# Best AI model for reasoning — October 2026

As of Oct 14, 2026, Gemini 4 Argon & Claude Opus 5.5 are tied for state of the art in Reasoning (since Oct 2, 2026; sources LMArena Text (style-controlled, hard prompts); methodology v1.0).

Leading, crown pending confirmation: Muse Wonder.

Category board: https://isitsota.com/c/reasoning

## Top 10

- #1 Gemini 4 Argon
- #1 Claude Opus 5.5
- #2 Claude Opus 4.6
- #3 Claude Fable 5
- #4 Claude Opus 4.7
- #1 Muse Wonder
- #5 Claude Fable 5.1
- #6 Gemini 3.8 Flash
- #7 Kimi K3
- #8 Muse Spark 1.3

## Crown changes

- Oct 2, 2026 — Reasoning: Gemini 4 Argon and Claude Opus 5.5 are co-SOTA
- Sep 11, 2026 — Reasoning: Claude Opus 4.6 and Claude Fable 5 and Claude Opus 4.7 and Claude Fable 5.1 are co-SOTA
- Aug 19, 2026 — Reasoning: Claude Opus 4.6 and Claude Fable 5 and Claude Opus 4.7 are co-SOTA

## Weights

- Humanity's Last Exam: primary, weight 1
- GPQA Diamond: primary, weight 1
- LMArena Text (style-controlled, hard prompts): primary, weight 1
- LiveBench: secondary, weight 0.35