Use when the user asks for investigation, planning, or design without implementation - triggers include "analyze this first", "don't fix it yet", "plan how to fix", "just create the structure", "understand the context, plan, then execute", "write the findings to a file", "explain the cause before changing anything", or any request that names a stopping point. Also use proactively before any multi-file change, and whenever the user mentions saving tokens on exploratory work. Covers honoring an explicit stop line, writing findings to a file rather than into chat, and separating diagnosis from repair.
