<h2 style="margin:26px 0 12px 0; line-height:1.3;">“The robot acted strangely” is not a diagnosis</h2><p style="text-align:justify; margin:0 0 16px 0; line-height:1.65;">When an EA opens, rejects or closes a position, the event should be explainable from recorded state. A useful audit trail turns vague surprises into testable questions.</p><h2 style="margin:26px 0 12px 0; line-height:1.3;">Record the decision context</h2><p style="text-align:justify; margin:0 0 16px 0; line-height:1.65;">Log timestamp, symbol, timeframe, model version, signal values, filters, volatility regime, spread and active risk limits. The record should show not only what happened but which gates allowed or blocked the action.</p><h2 style="margin:26px 0 12px 0; line-height:1.3;">Separate signals from orders</h2><p style="text-align:justify; margin:0 0 16px 0; line-height:1.65;">A valid signal does not guarantee a filled trade. Record signal creation, order request, broker response, fill details and subsequent management as separate events. This makes execution problems distinguishable from strategy logic.</p><h2 style="margin:26px 0 12px 0; line-height:1.3;">Use stable reason codes</h2><p style="text-align:justify; margin:0 0 16px 0; line-height:1.65;">Human-readable notes help, but structured codes make analysis easier: SIGNAL_EXPIRED, SPREAD_BLOCK, RISK_LIMIT, REGIME_MISMATCH, ORDER_REJECTED. Keep the vocabulary small and consistent.</p><h2 style="margin:26px 0 12px 0; line-height:1.3;">Protect performance</h2><p style="text-align:justify; margin:0 0 16px 0; line-height:1.65;">Logging should be detailed enough for analysis without overwhelming storage or slowing execution. Use event-based records, appropriate rotation and summary statistics. Never write secrets or unnecessary personal information.</p><h2 style="margin:26px 0 12px 0; line-height:1.3;">Connect logs to validation</h2><p style="text-align:justify; margin:0 0 16px 0; line-height:1.65;">Compare live frequency, holding time, costs and decision reasons with the distributions observed in testing. The audit trail becomes part of model monitoring rather than a file opened only after failure.</p><p style="text-align:justify; margin:0 0 16px 0; line-height:1.65;">A transparent EA is easier to improve because every action has evidence. Explainability begins with disciplined instrumentation.</p><p style="text-align:justify; margin:0 0 16px 0; line-height:1.65;"><em>Monitoring improves oversight but does not remove trading risk.</em></p>
