Glossary · AI

What is
Function Calling?

A structured way for LLMs to invoke developer-defined functions with typed arguments.

By Anish· Founder · Vedwix
·

Definition

Function calling is the API-level mechanism that lets you describe a function (name, description, JSON schema for arguments) to an LLM and have it return a structured call when relevant. The LLM doesn't actually execute the function — it produces a structured request that your code executes. Both Anthropic and OpenAI APIs support this natively.

Example

A travel app describes a "search_flights" function with parameters (origin, destination, date), and the LLM produces a typed call when a user says "find me flights to Tokyo next Tuesday."

How Vedwix uses Function Calling in client work

Default for any agent or workflow that needs deterministic structured output.

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