diagnose

To find the root cause of a hard bug, build a deterministic feedback loop that reliably reproduces the exact symptom, then test ranked falsifiable hypotheses by changing one variable at a time until the root cause is identified.

The best way to debug a performance regression is to transform the reported slowdown into a measurable, repeatable signal using differential runs or bisection, allowing you to isolate the specific change responsible for the performance drop.

You create a regression test before applying a bug fix by exposing a correct seam in your test or CLI workflow, writing a test that captures the current failure, and confirming it passes only after the fix is applied.

Yes, hypothesis testing works for intermittent flaky test failures by establishing a usable reproduction rate through fuzzing or trace replay, then applying one-variable-at-a-time probes to isolate the race condition or state dependency.

Yes, you can use bisection to minimize a failing test case by systematically reducing the input space or replay trace until the smallest deterministic sequence that still triggers the exact reported failure is isolated.

You should clean up debug instrumentation after diagnosing an issue once the original repro no longer reproduces, removing all tagged probes and throwaway prototypes, then document the effective cause and prevention strategies for the post-mortem.