diff --git a/identify/README.md b/identify/README.md
index e580e7c97..d83a85d05 100644
--- a/identify/README.md
+++ b/identify/README.md
@@ -120,3 +120,11 @@ observable source address.
 ### protocols
 
 This is a list of protocols supported by the peer.
+
+A node should only advertise a protocol if it's willing to receive inbound
+streams on that protocol. This is relevant for asymmetrical protocols. For
+example assume an asymmetrical request-response style protocol `foo` where some
+clients only support initiating requests while some servers (only) support
+responding to requests. To prevent clients from initiating requests to other
+clients, which given them being clients they fail to respond, clients should not
+advertise `foo` in their `protocols` list.