Noometry

Model comparison

Claude Mythos Preview vs GPT-5

GPT-5 has enough public results to be ranked (#37); Claude Mythos Preview does not yet, so treat this comparison as directional.

Last verified . 1 shared benchmarks.

Claude Mythos Preview Anthropic

40.8

Unranked Sparse

GPT-5 OpenAI

50.9

Rank #37 Confirmed

Summary

  • They share 1 benchmark with published results for both. Claude Mythos Preview scores higher in 1 category and GPT-5 in 0 categories; one gap is clear of the uncertainty.
  • The widest gap is in agentic & tool use, where Claude Mythos Preview leads 41.1 to 33.0.

Side by side

Claude Mythos PreviewGPT-5
ProviderAnthropicOpenAI
Noometry Index40.850.9
Released2026-04-072025-08-07
WeightsProprietaryProprietary
Context window—400K
Max output—128K
Input $ / M tokens—$1.25
Output $ / M tokens—$10
Results tracked269

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Category by category

Coding Not comparable

Claude Mythos Preview: —, GPT-5: 50.7 (#39)

BenchmarkClaude Mythos PreviewGPT-5
SWE-bench Verified—73.6%
SWE-bench Verified (bash only)—65%
Aider Polyglot—88%
LMArena WebDev—1417
SciCode—42.9%
GSO—6.9%
WeirdML—60.7%
LMArena Coding—1436
ALE-Bench—1,162
AlgoTune—1.67

Agentic & Tool Use Claude Mythos Preview leads

Claude Mythos Preview: 41.1, GPT-5: 33.0 (#53)

BenchmarkClaude Mythos PreviewGPT-5
METR Time Horizons85.2%69.6%
Terminal-Bench—49.6%
GDPval—34.8%
Remote Labor Index—1.7%
DeepResearch Bench—49.6%
BALROG—32.8%
ExploitBench73.8%—
LMArena Search—1133

Reasoning Not comparable

Claude Mythos Preview: —, GPT-5: 38.3 (#55)

BenchmarkClaude Mythos PreviewGPT-5
ARC-AGI-2—9.9%
SimpleBench—56.7%
Kagi LLM Benchmark—72.7%
ARC-AGI-1—65.7%
CritPt—12.6%
Chess Puzzles—37%
EnigmaEval—10.5%
EBR-Bench—12.7%
LMArena Hard Prompts—1415
Mystery Game Puzzles—23%
DTBench—90.7%
LMCA—40%
Epoch Capabilities Index—150
ForecastBench—61.4

Math Not comparable

Claude Mythos Preview: —, GPT-5: 54.6 (#36)

BenchmarkClaude Mythos PreviewGPT-5
FrontierMath (Tiers 1-3)—55.4%
FrontierMath Tier 4—22%
OTIS Mock AIME 2024-2025—91.4%
ProofBench—18%
Omni-MATH—64.7%
LMArena Math—1406
MATH Level 5—98.1%
FrontierMath (Feb 2025 set)—32.4%
FrontierMath Tier 4 (v1)—12.5%

Knowledge Not comparable

Claude Mythos Preview: —, GPT-5: 56.5 (#37)

BenchmarkClaude Mythos PreviewGPT-5
GPQA Diamond—86.2%
Humanity's Last Exam—25.3%
SimpleQA Verified—50.1%
MMLU-Pro—86.3%
Confabulations—10.3%
Vectara Hallucination Rate—14.7%
GPQA (HELM)—79.2%
LMArena Expert—1420

Multimodal Not comparable

Claude Mythos Preview: —, GPT-5: 46.1 (#12)

BenchmarkClaude Mythos PreviewGPT-5
LMArena Vision—1232
GeoBench—81%
VPCT—66%

Multilingual Not comparable

Claude Mythos Preview: —, GPT-5: 51.5 (#105)

BenchmarkClaude Mythos PreviewGPT-5
LMArena Non-English—1397
LMArena Chinese—1423
LMArena French—1409
LMArena German—1415
LMArena Japanese—1411
LMArena Korean—1361
LMArena Russian—1406
LMArena Spanish—1398

Instruction Following Not comparable

Claude Mythos Preview: —, GPT-5: 74.0 (#107)

BenchmarkClaude Mythos PreviewGPT-5
IFEval—87.5%
LMArena Instruction Following—1388

Long Context Not comparable

Claude Mythos Preview: —, GPT-5: 69.5 (#2)

BenchmarkClaude Mythos PreviewGPT-5
Fiction.LiveBench—97.2%
LMArena Longer Query—1399

Writing & Preference Not comparable

Claude Mythos Preview: —, GPT-5: 63.5 (#63)

BenchmarkClaude Mythos PreviewGPT-5
LMArena Text—1406
LMArena Creative Writing—1365
Short-Story Creative Writing—86%
EQ-Bench Creative Writing—1627
WildBench—85.7%
LMArena Multi-Turn—1426

Frequently asked questions

Is Claude Mythos Preview better than GPT-5?

GPT-5 has enough public results to be ranked (#37); Claude Mythos Preview does not yet, so treat this comparison as directional.

How many benchmarks do Claude Mythos Preview and GPT-5 share?

1 benchmark has published results for both models. Claude Mythos Preview has 2 scored results on Noometry and GPT-5 has 69.

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