Glossary · AI Agents

What is Tool Calling (Function Calling)?

A model capability where the AI returns a structured request to run a function with specific arguments, instead of plain text.

In more detail

You describe tools with names, descriptions and JSON schemas. The model chooses a tool and arguments; your application validates and runs it and sends back the result.

Example

The model asks for check_train_seats(train_number="12127", date="2026-11-13").

Learn it properlyTool Calling Explained: How AI Agents Use Functions and APIs11 min lesson · AI Agents

Related terms

Full glossary

EmbeddingA list of numbers that represents the meaning of a piece of text, so similar meanings are close together.Human-in-the-LoopA design where a person reviews or approves an AI system’s action before it takes effect.Model Context Protocol (MCP)An open standard for connecting AI applications to tools and data sources through reusable servers.ReAct PatternAn agent pattern that alternates reasoning about the next step with acting through a tool, then observing the result.Vector DatabaseA database designed to store embeddings and quickly find the most similar ones to a query.