HEAD TO HEAD
Make the
right call.
Pick two to four models. Compare category evidence, price, context, speed and capabilities side by side.
Sign in to save this comparison →01 / SCORECARD
Coding focus · side by side
| Metric | Claude Fable 5.1 | Claude Opus 5.5 |
|---|---|---|
| Quantum Score | Insufficient verified data73% coverage | 86QUANTUM SCORE |
| Confidence / coverage | Limited evidence · 73% · 2 independent domains | Moderate confidence · 73% · 3 independent domains |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Modalities / tools | text, image · tool use, vision | text, image · tool use, vision |
| Coding | 43 | 87 +44 vs first |
| Reasoning | 92 | 97 +5 vs first |
| Math | 99 | 92 -7 vs first |
| Research | — | — |
| Agents | 40 | 100 +60 vs first |
| Multimodal | — | — |
| Speed | — | — |
| Value | 23 | 52 +29 vs first |
| Input / 1M | $10.00 | $4.00 |
| Output / 1M | $50.00 | $20.00 |
| Measured output speed | — | 92 tokens/s · Max effort |
02 / EVIDENCE
Published benchmark evidence
| Benchmark | Claude Fable 5.1 | Claude Opus 5.5 |
|---|---|---|
| Terminal-Bench 4.0 Vals mini-SWE-agent avg@3 fallbacks failed · 4.0 · Vals mini-SWE-agent avg@3; Anthropic fallbacks treated as failures | 50 % independent lab ↗ | 58.08 % independent lab ↗ |
| ProofBench v1.1 Vals 100 proof tasks · 1.1 · Vals 100 proof tasks; ceiling effect at top scores | 100 % independent lab ↗ | 100 % independent lab ↗ |
| ProgramBench Vals 200 public tasks raw pass rate · Vals 2026-09-27 · Vals 200 public tasks; raw pass rate; mini-SWE-agent | 82.7 % independent lab ↗ | 87 % independent lab ↗ |
| LiveBench code_completion · 2026-06-25 · Public table; published model effort variant | 82.609 % benchmark maintainer ↗ | 86.957 % benchmark maintainer ↗ |
| LiveBench code_generation · 2026-06-25 · Public table; published model effort variant | 90.141 % benchmark maintainer ↗ | 91.549 % benchmark maintainer ↗ |
| LiveBench javascript · 2026-06-25 · Public table; published model effort variant | 68.182 % benchmark maintainer ↗ | 81.818 % benchmark maintainer ↗ |
| LiveBench AMPS_Hard · 2026-06-25 · Public table; published model effort variant | 99 % benchmark maintainer ↗ | 98 % benchmark maintainer ↗ |
| LiveBench olympiad · 2026-06-25 · Public table; published model effort variant | 92.968 % benchmark maintainer ↗ | 93.251 % benchmark maintainer ↗ |
| LiveBench theory_of_mind · 2026-06-25 · Public table; published model effort variant | 80.769 % benchmark maintainer ↗ | 84.615 % benchmark maintainer ↗ |
| LiveBench zebra_puzzle · 2026-06-25 · Public table; published model effort variant | 100 % benchmark maintainer ↗ | 100 % benchmark maintainer ↗ |
AS THE EVIDENCE CHANGED
Comparison history
Dated releases, price events, and benchmark publications. A price or test change can alter the factual comparison; this timeline does not pick a winner.
2026-09-22 · Claude Opus 5.5 released ↗ · source
2026-09-01 · Claude Fable 5.1 released ↗ · source
2026-09-30 verified (test date not published) · claude-fable-5-1 entered LiveBench code_completion (2026-06-25) at 82.609 % · source ↗
2026-09-30 verified (test date not published) · claude-fable-5-1 entered LiveBench code_generation (2026-06-25) at 90.141 % · source ↗
2026-09-30 verified (test date not published) · claude-fable-5-1 entered LiveBench javascript (2026-06-25) at 68.182 % · source ↗
2026-09-30 verified (test date not published) · claude-fable-5-1 entered LiveBench AMPS_Hard (2026-06-25) at 99 % · source ↗
2026-09-30 verified (test date not published) · claude-fable-5-1 entered LiveBench olympiad (2026-06-25) at 92.968 % · source ↗
2026-09-30 verified (test date not published) · claude-fable-5-1 entered LiveBench theory_of_mind (2026-06-25) at 80.769 % · source ↗
2026-09-30 verified (test date not published) · claude-fable-5-1 entered LiveBench zebra_puzzle (2026-06-25) at 100 % · source ↗
2026-09-30 verified (test date not published) · claude-opus-5-5 entered LiveBench code_completion (2026-06-25) at 86.957 % · source ↗
2026-09-30 verified (test date not published) · claude-opus-5-5 entered LiveBench code_generation (2026-06-25) at 91.549 % · source ↗
2026-09-30 verified (test date not published) · claude-opus-5-5 entered LiveBench javascript (2026-06-25) at 81.818 % · source ↗
2026-09-30 verified (test date not published) · claude-opus-5-5 entered LiveBench AMPS_Hard (2026-06-25) at 98 % · source ↗
2026-09-30 verified (test date not published) · claude-opus-5-5 entered LiveBench olympiad (2026-06-25) at 93.251 % · source ↗
An overall score appears only after enough current, comparable, independently sourced results exist. Pricing and individual benchmark results remain visible meanwhile.