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Claude Fable 5 vs Claude Opus 5

Claude Fable 5 · Anthropic, released 2026-06-09
Claude Opus 5 · Anthropic, released 2026-07-24

“Epoch AI, 'AI Benchmarking Hub'. Published online at epoch.ai. Retrieved from 'https://epoch.ai/benchmarks' [online resource].” · epoch.ai/benchmarks · Licensed CC BY 4.0 · data last verified 2026-07-26 · Methodology · Data Sources

Head-to-head

Measured on 4 of 9 tracked benchmarks for both models — Claude Fable 5 leads on 3, Claude Opus 5 leads on 1.

BenchmarkClaude Fable 5 Claude Opus 5Leads
Epoch Capabilities Index (ECI)160.7159.4Claude Fable 5
SWE-bench VerifiedNot measuredNot measuredNot measured on both
GPQA DiamondNot measured0.939 (max)Not measured on both
MATH Level 5Not measuredNot measuredNot measured on both
OTIS Mock AIME 2024-20250.997 (max)0.989 (max)Claude Fable 5
FrontierMathNot measuredNot measuredNot measured on both
FrontierMath Tier 4Not measuredNot measuredNot measured on both
SimpleQA Verified0.683 (xhigh)0.567 (max)Claude Fable 5
Chess Puzzles0.410 (max)0.420 (max)Claude Opus 5
Benchmark results measure specific tasks and should not be treated as a universal measure of model quality. A model with no row here for a benchmark has not been measured on it — that is left blank, never estimated.

Full profiles

Claude Fable 5 → · Claude Opus 5 → · the full AI Model Rankings table