  Though widely used in industry, traditional task-oriented dialogue systems
suffer from three bottlenecks: (i) difficult ontology construction (e.g.,
intents and slots); (ii) poor controllability and interpretability; (iii)
annotation-hungry. In this paper, we propose to represent utterance with a
simpler concept named Dialogue Action, upon which we construct a
tree-structured TaskFlow and further build task-oriented chatbot with TaskFlow
as core component. A framework is presented to automatically construct TaskFlow
from large-scale dialogues and deploy online. Our experiments on real-world
after-sale customer services show TaskFlow can satisfy the major needs, as well
as reduce the developer burden effectively.
