Grok 4.1 Fast
Released
Grok 4.1 Fast is an AI model released by SpaceXAI on Wednesday, Nov 19 2025, 2 days after Grok 4.1. Benchmark results (shown below) cover BullshitBench v2.
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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.
19%
#66 of 84Best: Claude Opus 4.8 · 95%
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Grok 4.1 Fast was released by SpaceXAI on Wednesday, Nov 19 2025.