Claude Sonnet 4.5 vs GPT-5-Codex-Mini
Anthropic Claude Sonnet 4.5 | OpenAI GPT-5-Codex-Mini | |
|---|---|---|
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | Sep 29 2025 | Nov 7 2025 |
| Access | Proprietary | Proprietary |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 79% | — |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 77.2% | — |
Next.js coding Next.js EvalsVercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | 50% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 83.4% | — |
Multimodal MMMUTests the AI on understanding images and text together across many college subjects. Higher is better. | 68% | — |
| Timeline | ||
| Release gap | Claude Sonnet 4.5 shipped 39 days before GPT-5-Codex-Mini | |
Which is better: Claude Sonnet 4.5 or GPT-5-Codex-Mini?
Claude Sonnet 4.5 and GPT-5-Codex-Mini don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude Sonnet 4.5 shipped 39 days before GPT-5-Codex-Mini, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
Direct benchmark comparisons are unavailable — Claude Sonnet 4.5 and GPT-5-Codex-Mini don't publish scores on any of the same benchmarks.
Frequently asked questions
Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.
GPT-5-Codex-Mini was released by OpenAI on Nov 7 2025.
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