diff --git a/docs/API/chats.md b/docs/API/chats.md
index 761047336..81ff57941 100644
--- a/docs/API/chats.md
+++ b/docs/API/chats.md
@@ -79,6 +79,11 @@ To set the `unread` count of a chat to 0, call
 
 `POST /api/v1/pleroma/chats/:id/read`
 
+
+Parameters:
+- last_read_id: Given this id, all chat messages until this one will be marked as read. This should always be used.
+
+
 Returned data:
 
 ```json