Harness comparisonAI Coding

Claude Code (Claude Opus 4.1) vs OpenAI Codex (GPT-5) vs Cursor (GPT-5)

Next.js customer feedback app

Claude Code with Claude Opus 4.1, Codex with GPT-5 and Cursor's CLI agent with GPT-5 get the same prompt: a Next.js app with Tailwind 4 and shadcn that collects customer feedback and shows it in a widget, with 30 minutes each.

Each side pairs a coding harness with its own model, so harness and model differences are mixed. More Claude Code vs OpenAI Codex. All harness comparisons.

The post, itemised

Task
Next.js customer feedback app
Category
Web/UI
Mode
Not stated
Posted
Video length
78.3 s
Likes
1,218
Views
195,403
Bookmarks
835
Sponsored
No

Cost & time, as stated in the postEach harness got the same prompt and 30 minutes. Token counts are as the post states them.

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