DeskPet is a native macOS desktop pet application (Swift / AppKit + WKWebView). A Live2D character resides on the desktop in a transparent window and provides idle motions, gaze tracking, swaying to the beat of music, and speech bubbles above its head; the dialogue content and motion changes are generated by a large language model (LLM) as structured JSON. The application additionally integrates routine reminders, weather-change alerts, a memory store, a daily task briefing, and a research mode that supports literature, news, market and weather retrieval and renders Markdown and LaTeX. The source code is open-sourced under the MIT License: Yu-Xiang-Yang/deskpet. All screenshots in this article were taken from DeskPet running on the author’s machine (the character is Tororo, an official Live2D sample model); none were composited or rendered from simulated data.