LIVE INTELLIGENCE · part of the Xentir AI Index

Claude Fable 5 vs Claude Opus 5

Name: Claude Fable 5 vs Claude Opus 5 — benchmark results
Creator: Epoch AI
License: https://creativecommons.org/licenses/by/4.0/

Updated 9 September 2026

What remains uncertain

4 tracked benchmarks have no published result for either model.

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 2026-09-09 · Methodology · Data Sources

Claude Fable 5 leads on more of the 5 benchmarks where both are measured — Claude Fable 5 on 3, Claude Opus 5 on 2. The remaining 4 of 9 tracked benchmarks cannot be compared: 0 have a result for only one of the two models, 4 for neither. Nothing on this page is estimated to fill those in.

Head-to-head

Measured on 5 of 9 tracked benchmarks for both models — Claude Fable 5 leads on 3, Claude Opus 5 leads on 2.

Benchmark	Claude Fable 5	Claude Opus 5	Leads
Epoch Capabilities Index (ECI)	163.4	162.6	Claude Fable 5
SWE-bench Verified	Not measured	Not measured	Not measured on both
GPQA Diamond	0.859 (max)	0.939 (max)	Claude Opus 5
MATH Level 5	Not measured	Not measured	Not measured on both
OTIS Mock AIME 2024-2025	1.000 (high)	0.989 (max)	Claude Fable 5
FrontierMath	Not measured	Not measured	Not measured on both
FrontierMath Tier 4	Not measured	Not measured	Not measured on both
SimpleQA Verified	0.707 (xhigh)	0.599 (max)	Claude Fable 5
Chess Puzzles	0.410 (high)	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.

What remains uncertain

4 tracked benchmarks have no published result for either model.

A missing result means Xentir has not found one published by the source it cites, not that the model performs badly. See Data Sources.

Reference price

Per 1M tokens	Claude Fable 5	Claude Opus 5
Output	$50.00 stale	$25.00 stale

List price as published by the vendor. Xentir does not verify negotiated or enterprise rates, and price is not a measure of capability — see Data Sources.

Full profiles

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