Tickler introduces checklists to Zendesk. Manage standard tasks/procedures with preconfigured checklists (AKA todo lists). Your agents can also create one off checklists for a ticket.
Tickler can be pre-configured with checklists relating to common issues your agent have to address. Specific ticket tags and/or ticket field values are defined to make the appropriate checklist appear within tickets. This means Tickler will spring into action based on a field selected by the agent or end-user.
Tickler list items can be configured to set tags and field values when they are ticked.