Leakage Audit

Outcome and stance

Assume leakage until the pipeline proves time-safe. Produce an adversarial, evidence-backed verdict: CLEAN, REVIEW REQUIRED, or NOT CLEAN, with contaminated fields, affected claims, required repairs, and retest conditions. A strong metric is never evidence of cleanliness.

When to Use This Skill

Use when:

• trusting a backtest or “good” metric for the first time;
• reviewing a feature table before modeling or after a suspiciously strong result;
• auditing target aliases, joins, shifts, preprocessing, or split design;
• the user says the model looks too good / results are unexpected.

Do not use this skill as a substitute for: