Model comparison
Claude Mythos Preview vs Claude Opus 4.8
Claude Opus 4.8 has enough public results to be ranked (#13); Claude Mythos Preview does not yet, so treat this comparison as directional.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in agentic & tool use, where Claude Opus 4.8 leads 47.6 to 41.4.
Side by side
| Claude Mythos Preview | Claude Opus 4.8 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 41.2 | 60.7 |
| Released | 2026-04-07 | 2026-05-28 |
| Weights | Proprietary | Proprietary |
| Context window | — | 1M |
| Max output | — | 128K |
| Input $ / M tokens | — | $5 |
| Output $ / M tokens | — | $25 |
| Results tracked | 2 | 65 |
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Category by category
Coding Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 59.9 (#12)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| DeepSWE | — | 59% |
| FrontierCode | — | 46.5% |
| LMArena WebDev | — | 1556 |
| SciCode | — | 53.5% |
| GSO | — | 47.1% |
| WeirdML | — | 82.9% |
| LMArena Coding | — | 1490 |
| ALE-Bench | — | 1,564 |
Agentic & Tool Use Claude Opus 4.8 leads
Claude Mythos Preview: 41.4, Claude Opus 4.8: 47.6 (#11)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| APEX-Agents | — | 48.9% |
| OSWorld 2.0 | — | 20.6% |
| Remote Labor Index | — | 8.3% |
| τ²-bench Banking | — | 39.7% |
| DeepResearch Bench | — | 50.2% |
| PostTrainBench | — | 33.8% |
| ExploitBench | 73.8% | — |
| GBAEval | — | 70.9% |
| GDP.pdf | — | 24% |
| LMArena Search | — | 1204 |
| METR Time Horizons | 85.2% | — |
| Vending-Bench 2 | — | 5,787 |
Reasoning Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 64.7 (#16)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| ARC-AGI-2 | — | 72.1% |
| SimpleBench | — | 64.8% |
| Kagi LLM Benchmark | — | 88.8% |
| NYT Connections (extended) | — | 91.1% |
| ARC-AGI-1 | — | 92.5% |
| CritPt | — | 20.9% |
| Chess Puzzles | — | 34% |
| EnigmaEval | — | 23.5% |
| EBR-Bench | — | 28.6% |
| LMArena Hard Prompts | — | 1482 |
| Mystery Game Puzzles | — | 36% |
| DTBench | — | 94.9% |
| LMCA | — | 57.5% |
| Surface Evolver Bench | — | 87.5% |
| Bench to the Future 3 | — | 0.14 |
| Epoch Capabilities Index | — | 158.21 |
| ForecastBench | — | 59.9 |
Math Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 78.4 (#13)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 80% |
| FrontierMath Tier 4 | — | 56.1% |
| MathArena Final-Answer Competitions | — | 91.8% |
| OTIS Mock AIME 2024-2025 | — | 98.3% |
| ProofBench | — | 69% |
| LMArena Math | — | 1487 |
| FrontierMath (Feb 2025 set) | — | 47.2% |
| FrontierMath Tier 4 (v1) | — | 31.3% |
Knowledge Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 61.3 (#29)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| GPQA Diamond | — | 91% |
| SimpleQA Verified | — | 53% |
| LMArena Expert | — | 1502 |
Multimodal Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 42.9 (#26)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| LMArena Vision | — | 1294 |
| Blueprint-Bench 2 | — | 14.5% |
| Furniture Assembly | — | 42.5% |
| LMArena Document | — | 1475 |
Multilingual Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 55.2 (#33)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| LMArena Non-English | — | 1450 |
| LMArena Chinese | — | 1507 |
| LMArena French | — | 1481 |
| LMArena German | — | 1472 |
| LMArena Japanese | — | 1440 |
| LMArena Korean | — | 1432 |
| LMArena Russian | — | 1474 |
| LMArena Spanish | — | 1466 |
Instruction Following Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 77.4 (#24)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| LMArena Instruction Following | — | 1476 |
Long Context Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 45.4 (#35)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| LMArena Longer Query | — | 1483 |
Writing & Preference Not comparable
Claude Mythos Preview: —, Claude Opus 4.8: 72.0 (#16)
| Benchmark | Claude Mythos Preview | Claude Opus 4.8 |
|---|---|---|
| LMArena Text | — | 1461 |
| LMArena Creative Writing | — | 1454 |
| EQ-Bench Creative Writing | — | 1840 |
| EQ-Bench 4 | — | 1281 |
| LMArena Multi-Turn | — | 1476 |
Frequently asked questions
Is Claude Mythos Preview better than Claude Opus 4.8?
Claude Opus 4.8 has enough public results to be ranked (#13); Claude Mythos Preview does not yet, so treat this comparison as directional.
How many benchmarks do Claude Mythos Preview and Claude Opus 4.8 share?
0 benchmarks have published results for both models. Claude Mythos Preview has 2 scored results on Noometry and Claude Opus 4.8 has 65.