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xAI Intermediate

Grok 4.1 Fast

Grok 4.1 Fast is xAI’s low-cost 2M-context model for tool calling, search and production agents, priced at $0.20/M input and $0.50/M output.

Language Models (LLMs)Text Paid
In plain English

What is this model and why does it matter?

Grok 4.1 Fast is xAI's low-cost 2M-context family for tool calling, search and production agents, offered in reasoning and non-reasoning API variants.

Tool-calling agentsCustomer supportSearch agentsFinance workflowsHigh-volume automation
Model overview

Grok 4.1 Fast: features, use cases and important details

Grok 4.1 Fast is a current AI model covered in the Simplify AI Tools model directory.

Grok 4.1 Fast verified specifications

Grok 4.1 Fast is xAI’s low-cost 2M-context family for tool calling, search and production agents, offered in reasoning and non-reasoning API variants. The verified context or generation limit is 2000000 tokens.

Grok 4.1 Fast pricing and access

Grok 4.1 Fast costs $0.20 per 1M input tokens, $0.05 per 1M cached input tokens and $0.50 per 1M output tokens; xAI Agent Tools are billed separately.

Grok 4.1 Fast best uses

Tool-calling agents, Customer support, Search agents, Finance workflows, High-volume automation.

Grok 4.1 Fast limitations

Agent actions need safeguards, Realtime quality depends on tools, No downloadable weights.

Get started

How to use this model

  1. Create an xAI API key.
  2. Choose the reasoning or non-reasoning variant.
  3. Provide tools.
  4. Use web, X or code tools as needed.
  5. Track tool charges.
Copy and try

Example prompts

  • Resolve this support request using tools.
  • Research current information.
  • Analyze this data and return a recommendation.
Capabilities

What it can do

  • 2M context
  • Reasoning and non-reasoning variants
  • Tool calling
  • Web/X search
  • Code execution
  • MCP
Best for

Practical use cases

  • Production agents
  • Customer support
  • Research
  • Realtime search
  • Business workflows
Pricing

What does it cost?

Grok 4.1 Fast costs $0.20 per 1M input tokens, $0.05 per 1M cached input tokens and $0.50 per 1M output tokens; xAI Agent Tools are billed separately.

Input$0.20 / 1M tokens
Output$0.50 / 1M tokens
Simple summaryLow token rates are attractive, but server-side tool use creates separate charges.

What stands out

  • 2M context
  • Low token price
  • Strong agent tools

Things to consider

  • Tool calls cost extra
  • Proprietary
Limitations

Important restrictions and trade-offs

  • Agent actions need safeguards
  • Realtime quality depends on tools
  • No downloadable weights
SimplifyAITools verdict

Our editorial take

A high-demand agent model for developers prioritizing long context, tool use and low token pricing.

References

Primary sources

  1. Open source 1 ↗
  2. Open source 2 ↗
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