This is awesome!! Especially for developers wishing to integrate with other APIs and/or call custom code within their applications. Looking forward to trying this out!
From OpenAI:
"Developers can now describe functions to gpt-4-0613 and gpt-3.5-turbo-0613, and have the model intelligently choose to output a JSON object containing arguments to call those functions. This is a new way to more reliably connect GPT's capabilities with external tools and APIs.
These models have been fine-tuned to both detect when a function needs to be called (depending on the userās input) and to respond with JSON that adheres to the function signature. Function calling allows developers to more reliably get structured data back from the model."