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Muse Spark Open (816B-A42B)

Meta's open-weights Muse Spark model, an 816B-parameter MoE with 42B active, under the Muse Model License.

  • Meta
  • Open weights
  • Released 15 Oct 2026

Official page

Where it ranks

  • C
    Chat & assistants
    Models · Local · 39 on Artificial Analysis Intelligence Index (secondary benchmark)
  • C
    Coding
    Models · Local · 1,524 on LMArena WebDev / Code Arena (overall)
  • A
    Image understanding
    Models · Local · 80.9% on Artificial Analysis MMMU-Pro (independent evaluation) (secondary benchmark)
  • C
    Workflow automation
    Models · Local · 49.7% on AutomationBench-AA (Artificial Analysis)

Facts

Vendor
Meta
Family
Muse Spark Open
Released
15 Oct 2026
Weights
Open: download and run it yourself
License
Muse Model License
Parameters
816B (42B active)
GPU memory to run locally
~470 GB (4-bit ≈ 816 B × 0.57 GB + overhead ≈ 470 GB, estimate (multi-GPU datacenter); an NVFP4 checkpoint is published.)
API price
$1.25 in / $4.25 out per 1M tokens
Access
Free (open weights)
Last verified
18 Oct 2026

Price from openrouter.ai, 18 Oct 2026.

Benchmark results

BenchmarkResultEntry on the leaderboardAs ofSource
Artificial Analysis Intelligence Index39Muse Spark Open (Xhigh)
Raw value from the page's embedded model data; the site displays it rounded to an integer.
18 Oct 2026artificialanalysis.ai
Artificial Analysis MMMU-Pro (independent evaluation)80.9%Muse Spark Open (Xhigh)
Raw fraction 0.8092 from the model data embedded in https://artificialanalysis.ai/leaderboards/models, converted to percent; rank 22 of 124 entries with an MMMU-Pro result; no last-updated date shown.
19 Oct 2026artificialanalysis.ai
AutomationBench-AA (Artificial Analysis)49.7%Muse Spark Open (Xhigh)
AutomationBench-AA Score (share of each task's objectives completed, a task with any guardrail violation scoring zero); raw value from the page's embedded model data (displayed rounded); rank 26 of 32; Tasks Completed 20.85%, Objectives Completed 76.30%; no last-updated date shown, so as_of = retrieval date.
19 Oct 2026artificialanalysis.ai
LMArena WebDev / Code Arena (overall)1,524Muse Spark Open (Max)
From LMArena's official leaderboard-dataset (webdev = Code Arena, split latest, category overall, published 2026-10-18), which mirrors https://arena.ai/leaderboard/webdev. Rank 50; 1337 votes; 95% CI 1506.6-1541.3.
18 Oct 2026huggingface.co
SWE-Bench Pro V2 (public set, full)95%Muse Spark Open (mini-swe-agent) xhigh
SWE-Bench Pro V2 Full (642 tasks); row added 2026-10-16; 95% CI +/-1.43; harness in the variant name; read from the leaderboard page's embedded data.
19 Oct 2026labs.scale.com

Where you can use it

Sources