Claude Fable 5 vs GPT-6 Astra

Anthropic's Claude Fable 5 against OpenAI's GPT-6 Astra — price, context and what each is best at. Both are available through one OpenAI-compatible API.

AnyModel — you pay	Claude Fable 5	GPT-6 Astra
Vendor	Anthropic	OpenAI
Input / 1M	$0.8	$0.3
Output / 1M	$0.8	$0.3
Context	1M	1M
Best for	Hardest problems	Codex CLI

Claude Fable 5

Anthropic's Mythos-class tier above Opus — #1 on our AI Arena.

Claude Fable 5 is the first model of Anthropic's Claude 5 family — a Mythos-class tier that sits above Opus in capability. It tops our agentic AI Arena ranking and comes with a 1M-token window. Vendor list price is $10/$50 per 1M.

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GPT-6 Astra

OpenAI's most capable model for complex, demanding work.

GPT-6 Astra is OpenAI's flagship reasoning and agentic-coding model: the top of the Codex line for multi-step engineering, deep debugging and long autonomous sessions, with reasoning effort up to max. Pick it when Sol is not enough. Served by ChatGPT Pro accounts, so capacity is limited.

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Quick take: GPT-6 Astra is cheaper on output tokens ($0.3 vs $0.8 per 1M). Compare their strengths and context for your task; you can switch the model id at any time.

FAQ

Which is cheaper, Claude Fable 5 or GPT-6 Astra?

GPT-6 Astra is cheaper on output tokens ($0.3 vs $0.8 per 1M).

Which has a larger context window, Claude Fable 5 or GPT-6 Astra?

Claude Fable 5: 1M; GPT-6 Astra: 1M.