Here is a handler that makes creating Reminders convenient:
use AppleScript version "2.4" -- Yosemite (10.10) or later
use scripting additions
on makeReminder(reminderName, reminderBody, reminderDueDate, reminderListName)
tell application "Reminders"
if not (exists list reminderListName) then
make new list with properties {name:reminderListName}
end if
-- See if there is an existing reminder. This could happen if the rule was accidently
-- trigged more than once.
set existingReminder to reminders where due date = reminderDueDate and name = reminderName
if existingReminder is {} then
-- No existing reminder found, create one...
return make new reminder ¬
with properties {name:reminderName, body:reminderBody, due date:reminderDueDate} ¬
at list reminderListName
end if
return missing value
end tell
end makeReminder
set today to current date
set tomorrow to today + 60 * 60 * 24 -- + 1 day
makeReminder("Return Library Book", "Return Library Book 1234", tomorrow, "Library Books")