ITG NowHome › AI glossary › Tool calling
What is Tool calling?
Short answer
Tool calling is when an AI model asks to use an outside tool, like search or a calculator, and then uses the result.
- Category Agents & tools
- Also called function calling, tool use
- Updated 20 Oct 2026
Tool calling, explained simply
A model on its own can only produce text. With tool calling, it can say: please run this search, then read what comes back.
The app runs the tool and hands the result to the model. The model then uses it to write the final answer.
This is how chatbots check live weather, read your calendar or run code.
On ITG Now, our free tool guides explain which tools an AI app can call and what it needs from you to do it.
Related terms
AI agentMCPAPIStructured outputJSONLLM
Where you'll see it on ITG Now
Questions people ask about Tool calling
Tool calling vs function calling: what is the difference?
They mean nearly the same thing. Both let a model ask an app to run a tool.
Is tool calling safe?
It is safer when you limit what the tools can do and review risky actions.