker AI, Google Cloud Model Garden, Hugging Face, and Microsoft Foundry Models. Meta lists SGLang, vLLM, TensorRT-LLM, Hugging Face Transformers, Apple MLX, llama.cpp, and Unsloth as inference engines. The weights ship under the Muse Model License with limited commercial terms.
Who it's for: people who want an open-weight model for coding and agent work, including a desktop setup on two M5 Ultra Mac Studios.
Fits: Best Agent Builder and Best for Vibe Coding as a model you can host, not a replacement for the editors and agents already ranked there.