Glossary · Agents & harnesses

function calling

The specific API feature (popularized by OpenAI) that lets a model output a structured JSON call to a predefined function based on the conversation.

Related terms

• AI agent
• JSON mode
• LangChain
• LlamaIndex
• MCP server
• Model Context Protocol (MCP)

Vynaris is an inference gateway that routes each request to the cheapest right-sized model and shows the receipt. Get an API key or read the docs.