diff --git a/src/Course.ts b/src/Course.ts
index 5fe7dfe..67a1555 100644
--- a/src/Course.ts
+++ b/src/Course.ts
@@ -7,6 +7,7 @@ import { Enrollment } from './Enrollment';
 
 export interface LabeledLink {
   title: string;
+  tooltip?: string;
   url: string;
 }