Claude Fable 5.1 vs Muse Spark

  • Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1474.
  • On the 5 Vals AI benchmarks both have taken, Claude Fable 5.1 wins 5 and Muse Spark wins 0.
LMArena text rating over time
14601468147514831490Apr 26May 26Jul 26Sep 26Oct 26
LatestMuse Spark 1474

Side by side

Models (2/6)
  • Claude Fable 5.1
  • Muse Spark
BenchmarkClaude Fable 5.1Muse Spark
The model
LabAnthropicMeta
Released2026-09-01—
WeightsProprietaryProprietary
Context window1M—
Input, per 1M tokens$10—
Output, per 1M tokens$50—
LMArena, people’s votes
LMArena TextMillions of people compare two anonymous models side by side and vote for the better answer1513#3 of 3511474#26 of 351
LMArena WebDevPeople ask two anonymous models to build the same web app, try both and vote for the better one1743#5 of 124—
LMArena VisionSide-by-side votes on prompts that include an image1320#4 of 1461306#15 of 146
LMArena CodingLMArena’s text votes on prompts that ask for code1531#7 of 3461481#56 of 346
LMArena MathLMArena’s text votes on math prompts1532#3 of 3391456#65 of 339
LMArena Creative writingLMArena’s text votes on stories, poems and other creative writing1510#3 of 3491459#26 of 349
LMArena Hard promptsLMArena’s text votes on the hardest prompts1528#3 of 3511474#41 of 351
LMArena Instruction followingLMArena’s text votes on prompts with specific instructions to follow1519#4 of 3511443#58 of 351
Vals AI, coding
Terminal-Bench 4.0Frontier-difficulty tasks an agent completes in a real terminal58.08%#5 of 55—
SWE-benchReal GitHub issues from open-source projects—74.40%#45 of 85
Vibe Code BenchBuilding complete web apps from a plain-language brief, graded on whether the app works90.26%#6 of 11519.67%#84 of 115
LiveCodeBenchFresh competitive programming problems, collected after models’ training cut-offs to avoid contamination90.52%#1 of 143—
Vals AI, finance
Tax Agent BenchAgentic research into US corporate tax questions49.19%#2 of 76—
Vals AI, law
Legal Research BenchAgentic US legal research55.29%#3 of 85—
Vals AI, medicine
MedCodeAssigning the right medical billing codes from clinical notes53.51%#8 of 10751.31%#16 of 107
Vals AI, reasoning
GPQA DiamondGraduate-level questions in biology, physics and chemistry that experts answer well and search does not93.43%#9 of 13889.65%#28 of 138
MMLU-ProHarder, reasoning-focused multiple choice across 14 subjects, from law to engineering92.38%#1 of 13887.32%#30 of 138
AIMEProblems from the American Invitational Mathematics Examination, a qualifier for the US Math Olympiad—96.88%#3 of 96
MMMUCollege-level questions that need both an image and text90.64%#1 of 9387.40%#16 of 93
Terminal-Bench ScienceExpert-written scientific research workflows, run by an agent in a terminal40.00%#6 of 42—

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Questions

Which is better, Claude Fable 5.1 or Muse Spark?

Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1474. On the 5 Vals AI benchmarks both have taken, Claude Fable 5.1 wins 5 and Muse Spark wins 0.

Sources

Every number on this page comes from these sources; models without a published number show none. Download the data. Cite as “Nexus Explorer, nexus.inc/models”.