diff --git a/src/endpoints/forms.tsp b/src/endpoints/forms.tsp
index 616732a..755f332 100644
--- a/src/endpoints/forms.tsp
+++ b/src/endpoints/forms.tsp
@@ -289,6 +289,20 @@ namespace Forms {
         @statusCode statusCode: 400 | 401 | 403 | 404 | 500;
         @body body: Error;
       };
+
+      @patch
+      @summary("フォームの回答につけられるラベルを更新する")
+      op updateLabel(
+        @body body: {
+          label_id: uint32;
+          name: string;
+        },
+      ): {
+        @statusCode statusCode: 200;
+      } | {
+        @statusCode statusCode: 400 | 401 | 403 | 404 | 500;
+        @body body: Error;
+      };
     }
 
     @route("/comment")