Practice — Case Study: Design a Customer-Support Assistant (5 questions)

A B2B SaaS company asks you to "build an AI support assistant". In the first five minutes of the design interview you learn that (a) the help centre has ~5,000 articles updated daily, (b) about 40% of tickets are "where is my invoice / change my plan / refund this charge" requests that today require a human to look at the account, and (c) the company serves several thousand customer organisations from one system.

1. Explain why "can the assistant act, or only answer?" is the first architectural fork, and what changes in the design on each side of it.
2. Recommend a phasing and justify it in terms of risk, evaluation and cost.
3. Which single requirement from (a)–(c) is a hard-failure constraint, and where in the system do you enforce it?