I develop a little command-line app to bring google tasks, but return all tasks in a specified task list does not return completed tasks, wish showCompleted is true by default
So I tried many times in Live API and only uncompleted tasks are returned, see by your self: https://developers.google.com/tasks/v1/reference/tasks/list
For those who did not understand go to you Gmail and add a non concluded task and a concluded one, then go to the live API and test it, you will see the concluded task doesn't appear even if you set showCompleted to True! How in the online version of Google Tasks can they get the tasks completed?
tasks = service.tasks().list(tasklist='@default').execute()
for task in tasks['items']:
print task['title']
print task['status']
print task['completed']