Compare AI models
| Specifications | ||
Context windowHow much information the model can work with in one request, measured in tokens — pieces of words or other data. This includes your question, attachments, conversation and reply. Limits can vary by model variant and provider. | 400k | 2M |
| Benchmarks | ||
BullshitBench v2Nonsense detection — Given 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. | 32% | 19% |
| Overview | ||
| Company | OpenAI | SpaceXSI |
| Release date | Nov 13 2025 | Nov 19 2025 |
| Access | Closed | Closed |
| Model details | View model | View model |
Other comparisons
GPT-5.1-CodexvsClaude Fable 5.2Grok 4.1 FastvsClaude Fable 5.2GPT-5.1-CodexvsGemini 4 CarbonGrok 4.1 FastvsGemini 4 CarbonGPT-5.1-CodexvsMuse EmberGrok 4.1 FastvsMuse EmberGPT-5.1-CodexvsDeepSeek-V4.1-Flash-1017Grok 4.1 FastvsDeepSeek-V4.1-Flash-1017GPT-5.1-CodexvsMistral Large 4Grok 4.1 FastvsMistral Large 4GPT-5.1-CodexvsKimi K3.1 ProGrok 4.1 FastvsKimi K3.1 ProFrequently asked questions
GPT-5.1-Codex leads Grok 4.1 Fast on 1 of the 1 benchmark they both report (BullshitBench v2). GPT-5.1-Codex shipped 6 days before Grok 4.1 Fast, so benchmark comparisons should account for the intervening progress.
Context windows are 400k (GPT-5.1-Codex) vs 2M (Grok 4.1 Fast).
On BullshitBench v2, GPT-5.1-Codex leads at 32% vs Grok 4.1 Fast at 19%.