Muse Spark Open
Meta's open-weight frontier model — an 816B mixture-of-experts with 42B active, natively multimodal, built for coding and long-horizon agents, and able to run on two Mac Studios
Muse Spark Open
Meta • October 2026
Training Data
Text, images, audio and video from public sources, web crawls, third-party acquisitions, Meta products and synthetic data; 100+ languages
Muse Spark Open
October 2026
Parameters
816B total / 42B active (MoE, 256 experts, 8 per token)
Training Method
Not disclosed; additional safety post-training for the open-weights release
Context Window
1,000,000 tokens
Knowledge Cutoff
Not disclosed
Key Features
Open Weights (Muse Model License) • Runs on Two M5 Ultra Mac Studios • Text, Image, Video & Audio Input • Adjustable Reasoning Effort
Capabilities
Agentic: Outstanding (MCP-Atlas 89.2, OSWorld Verified 80.4)
Coding: Excellent (Terminal-Bench 2.1 76.4)
Reasoning: Excellent (GPQA Diamond 89.0)
What's New in This Version
Meta calls it 'the most capable US open-weight model to date' — a far larger open release than the 30B Muse Glimmer, though under the Muse Model License rather than Apache 2.0, and scoring 39 on the Artificial Analysis Intelligence Index against Muse Wonder's 52
Meta's open-weight frontier model — an 816B mixture-of-experts with 42B active, natively multimodal, built for coding and long-horizon agents, and able to run on two Mac Studios
What's New in This Version
Meta calls it 'the most capable US open-weight model to date' — a far larger open release than the 30B Muse Glimmer, though under the Muse Model License rather than Apache 2.0, and scoring 39 on the Artificial Analysis Intelligence Index against Muse Wonder's 52
Technical Specifications
Key Features
Capabilities
Other Meta Models
Explore more models from Meta
Muse Wonder
Meta's first frontier-class model, closed-weight and built for personal and professional agents, with Active Memory across conversations and Active Focus on long goals; its larger sibling, Muse Wonder Full, is reserved for paid Muse Code subscribers
Muse Spark 1.3
Meta's most capable Muse model, built for long-horizon agentic work — it collaborates, asks before consequential actions, and holds complex instructions across multi-step tasks
Muse Spark 1.2
Coding-focused update to Muse Spark 1.1, released alongside Muse Code, Meta's terminal coding agent
