Claude Fable 5.1 vs GPT-6 Astra
Claude Fable 5.1 and GPT-6 Astra are closely matched at 56.8 and 60.7 on the LLM Stats Score. Claude Fable 5.1 and GPT-6 Astra cost the same.
Anthropic · OpenAI · Updated for 2026
Which is better?
Claude Fable 5.1 and GPT-6 Astra are closely matched on the overall LLM Stats Score at 56.8 and 60.7.
In the 4 individual benchmarks reported for both models, GPT-6 Astra wins 3; this is a narrower head-to-head signal than the composite indexes.
GPT-6 Astra also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose Claude Fable 5.1
- you want predictable pricing at $10.00/M input and $50.00/M output
Choose GPT-6 Astra
- you value its reported benchmark strengths — it wins 3 of 4 exact shared results
- you process long inputs — it offers a 1,050,000 token context window
- you want the most recent training data — it shipped Sep 2026
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
7 reported for Claude Fable 5.1 · 22 for GPT-6 Astra
Claude Fable 5.1 outperforms in 1 benchmarks (OSWorld 2.0), while GPT-6 Astra is better at 3 benchmarks (AutomationBench, Terminal-Bench 4.0, Terminal-Bench-Science 0.1).
GPT-6 Astra shows notably better performance in the majority of benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Fable 5.1 ($10.00/1M tokens) costs the same as GPT-6 Astra ($10.00/1M tokens).
For output processing, Claude Fable 5.1 ($50.00/1M tokens) costs the same as GPT-6 Astra ($50.00/1M tokens).
In conclusion, Claude Fable 5.1 and GPT-6 Astra cost the same.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-6 Astra accepts 1,050,000 input tokens compared to Claude Fable 5.1's 1,000,000 tokens. Both models can generate responses up to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both Claude Fable 5.1 and GPT-6 Astra support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Fable 5.1
GPT-6 Astra
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Fable 5.1 was released on 2026-09-01, while GPT-6 Astra was released on 2026-09-03.
GPT-6 Astra is 0 month newer than Claude Fable 5.1.
Sep 1, 2026
2 days ago
Sep 3, 2026
0 days ago
2d newerKnowledge Cutoff
When training data ends
GPT-6 Astra has a documented knowledge cutoff of 2026-04-30, while Claude Fable 5.1's cutoff date is not specified.
We can confirm GPT-6 Astra's training data extends to 2026-04-30, but cannot make a direct comparison without Claude Fable 5.1's cutoff date.
—
Apr 2026
Provider Availability
Claude Fable 5.1 is available from Anthropic. GPT-6 Astra is available from OpenAI.
Claude Fable 5.1
GPT-6 Astra
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Fable 5.1 and GPT-6 Astra side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Fable 5.1 vs GPT-6 Astra.