--- a/mod_ping_muc/README.md	Thu Jul 11 10:15:21 2024 +0100
+++ b/mod_ping_muc/README.md	Thu Jul 11 15:14:33 2024 +0200
@@ -35,6 +35,27 @@
 }
 ```
 
+# Client facing protocol
+
+If the module determines that the client has dropped out a MUC,
+it sends it [a stanza to indicate this](https://xmpp.org/extensions/xep-0045.html#service-error-kick):
+
+``` xml
+<presence type="unavailable" id="random123" from="room@muc.host/nickname" to="user@example.net/resource">
+  <x xmlns="http://jabber.org/protocol/muc#user">
+    <item affiliation="none" role="none">
+      <reason>Connection to remote server lost</reason>
+    </item>
+    <status code="110"/>
+    <status code="330"/>
+  </x>
+</presence>
+```
+
+The `reason` message may vary.
+
+Upon receiving this, the client may attempt to [rejoin](https://xmpp.org/extensions/xep-0045.html#enter).
+
 # Compatibility
 
 Requires Prosody 0.12.x or trunk