DEFINITION
Function Calling
Function Calling (OpenAI)
Definition
OpenAI's original name for tool-calling — the ability for GPT models to output structured JSON matching a function signature. Now standardized across most major LLMs. MCP extends this concept into a full protocol for server-based tools.
Examples in the Wild
- Example 1:GPT-4o calls `get_weather({location: 'Paris'})` and receives structured weather data