Agentic Development · Core Concepts
The ability of an LLM to call predefined functions or external APIs as part of generating a response. The model outputs a structured call (e.g. search(query='...')) and the host application actually executes it.
Example: An agent calls a web_search tool, gets back results, then incorporates those results into its next reasoning step.
In practice: Tool use is what turns a chatbot into an agent. Without it, the model can only produce text. With it, the model can fetch data, run code, send emails, and more.