diff --git a/_locales/en/messages.json b/_locales/en/messages.json
index 82119473..51bb7091 100644
--- a/_locales/en/messages.json
+++ b/_locales/en/messages.json
@@ -2008,6 +2008,10 @@
     "message": "Antispam by",
     "description": ""
   },
+  "summary_by": {
+    "message": "Summary by",
+    "description": ""
+  },
   "prefs_THStats_1": {
     "message": "Do you want beautiful statistics about your emails?",
     "description": ""
diff --git a/js/mzta-compose-script.js b/js/mzta-compose-script.js
index 7ef594d0..1295148f 100644
--- a/js/mzta-compose-script.js
+++ b/js/mzta-compose-script.js
@@ -878,8 +878,17 @@ switch (message.command) {
         }
     ], { bg: bgColorSummary, border: borderColorSummary, text: textColorSummary });
 
+    const summaryBranding = document.createElement('span');
+    summaryBranding.textContent = browser.i18n.getMessage("summary_by") + " ThunderAI";
+    summaryBranding.style.cssText = 'font-style: italic; font-size: 10px; opacity: 0.5;';
+
+    const summaryRightGroup = document.createElement('span');
+    summaryRightGroup.style.cssText = 'display: flex; align-items: center; gap: 5px;';
+    summaryRightGroup.appendChild(summaryBranding);
+    summaryRightGroup.appendChild(summaryMenu);
+
     summaryHeader.appendChild(summaryTitle);
-    summaryHeader.appendChild(summaryMenu);
+    summaryHeader.appendChild(summaryRightGroup);
     summaryContainer.appendChild(summaryHeader);
 
     const summaryText = document.createElement('div');