The tool is an AI-powered email rewriting tool that can help improve language and refine email content for workplace use. It is free to use online, but running the tool's advanced GPT-4 prompt may cost up to 15 times the normal cost. The tool's function is to quickly fix and improve rough emails, taking only 20 seconds to load OpenAI's response. The tool is available for trial use, and every use helps keep the site running with the contribution of about $0.002 per email.