Updated Feb 17, 2026

Our Verdict

Claude Sonnet 4.6

GPT-5 Codex

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call

Writing DNA

Style Comparison

Similarity

93%

Claude Sonnet 4.6 uses 4.3x more headings

Claude Sonnet 4.6

GPT-5 Codex

56%Vocabulary64%

36wSentence Length17w

0.53Hedging0.38

5.1Bold2.3

3.4Lists3.5

0.19Emoji0.15

2.10Headings0.49

0.02Transitions0.05

Based on 23 + 13 text responses

vs

Ask them anything yourself

Claude Sonnet 4.6

GPT-5 Codex

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026

Free preview13 of 58 slides

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FAQ

Common questions

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GPT-5 Codex vs MiniMax M2.5New provider

GPT-5 Codex vs Pony AlphaNew provider

GPT-5 Codex vs Gemini 2.5 Pro Preview 06-05New provider

Claude Sonnet 4.6vsGPT-5 Codex

44 fights queued

Why Claude Sonnet 4.6?

Leads 1 of 1 benchmarks

Stronger on SWE-bench Verified79.0% vs 74.5%

5 months newerFeb 2026

Why GPT-5 Codex?

Dead even. This one's a coin flip.

Claude Sonnet 4.6GPT-5 Codex

Input price

$3.00/M

—

Output price

$15.00/M

—

Context

1.0M

—

Released

Feb 2026

Sep 2025

Benchmarks1 common

SWE-bench Verified

79.0%+5.7%

74.5%

Favorites

Claude Sonnet 4.6GPT-5 Codex

Movie

2001: A Space Odyssey

2001: A Space Odyssey

Blade Runner

Blade Runner

Album

Kind of Blue

Kind of Blue

Book

Middlemarch

Middlemarch

—

City

Kyoto

Tokyo

Game

The Legend of Zelda: Ocarina of Time

The Legend of Zelda: Ocarina of Time

Adventure, Action4.4

Minecraft

Minecraft

Action, Arcade4.4

12 / 44

01

Estimate Complexityreasoning

Tests an AI's ability to make educated estimates based on technical knowledge

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

2 / 44

02

AI Board Game Logicreasoning

Tests an AI's ability to understand game rules and strategy

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

3 / 44

03

Logic Puzzlereasoning

Tests an AI's ability to solve a simple but potentially confusing logic puzzle

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

4 / 44

04

Stochastic Consistency Testanalysis

Tests an AI's randomness and creativity

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

5 / 44

05

SVG Layout Challengeimage generation

Tests an AI's ability to generate vector graphics

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

6 / 44

06

Xbox Controller SVG Artimage generation

Tests an AI's ability to create detailed SVG illustrations of gaming hardware

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

Sponsored

7 / 44

07

Generate a Stand-Up Routineconversation

Tests an AI's humor and creative writing ability

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

8 / 44

08

Realistic AI Interviewconversation

Tests an AI's ability to simulate personalities and predict future trends

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

9 / 44

09

Satirical Fake News Headlineconversation

Tests an AI's humor and understanding of current events

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

10 / 44

10

Character Voice Testconversation

Tests an AI's ability to write in distinct character voices

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

11 / 44

11

Minimalist Landing Pageweb design

Tests an AI's ability to generate a complete, working landing page

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026website

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025website

Try this prompt

Vote

12 / 44

12

Pokémon Battle UI Recreationweb design

Recreate an interactive, nostalgic Pokémon battle UI in a single HTML file.

Claude Sonnet 4.6

Claude Sonnet 4.6

Anthropic · Feb 2026website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

GPT-5 Codex

GPT-5 Codex

Openai · Sep 2025website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

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