diff --git a/Documentation/extensions/steam-broker.md b/Documentation/extensions/steam-broker.md
new file mode 100644
index 00000000..b5c4c016
--- /dev/null
+++ b/Documentation/extensions/steam-broker.md
@@ -0,0 +1,8 @@
+# Steam broker protocol
+`sb_connect <ip:port> <server's steam id> <secure> <challenge>` - used for obtaining auth ticket during connection to GoldSrc server
+
+`sb_disconnect <ip:port> <challenge>` - used for signaling broker about disconnecting from GoldSrc server
+
+`sb_gamedir <gamedir>` - used for signaling broker about game startup and for announcing started mod, so broker could choose proper AppID for Steam API initialization
+
+`sb_terminate` - used for signaling broker about game shutdown, ideally broker should be terminated too (and later restarted automatically and waiting for sb_gamedir message)