Domain 2: Tool Design & MCP Integration — Giving Claude Hands to Act in the World

Covers the full tool design lifecycle: when to use built-in tools vs. custom MCP tools, how to design clean tool schemas, error handling, and trust boundaries. The Customer Support Resolution Agent scenario brings it to life — wiring up get_customer, lookup_order, process_refund, and escalate_to_human as MCP tools and designing for 80%+ first-contact resolution.