Claude Fable 5.1 vs GPT-6 Astra
How does Claude Fable 5.1 (Anthropic) compare against GPT-6 Astra (OpenAI)? Side-by-side scores, capability ratings and pricing, plus a clear verdict.
🏆 Quick verdict
Claude Fable 5.1 comes out ahead with an AIVerso score of 99 vs 98 and an aggregate capability rating of 662 vs 665 across 7 categories. GPT-6 Astra still leads on Math & Logic, Reasoning and Knowledge.
Overall winner
Claude Fable 5.1
by Anthropic
Score: 99/100
Price$10/$50 per 1M tokens
Context window1M
Free tierNo
API accessYes
Open sourceNo
Headline factsAnthropic's most capable model overall · doubles Terminal-Bench (52.6%) · always-on adaptive thinking · SWE-bench Pro 81.2%
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Full Claude Fable 5.1 profile →
GPT-6 Astra
by OpenAI
Score: 98/100
PriceFrom $20/mo (Plus)
Pricing details$10/$50 per 1M
Context window1M
Free tierNo
API accessYes
Open sourceNo
Headline factsOpenAI's "AGI-era" flagship · FrontierMath Tier 4 97.6% · Terminal-Bench 4.0 57.9% · 1M context
Try GPT-6 Astra →
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📊 Capability ratings
AIVerso capability ratings (0–100) per category — an editorial summary informed by public benchmark results. Higher is better.
Category
Claude Fable 5.1
GPT-6 Astra
Math & Logice.g. AIME, MATH-500
96
97
Programminge.g. SWE-bench, LiveCodeBench
95
92
Reasoninge.g. GPQA, ARC
94
96
Knowledgee.g. MMLU-Pro
91
94
Long Contexte.g. MRCR, needle tests
96
96
Instruction Followinge.g. IFEval
95
95
Agent Capabilitye.g. Terminal-Bench, tool use
95
95
Why Claude Fable 5.1
Higher overall score (99 vs 98)
Leads on Programming (95 vs 92)
Anthropic's most capable model overall
doubles Terminal-Bench (52.6%)
Why GPT-6 Astra
Leads on Math & Logic (97 vs 96)
Leads on Reasoning (96 vs 94)
Leads on Knowledge (94 vs 91)
OpenAI's "AGI-era" flagship
FrontierMath Tier 4 97.6%
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❓ Frequently Asked Questions
Which is better: Claude Fable 5.1 or GPT-6 Astra?
Claude Fable 5.1 has the higher AIVerso score (99 vs 98). The better choice still depends on your use case — GPT-6 Astra leads on Math & Logic and Reasoning.
How much does Claude Fable 5.1 cost compared to GPT-6 Astra?
Claude Fable 5.1: $10/$50 per 1M tokens. GPT-6 Astra: From $20/mo (Plus) ($10/$50 per 1M). Neither has a free tier.
What context window does each support?
Claude Fable 5.1: 1M tokens. GPT-6 Astra: 1M tokens. The context window determines how much text, code or chat history a model can process at once.
Are Claude Fable 5.1 and GPT-6 Astra open source?
Claude Fable 5.1 is a closed, proprietary model. GPT-6 Astra is a closed, proprietary model.
How we compare: Scores and capability ratings are based on public benchmarks and provider documentation — not on commission rates. Last updated: September 29, 2026.