Every BC ISV partner faces the same architecture problem: a bug report could originate in the core add-on, in a client's custom extension override, or in standard BC behavior the client misunderstood. Locating which layer actually owns the bug is the real bottleneck, not writing the fix. This session walks through a concrete triage method using AI coding assistants (Claude Code) to search and cross-reference product code, client custom code, and BC standard behavior before touching a single line, including a real case where this cut a feature investigation from an estimated multi-day effort to under a day. The talk covers what worked, what the AI got wrong, and where human judgment still has to override the tool.