OpenAI announced some updates for its GPT-3.5 turbo and GPT-4 generative AI models this week, along with price cuts for developers. The company’s updated AI models add support for function calling, which let developers describe functions to GPT-4 and GPT-3.5 turbo and have the AI models intelligently create a JSON object that contains arguments for those functions.

“This is a new way to more reliably connect GPT’s capabilities with external tools and APIs,” the company explained. One of the possible use cases for function calling is the creation of chatbots that answer questions by calling external tools such as ChatGPT plugins.

The new GPT-4 and GPT-3.5 turbo models will automatically replace the existing ones, which will be eventually deprecated. The company also said that it will invite more developers who signed up for the GPT-4 API waitlist over the coming weeks, and that waitlist should eventually disappear.

Lastly, OpenAI announced that it’s reducing the cost of the output tokens for its existing GPT-3.5 turbo model by 25%. Developers can now use OpenAI’s most popular chat model for just $0.0015 per 1K input tokens and $0.002 per 1K output tokens, which equates to roughly 700 pages per dollar.

However, the new GPT-3.5 turbo-16k model OpenAI announced today (with support for function calling) will be priced at $0.003 per 1K input tokens and $0.004 per 1K output tokens. The older GPT-3.5 turbo older models will remain accessible for developers through September 13.