Systematically debug CppTLM test failures using file-based logging, 5-layer diagnostic funnel, 4-step fix verification, and 6-step response loop template. Use when test fails, fix appears not to work, or message-passing chain breaks. Triggers on phrases like "test fail", "fix doesn't work", "X not received", "response lost", "where is it failing", "diagnose".
2026-06-13