The capstone of the AI Engineer track. Shieldline Insurance, from the Business Analyst Capstone, wants a WhatsApp assistant that turns a customer's first message into a structured claim, asks for exactly the documents still needed, answers policy questions, and hands serious cases to a person. Working from recorded outputs of three configurations on 600 real messages, you'll write the validator that repairs plate numbers and catches invented ones, put escalation rules in code and measure their recall, test retrieval against a keyword baseline, and find out why an LLM judge that agrees with people 90% of the time still can't run alone. Then you'll red-team two guardrails and discover one blocks Pidgin speakers and angry customers far more often, price and time each configuration, pass one through a release gate, and watch it in production as an unannounced voice-note feature quietly breaks it. No API key needed; every number comes from running the code.