diff --git a/src/mention.test.ts b/src/mention.test.ts
index 6d3da96..77d3c70 100644
--- a/src/mention.test.ts
+++ b/src/mention.test.ts
@@ -67,7 +67,9 @@ describe('appMention', () => {
             text: 'GPTの回答'
           }
         }
-      ]
+      ],
+      text: 'GPTの回答',
+      thread_ts: 'test_ts'
     })
   })
 
@@ -133,7 +135,9 @@ describe('appMention', () => {
             text: 'サマリの内容'
           }
         }
-      ]
+      ],
+      text: 'GPTの回答',
+      thread_ts: 'test_ts'
     })
   })
 })
diff --git a/src/mention.ts b/src/mention.ts
index 29ecf4c..de13a80 100644
--- a/src/mention.ts
+++ b/src/mention.ts
@@ -78,6 +78,8 @@ export const appMention: any = async ({ event, client, say }) => {
     }
 
     await say({
+      thread_ts: event.ts,
+      text: 'GPTの回答',
       blocks: [
         {
           type: 'section',