Grok 4.1 Fast
Grok 4.1 Fast is a proprietary xAI language-model release. The tool-oriented fast tier improves agent task performance and instruction following while retaining a two-million-token context. It was offered through the API with reasoning and non-reasoning variants. Later endpoint retirement redirects access to newer models; this page describes the original released tier. Weights are not publicly downloadable. Published agent and coding results depend on the evaluation harness, tool permissions, and inference settings, so no unsupported standalone benchmark score is assigned.
2025-11-19
Undisclosed
Proprietary
Specifications
- Architecture
- Undisclosed
- License
- Proprietary
- Context Window
- 2,000,000 tokens
- Type
- multimodal
- Modalities
- textimage
Benchmark Scores
Advanced Specifications
- Model Family
- Grok
- API Access
- Available
- Chat Interface
- Not Available
- Variants
- ReasoningNon-reasoning
Capabilities & Limitations
- Capabilities
- agentic reasoningtool uselong context
- Known Limitations
- Closed weightsAvailability and aliases can changeOutputs may hallucinate
- Notable Use Cases
- developer assistantsagent workflowsgeneral assistance
- Tool Use Support
- Yes