Software Debugging

Preserve diagnosis as read-only unless the user also asks for a fix.

1. State the exact observable symptom and establish a fast deterministic reproduction or the closest controlled probe available.
2. Minimize the reproduction and rank falsifiable causes from available evidence. Test one cause at a time.
3. Trace the failing path through its real public seam and affected external boundary. Add temporary instrumentation only where it distinguishes causes.
4. When a fix is authorized, first preserve the symptom as a red-capable regression test at the cheapest layer that proves it completely.
5. Apply the smallest causal correction, rerun the focused test and original scenario, then remove temporary instrumentation.

For performance regressions, measure a comparable baseline before changing code and inspect unbounded queries, fan-out, concurrency, memory, collections, and per-item external calls before micro-optimizing.