TLDRocket
15 October 2026
Meta’s big move today wasn’t just another model release—it was a licensing-and-distribution statement. Muse Spark Open ships as an 816B-parameter, coding-optimized multimodal model with a 1 million–token context window and 42B active parameters per token, now available as downloads for developers (with restrictions) and deployable through Amazon SageMaker JumpStart into customer-controlled endpoints. The “open” part comes with strings: a custom Muse Model License, advance notification above $20 million revenue, and a required “Built with Muse Spark Open” attribution. Meta still keeps its top systems closed, but it’s clearly betting that more developers will build long-running agent workflows when they can run, fine-tune, and adapt the weights.
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