What is an Agent Tools?

A large language model on its own only predicts text. Tools are what turn it into an agent: a tool definition tells the model exactly what a function does and what arguments it needs, the model decides when to call it based on the conversation, and the surrounding system executes the actual function, be it a web search, a file write, or an API request, and returns the result back into the model's context. Good tool design keeps each tool narrow and well-documented, since an overloaded or ambiguous tool schema causes the model to call it incorrectly or hallucinate arguments. Production systems also gate tool calls behind permission and verification layers so an agent can't silently take a destructive action, and they log every call for auditability.