diff --git a/docs/external_api_websocket.md b/docs/external_api_websocket.md
index 99d79005..d38053e3 100644
--- a/docs/external_api_websocket.md
+++ b/docs/external_api_websocket.md
@@ -345,7 +345,8 @@ Return a b64 encoded thumbnail of a camera entity.
 ```json
 {
   "id": 19,
-  "type": "camera_thumbnail"
+  "type": "camera_thumbnail",
+  "entity_id": "camera.driveway"
 }
 ```