OpenAI API: Function Calling

Tools and function calling unlock the potential of AI apps by letting the apps run software and perform tasks. In this course, explore how tools work in the OpenAI Responses API and how to choose the right approach for the capability you need. You integrate built-in tools such as web browsing, then add new behavior with custom functions that let your app take real actions and return structured results. You can also extend your app beyond a single environment by connecting it to local and hosted Model Context Protocol (MCP) servers, enabling your AI to access the services and resources you want—without hardwiring every integration directly into your app.

Learning objectives
Define tools and function calling and explain how they work in the OpenAI Responses API.
Integrate built-in tools (such as web browsing) into an AI app to enable tool-driven tasks.
Design and implement custom functions that let your AI app run software actions and return structured outputs.
Connect an AI app to local and hosted Model Context Protocol (MCP) servers to access external services and resources.
Evaluate when to use built-in tools vs. custom functions vs. MCP servers for a given requirement and justify your choice based on the desired capability.