Grok 4.1 Fast Reasoning is xAI's most capable tool-calling model, engineered for production-grade agentic applications with a 2M token context window. Achieving state-of-the-art results on Berkeley Function Calling v4 and leading agentic search benchmarks like Research-Eval Reka (63.9) and FRAMES (87.6), it excels at multi-turn conversations, long-horizon planning, and autonomous task execution. Built through RL training in real-world simulated environments, Grok 4.1 Fast Reasoning delivers exceptional performance on complex enterprise scenarios like customer support and finance while cutting hallucination rates in half compared to its predecessor.
Retired on Aug 22, 2026: requests to this model ID now return an error. These models are live and work with the same API key.
Grok 4.1 Fast Reasoning is xAI's most capable tool-calling model, engineered for production-grade agentic applications with a 2M token context window.
No. Grok 4.1 Fast Reasoning was retired on NagaAI on Aug 22, 2026, and requests to it now return an error. Live models you can use instead with the same API key: Grok 4.7, Grok 4.6 and Grok 4.5.
It takes text and images as input and returns text.
