diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 63d5d8d..934af5b 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -674,6 +674,13 @@ trade.realizedPnL += actualRealizedPnL  // NOT: result.realizedPnL from SDK
     - **ActiveTrade interface:** Must include `atrAtEntry?: number` field for calculation
     - See `ATR_TRAILING_STOP_FIX.md` for full details and database analysis
 
+21. **CreateTradeParams interface sync:** When adding new database fields to Trade model, MUST update `CreateTradeParams` interface in `lib/database/trades.ts`:
+    - Interface defines what parameters `createTrade()` accepts
+    - Must add new field to interface (e.g., `indicatorVersion?: string`)
+    - Must add field to Prisma create data object in `createTrade()` function
+    - TypeScript build will fail if endpoint passes field not in interface
+    - Example: indicatorVersion tracking required 3-file update (execute route.ts, CreateTradeParams interface, createTrade function)
+
 ## File Conventions
 
 - **API routes:** `app/api/[feature]/[action]/route.ts` (Next.js 15 App Router)