GPT-5.6 Luna vs Grok 4.20 Beta
OpenAI GPT-5.6 Luna | xAI Grok 4.20 Beta | |
|---|---|---|
| Overview | ||
| Company | OpenAI | xAI |
| Release date | Jun 26 2026 | Feb 17 2026 |
| 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. | — | 56% |
| Timeline | ||
| Release gap | Grok 4.20 Beta shipped 129 days before GPT-5.6 Luna | |
Which is better: GPT-5.6 Luna or Grok 4.20 Beta?
GPT-5.6 Luna and Grok 4.20 Beta don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Grok 4.20 Beta shipped 129 days before GPT-5.6 Luna, 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 — GPT-5.6 Luna and Grok 4.20 Beta don't publish scores on any of the same benchmarks.
Frequently asked questions
GPT-5.6 Luna was released by OpenAI on Jun 26 2026.
Grok 4.20 Beta was released by xAI on Feb 17 2026.
Other comparisons
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