The Todoist Indicator plugin enhances project file management in Obsidian by displaying badges based on the availability of Todoist links. It identifies project files tagged as 'project' and checks for the presence of a Todoist link within the file metadata. If the link is missing, the plugin highlights the file with a 'Missing todoist' badge in the file tree. Users can customize the project folder prefix and Todoist property name through the settings, and optionally require a specific tag for badge application. This tool streamlines tracking of Todoist integration across project files for better organization.