diff --git a/l4d2web/services/rcon.py b/l4d2web/services/rcon.py
index 49bb699..19bd2cf 100644
--- a/l4d2web/services/rcon.py
+++ b/l4d2web/services/rcon.py
@@ -32,7 +32,9 @@ SERVERDATA_EXECCOMMAND = 2
 SERVERDATA_AUTH_RESPONSE = 2
 SERVERDATA_RESPONSE_VALUE = 0
 
-# req_id values used by execute_command
+# req_id values for execute_command's exec + marker packets.
+# These are arbitrary positive ints chosen by the client; the values
+# happen to be unrelated to the SERVERDATA_* packet-type constants.
 _EXEC_REQ_ID = 2
 _MARKER_REQ_ID = 0xC0DE
 
@@ -68,10 +70,13 @@ class StatusResponse:
 def _connect_and_auth(
     sock: socket.socket, host: str, port: int, password: str
 ) -> None:
-    """Open TCP connection and authenticate.  Raises:
+    """Open TCP connection and authenticate.
 
-    * RconError   – on connect failure or i/o error during handshake
-    * RconAuthError – when the server returns req_id == -1 (bad password)
+    Raises:
+      RconError      – on connect failure
+      RconAuthError  – when the server returns req_id == -1 (bad password)
+      OSError / socket.timeout – raw, from the post-connect send/recv;
+                                 callers wrap these into RconError.
     """
     try:
         sock.connect((host, port))