The Harper plugin integrates a local grammar checker directly into Obsidian, providing users with instant, private, and open-source grammar correction. Unlike other tools, Harper runs entirely on your device, ensuring your data stays secure without the need for additional setup or internet connectivity. The plugin automatically checks your documents in real-time, highlighting errors as you type. Hovering over an error reveals suggested corrections for a seamless editing experience. With a lightweight design and efficient functionality, Harper enhances writing productivity while maintaining user privacy.