Muse Spark Open

Meta's open-weight release of Muse Spark, October 15, 2026: an 816B-total / 42B-active natively multimodal MoE (text, image, video and audio in, text out) with a 1M-token context, shipped in BF16 and NVFP4 under the Muse Model License and served by third-party hosts (Baseten, Fireworks, Groq, Modal, Nebius, OpenRouter, Together); Meta sets no first-party price. Meta's table runs it at xhigh effort against open-weight peers: it leads JobBench (61.8) and MCP-Atlas (89.2) but trails GLM 5.3 and Kimi K3 on DeepSWE 1.1 (60) and Terminal-Bench 2.1 (76.4). NOT FILED: Artificial Analysis Intelligence Index (39) has no corpus column; GDPVal-AA v2 (1401) is not filed because the corpus gdpval-aa column and AA's re-based v2.x launch figures are on different scales; HLE-Diamond no-tools (26.1) is a subset, not the full HLE; AA Omniscience (25), ZeroBench, BabyVision, SimpleVQA, WorldVQA, IntPhys2 and VideoMME v2 have no matching column; FORTRESS and StrongREJECT are safety metrics.