Compare Claude Opus 4.1 by Anthropic against GPT-5 Codex by OpenAI, in 66 community votes, claude opus 4.1 wins 62% of head-to-head duels, tested across 25 shared challenges. Updated February 2026.
In 66 community votes, Claude Opus 4.1 wins 62% of head-to-head duels. Claude Opus 4.1 leads in Web Design, Analysis, Conversation, while GPT-5 Codex leads in Image Generation, Reasoning. Based on blind community voting from the RIVAL open dataset of 66+ human preference judgments for this pair.
25 challenges
Tests an AI's ability to solve a simple but potentially confusing logic puzzle
Let me work through this step-by-step.
Sally has 3 brothers.
Each of Sally's brothers has 2 sisters.
Since Sally is a girl, she is one of the sisters that each brother has.
If each brother has 2 sisters total, and Sally is one of them, then there must be 1 other sister besides Sally.
Therefore, Sally has 1 sister.
Sally has 1 sister.
Tests an AI's randomness and creativity
Here are 5 jokes:
Why don't scientists trust atoms? Because they make up everything!
What do you call a bear with no teeth? A gummy bear!
Why did the scarecrow win an award? He was outstanding in his field!
What do you call a fake noodle? An impasta!
Why don't eggs tell jokes? They'd crack each other up!
All 5 jokes are unique - each one has a different setup and punchline with no repeats.
Tests an AI's ability to create detailed SVG illustrations of gaming hardware
Tests an AI's ability to simulate personalities and predict future trends
Tests an AI's humor and understanding of current events
Tests an AI's ability to generate a complete, working landing page
Recreate an interactive, classic Mario level in a single HTML file.
Tests an AI's UI design skills with theming support
Tests an AI's ability to engage in philosophical discourse about AI rights
Generate SVG art of a randomly chosen animal in a setting of its choosing.
Generate a unique and simple recipe with common ingredients.
Create a starter plan for improving long-term health.
