Diurnal is a native macOS notepad application that converts written content into tasks. The application combines a blank-page writing interface with task management, where each paragraph the user types becomes a task and blank lines separate individual items. Users can invoke the writing interface with a keyboard shortcut (Shift+Command+A) and begin typing immediately. The app functions entirely offline and does not require calendar integration. The workflow operates in three stages. First, the user writes freely, and the application converts each paragraph into a task. Second, tasks remain undated by default, so nothing on the page becomes overdue on its own. Third, the application performs automatic upkeep: it asks about quiet tasks and moves unanswered items to the following week. Unfinished tasks turn red and remain visible until the user reschedules them, while newly added items accumulate in a dumping ground until the user organizes them. Diurnal requires a user account, though the account is not a profile and no in-app activity is tracked. The application is built specifically for macOS and includes a browser-based demo that allows users to try the interface on a Mac with sample data. The design focuses on reducing the maintenance typically associated with task management, allowing the user to concentrate on writing while the application handles task organization.