Codex 5.1: functional but poor design

I put three cutting-edge AI models to the test in a head-to-head design competition. Using the exact same prompt, I challenged Google’s Gemini 3, Anthropic’s Opus 4.5, and OpenAI’s Codex 5.1 to redesign my blog page, evaluating them on visual design quality, user experience improvements, and SEO optimization capabilities. One model produced a beautiful, polished, production-ready redesign. One was fine. And one completely whiffed. If you’re trying to figure out where each model fits in your workflow—design, planning, back-end, or something else—this episode will save you a lot of trial and error.

What you’ll learn:

1. How each AI model approaches the same design challenge differently
2. Why planning capabilities dramatically impact design quality
3. The specific visual and functional improvements each model made
4. Which model excels at front-end design versus back-end functionality
5. How to strategically choose the right AI model for different parts of your workflow
6. The importance of model-switching based on specific use cases

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Blog design: https://www.chatprd.ai/blog

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Brought to you by:

Lovable—Build apps by simply chatting with AI

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Where to find Claire Vo:

ChatPRD: https://www.chatprd.ai/

Website: https://clairevo.com/

LinkedIn: https://www.linkedin.com/in/clairevo/

X: https://x.com/clairevo

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In this episode, we cover:

(00:00) Introduction to the AI design challenge

(01:25) The question: Which model is the better designer?

(03:08) The prompt used for all three models

(04:10) Gemini 3 Pro’s approach and results

(06:00) Opus 4.5’s approach and results

(10:54) Codex 5.1’s approach and disappointing results

(14:51) Comparing the three designs side by side

(16:03) Analyzing the change logs and SEO improvements from each model

(22:43) Final verdict

(23:00) Conclusion and next steps

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Tools referenced:

• Gemini 3 Pro: https://deepmind.google/models/gemini/pro/

• Anthropic Opus 4.5: https://www.anthropic.com/news/claude-opus-4-5

• OpenAI Codex 5.1: https://platform.openai.com/docs/models/gpt-5.1-codex

• Cursor: https://cursor.com/

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Production and marketing by https://penname.co/. For inquiries about sponsoring the podcast, email jordan@penname.co.