diff --git a/websocket-sharp/WebSocket.cs b/websocket-sharp/WebSocket.cs
index 202da89d..f791eca8 100644
--- a/websocket-sharp/WebSocket.cs
+++ b/websocket-sharp/WebSocket.cs
@@ -2488,17 +2488,35 @@ namespace WebSocketSharp
     }
 
     /// <summary>
-    /// Closes the WebSocket connection with the specified <paramref name="code"/>,
-    /// and releases all associated resources.
+    /// Closes the connection with the specified <paramref name="code"/>.
     /// </summary>
     /// <remarks>
     /// This method does nothing if the current state of the connection is
     /// Closing or Closed.
     /// </remarks>
     /// <param name="code">
-    /// One of the <see cref="CloseStatusCode"/> enum values that represents
-    /// the status code indicating the reason for the close.
+    ///   <para>
+    ///   One of the <see cref="CloseStatusCode"/> enum values.
+    ///   </para>
+    ///   <para>
+    ///   It represents the status code indicating the reason for the close.
+    ///   </para>
     /// </param>
+    /// <exception cref="ArgumentException">
+    ///   <para>
+    ///   <paramref name="code"/> is
+    ///   <see cref="CloseStatusCode.ServerError"/>.
+    ///   It cannot be used by clients.
+    ///   </para>
+    ///   <para>
+    ///   -or-
+    ///   </para>
+    ///   <para>
+    ///   <paramref name="code"/> is
+    ///   <see cref="CloseStatusCode.MandatoryExtension"/>.
+    ///   It cannot be used by servers.
+    ///   </para>
+    /// </exception>
     public void Close (CloseStatusCode code)
     {
       if (_client && code == CloseStatusCode.ServerError) {