Systematic Debugging

A structured 4-phase methodology for diagnosing and fixing non-obvious bugs. Prevents the common failure modes of "shotgun debugging" (random changes hoping something sticks) and "symptom patching" (fixing the visible error without understanding the cause).

When to Use

• A bug has resisted one or more quick-fix attempts
• The bug only appears in certain environments (prod but not dev, intermittent)
• The cause is unclear after an initial look
• A "fixed" bug keeps coming back
• Multiple engineers have looked at it without resolution

When NOT to Use