Claude Fable 5.2 vs Gemini 3.1 Pro Preview Custom Tools vs GPT-6 Astra

Compare Claude Fable 5.2 from Anthropic, Gemini 3.1 Pro Preview Custom Tools from Google, and GPT-6 Astra from OpenAI on key metrics including benchmarks, price, context length, and other model features. Access all 3 models and hundreds of others through the OpenRouter API.

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Claude Fable 5.2
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Gemini 3.1 Pro Preview Custom Tools
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GPT-6 Astra

Overview

Claude Fable 5.2
Author
Anthropic
Gemini 3.1 Pro Preview Custom Tools
Author
Google
GPT-6 Astra
Author
OpenAI
Claude Fable 5.2
Context length
1Mtokens
Gemini 3.1 Pro Preview Custom Tools
Context length
1.05Mtokens
GPT-6 Astra
Context length
1.05Mtokens
Claude Fable 5.2
Reasoning
Gemini 3.1 Pro Preview Custom Tools
Reasoning
GPT-6 Astra
Reasoning
Claude Fable 5.2
Input modalities
Gemini 3.1 Pro Preview Custom Tools
Input modalities
GPT-6 Astra
Input modalities
Claude Fable 5.2
Output modalities
Gemini 3.1 Pro Preview Custom Tools
Output modalities
GPT-6 Astra
Output modalities

Analysis

Claude Fable 5.2 vs Gemini 3.1 Pro Preview Custom Tools vs GPT-6 Astra: side-by-side summary

Claude Fable 5.2, Gemini 3.1 Pro Preview Custom Tools, and GPT-6 Astra are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

Claude Fable 5.2, from Anthropic, has a 1,000,000-token context window and is priced at $8/M tokens input, $40/M tokens output on OpenRouter.

Gemini 3.1 Pro Preview Custom Tools, from Google, has a 1,048,576-token context window and is priced at $2/M tokens input, $12/M tokens output on OpenRouter.

GPT-6 Astra, from OpenAI, has a 1,050,000-token context window and is priced at $10/M tokens input, $50/M tokens output on OpenRouter.

Claude Fable 5.2
Context window
1,000,000 tokens
Gemini 3.1 Pro Preview Custom Tools
Context window
1,048,576 tokens
GPT-6 Astra
Context window
1,050,000 tokens
Claude Fable 5.2
Price
$8/M tokens input, $40/M tokens output
Gemini 3.1 Pro Preview Custom Tools
Price
$2/M tokens input, $12/M tokens output
GPT-6 Astra
Price
$10/M tokens input, $50/M tokens output
Claude Fable 5.2
Provided by
Anthropic
Gemini 3.1 Pro Preview Custom Tools
Provided by
Google
GPT-6 Astra
Provided by
OpenAI