In the Hobonichi Techo App, Senpai (your guide/companion character) may occasionally leave comments on the content recorded in your daily timeline.
Regarding these comments from Senpai, the official website explains the following:
Senpai's lines are created with Hobonichi's original "Handmade AI (Human-Powered 'Thought' Intelligence)." They’ll leave comments on your entries, cheer you on, and share their thoughts. That said, since it's not true artificial intelligence, expect some wonderfully random and completely unrelated comments from time to time!
All of Senpai's comments are created by professional writers. The system automatically selects and displays comments that match the posted content.
The system also automatically categorizes photos and videos in a similar way to standard smartphone photo apps. The app then uses those categorizations to display comments that match the photo or video.
For more options regarding Senpai's comments, please refer to the following help pages: