Add reminders support to add-tasks and update-tasks tools

[Sarozs2863]

Current Limitations

The current add-tasks and update-tasks tools don't support two core Todoist features that are available in the official REST API:

Missing functionality:

• add-tasks tool parameters only include: content, description, dueString, duration, priority, projectId, sectionId, parentId
• ❌ No reminders parameter available
• ❌ No labels parameter available (labels support was added in feat: add label support for add-tasks and update-tasks tools #103)
• Users must manually add reminders and labels in the Todoist app after creating tasks via API

Proposed Enhancement

Add reminders and labels parameters to add-tasks and update-tasks tools:

1. Reminders Support

Reminder types:

• Multiple reminders per task
• Relative reminders (e.g., "1 day before due date", "2 hours before due date")
• Absolute reminders (e.g., "2025-09-26T10:00:00")

2. Labels Support

Label functionality:

• Add multiple labels to tasks during creation
• Update task labels
• Support both label names and label IDs
• Maintain consistency with existing Todoist labeling system

Example usage:

await addTasks({
  tasks: [{
    content: "Important meeting",
    dueString: "tomorrow at 2pm",
    labels: ["urgent", "meeting", "work"],
    reminders: [
      { type: "relative", value: "1 day" },
      { type: "relative", value: "1 hour" },
      { type: "absolute", value: "2025-09-26T09:00:00" }
    ]
  }]
});

Use Cases

• Travel planning: Set multiple advance reminders + travel labels for flights, trains, etc.
• Meeting preparation: Remind users days/hours before important meetings + appropriate labels (urgent, meeting, etc.)
• Project management: Categorize tasks with labels while setting up deadline reminders
• Workflow automation: Programmatically create fully-configured tasks with complete reminder and labeling setup
• GTD implementation: Support Getting Things Done methodology with proper categorization and timing

Technical Implementation

Both features are already supported in the Todoist REST API:

Reminders API Support

• API Reference: https://developer.todoist.com/rest/v2/#create-a-new-task
• Reminders field: Already documented and available in official API
• Data structure: Well-defined reminder object format

Labels API Support

• API Reference: https://developer.todoist.com/rest/v2/#create-a-new-task
• Labels field: Already documented and available in official API
• Data structure: Simple array of label names or IDs

Impact

This enhancement would:

• ✅ Complete the feature parity with Todoist's native capabilities
• ✅ Reduce friction in automated task management workflows
• ✅ Eliminate the need for manual reminder/label setup after API task creation
• ✅ Enable more sophisticated AI-driven productivity scenarios
• ✅ Support advanced organizational methodologies (GTD, PARA, etc.)
• ✅ Address existing community requests (see related issue Add support for label management #55 for labels)

Alternative Workaround (Current)

Users currently need to:

1. Create task via API (incomplete)
2. Open Todoist app manually
3. Find the task
4. Add reminders manually
5. Add labels manually

This breaks the automation flow and significantly reduces the value of the AI integration.

Related Issues

• Issue Add support for label management #55: "Add support for label management" - shows community demand for labels support
• This issue extends that request to include labels in the core task creation/update tools

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Implementation Priority: Both features use existing, well-documented Todoist API endpoints, making implementation straightforward and high-impact.