deep-dive

<Use_When>

• User has a problem but doesn't know the root cause — needs investigation before requirements
• User says "deep dive", "deep-dive", "investigate deeply", "trace and interview"
• User wants to understand existing system behavior before defining changes
• Bug investigation: "Something broke and I need to figure out why, then plan the fix"
• Feature exploration: "I want to improve X but first need to understand how it currently works"
• The problem is ambiguous, causal, and evidence-heavy — jumping to code would waste cycles </Use_When>