Noometry

Model comparison

Claude Opus 5.5 vs Longcat Flash Chat

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 42.1 on the Noometry Index.

Last verified . 15 shared benchmarks.

Claude Opus 5.5 Anthropic

68.6

Rank #3 Confirmed

Longcat Flash Chat Meituan

42.1

Rank #120 Confirmed

Summary

  • They share 15 benchmarks with published results for both. Claude Opus 5.5 scores higher in 8 categories and Longcat Flash Chat in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 5.5 leads 80.2 to 19.0.
  • The biggest single-benchmark swing is NYT Connections (extended): 88.5% for Claude Opus 5.5 and 17.7% for Longcat Flash Chat.
  • Longcat Flash Chat has downloadable open weights; the other is API-only.

Side by side

Claude Opus 5.5Longcat Flash Chat
ProviderAnthropicMeituan
Noometry Index68.642.1
Released2026-09-22—
WeightsProprietaryOpen
Context window1M—
Max output128K—
Input $ / M tokens$4—
Output $ / M tokens$20—
Results tracked4419

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.9 (#3), Longcat Flash Chat: 43.5 (#87)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Coding15471471
FrontierCode54.6%—
CursorBench57.8%—
LMArena WebDev1813—
FrontierSWE62.3%—
SciCode66.9%—
MirrorCode77.4%—
ALE-Bench2,147—

Agentic & Tool Use Not comparable

Claude Opus 5.5: 45.3 (#15), Longcat Flash Chat: —

BenchmarkClaude Opus 5.5Longcat Flash Chat
APEX-Agents73.5%—
GDP.pdf30.6%—
Vending-Bench 29,235—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 80.2 (#3), Longcat Flash Chat: 19.0 (#272)

BenchmarkClaude Opus 5.5Longcat Flash Chat
NYT Connections (extended)88.5%17.7%
LMArena Hard Prompts15351440
ARC-AGI-293.3%—
Kagi LLM Benchmark—43.9%
ARC-AGI-198.5%—
CritPt31.7%—
EBR-Bench71.4%—
Mystery Game Puzzles71%—
DTBench98.9%—
LMCA68.2%—
Epoch Capabilities Index167.33—

Math Claude Opus 5.5 leads

Claude Opus 5.5: 91.8 (#3), Longcat Flash Chat: 39.4 (#107)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Math15061442
FrontierMath (Tiers 1-3)91.2%—
FrontierMath Tier 495%—
OTIS Mock AIME 2024-2025100%—
ProofBench100%—
FrontierMath Erdős2.9%—

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.4 (#10), Longcat Flash Chat: 40.6 (#116)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Expert15471454
GPQA Diamond90.6%—
SimpleQA Verified72.2%—

Multimodal Not comparable

Claude Opus 5.5: 57.8 (#1), Longcat Flash Chat: —

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Vision1321—
Blueprint-Bench 251.2%—
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.1 (#2), Longcat Flash Chat: 51.9 (#101)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Non-English15071404
LMArena Chinese15881465
LMArena French15141456
LMArena Russian15201395
LMArena Spanish15071445
LMArena German—1408
LMArena Japanese—1373
LMArena Korean—1371

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.0 (#3), Longcat Flash Chat: 74.4 (#96)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Instruction Following15371411

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.1 (#19), Longcat Flash Chat: 43.5 (#93)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Longer Query15321425

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.2 (#3), Longcat Flash Chat: 61.0 (#91)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Text15151427
LMArena Creative Writing15331388
LMArena Multi-Turn14991418
EQ-Bench Creative Writing2050—

Frequently asked questions

Is Claude Opus 5.5 better than Longcat Flash Chat?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 42.1 on the Noometry Index.

Is Claude Opus 5.5 or Longcat Flash Chat better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 43.5 in the Noometry coding category.

How many benchmarks do Claude Opus 5.5 and Longcat Flash Chat share?

15 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and Longcat Flash Chat has 19.

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