LegacyAI is a ChatGPT (Generative Pre-training Transformer) client designed for older Mac OS systems and allows users to converse with OpenAI's ChatGPT from their desktop.

It is a tool that can efficiently serve as an AI-powered personal assistant for anyone using older Macintosh computers. The application supports Mac OS 9 - 10.6.8 and allows users to choose AI models depending on their requirements and even set proxy servers if required.

LegacyAI also provides users with options to save conversations for future reference, change AI models to adapt to their needs, and fully customize preferences.

The tool is free to use, but API access is dependent on donations. Running costs are involved in hosting the server and using OpenAI's API, so if users are in a position to donate, they can do so through a link provided.

It requires a Macintosh computer running Mac OS 9 - 10.6.8, preferably a G3 processor, at least 16mb RAM, and 1mb disk space. It should be noted that LegacyAI does not transmit information over HTTPS as Mac OS 9 was developed before HTTPS was a standard protocol on the internet.

While LegacyAI is free to use, the transmissions made using it on an older Macintosh are not secure. It is essential to understand this and not use it for sensitive matters.

The tool was built by Manticore Software, a software development agency in New Zealand, and its founder, Jordan Trbuhovic.