Claude Fable 5 vs Claude Opus 4.6
Different efforts: max · high · Compare all at high
Humanity's Last Exam Humanity's Last Exam: Very hard expert questions across many fields, written to stump today’s models
Fable 555.5
Opus 4.619.1
Arena Text · overall Arena Text · overall: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,504
Opus 4.61,503
Arena Text · Chinese Arena Text · chinese: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,542.3
Opus 4.61,550.2
Arena Text · English Arena Text · english: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,499
Opus 4.61,512
Arena Text · French Arena Text · french: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,503.6
Opus 4.61,512.8
Arena Text · German Arena Text · german: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,486.7
Opus 4.61,501.8
Arena Text · instruction following Arena Text · instruction following: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,502.3
Opus 4.61,522
Arena Text · Japanese Arena Text · japanese: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,506.4
Opus 4.61,488
Arena Text · Korean Arena Text · korean: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,491
Opus 4.61,449.8
Arena Text · non-English Arena Text · non english: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,480.7
Opus 4.61,488.1
Arena Text · Polish Arena Text · polish: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,493.4
Opus 4.61,496.6
Arena Text · Russian Arena Text · russian: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,503
Opus 4.61,496.1
Arena Text · Spanish Arena Text · spanish: Human pairwise preferences in the stated text vote pool
Fable 5 · high1,495.8
Opus 4.61,504.2
AA Omniscience Index AA Omniscience Index: Scores factual knowledge while penalizing incorrect answers to encourage admitting uncertainty
Fable 543.3
Opus 4.62.4
SimpleQA Verified v1 SimpleQA Verified v1: Accuracy on short factual questions with verified answers, answered without web access
Fable 5 · xhigh70.7
Opus 4.6 · max47
CritPt (physics) CritPt (physics): Research-level physics problems that need many careful reasoning steps
Fable 528.6
Opus 4.62.8
AA Intelligence Index 4.3.2 AA Intelligence Index 4.3.2: Artificial Analysis combines tests of knowledge, reasoning, coding and tool use into one score
Fable 549.6
Opus 4.626.4
AA Omniscience · Accuracy AA Omniscience · Accuracy: Measures correct answers on the AA Omniscience factual knowledge test
Fable 565.4
Opus 4.645.8
AA Omniscience · Hallucination Rate AA Omniscience · Hallucination Rate: Measures how often attempted answers are incorrect on the AA Omniscience factual knowledge test · lower is better
Fable 563.6
Opus 4.680.1
AA-LCR (long context) 1.1 AA-LCR (long context) 1.1: Questions that need reading and connecting facts across very long documents (around 100K tokens)
Fable 582.3
Opus 4.667
IFBench (instructions) IFBench (instructions): Checks whether the model follows precise formatting and content instructions
Fable 563.5
Opus 4.644.6
ARC-AGI-1 · public evaluation ARC-AGI-1 · public-eval: Models infer transformations from examples and solve unseen grid puzzles; the evaluation split is explicit
Fable 597.6
Opus 4.696.3
ARC-AGI-1 · semi-private ARC-AGI-1 · semi-private: Models infer transformations from examples and solve unseen grid puzzles; the evaluation split is explicit
Fable 598.5
Opus 4.694
ARC-AGI-2 · public evaluation ARC-AGI-2 · public-eval: Models infer transformations from examples and solve unseen grid puzzles; the evaluation split is explicit
Fable 596.4
Opus 4.679
ARC-AGI-2 · semi-private ARC-AGI-2 · semi-private: Models infer transformations from examples and solve unseen grid puzzles; the evaluation split is explicit
Fable 589.2
Opus 4.669.2
EQ-Bench 3 EQ-Bench 3: Judge-rated responses to social and emotionally nuanced scenarios, scored through the source pairwise ranking
Fable 52,049.7
Opus 4.61,717.4
Chess Puzzles Chess Puzzles: Models choose the best next move from a novel chess position
Fable 547
Opus 4.6 · max21
FrontierMath Tier 4 (v2) FrontierMath Tier 4 (v2): Models solve expert-written advanced mathematics problems on the named tier and edition
Fable 590.2
Opus 4.6 · max26.8
FrontierMath Tiers 1–3 (v2) FrontierMath Tiers 1–3 (v2): Models solve expert-written advanced mathematics problems on the named tier and edition
Fable 587
Opus 4.6 · max66
Mystery Game Puzzles Mystery Game Puzzles: Models choose the best move in puzzle positions from an undisclosed game
Fable 552
Opus 4.6 · max25
Vals LegalBench Vals LegalBench: Legal reasoning and legal-language understanding on LegalBench
Fable 588.6
Opus 4.685.3
Vals MedCode Vals MedCode: Medical coding accuracy on patient encounters
Fable 556.1
Opus 4.649.1
Vals MedScribe Vals MedScribe: Accuracy of clinical notes produced from consultation transcripts
Fable 588.5
Opus 4.686.1
GDP.pdf · AA all-pass GDP.pdf · AA all-pass: Models reason over professional PDF documents; an attempt passes only when every atomic criterion passes
Fable 524
Opus 4.6—
MLCR-AA MLCR-AA: Models synthesize long medical records; the headline credits concise answers judged both accurate and complete
Fable 564.4
Opus 4.6—
FrontierMath FrontierMath: Models solve expert-written advanced mathematics problems on the named tier and edition
Fable 5—
Opus 4.6 · max40.7
FrontierMath Erdos FrontierMath Erdos: Models solve expert-written advanced mathematics problems on the named tier and edition
Fable 50
Opus 4.6—
FrontierMath Tier 4 FrontierMath Tier 4: Models solve expert-written advanced mathematics problems on the named tier and edition
Fable 5—
Opus 4.6 · max22.9
MathArena · Apex MathArena · apex · Apex: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.634.5
MathArena · Apex Shortlist MathArena · apex · Apex Shortlist: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.686.7
MathArena · ArXivMath · April 2026 MathArena · arxiv · 04/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 572.5
Opus 4.6—
MathArena · ArXivMath · December 2025 MathArena · arxiv · 12/2025: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.657.4
MathArena · ArXivMath · February 2026 MathArena · arxiv · 02/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.640.6
MathArena · ArXivMath · January 2026 MathArena · arxiv · 01/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.672.8
MathArena · ArXivMath · June 2026 MathArena · arxiv · 06/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 585.4
Opus 4.6—
MathArena · ArXivMath · March 2026 MathArena · arxiv · 03/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.662.5
MathArena · ArXivMath · May 2026 MathArena · arxiv · 05/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 587.5
Opus 4.6—
MathArena · BrokenArXiv · April 2026 MathArena · arxiv_false · 04/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 554.1
Opus 4.6—
MathArena · BrokenArXiv · February 2026 MathArena · arxiv_false · 02/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.63.2
MathArena · BrokenArXiv · June 2026 MathArena · arxiv_false · 06/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 547.8
Opus 4.6—
MathArena · BrokenArXiv · March 2026 MathArena · arxiv_false · 03/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.65.8
MathArena · BrokenArXiv · May 2026 MathArena · arxiv_false · 05/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 544.5
Opus 4.6—
MathArena · ArXivLean · June 2026 MathArena · arxivlean · 06/2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 515.2
Opus 4.6—
MathArena · Project Euler MathArena · euler · Project Euler: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.687.7
MathArena · Kangaroo 2025 1-2 MathArena · kangaroo · Kangaroo 2025 1-2: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.659.4
MathArena · Kangaroo 2025 11-12 MathArena · kangaroo · Kangaroo 2025 11-12: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.687.5
MathArena · Kangaroo 2025 3-4 MathArena · kangaroo · Kangaroo 2025 3-4: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.650
MathArena · Kangaroo 2025 5-6 MathArena · kangaroo · Kangaroo 2025 5-6: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.658.3
MathArena · Kangaroo 2025 7-8 MathArena · kangaroo · Kangaroo 2025 7-8: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.686.7
MathArena · Kangaroo 2025 9-10 MathArena · kangaroo · Kangaroo 2025 9-10: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.691.7
MathArena · USAMO 2026 MathArena · usamo · USAMO 2026: Answer accuracy on the named mathematics competition under the recorded effort
Fable 5—
Opus 4.647
Vals Legal Research Bench Vals Legal Research Bench: Grounded legal research; a task passes only if all criteria pass
Fable 549.5
Opus 4.6—
| Benchmark | Fable 5 | Opus 4.6 |
|---|---|---|
| Humanity's Last Exam | 55.5 | 19.1 |
| Arena Text · overall | 1,504 · high | 1,503 |
| Arena Text · Chinese | 1,542.3 · high | 1,550.2 |
| Arena Text · English | 1,499 · high | 1,512 |
| Arena Text · French | 1,503.6 · high | 1,512.8 |
| Arena Text · German | 1,486.7 · high | 1,501.8 |
| Arena Text · instruction following | 1,502.3 · high | 1,522 |
| Arena Text · Japanese | 1,506.4 · high | 1,488 |
| Arena Text · Korean | 1,491 · high | 1,449.8 |
| Arena Text · non-English | 1,480.7 · high | 1,488.1 |
| Arena Text · Polish | 1,493.4 · high | 1,496.6 |
| Arena Text · Russian | 1,503 · high | 1,496.1 |
| Arena Text · Spanish | 1,495.8 · high | 1,504.2 |
| AA Omniscience Index | 43.3 | 2.4 |
| SimpleQA Verified v1 | 70.7 · xhigh | 47 · max |
| CritPt (physics) | 28.6 | 2.8 |
| AA Intelligence Index 4.3.2 | 49.6 | 26.4 |
| AA Omniscience · Accuracy | 65.4 | 45.8 |
| AA Omniscience · Hallucination Rate | 63.6 | 80.1 |
| AA-LCR (long context) 1.1 | 82.3 | 67 |
| IFBench (instructions) | 63.5 | 44.6 |
| ARC-AGI-1 · public evaluation | 97.6 | 96.3 |
| ARC-AGI-1 · semi-private | 98.5 | 94 |
| ARC-AGI-2 · public evaluation | 96.4 | 79 |
| ARC-AGI-2 · semi-private | 89.2 | 69.2 |
| EQ-Bench 3 | 2,049.7 | 1,717.4 |
| Chess Puzzles | 47 | 21 · max |
| FrontierMath Tier 4 (v2) | 90.2 | 26.8 · max |
| FrontierMath Tiers 1–3 (v2) | 87 | 66 · max |
| Mystery Game Puzzles | 52 | 25 · max |
| Vals LegalBench | 88.6 | 85.3 |
| Vals MedCode | 56.1 | 49.1 |
| Vals MedScribe | 88.5 | 86.1 |
| GDP.pdf · AA all-pass | 24 | — |
| MLCR-AA | 64.4 | — |
| FrontierMath | — | 40.7 · max |
| FrontierMath Erdos | 0 | — |
| FrontierMath Tier 4 | — | 22.9 · max |
| MathArena · Apex | — | 34.5 |
| MathArena · Apex Shortlist | — | 86.7 |
| MathArena · ArXivMath · April 2026 | 72.5 | — |
| MathArena · ArXivMath · December 2025 | — | 57.4 |
| MathArena · ArXivMath · February 2026 | — | 40.6 |
| MathArena · ArXivMath · January 2026 | — | 72.8 |
| MathArena · ArXivMath · June 2026 | 85.4 | — |
| MathArena · ArXivMath · March 2026 | — | 62.5 |
| MathArena · ArXivMath · May 2026 | 87.5 | — |
| MathArena · BrokenArXiv · April 2026 | 54.1 | — |
| MathArena · BrokenArXiv · February 2026 | — | 3.2 |
| MathArena · BrokenArXiv · June 2026 | 47.8 | — |
| MathArena · BrokenArXiv · March 2026 | — | 5.8 |
| MathArena · BrokenArXiv · May 2026 | 44.5 | — |
| MathArena · ArXivLean · June 2026 | 15.2 | — |
| MathArena · Project Euler | — | 87.7 |
| MathArena · Kangaroo 2025 1-2 | — | 59.4 |
| MathArena · Kangaroo 2025 11-12 | — | 87.5 |
| MathArena · Kangaroo 2025 3-4 | — | 50 |
| MathArena · Kangaroo 2025 5-6 | — | 58.3 |
| MathArena · Kangaroo 2025 7-8 | — | 86.7 |
| MathArena · Kangaroo 2025 9-10 | — | 91.7 |
| MathArena · USAMO 2026 | — | 47 |
| Vals Legal Research Bench | 49.5 | — |
Specs
| Spec | Fable 5 | Opus 4.6 |
|---|---|---|
| Input, per 1M | $10 | $5 |
| Output, per 1M | $50 | $25 |
| Cost per task? | $8.75 | — |
| Speed, tok/s | 67 | 45 |
| Context | 1M | 1M |
| Weights | Closed | Closed |
| Released | Jun 2026 | Feb 2026 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | Partial |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ✓ | ✓ |
| Force a tool call | Partial | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ? |
| Run code | ? | ? |
| Use a computer | ? | ? |
What breaks when you switch
Fable 5 → Opus 4.6
Nothing known.
Opus 4.6 → Fable 5
Nothing known.