diff --git a/frontend/src/pages/CampaignDetailPage.tsx b/frontend/src/pages/CampaignDetailPage.tsx
index 9a2926f..d1f1ec2 100644
--- a/frontend/src/pages/CampaignDetailPage.tsx
+++ b/frontend/src/pages/CampaignDetailPage.tsx
@@ -90,8 +90,8 @@ export default function CampaignDetailPage() {
     enabled: !!campaignId,
   });
 
-  const activateMutation = useMutation({
-    mutationFn: (force = false) => activateCampaign(campaignId!, force ? { force: true } : undefined),
+  const activateMutation = useMutation<Campaign, unknown, boolean>({
+    mutationFn: (force: boolean) => activateCampaign(campaignId!, force ? { force: true } : undefined),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ["campaign", campaignId] });
       setStartDateWarning(null);