Meta Launches Muse Spark, First Proprietary Model from Rebuilt AI Stack

Meta released Muse Spark on April 8, marking the inaugural model from its new Muse series and representing a significant departure from the open-source Llama approach. The proprietary model emerged from a nine-month overhaul of Meta's AI stack led by Chief AI Officer Alexandr Wang, designed as a fast, compact personal assistant with multimodal perception through cameras and glasses integration. Muse Spark features three reasoning modes: Instant, Thinking, and Contemplating, with particular strength in healthcare applications due to collaboration with over 1,000 physicians. The launch signals Meta's strategic shift toward competing directly with closed-source providers while maintaining selective open-source releases.