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Claude Fable 5.1 vs GPT 6 Astra vs Grok 4.6

The frontier tier: the newest reasoning-first flagships from Anthropic, OpenAI, and xAI. Benchmarks tell part of the story; the shared output band shows how differently they write and reason on the same prompt.Last reviewed 2026-09-09.

Claude Fable 5.1 vs GPT 6 Astra vs Grok 4.6

At a glance

Anthropic's upgraded Mythos-class flagship, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work.

1M ctx$10.00/$50.00 per M

OpenAI's new flagship for demanding end-to-end work: advanced analysis, software engineering, deep research, scientific work, and document creation.

1.1M ctx$10.00/$50.00 per M

xAI's smartest model, with frontier performance on coding, knowledge work, and STEM.

500K ctx$2.00/$6.00 per M
Demos
All demos

No shared demos for these models yet.

AI Output
All AI outputs

No captured outputs for these models yet.

Benchmarks
See rankings
The paired significance test (McNemar, in "Measured on Idapt") appears only when exactly two models are pinned.
Reasoning
CodingInsufficient data
AgenticInsufficient data
ReasoningInsufficient data
MathInsufficient data
Sources:OpenRouter
Reasoning
CodingInsufficient data
AgenticInsufficient data
ReasoningInsufficient data
MathInsufficient data
Sources:OpenRouter
Reasoning
CodingInsufficient data
AgenticInsufficient data
ReasoningInsufficient data
MathInsufficient data
Sources:OpenRouter
Cheaper85%
Specs
1M
Context
128K
Max output
Sep 2026
Released
1.1M
Context
128K
Max output
Sep 2026
Released
500K
Context
128K
Max output
Aug 2026
Released
Capabilities
Vision
Audio
Reasoning
Vision
Audio
Reasoning
Vision
Audio
Reasoning
Pricing
Live pricing, shown before you run
Input$10.00/M tokens
Output$50.00/M tokens
Cache read50%$0.25/M tokens
Cache write$12.50/M tokens
Web search$0.01/search
Live pricing, shown before you run
Input$10.00/M tokens
Output$50.00/M tokens
Cache read$1.00/M tokens
Cache write$12.50/M tokens
Web search$0.01/search
Live pricing, shown before you run
Input80%$2.00/M tokens
Output88%$6.00/M tokens
Cache read$0.50/M tokens
Web search50%$0.005/search
Chat with Claude Fable 5.1Go to model
Chat with GPT 6 AstraGo to model
Chat with Grok 4.6Go to model

Frequently asked

Which of Claude Fable 5.1, GPT 6 Astra, and Grok 4.6 is the cheapest?

Grok 4.6 has the lowest blended list price. Per 1M tokens: Claude Fable 5.1 at $10.00 in / $50.00 out; GPT 6 Astra at $10.00 in / $50.00 out; Grok 4.6 at $2.00 in / $6.00 out.

Which of Claude Fable 5.1, GPT 6 Astra, and Grok 4.6 has the largest context window?

GPT 6 Astra leads with 1.1M tokens. The other two: Claude Fable 5.1 at 1M, Grok 4.6 at 500K.

Do Claude Fable 5.1, GPT 6 Astra, and Grok 4.6 support image input?

Yes, all three accept images.

Where can I run Claude Fable 5.1, GPT 6 Astra, and Grok 4.6 side by side?

This idapt comparison runs all three in aligned columns: the same prompt, plus benchmarks, specs, and prices per model. Open any model in chat from its column to keep working with it.

More three-way comparisons

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