Help center answer bot

Design a chat widget for a software company's help center that answers customer questions using the company's own 400 help articles. Answers must come from the articles and link to the ones used; when the articles do not cover a question, the bot should say so and offer to open a support ticket. Articles are edited a few times a day, and an edit should show up in answers within an hour. Expect about 8,000 questions a day. Describe how articles are prepared for retrieval, the path of a single question, and how you keep the bot from making things up.