Backtesting and simulation guardrails: survivorship, drawdown, Sharpe, day-of-week. REQUIRES get_database_schema then get_query_patterns to be called first (in that order). Call BEFORE writing SQL when the user asks to backtest, simulate, validate a strategy, test "what happens after X", compare forward returns, measure win rates or hit rates, compute Sharpe, drawdown, profit factor, rotation strategies, basket returns, or any hypothetical return over past data. Contains hard rules for survivorship bias, outlier handling, sampling design, day-of-week filters, and risk-adjusted metrics (Sharpe, Sortino, drawdown). Can be combined with other workflow tools.