Claude Opus 4.5 vs GPT-5.1-Codex-Max
Anthropic Claude Opus 4.5 | OpenAI GPT-5.1-Codex-Max | |
|---|---|---|
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | Nov 24 2025 | Nov 19 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. | 90% | — |
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. | 80.9% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 87% | — |
| Timeline | ||
| Release gap | GPT-5.1-Codex-Max shipped 5 days before Claude Opus 4.5 | |
Which is better: Claude Opus 4.5 or GPT-5.1-Codex-Max?
Claude Opus 4.5 and GPT-5.1-Codex-Max don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GPT-5.1-Codex-Max shipped 5 days before Claude Opus 4.5, 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 Opus 4.5 and GPT-5.1-Codex-Max don't publish scores on any of the same benchmarks.
Frequently asked questions
Claude Opus 4.5 was released by Anthropic on Nov 24 2025.
GPT-5.1-Codex-Max was released by OpenAI on Nov 19 2025.
Other comparisons
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