# 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.

- Canonical page: https://noometry.com/compare/claude-opus-5-5-vs-longcat-flash-chat
- Last updated: 2026-10-10
- Shared benchmarks: 12

## 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.

## Snapshot

| | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| Provider | Anthropic | Meituan |
| Noometry Index | 68.5 | 41.5 |
| Rank | 3 | 121 |
| Context | 1M | — |
| Input $/M | $4 | — |
| Output $/M | $20 | — |
| Weights | Proprietary | Open |

## Coding

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Coding | 1545 | 1471 |
| FrontierCode | 54.4% | — |
| CursorBench | 57.8% | — |
| LMArena WebDev | 1820 | — |
| FrontierSWE | 62.3% | — |
| SciCode | 66.9% | — |
| MirrorCode | 77.4% | — |

## Agentic & Tool Use

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| APEX-Agents | 73.5% | — |
| GDP.pdf | 30.6% | — |

## Reasoning

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| NYT Connections (extended) | 88.5% | 17.7% |
| LMArena Hard Prompts | 1545 | 1440 |
| ARC-AGI-2 | 92.5% | — |
| Kagi LLM Benchmark | — | 43.9% |
| ARC-AGI-1 | 97.5% | — |
| CritPt | 31.7% | — |
| EBR-Bench | 71.4% | — |
| Mystery Game Puzzles | 71% | — |
| DTBench | 98.9% | — |
| LMCA | 68.2% | — |

## Math

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| FrontierMath (Tiers 1-3) | 91.2% | — |
| FrontierMath Tier 4 | 95% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
| LMArena Math | — | 1441 |

## Knowledge

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Expert | 1564 | 1454 |
| GPQA Diamond | 90.6% | — |
| SimpleQA Verified | 72.2% | — |

## Multimodal

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| Furniture Assembly | 83.3% | — |

## Multilingual

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Non-English | 1513 | 1404 |
| LMArena Chinese | 1572 | 1465 |
| LMArena Russian | 1532 | 1396 |
| LMArena French | — | 1457 |
| LMArena German | — | 1409 |
| LMArena Japanese | — | 1373 |
| LMArena Korean | — | 1372 |
| LMArena Spanish | — | 1445 |

## Instruction Following

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Instruction Following | 1535 | 1411 |

## Long Context

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Longer Query | 1540 | 1425 |

## Writing & Preference

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

| Benchmark | Claude Opus 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Text | 1518 | 1427 |
| LMArena Creative Writing | 1538 | 1388 |
| LMArena Multi-Turn | 1520 | 1418 |
| EQ-Bench Creative Writing | 2050 | — |

## FAQ

### 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.