diff --git a/src/features/background-agent/loop-detector.ts b/src/features/background-agent/loop-detector.ts
index ecfcf23f3..6120a168c 100644
--- a/src/features/background-agent/loop-detector.ts
+++ b/src/features/background-agent/loop-detector.ts
@@ -36,7 +36,7 @@ export function recordToolCall(
   settings: CircuitBreakerSettings,
   toolInput?: Record<string, unknown> | null
 ): ToolCallWindow {
-  if (toolInput === undefined || toolInput === null) {
+  if (toolInput == null) {
     return {
       lastSignature: `${toolName}::__unknown-input__`,
       consecutiveCount: 1,
@@ -78,7 +78,7 @@ export function createToolCallSignature(
   toolName: string,
   toolInput?: Record<string, unknown> | null
 ): string {
-  if (toolInput === undefined || toolInput === null) {
+  if (toolInput == null) {
     return toolName
   }
   if (Object.keys(toolInput).length === 0) {