The AI tool called "Recap: Smart Split and Summarize with ChatGPT" is an open-source browser extension that allows users to easily summarize any portion of a webpage using ChatGPT. With the extension installed, users can highlight and summarize text on webpages they visit. It supports customization options such as choosing the model used in the ChatGPT webapp and selecting the OpenAI API model. Users can also customize the OpenAI API host if desired. The tool is free to use and does not require a ChatGPT account. Potential applications of this tool include quickly summarizing articles, blog posts, and research papers, as well as extracting key information from lengthy webpages.