← All terms

Definition

Tool Use

The ability of an AI agent to invoke external tools — APIs, databases, code interpreters, web browsers — to gather information or take actions in the real world.

In Depth

Tool use (also called function calling) is what transforms a language model from a text generator into a capable agent. When an LLM has access to tools, it can retrieve live data, execute code, send emails, update databases, and interact with any system that has an API. The model decides which tool to call, generates the appropriate parameters, processes the result, and decides what to do next. Tool use is fundamental to building agents that can actually accomplish tasks rather than just talk about them.

Build production AI agents with EigenForge

Join the Waitlist