Meta just put an 816B open-weight model within reach of your desktop
The open-weight race just moved to agentic work at the top end, and Meta is back in it after a year of trailing the Chinese labs.
Meta released Muse Spark Open yesterday. It’s 816B total parameters with 42B active, a 1M-token context window, and it’s built for coding and agent work. The weights are on Hugging Face, and you can call it today through OpenRouter, Together, Fireworks, Baseten, Groq, Modal, or Nebius. Meta also says it runs on two Apple M5 Ultra Mac Studios with MLX, which no model in this class has managed before.
Sources: research.meta.ai/blog/muse-spark-open and huggingface.co/meta-models/Muse-Spark-Open-816B-A42B
My read: the open-weight race just moved to agentic work at the top end, and Meta is back in it after a year of trailing the Chinese labs.
Your pick: try it on OpenRouter or Groq this week, and run it against GLM 5.3 Flash on your own coding tasks before you switch anything.
12 months: open agentic models become the default for internal dev tools.
24 months: desktop-class frontier models put pressure on API pricing.
36 months: the open-weight gap between countries matters more than the closed-model race.
Why I may be wrong: early tests have it behind Qwen3.8 Flash Next and GLM 5.3 Flash on some benchmarks, and the license limits large model-as-a-service businesses.
So: real shift, or Meta catching up?