CtrlK
Agent Tools API is xAI's server-side tool suite for agentic workflows. xAI announced it on November 19, 2025 together with Grok 4.1 Fast and described it as a way to give agents access to real-time X data, web search, remote code execution, and other hosted tools without forcing developers to manage those systems themselves.[1]
The API is tightly connected to Grok's Responses API surface. xAI's central idea is that Grok should decide when to call tools, often using several tools in parallel, while the execution infrastructure stays on xAI's side.[1]
Public xAI documentation describes several built-in tool families that fit under this server-side tooling model.[1][2][3][4]
| Tool | What it does |
|---|---|
| Web Search | Searches the live web and browses pages for current information |
| X Search | Pulls information from X |
| Code Execution | Runs code on xAI-managed infrastructure |
| Collections Search | Searches uploaded collections and files |
| Remote MCP Tools | Connects Grok to remote MCP servers |
| Citations | Returns all-source and inline citation metadata for tool-backed answers |
xAI says these tools run entirely on its infrastructure, so developers do not need to manage API keys, rate limits, retrieval systems, or sandboxes for each tool separately. The model can keep calling tools over multiple turns until it has enough information to answer.[1]
The Remote MCP Tools documentation shows the same hosted approach for external MCP servers: developers provide a server URL and optional access controls, and xAI handles the connection and tool interaction on Grok's behalf.[4]
A notable part of the Agent Tools API is citation support. xAI documents two citation forms: a complete list of all sources encountered during tool use, and inline markdown citations placed directly in the generated answer. The docs describe this as a traceability feature for agentic responses rather than a separate product.[2]
xAI's documentation says server-side tools are supported in the native xAI SDK, the OpenAI-compatible Responses API, and newer surfaces such as the Voice Agent API.[3][4]