A simple guide to OpenAI tool use for building AI agents

Kenneth Pangan
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Kenneth Pangan

Katelin Teen
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Katelin Teen

Last edited October 14, 2025

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Welcome to our guide on OpenAI Tool Use! In this blog, we'll explore everything you need to know. OpenAI's tools are changing the world.

What is OpenAI Tool Use?

OpenAI Tool Use, also known as function calling, allows models like GPT to connect to external tools. This means the AI can perform actions, like searching a database or sending an email, by calling functions you define. It's a game-changer for creating powerful AI applications.

The benefits of OpenAI Tool Use

There are many benefits to implementing OpenAI Tool Use.

  • Enhanced capabilities

  • Real-time data access

  • Increased automation

OpenAI Tool Use: How does it work?

The process is straightforward. First, you define your tools (functions) in your code. Then, when you make an API call, you pass these definitions along with the user's prompt. The model then decides if it needs to call one of your tools to answer the prompt. If it does, it returns a JSON object with the function name and arguments. Your code then executes that function and sends the result back to the model, which uses that information to generate the final response.

Popular OpenAI Tool Use examples

Let's look at some popular OpenAI Tool Use examples.

  1. Weather Bot: An AI that can fetch the current weather for any location by calling a weather API.

  2. Calendar Assistant: A chatbot that can schedule, modify, or cancel events in your calendar.

  3. E-commerce Helper: An assistant that can check product inventory or order status by querying a database.

Getting started with OpenAI Tool Use

Ready to start? The first step is to check out the official OpenAI documentation. They have excellent guides and code samples to get you up and running quickly. It's easier than you think!

The future of OpenAI Tool Use

OpenAI Tool Use is a powerful feature that unlocks new possibilities for AI. As models become more capable, the integration with external tools will become even more seamless and essential.

Frequently asked questions

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Kenneth Pangan

Writer and marketer for over ten years, Kenneth Pangan splits his time between history, politics, and art with plenty of interruptions from his dogs demanding attention.