Grok 4 Fast Reasoning is a xAI model tracked in Sim. It supports a 1M token context window. Pricing starts at $1.25/1M input tokens and $2.5/1M output tokens. Key capabilities include Temperature 0-2, Tool choice, Structured outputs. Best for long-context retrieval, large documents, and high-memory workflows.
Best forBest for long-context retrieval, large documents, and high-memory workflows.
Temperature0 to 2
Reasoning effortNot supported
VerbosityNot supported
Thinking levelsNot supported
Structured outputsSupported
Tool choiceSupported
Computer useNot supported
Deep researchNot supported
Memory supportSupported
Max output tokensNot published
Frequently asked questions
Grok 4 Fast Reasoning is a xAI model available in Sim. Grok 4 Fast Reasoning is a xAI model tracked in Sim. It supports a 1M token context window. Pricing starts at $1.25/1M input tokens and $2.5/1M output tokens. Key capabilities include Temperature 0-2, Tool choice, Structured outputs.
Grok 4 Fast Reasoning starts at $1.25/1M input tokens, $0.2/1M cached input tokens, and $2.5/1M output tokens.
Grok 4 Fast Reasoning supports a context window of 1M tokens in Sim. In an agent, this determines how much conversation history, tool outputs, and retrieved documents the model can hold in a single call.
Grok 4 Fast Reasoning supports the following capabilities in Sim: Temperature 0-2, Tool choice, Structured outputs.
Best for long-context retrieval, large documents, and high-memory workflows. When used in a Sim workflow, it can be selected in any Agent block from the model picker.
