diff --git a/Sieve.php b/Sieve.php
index e7237bc..400be37 100644
--- a/Sieve.php
+++ b/Sieve.php
@@ -934,7 +934,8 @@ function _authEXTERNAL($user, $pass, $euser)
      * Authenticates the user using the XOAUTH2 method.
      *
      * @param string $user  The userid to authenticate as.
-     * @param string $token The token to authenticate with.
+     * @param string $token The access token prefixed by it's type
+     *                      example: "Bearer $access_token".
      * @param string $euser The effective uid to authenticate as.
      *
      * @return void
@@ -954,7 +955,8 @@ function _authXOAUTH2($user, $token, $euser)
      * Authenticates the user using the OAUTHBEARER method.
      *
      * @param string $user  The userid to authenticate as.
-     * @param string $token The token to authenticate with.
+     * @param string $token The access token prefixed by it's type
+     *                      example: "Bearer $access_token".
      * @param string $euser The effective uid to authenticate as.
      *
      * @return void