This is a sample of how to add actionable button for Reminders (private API); demo video: https://youtu.be/q7LrO3VhI64

rich-reminders.swift

import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true

let reminderListName = "Test"

import EventKit

extension EKCalendarItem {
  var hack_action: AnyObject? {
    set {
      setValue(newValue, forKey: "action")
    }
    get {
      return value(forKey: "action") as AnyObject?
    }
  }
}

let modifier: (EKReminder) -> Void = { reminder in
  guard let title = reminder.title else {
    return
  }

  if let action = reminder.hack_action, !(action is NSNull) {
    print("Action for reminder \"\(title)\" already set to \"\(action)\"")
    return
  }

  let types: NSTextCheckingResult.CheckingType = [.address, .phoneNumber, .link, .date]
  let detector = try! NSDataDetector(types: types.rawValue)
  let range = NSRange(location: 0, length: title.count)
  let results = detector.matches(in: title, options: [], range: range)
  guard let result = results.first else {
      return
  }
  let match = String(title[title.index(title.startIndex, offsetBy: result.range.location)
                     ..<
                     title.index(title.startIndex, offsetBy: NSMaxRange(result.range))])
  if result.resultType == .phoneNumber {
    let phone = match.filter { CharacterSet.decimalDigits.contains(UnicodeScalar("\($0)")!) }
    print("Updating phone number: \(phone)")
    reminder.hack_action = URL(string: "tel://\(phone)") as AnyObject
  } else if result.resultType == .address {
    let address = match.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlFragmentAllowed)!
    print("Upading address \"\(match)\"")
    reminder.hack_action = URL(string: "https://maps.apple.com?address=\(address)") as AnyObject?
  } else if result.resultType == .link {
    print("Updating url: \(match)")
    reminder.hack_action = URL(string: match) as AnyObject
  }
}

func fetchAllReminders(for store: EKEventStore) {
  let targetCalendar = store.calendars(for: .reminder).first(where: { $0.title == reminderListName })!
  let predicate = store.predicateForIncompleteReminders(withDueDateStarting: nil, ending: nil, calendars: [targetCalendar])

  store.fetchReminders(matching: predicate) { reminders in
    guard let reminders = reminders else {
      assertionFailure("No reminders found")
      return
    }
    if reminders.isEmpty {
      print("No reminders passed the filter")
      return
    }

    for reminder in reminders {
      modifier(reminder)
      do {
        try store.save(reminder, commit: false)
      } catch {
        fatalError("Failed to save reminder \(reminder.title): \(error)")
      }
    }
    do {
      try store.commit()
    } catch {
      fatalError("failed to save reminders \(error)")
    }
    print("Saved")
  }
}

let store = EKEventStore()
store.requestAccess(to: .reminder) { result, error in
  if let error = error {
    assertionFailure("\(error)")
  }
  if (result) {
    fetchAllReminders(for: store)
  }
}