Noometry

Model comparison

Claude Opus 5.5 vs Longcat Flash Chat

Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 41.5 on the Noometry Index.

Last verified . 12 shared benchmarks.

Claude Opus 5.5 Anthropic

68.5

Rank #3 Confirmed

Longcat Flash Chat Meituan

41.5

Rank #121 Confirmed

Summary

  • They share 12 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 79.5 to 18.3.
  • 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 Index68.541.5
Released2026-09-22—
WeightsProprietaryOpen
Context window1M—
Max output128K—
Input $ / M tokens$4—
Output $ / M tokens$20—
Results tracked3519

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.4 (#1), Longcat Flash Chat: 42.9 (#85)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Coding15451471
FrontierCode54.4%—
CursorBench57.8%—
LMArena WebDev1820—
FrontierSWE62.3%—
SciCode66.9%—
MirrorCode77.4%—

Agentic & Tool Use Not comparable

Claude Opus 5.5: 45.3 (#13), Longcat Flash Chat: —

BenchmarkClaude Opus 5.5Longcat Flash Chat
APEX-Agents73.5%—
GDP.pdf30.6%—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 79.5 (#2), Longcat Flash Chat: 18.3 (#267)

BenchmarkClaude Opus 5.5Longcat Flash Chat
NYT Connections (extended)88.5%17.7%
LMArena Hard Prompts15451440
ARC-AGI-292.5%—
Kagi LLM Benchmark—43.9%
ARC-AGI-197.5%—
CritPt31.7%—
EBR-Bench71.4%—
Mystery Game Puzzles71%—
DTBench98.9%—
LMCA68.2%—

Math Claude Opus 5.5 leads

Claude Opus 5.5: 92.4 (#2), Longcat Flash Chat: 36.6 (#107)

BenchmarkClaude Opus 5.5Longcat Flash Chat
FrontierMath (Tiers 1-3)91.2%—
FrontierMath Tier 495%—
OTIS Mock AIME 2024-2025100%—
ProofBench100%—
LMArena Math—1441

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.6 (#9), Longcat Flash Chat: 40.0 (#111)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Expert15641454
GPQA Diamond90.6%—
SimpleQA Verified72.2%—

Multimodal Not comparable

Claude Opus 5.5: 56.5 (#2), Longcat Flash Chat: —

BenchmarkClaude Opus 5.5Longcat Flash Chat
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.8 (#1), Longcat Flash Chat: 52.1 (#95)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Non-English15131404
LMArena Chinese15721465
LMArena Russian15321396
LMArena French—1457
LMArena German—1409
LMArena Japanese—1373
LMArena Korean—1372
LMArena Spanish—1445

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.1 (#2), Longcat Flash Chat: 74.6 (#92)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Instruction Following15351411

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.3 (#18), Longcat Flash Chat: 43.5 (#89)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Longer Query15401425

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.7 (#3), Longcat Flash Chat: 61.2 (#88)

BenchmarkClaude Opus 5.5Longcat Flash Chat
LMArena Text15181427
LMArena Creative Writing15381388
LMArena Multi-Turn15201418
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 68.5 to 41.5 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: 71.4 versus 42.9 in the Noometry coding category.

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

12 benchmarks have published results for both models. Claude Opus 5.5 has 35 scored results on Noometry and Longcat Flash Chat has 19.

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