Noometry

Model comparison

Claude Fable 5.1 vs Mercury

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 37.6 on the Noometry Index.

Last verified . 8 shared benchmarks.

Claude Fable 5.1 Anthropic

69.0

Rank #2 Confirmed

Mercury Inception

37.6

Rank #199 Confirmed

Summary

  • They share 8 benchmarks with published results for both. Claude Fable 5.1 scores higher in 6 categories and Mercury in 0 categories; 6 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Fable 5.1 leads 76.7 to 17.5.

Side by side

Claude Fable 5.1Mercury
ProviderAnthropicInception
Noometry Index69.037.6
Released2026-09-01—
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$10—
Output $ / M tokens$50—
Results tracked529

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Category by category

Coding Claude Fable 5.1 leads

Claude Fable 5.1: 74.7 (#1), Mercury: 38.7 (#170)

BenchmarkClaude Fable 5.1Mercury
LMArena Coding15281322
FrontierCode50.9%—
CursorBench51.8%—
LMArena WebDev1744—
FrontierSWE56.3%—
SciCode63.1%—
GSO88.2%—
WeirdML92.9%—
MirrorCode73.3%—
ALE-Bench2,143—

Agentic & Tool Use Not comparable

Claude Fable 5.1: 50.7 (#5), Mercury: —

BenchmarkClaude Fable 5.1Mercury
APEX-Agents68.6%—
Remote Labor Index17.9%—
GDP.pdf29.6%—
Vending-Bench 25,422—

Reasoning Claude Fable 5.1 leads

Claude Fable 5.1: 76.7 (#7), Mercury: 17.5 (#293)

BenchmarkClaude Fable 5.1Mercury
LMArena Hard Prompts15261285
ARC-AGI-290%—
Kagi LLM Benchmark—21.6%
NYT Connections (extended)90%—
ARC-AGI-197.5%—
CritPt31.1%—
Chess Puzzles47%—
EBR-Bench57.1%—
Mystery Game Puzzles58%—
DTBench97.6%—
LMCA65.5%—
Epoch Capabilities Index164.7—

Math Not comparable

Claude Fable 5.1: 89.6 (#4), Mercury: —

BenchmarkClaude Fable 5.1Mercury
FrontierMath (Tiers 1-3)90.2%—
FrontierMath Tier 487.8%—
OTIS Mock AIME 2024-2025100%—
ProofBench100%—
LMArena Math1525—
FrontierMath Erdős0%—

Knowledge Not comparable

Claude Fable 5.1: 69.6 (#6), Mercury: —

BenchmarkClaude Fable 5.1Mercury
Humanity's Last Exam46.5%—
SimpleQA Verified70.8%—
LMArena Expert1535—

Multimodal Not comparable

Claude Fable 5.1: 53.9 (#4), Mercury: —

BenchmarkClaude Fable 5.1Mercury
LMArena Vision1318—
Blueprint-Bench 241.9%—
Furniture Assembly70%—
LMArena Document1513—

Multilingual Claude Fable 5.1 leads

Claude Fable 5.1: 59.1 (#3), Mercury: 41.6 (#206)

BenchmarkClaude Fable 5.1Mercury
LMArena Non-English15071260
LMArena Chinese1586—
LMArena French1525—
LMArena German1500—
LMArena Japanese1543—
LMArena Korean1534—
LMArena Russian1521—
LMArena Spanish1516—

Instruction Following Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#6), Mercury: 65.2 (#224)

BenchmarkClaude Fable 5.1Mercury
LMArena Instruction Following15171239

Long Context Claude Fable 5.1 leads

Claude Fable 5.1: 46.7 (#20), Mercury: 38.4 (#198)

BenchmarkClaude Fable 5.1Mercury
LMArena Longer Query15221266

Writing & Preference Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#2), Mercury: 46.2 (#221)

BenchmarkClaude Fable 5.1Mercury
LMArena Text15101282
LMArena Creative Writing15071191
LMArena Multi-Turn14921282
EQ-Bench Creative Writing2162—

Frequently asked questions

Is Claude Fable 5.1 better than Mercury?

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 37.6 on the Noometry Index.

Is Claude Fable 5.1 or Mercury better for coding?

Claude Fable 5.1 scores higher on coding benchmarks: 74.7 versus 38.7 in the Noometry coding category.

How many benchmarks do Claude Fable 5.1 and Mercury share?

8 benchmarks have published results for both models. Claude Fable 5.1 has 52 scored results on Noometry and Mercury has 9.

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