diff --git a/scripts/harb-evaluator/helpers/swap.ts b/scripts/harb-evaluator/helpers/swap.ts
index 01b83a9..ed7e480 100644
--- a/scripts/harb-evaluator/helpers/swap.ts
+++ b/scripts/harb-evaluator/helpers/swap.ts
@@ -297,7 +297,7 @@ export async function sellKrk(
  * This is the "sovereign exit" path — it bypasses the UI swap widget and
  * sends transactions directly so the test is not gated on the sell-side UI.
  *
- * Logs a warning if the WETH balance does not increase after the swap, which
+ * Throws if the WETH balance does not increase after the swap, which
  * indicates the pool returned 0 output (possible with amountOutMinimum: 0n on
  * a partially-drained pool).
  *
@@ -360,9 +360,8 @@ export async function sellAllKrk(page: Page, config: SellConfig): Promise<bigint
   const wethAfter = await erc20BalanceOf(config.rpcUrl, WETH, config.accountAddress);
   const wethReceived = wethAfter - wethBefore;
   if (wethReceived <= 0n) {
-    console.warn('[swap] WARNING: WETH balance did not increase after sell — pool may have returned 0 output');
-  } else {
-    console.log(`[swap] Received ${wethReceived} WETH`);
+    throw new Error('sellAllKrk: swap returned 0 WETH — pool may be drained or price impact exceeded balance');
   }
+  console.log(`[swap] Received ${wethReceived} WETH`);
   return wethReceived;
 }