diff --git a/200.md b/200.md
index 6ea40e1..7214e37 100644
--- a/200.md
+++ b/200.md
@@ -67,3 +67,5 @@ Relay may start streaming to client when connected to `stream` endpoint by sendi
 { "id": ..., "content": .... }
 { "id": ..., "content": .... }
 ```
+
+Relay must ensure that the `stream` endpoint **MUST** be served with `Transfer-Encoding: chunked` header.