Gemini 4 Argon vs Claude Fable 5.1

Pyyan / Compare / Gemini 4 Argon vs Claude Fable 5.1

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Language Models · verified 20 Oct 2026

Gemini 4 ArgonGooglecurrent

Claude Fable 5.1Anthropiccurrent

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Specification	Gemini 4 Argon	Claude Fable 5.1
Summary	First on one independent board, fifth on another, and cheap until December.	Same price as Fable 5, and cache reads cost a quarter of what they did.
Context	1M	1M
Input ($/Mtok)	$2	$10
Output ($/Mtok)	$10	$50
Licence	Proprietary	Proprietary
Max output	262K	128K
Parameters	Not published	Not published
Released	30 Sep 2026, GA 13 Oct	1 Sep 2026
Model ID	gemini-4-argon	claude-fable-5-1
Category	Language Models	Language Models
Official	Google ↗	—

Highlighted rows are where these differ.

The price doubles to $4 and $20 on 1 December, and cached input is discounted 95%
First of 41 on the Vals Index at 68.90%, but 52.6 on Artificial Analysis against 57.6 for Opus 5.5
77.9 on DeepSWE v1.1 in Google's table, and 55.0 on FrontierSWE v2 where GPT-6 Astra scores 65.5

Best for frontier work while the introductory rate lasts.

Matches or beats Fable 5 at low and medium effort, and pulls clear at high effort
Cache reads cut to 25% of the old price, so re-reading a long context got much cheaper
Identical model to Mythos 5.1 underneath; the difference is the safeguards

Best for coding and long-running work.