Harvey is a verticalised version powered by GPT-4, which has been trained on the entire corpus of the internet. It trained the model with legal sector-specific data.

Companies are quickly building new tools with GPT-4, like [Allen & Overy](https://legaltechnology.com/2023/02/16/allen-overy-breaks-the-internet-and-new-ground-with-co-pilot-harvey/) and accounting giant PwC, which just signed a 12-month deal with startup Harvey that will give its lawyers access to an AI tool built on the newest technology.