Anthropic Claude 1 vs OpenAI GPT-5-Codex — side-by-side specs.
Anthropic Claude 1 | OpenAI GPT-5-Codex | |
|---|---|---|
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | Mar 14 2023 | Sep 15 2025 |
| Model type | — | — |
| Open source | No | No |
| Specifications | ||
Parameters | — | — |
Context window | — | — |
| Benchmarks | ||
Science reasoning GPQA Diamond | — | — |
Software engineering SWE-Bench Verified | — | — |
Multimodal understanding MMMU | — | — |
| Timeline | ||
| Release gap | Claude 1 shipped 916 days before GPT-5-Codex | |
Claude 1 and GPT-5-Codex do not have directly comparable benchmark scores published on GPQA Diamond, SWE-Bench Verified, or MMMU. Claude 1 shipped 916 days before GPT-5-Codex, 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 — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.