Debugging Workflow

Debugging is a search over hypotheses, not an inspection of code. The fastest route to a cause is a sequence of experiments that each halve the space of possible explanations.

When to Use This Skill

• A defect has been reported and the cause is unknown
• A test fails intermittently
• Behaviour differs between environments
• A performance or memory regression appeared
• Something worked before and does not now
• The user asks "why does this happen?" about running code

If the cause is already known, skip this and fix it. This procedure is for the case where you do not yet know.

Core Concepts