diff --git a/lib/shared/messages/create-sidebar-message-spec.js b/lib/shared/messages/create-sidebar-message-spec.js
--- a/lib/shared/messages/create-sidebar-message-spec.js
+++ b/lib/shared/messages/create-sidebar-message-spec.js
@@ -22,7 +22,6 @@
   type EntityText,
   pluralizeEntityText,
 } from '../../utils/entity-text';
-import { stringForUser } from '../user-utils';
 import { hasMinCodeVersion } from '../version-utils';
 import {
   pushTypes,
@@ -186,20 +185,26 @@
       messageInfo.type === messageTypes.CREATE_SIDEBAR,
       'messageInfo should be messageTypes.CREATE_SIDEBAR!',
     );
-    const prefix = stringForUser(messageInfo.creator);
-    const title = threadInfo.uiName;
-    const sourceMessageAuthorPossessive = messageInfo.sourceMessageAuthor
-      .isViewer
-      ? 'your'
-      : `${stringForUser(messageInfo.sourceMessageAuthor)}'s`;
-    const body =
-      `started a thread in response to ${sourceMessageAuthorPossessive} ` +
-      `message "${messageInfo.initialThreadState.name ?? ''}"`;
-    const merged = `${prefix} ${body}`;
+
+    const creator = ET.user({ userInfo: messageInfo.creator });
+    const prefix = ET`${creator}`;
+
+    const initialName = messageInfo.initialThreadState.name;
+    const sourceMessageAuthorPossessive = ET.user({
+      userInfo: messageInfo.sourceMessageAuthor,
+      possessive: true,
+    });
+
+    let body = `started a thread in response to `;
+    body = ET`${body} ${sourceMessageAuthorPossessive} message`;
+    if (initialName) {
+      body = ET`${body} "${initialName}"`;
+    }
+
     return {
-      merged,
+      merged: ET`${prefix} ${body}`,
       body,
-      title,
+      title: threadInfo.uiName,
       prefix,
     };
   },