diff --git a/src/js/game/base_item.js b/src/js/game/base_item.js
index ae569ddf..f6ed1672 100644
--- a/src/js/game/base_item.js
+++ b/src/js/game/base_item.js
@@ -15,7 +15,7 @@ export class BaseItem extends BasicSerializableObject {
         return "base_item";
     }
 
-    /** @returns {object} */
+    /** @returns {import("../savegame/serialization").Schema} */
     static getSchema() {
         return {};
     }
diff --git a/src/js/savegame/serialization.js b/src/js/savegame/serialization.js
index 770f166f..682558b6 100644
--- a/src/js/savegame/serialization.js
+++ b/src/js/savegame/serialization.js
@@ -192,7 +192,7 @@ export class BasicSerializableObject {
         return schema;
     }
 
-    /** @returns {object} */
+    /** @returns {object | string | number} */
     serialize() {
         return serializeSchema(
             this,