GPT-6 Astra vs Claude Fable 5
Head-to-head technical comparison of intelligence, capabilities, and API pricing.
Which should you use?
GPT-6 Astra and Claude Fable 5 score within 0.3 points of each other on the composite index, which is too close to call a winner on capability alone.
Their Arena Elo differs by only 11 points, inside the confidence intervals the public board reports, so human preference does not separate them.
Pick GPT-6 Astra when
- Stronger on MMLU-Pro: 95.8% against 95.6%.
Pick Claude Fable 5 when
On these measures Claude Fable 5 does not lead GPT-6 Astra anywhere, so pick it only for reasons outside this table — an existing integration, a region, or a contract.
Value per point of measured capability, at list input pricing: GPT-6 Astra $0.103 · Claude Fable 5 $0.104 per index point. Run your own token mix through the token cost calculator — a comparison at list price ignores caching and batch discounts, which move real bills more than this gap does.
Where these numbers come from
Figures as of 2026-09-07. Arena Elo and pricing are read from the public board and each vendor's own pricing page; see the full leaderboard for all 34 models and which columns are measured rather than estimated, or the benchmark matrix for scores benchmark by benchmark.
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