Build a customer-support agent over a fake product/SQL database: tool-calling, retrieval, and a control loop.

A live-coding round that separates people who have shipped agents from people who have read about them. The signal is a real plan-act-observe loop, tools that hit an actual SQL database, guardrails that stop the obvious failures, and a concrete evaluation plan, not a single prompt that pretends to be an agent.

Updated Aug 2026 · Grounded in real Applied AI Engineer interview loops and written to a senior-engineer editorial bar.