Evidence-based debugging

Own the investigation from the reported symptom through a supported diagnosis. Continue through repair and verification when the user asks to fix it. A diagnosis request alone does not authorize a production repair; existing repair authorization carries forward without another permission prompt.

Adapted in part from the former Toolbox debugging procedure and mattpocock/skills diagnosing-bugs (MIT © 2026 Matt Pocock).

When two fixes on one assumption fail, apply attack the premise from engineering-principles.md. Performance claims follow measurement.md.

Entry gate

• The target is an observed software or system failure, including unexpected output, crashes, failed builds, timing problems, or degraded performance.
• A runnable reproduction is useful evidence, not a prerequisite for beginning investigation.
• A request only to assess a claim or explanation has a verdict as its outcome; this procedure owns investigating the reported failure.

Evidence and authority