diff --git a/packages/flutter_mozilla_components/android/src/main/assets/extensions/ml_engine/background.js b/packages/flutter_mozilla_components/android/src/main/assets/extensions/ml_engine/background.js
index e8f69609..22323fe8 100644
--- a/packages/flutter_mozilla_components/android/src/main/assets/extensions/ml_engine/background.js
+++ b/packages/flutter_mozilla_components/android/src/main/assets/extensions/ml_engine/background.js
@@ -28,7 +28,9 @@ port.onMessage.addListener(async (message) => {
     switch (message["action"]) {
         case "getContainerTopic":
             const documents = message["args"];
-            const keywords = await browser.experiments.nlp.extractKeywords([documents.slice(0, 3).join(" ")]);
+            const keywords = (documents.length > 1)
+                ? await browser.experiments.nlp.extractKeywords([documents.slice(0, 3).join(" ")])
+                : [[]];
 
             browser.experiments.ml.containerTopic(keywords[0], documents)
                 .then(sendJsonResultForRequest(requestId))