GPT-6 Astra vs Claude Fable 5.1
GPT-6 Astra scores higher on the Models at Work leaderboard (86 vs 80 out of 100). They cost about the same per million tokens ($20 vs $20 blended).
| GPT-6 Astra · OpenAI | Claude Fable 5.1 · Anthropic | |
|---|---|---|
| Leaderboard rank | #2 | #6 |
| Score (0–100) | 86 | 80 |
| Tier | Frontier | Frontier |
| Price per 1M tokens | $10 in · $50 out | $10 in · $50 out |
| Context window | 1M | 1M |
| Open weights | No | No |
| Artificial Analysis Intelligence Index | 53 | 53 |
| Humanity's Last Exam, Diamond (Scale) | 60.6 | 51.3 |
| Humanity's Sixth Sense (Scale) | 53.6 | — |
| FrontierMath Erdős (Epoch) | 3% (2 of 68) | — |
| Arena text score | — | 1501 |
| Best for | Hard reasoning, Research-grade analysis, When cost is not the constraint | Long-horizon agents, Problems Opus fails on, Demanding reasoning |
Choose GPT-6 Astra if…
- you need hard reasoning
- you need research-grade analysis
- you need when cost is not the constraint
The reasoning heavyweight: leads the hardest exams and the cipher-cracking party tricks, and charges like it.
Caveats: Long-context pricing doubles above 272K input tokens. Speed is the lowest of the frontier set in Artificial Analysis' measurement.
Choose Claude Fable 5.1 if…
- you need long-horizon agents
- you need problems opus fails on
- you need demanding reasoning
The specialist: Anthropic's own docs say to reach for it when Opus 5.5 at high effort still falls short, and the price says the same.
Caveats: Ten dollars per million input is the highest in this table alongside Astra.
What practitioners say
GPT-6 Astra: The launch drew the largest model thread of 2026 on Hacker News, and the stories that followed were about capability rather than cost: an Enigma message unsolved since 2005, a WWI cipher, a driving benchmark.
Questions people ask
Which is better, GPT-6 Astra or Claude Fable 5.1?
GPT-6 Astra scores higher on the Models at Work leaderboard (86 vs 80 out of 100). They cost about the same per million tokens ($20 vs $20 blended).
When should I choose GPT-6 Astra over Claude Fable 5.1?
Choose GPT-6 Astra for hard reasoning, research-grade analysis, when cost is not the constraint. The reasoning heavyweight: leads the hardest exams and the cipher-cracking party tricks, and charges like it.
When should I choose Claude Fable 5.1 over GPT-6 Astra?
Choose Claude Fable 5.1 for long-horizon agents, problems opus fails on, demanding reasoning. The specialist: Anthropic's own docs say to reach for it when Opus 5.5 at high effort still falls short, and the price says the same.
Which is cheaper, GPT-6 Astra or Claude Fable 5.1?
GPT-6 Astra costs $10 per million input tokens and $50 per million output tokens on OpenAI's list price (OpenAI API pricing, read Oct 10, 2026). Claude Fable 5.1 costs $10 per million input tokens and $50 per million output tokens on Anthropic's list price (Claude pricing, read Oct 10, 2026).
Scores come from the Models at Work leaderboard: Score is 0 to 100: 50% independent evals normalised within this table, 20% price-performance, 15% practitioner sentiment from Signals and community threads, 15% operational fit (context, speed, availability, open weights). Models within three points are a tie in practice. Vendor-published figures are labelled as such and never counted as independent. Prices are vendor list prices where published; blended figures assume three input tokens per output token.