Decoding the Grok 4.1 Full Platform Launch: Complete Guide to 4 New API Features and 50% Price Reduction for Tool Invocation

Grok 4.1 has just launched across all platforms, covering grok.com, X, iOS, and Android, while also introducing Grok 4.1 Fast to the xAI Enterprise API. At the same time, xAI has slashed prices for Agent tool calls by up to 50% and rolled out four major new API features: Collections Search, Remote MCP Tools, Live Search GA, and Voice Agent API GA.

Core Value: Spend 3 minutes getting up to speed on the key upgrades, API pricing changes, and new features of Grok 4.1 to determine if it's the right fit for your business needs.

Quick Overview: Grok 4.1 Full Platform Launch

Grok 4.1 was officially released following two weeks of A/B blind testing in early November, where 64.78% of users preferred the responses from Grok 4.1. Here are the key release details:

Grok 4.1 vs. Grok 4: Key Upgrades

Compared to the previous generation, Grok 4.1 has achieved significant improvements across several dimensions:

The Grok 4.1 Thinking mode secured the #1 spot in the LMArena Text Arena, leading non-xAI models by 31 points.

🎯 Technical Advice: With its 2M ultra-long context window and 65% reduction in hallucinations, Grok 4.1 is a powerful choice for complex analysis and long-document processing. We recommend using the APIYI (apiyi.com) platform to unify your access to Grok and other mainstream models, making it easier to quickly compare real-world performance.

description: A comprehensive guide to Grok 4.1 Fast API pricing, dual-mode capabilities, and significant cost reductions for Agent tool calls.

Grok 4.1 Fast API Pricing and Invocation

Grok 4.1 Fast is a specialized model designed for developers, optimized specifically for tool calling and Agent workflows. It supports both reasoning and non-reasoning modes.

Grok 4.1 Fast API Pricing Details

Key Takeaway: The input price for Grok 4.1 Fast is just 1/15th of Grok 4, and the output price is only 1/30th. Combined with a 2M token long context window, it's currently the most cost-effective model in the xAI product lineup.

Quick Invocation of Grok 4.1 Fast API

import openai

client = openai.OpenAI(
    api_key="YOUR_XAI_API_KEY",
    base_url="https://api.apiyi.com/v1"  # Invoke via the unified APIYI interface
)

response = client.chat.completions.create(
    model="grok-4.1-fast",
    messages=[
        {"role": "system", "content": "You are a professional technical analysis assistant."},
        {"role": "user", "content": "Analyze the competitive landscape of the 2025 Large Language Model market."}
    ],
)
print(response.choices[0].message.content)

Grok 4.1 Dual-Mode Explanation

Grok 4.1 supports two processing modes: Thinking (deep reasoning) and Non-Thinking (fast response):

Auto mode is the default setting on grok.com; the system automatically decides whether to use fast response or deep reasoning based on query complexity, so there's no need for manual switching.

Detailed Breakdown: Grok 4.1 Agent Tool Calling Price Cut by 50%

Alongside the release of Grok 4.1 Fast, xAI has significantly reduced the pricing for Agent tool calls, with cuts of up to 50%.

Tool Calling Price Overview

Price Reduction Rule: All tool call prices are capped at $5 per 1,000 successful calls, representing a maximum reduction of 50%. Collections Search is now the most affordable tool at $2.50 per 1,000 calls.

💰 Cost Optimization: The 50% reduction in tool calling costs means building AI Agents is significantly cheaper. By using the APIYI (apiyi.com) platform to call Grok 4.1 Fast, you can flexibly manage tool calls and costs under a unified interface.

Detailed Breakdown of the Four New Grok 4.1 API Features

The highlight of this release is the simultaneous launch of four brand-new API features, which significantly expand the boundaries of Grok's agent capabilities.

New Feature 1: Collections Search Tool

Collections Search is a vector-based knowledge base search tool that allows developers to upload document collections and perform semantic searches via API.

Key Features:

• Specify the document collection to search using a vector store ID.
• Configurable maximum number of results to return.
• Industry-leading performance for RAG tasks in finance, law, and coding.
• Hybrid search support for precise retrieval of tabular and numerical data (e.g., SEC financial report data).
• Priced at just $2.50 per 1,000 calls, making it the most cost-effective tool available.

Typical Use Cases:

• Enterprise internal knowledge base Q&A systems.
• Intelligent financial report analysis.
• Rapid legal document retrieval.
• RAG-enhanced technical documentation.

New Feature 2: Remote MCP Tools

The Remote MCP (Model Context Protocol) tool allows Grok to connect to external MCP servers, extending its custom capabilities.

Key Features:

• Developers specify the server URL and configuration, while xAI manages the connection.
• Supports xAI native SDK, OpenAI-compatible Responses API, and Voice Agent API.
• Mix and match client-side and server-side tools within the same conversation.
• Token-based billing with no additional tool invocation fees.

Extended Capabilities:

• Integrate internal enterprise APIs and business logic.
• Connect to third-party data sources and services.
• Custom data processing pipelines.
• Integration of specialized domain tools.

New Feature 3: Live Search GA

xAI's real-time search feature has officially reached General Availability (GA), migrating from the original standalone API to the Agent Tools architecture:

• The original Live Search API was retired on January 12, 2026.
• The new version is implemented via web_search and x_search server-side tools.
• Developers must migrate to the new agentic tool invocation method.
• In Auto and Fast modes on grok.com, search is automatically triggered as needed.

New Feature 4: Grok Voice Agent API GA

The Voice Agent API is one of the most groundbreaking features in the Grok 4.1 release:

The Voice Agent API supports integration with Collections Search, Web Search, X Search, and custom functions, allowing you to build fully functional voice-interactive agents.

🚀 Quick Start: If you want to test Grok 4.1's voice capabilities and new tool features, we recommend using the APIYI (apiyi.com) platform for rapid integration. It supports OpenAI-compatible interfaces, so no extra adaptation is required.

How to Use Grok 4.1 Across All Platforms

Grok 4.1 has been rolled out simultaneously for both consumers and developers. Depending on the platform you're using, the features and access methods vary slightly.

Access Permissions Overview

Complete Grok 4.1 API Code Examples

Basic Chat Invocation

import openai

client = openai.OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.apiyi.com/v1"  # APIYI unified interface
)

# Use Grok 4.1 Fast for conversation
response = client.chat.completions.create(
    model="grok-4.1-fast",
    messages=[
        {"role": "user", "content": "Explain the basic principles of quantum computing"}
    ],
    temperature=0.7,
)
print(response.choices[0].message.content)

import openai
import json

client = openai.OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.apiyi.com/v1"
)

tools = [
    {
        "type": "function",
        "function": {
            "name": "search_web",
            "description": "Search the web for real-time information",
            "parameters": {
                "type": "object",
                "properties": {
                    "query": {"type": "string", "description": "Search keywords"}
                },
                "required": ["query"]
            }
        }
    }
]

response = client.chat.completions.create(
    model="grok-4.1-fast",
    messages=[{"role": "user", "content": "What's the latest AI news today?"}],
    tools=tools,
    tool_choice="auto",
)

if response.choices[0].message.tool_calls:
    for call in response.choices[0].message.tool_calls:
        print(f"Tool: {call.function.name}")
        print(f"Arguments: {call.function.arguments}")

xAI Model Product Line Overview

With the release of Grok 4.1, xAI has built a comprehensive product line covering text, images, video, and audio.

💡 Recommendation: Use Grok 4.1 Fast ($0.20/M input) for daily Agent tasks, and Grok 4.20 ($2.00/M input) for complex reasoning. You can switch between models as needed under a single interface via APIYI (apiyi.com).

FAQ

Summary

The launch of Grok 4.1 across all platforms marks xAI's transition from a single-model provider to a comprehensive AI platform. With a 65% reduction in hallucination rates, a massive 2M context window, a 50% price cut for tool invocation, and new features like Collections Search, Remote MCP, and the Voice Agent API, Grok 4.1 is building a fully functional AI Agent ecosystem.

Key Takeaways:

• Full Platform Coverage: Available on grok.com, X, iOS, Android, and via the xAI Enterprise API.
• Performance Leap: Hallucination rates slashed by 65%, hitting #1 on the LMArena leaderboard.
• Cost Efficiency: Grok 4.1 Fast input is priced at $0.20/M, with tool invocation costs reduced by up to 50%.
• 4 Major New Features: Collections Search, Remote MCP, Live Search (GA), and Voice Agent API (GA).
• 2M Context Window: One of the largest in the industry, maintaining consistent performance throughout.

We recommend using APIYI (apiyi.com) to quickly integrate Grok 4.1 Fast and other mainstream AI models, allowing you to manage your model invocation needs in one place.

References

1. xAI Developer Release Notes: docs.x.ai/developers/release-notes
2. xAI API Model Documentation: docs.x.ai/developers/models
3. xAI Official Blog: x.ai/news

This article was written by the APIYI technical team. For more tutorials on using AI models, please follow APIYI at apiyi.com.