diff --git a/lib/shared/messages/create-sub-thread-message-spec.js b/lib/shared/messages/create-sub-thread-message-spec.js
--- a/lib/shared/messages/create-sub-thread-message-spec.js
+++ b/lib/shared/messages/create-sub-thread-message-spec.js
@@ -17,6 +17,7 @@
 import { threadPermissions, threadTypes } from '../../types/thread-types';
 import type { ThreadInfo } from '../../types/thread-types';
 import type { RelativeUserInfo } from '../../types/user-types';
+import { ET, type EntityText } from '../../utils/entity-text';
 import {
   robotextToRawString,
   robotextForMessageInfo,
@@ -123,23 +124,26 @@
     return { ...messageData, id };
   },
 
-  robotext(messageInfo: CreateSubthreadMessageInfo, creator: string): string {
-    const childName = messageInfo.childThreadInfo.name;
-    const childNoun =
-      messageInfo.childThreadInfo.type === threadTypes.SIDEBAR
-        ? 'thread'
-        : 'subchannel';
-    if (childName) {
-      return (
-        `${creator} created a ${childNoun}` +
-        ` named "<${encodeURI(childName)}|t${messageInfo.childThreadInfo.id}>"`
-      );
+  robotext(messageInfo: CreateSubthreadMessageInfo): EntityText {
+    const threadEntity = ET.thread({
+      display: 'shortName',
+      threadInfo: messageInfo.childThreadInfo,
+      subchannel: true,
+    });
+
+    let text;
+    if (messageInfo.childThreadInfo.name) {
+      const childNoun =
+        messageInfo.childThreadInfo.type === threadTypes.SIDEBAR
+          ? 'thread'
+          : 'subchannel';
+      text = ET`created a ${childNoun} named "${threadEntity}"`;
     } else {
-      return (
-        `${creator} created a ` +
-        `<${childNoun}|t${messageInfo.childThreadInfo.id}>`
-      );
+      text = ET`created a ${threadEntity}`;
     }
+
+    const creator = ET.user({ userInfo: messageInfo.creator });
+    return ET`${creator} ${text}`;
   },
 
   notificationTexts(
diff --git a/lib/utils/entity-text.js b/lib/utils/entity-text.js
--- a/lib/utils/entity-text.js
+++ b/lib/utils/entity-text.js
@@ -39,6 +39,7 @@
       +display: 'shortName',
       +threadType?: ?ThreadType,
       +alwaysDisplayShortName?: ?boolean, // don't default to name
+      +subchannel?: ?boolean, // short name should be "subchannel"
       +possessive?: ?boolean, // eg. `this thread's` instead of `this thread`
     };
 
@@ -98,6 +99,7 @@
   | {
       +display?: 'shortName',
       +threadInfo: ThreadInfo | RawThreadInfo,
+      +subchannel?: ?boolean,
       +possessive?: ?boolean,
     }
   | {
@@ -144,13 +146,14 @@
       possessive,
     };
   } else if (input.display === 'shortName' || !input.display) {
-    const { threadInfo, possessive } = input;
+    const { threadInfo, subchannel, possessive } = input;
     return {
       type: 'thread',
       id: threadInfo.id,
       name: threadInfo.name,
       display: 'shortName',
       threadType: threadInfo.type,
+      subchannel,
       possessive,
     };
   }
@@ -220,7 +223,7 @@
   let name = userGeneratedName;
   if (!name || entity.alwaysDisplayShortName) {
     const threadType = entity.threadType ?? threadTypes.PERSONAL;
-    name = threadNoun(threadType);
+    name = entity.subchannel ? 'subchannel' : threadNoun(threadType);
     if (entity.id === threadID) {
       name = `this ${name}`;
     }