本地使用没有限制；如果使用MLO 云同步，任务标题不能超过255个字符。

参考资料：
https://groups.google.com/forum/#!topic/mylifeorganized/QIwYs1j2bW0

MLO can handle that, please rest assured. There is a limit in MLO Cloud of 255 characters for a task name. If you do not use MLO Cloud Sync, it's very unlikely that you will ever reach the limits.