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Meta releases Muse Spark Open, 816B-parameter open-weight model

techOct 15, 20264758

Meta published Muse Spark Open, an 816-billion-parameter open-weight mixture-of-experts model that activates about 42 billion parameters per token and provides a 1,000,000-token context window. The model accepts text, images, documents, audio, and audio-video inputs and is trained on real developer workflows to support multi-step agentic coding tasks such as multi-file refactors, long debugging sessions, tool calling, and self-correction over long horizons. Meta released two SageMaker JumpStart variants: BF16 (Muse-Spark-Open-816B-A42B) and an NVFP4-quantized variant (Muse-Spark-Open-816B-A42B-NVFP4) with roughly one quarter the memory requirement for cost-efficient deployment. Amazon SageMaker JumpStart lets customers deploy Muse Spark Open into endpoints running in their own AWS accounts using the SageMaker console or the SageMaker Python SDK. Meta and Apple engineers also optimized a quantized build that can run locally across paired Apple M5 Ultra Mac Studio systems by combining multiple 512 GB machines to meet the model memory needs. Meta positions Muse Spark Open for enterprise engineering workflows that need to ingest entire projects including dependencies and thousands of files without splitting tasks, enabling longer-lived coding agents and multimodal engineering on cloud and high-memory desktop setups. Availability on SageMaker JumpStart and optimized local Mac deployments expand options for enterprises and developers to run the open-weight model either in their AWS accounts or on compatible Apple hardware.

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