diff --git a/packages/grafana-toolkit/src/cli/tasks/plugin.sign.ts b/packages/grafana-toolkit/src/cli/tasks/plugin.sign.ts
index 064e53eb445..bec898243f1 100644
--- a/packages/grafana-toolkit/src/cli/tasks/plugin.sign.ts
+++ b/packages/grafana-toolkit/src/cli/tasks/plugin.sign.ts
@@ -22,7 +22,7 @@ const pluginSignRunner: TaskRunner<PluginSignOptions> = async ({ signatureType,
     if (signatureType) {
       manifest.signatureType = signatureType;
     }
-    if (rootUrls) {
+    if (rootUrls && rootUrls.length > 0) {
       rootUrls.forEach(assertRootUrlIsValid);
       manifest.rootUrls = rootUrls;
     }