What is tool calling?

Definition

AI tool calling presents a model with named operations and input definitions. The model selects a tool and supplies arguments, the harness executes the operation, and the result returns to the model for the next decision.

Multi-step tool use requires consistent identifiers, valid arguments and recovery from errors. A fast response is valuable only if the model chooses the correct tools and the harness verifies consequential effects.

ELI5

Tool calling lets an AI model ask software to perform a structured action. The model chooses an available tool and provides the needed details, then receives the tool's result before deciding what to do next.

For example, a travel assistant can call a weather tool with a city and date, then use the returned forecast in its answer. The surrounding software should verify important inputs and permissions before carrying out actions with real consequences.

What tools can a coding model call?

A harness may expose file reads, searches, code edits, tests, builds or terminal commands through structured operations with bounded permissions.

Why is tool-calling quality important?

An incorrect tool or argument can corrupt later steps, so agents need reliable selection, clear errors and verification of the resulting state.

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Definition card for tool calling: What is tool calling?

AI tool calling lets a model request a structured operation from software instead of only returning natural-language text.