Claude Opus 5 vs GPT-5.6 Sol
Humanity's Last Exam Humanity's Last Exam: Very hard expert questions across many fields, written to stump today’s models
Opus 551.3
GPT-5.6 Sol42.2
Arena Text · overall Arena Text · overall: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,490
GPT-5.6 Sol · xhigh1,485
Arena Text · Chinese Arena Text · chinese: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,573.4
GPT-5.6 Sol · xhigh1,526.6
Arena Text · English Arena Text · english: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,507.3
GPT-5.6 Sol · xhigh1,458
Arena Text · French Arena Text · french: Human pairwise preferences in the stated text vote pool
Opus 5 · high1,519.5
GPT-5.6 Sol · xhigh1,474.5
Arena Text · German Arena Text · german: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,525.9
GPT-5.6 Sol · xhigh1,475.5
Arena Text · instruction following Arena Text · instruction following: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,517.8
GPT-5.6 Sol · xhigh1,482.3
Arena Text · Japanese Arena Text · japanese: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,515.4
GPT-5.6 Sol · xhigh1,470.9
Arena Text · Korean Arena Text · korean: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,520.7
GPT-5.6 Sol · xhigh1,442.1
Arena Text · non-English Arena Text · non english: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,500.5
GPT-5.6 Sol · xhigh1,450.8
Arena Text · Polish Arena Text · polish: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,519.9
GPT-5.6 Sol · xhigh1,461.4
Arena Text · Russian Arena Text · russian: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,507.2
GPT-5.6 Sol · xhigh1,470.4
Arena Text · Spanish Arena Text · spanish: Human pairwise preferences in the stated text vote pool
Opus 5 · max1,519.5
GPT-5.6 Sol · xhigh1,440.6
AA Omniscience Index AA Omniscience Index: Scores factual knowledge while penalizing incorrect answers to encourage admitting uncertainty
Opus 531
GPT-5.6 Sol19.4
SimpleQA Verified v1 SimpleQA Verified v1: Accuracy on short factual questions with verified answers, answered without web access
Opus 563.3
GPT-5.6 Sol · max69.7
CritPt (physics) CritPt (physics): Research-level physics problems that need many careful reasoning steps
Opus 526.9
GPT-5.6 Sol22.9
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
Opus 544.8
GPT-5.6 Sol39.2
AA Omniscience · Accuracy AA Omniscience · Accuracy: Measures correct answers on the AA Omniscience factual knowledge test
Opus 557.1
GPT-5.6 Sol57.8
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
Opus 560.7
GPT-5.6 Sol90.8
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)
Opus 582
GPT-5.6 Sol80.3
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
Opus 520
GPT-5.6 Sol26.2
MLCR-AA MLCR-AA: Models synthesize long medical records; the headline credits concise answers judged both accurate and complete
Opus 556.1
GPT-5.6 Sol15
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
Opus 5 · max99
GPT-5.6 Sol93.9
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
Opus 5 · max97.5
GPT-5.6 Sol92.5
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
Opus 5 · max97.1
GPT-5.6 Sol70.7
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
Opus 5 · max90.4
GPT-5.6 Sol67.1
ARC-AGI-3 · semi-private ARC-AGI-3 · semi-private: Measures interactive game solving through relative human action efficiency
Opus 5 · high30.2
GPT-5.6 Sol1.1
Chess Puzzles Chess Puzzles: Models choose the best next move from a novel chess position
Opus 5 · max43
GPT-5.6 Sol · max59
FrontierMath Erdos FrontierMath Erdos: Models solve expert-written advanced mathematics problems on the named tier and edition
Opus 5 · max0
GPT-5.6 Sol · max0
FrontierMath Tier 4 (v2) FrontierMath Tier 4 (v2): Models solve expert-written advanced mathematics problems on the named tier and edition
Opus 5 · max73.2
GPT-5.6 Sol · max82.9
FrontierMath Tiers 1–3 (v2) FrontierMath Tiers 1–3 (v2): Models solve expert-written advanced mathematics problems on the named tier and edition
Opus 5 · max85.6
GPT-5.6 Sol · max89.1
Mystery Game Puzzles Mystery Game Puzzles: Models choose the best move in puzzle positions from an undisclosed game
Opus 5 · max59
GPT-5.6 Sol · max58
MathArena · ArXivMath · June 2026 MathArena · arxiv · 06/2026: Answer accuracy on the named mathematics competition under the recorded effort
Opus 5 · max82.6
GPT-5.6 Sol · max88.5
MathArena · BrokenArXiv · June 2026 MathArena · arxiv_false · 06/2026: Answer accuracy on the named mathematics competition under the recorded effort
Opus 5 · max90.7
GPT-5.6 Sol · max67.3
Vals LegalBench Vals LegalBench: Legal reasoning and legal-language understanding on LegalBench
Opus 587
GPT-5.6 Sol87
Vals MedCode Vals MedCode: Medical coding accuracy on patient encounters
Opus 563.6
GPT-5.6 Sol44
Vals MedScribe Vals MedScribe: Accuracy of clinical notes produced from consultation transcripts
Opus 591
GPT-5.6 Sol85.2
Vals Legal Research Bench Vals Legal Research Bench: Grounded legal research; a task passes only if all criteria pass
Opus 555.3
GPT-5.6 Sol48.1
Vals Science Index Vals Science Index: Scientific problem solving across the index’s component evaluations
Opus 547.9
GPT-5.6 Sol41.5
IFBench (instructions) IFBench (instructions): Checks whether the model follows precise formatting and content instructions
Opus 5—
GPT-5.6 Sol69.6
MathArena · ArXivLean · June 2026 MathArena · arxivlean · 06/2026: Answer accuracy on the named mathematics competition under the recorded effort
Opus 5 · max32.6
GPT-5.6 Sol—
| Benchmark | Opus 5 | GPT-5.6 Sol |
|---|---|---|
| Humanity's Last Exam | 51.3 | 42.2 |
| Arena Text · overall | 1,490 · max | 1,485 · xhigh |
| Arena Text · Chinese | 1,573.4 · max | 1,526.6 · xhigh |
| Arena Text · English | 1,507.3 · max | 1,458 · xhigh |
| Arena Text · French | 1,519.5 · high | 1,474.5 · xhigh |
| Arena Text · German | 1,525.9 · max | 1,475.5 · xhigh |
| Arena Text · instruction following | 1,517.8 · max | 1,482.3 · xhigh |
| Arena Text · Japanese | 1,515.4 · max | 1,470.9 · xhigh |
| Arena Text · Korean | 1,520.7 · max | 1,442.1 · xhigh |
| Arena Text · non-English | 1,500.5 · max | 1,450.8 · xhigh |
| Arena Text · Polish | 1,519.9 · max | 1,461.4 · xhigh |
| Arena Text · Russian | 1,507.2 · max | 1,470.4 · xhigh |
| Arena Text · Spanish | 1,519.5 · max | 1,440.6 · xhigh |
| AA Omniscience Index | 31 | 19.4 |
| SimpleQA Verified v1 | 63.3 | 69.7 · max |
| CritPt (physics) | 26.9 | 22.9 |
| AA Intelligence Index 4.3.2 | 44.8 | 39.2 |
| AA Omniscience · Accuracy | 57.1 | 57.8 |
| AA Omniscience · Hallucination Rate | 60.7 | 90.8 |
| AA-LCR (long context) 1.1 | 82 | 80.3 |
| GDP.pdf · AA all-pass | 20 | 26.2 |
| MLCR-AA | 56.1 | 15 |
| ARC-AGI-1 · public evaluation | 99 · max | 93.9 |
| ARC-AGI-1 · semi-private | 97.5 · max | 92.5 |
| ARC-AGI-2 · public evaluation | 97.1 · max | 70.7 |
| ARC-AGI-2 · semi-private | 90.4 · max | 67.1 |
| ARC-AGI-3 · semi-private | 30.2 · high | 1.1 |
| Chess Puzzles | 43 · max | 59 · max |
| FrontierMath Erdos | 0 · max | 0 · max |
| FrontierMath Tier 4 (v2) | 73.2 · max | 82.9 · max |
| FrontierMath Tiers 1–3 (v2) | 85.6 · max | 89.1 · max |
| Mystery Game Puzzles | 59 · max | 58 · max |
| MathArena · ArXivMath · June 2026 | 82.6 · max | 88.5 · max |
| MathArena · BrokenArXiv · June 2026 | 90.7 · max | 67.3 · max |
| Vals LegalBench | 87 | 87 |
| Vals MedCode | 63.6 | 44 |
| Vals MedScribe | 91 | 85.2 |
| Vals Legal Research Bench | 55.3 | 48.1 |
| Vals Science Index | 47.9 | 41.5 |
| IFBench (instructions) | — | 69.6 |
| MathArena · ArXivLean · June 2026 | 32.6 · max | — |
Specs
| Spec | Opus 5 | GPT-5.6 Sol |
|---|---|---|
| Input, per 1M | $5 | $4 |
| Output, per 1M | $25 | $20 |
| Cost per task? | $2.19 | $0.50 |
| Speed, tok/s | 55 | 85 |
| Context | 1M | 1.05M |
| Weights | Closed | Closed |
| Released | Jul 2026 | Jul 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
Opus 5 → GPT-5.6 Sol
Nothing known.
GPT-5.6 Sol → Opus 5