diff --git a/includes/common.inc b/includes/common.inc
index 7d0bf85..604726e 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -296,14 +296,16 @@ function drupal_get_destination() {
  * statement in your menu callback.
  *
  * @param $path
- *   A Drupal path or a full URL.
+ *   (optional) A Drupal path or a full URL, which will be passed to url() to
+ *   compute the redirect for the URL.
  * @param $query
- *   A URL-encoded query string to append to the link, or an array of query
- *   key/value-pairs without any URL-encoding. Passed to url().
+ *   (optional) A URL-encoded query string to append to the link, or an array of
+ *   query key/value-pairs without any URL-encoding. Passed to url().
  * @param $fragment
- *   A destination fragment identifier (named anchor).
+ *   (optional) A destination fragment identifier (named anchor).
  * @param $http_response_code
- *   Valid values for an actual "goto" as per RFC 2616 section 10.3 are:
+ *   (optional) The HTTP status code to use for the redirection, defaults to
+ *   302. Valid values for an actual "goto" as per RFC 2616 section 10.3 are:
  *   - 301 Moved Permanently (the recommended value for most redirects)
  *   - 302 Found (default in Drupal and PHP, sometimes used for spamming search
  *         engines)
@@ -1423,8 +1425,9 @@ function format_date($timestamp, $type = 'medium', $format = '', $timezone = NUL
  * alternative than url().
  *
  * @param $path
- *   The internal path or external URL being linked to, such as "node/34" or
- *   "http://example.com/foo". A few notes:
+ *   (optional) The internal path or external URL being linked to, such as
+ *   "node/34" or "http://example.com/foo". The default value is equivalent to
+ *   passing in '<front>'. A few notes:
  *   - If you provide a full URL, it will be considered an external URL.
  *   - If you provide only the path (e.g. "node/34"), it will be
  *     considered an internal link. In this case, it should be a system URL,
@@ -1440,7 +1443,8 @@ function format_date($timestamp, $type = 'medium', $format = '', $timezone = NUL
  *     include them in $path, or use $options['query'] to let this function
  *     URL encode them.
  * @param $options
- *   An associative array of additional options, with the following elements:
+ *   (optional) An associative array of additional options, with the following
+ *   elements:
  *   - 'query': A URL-encoded query string to append to the link, or an array of
  *     query key/value-pairs without any URL-encoding.
  *   - 'fragment': A fragment identifier (named anchor) to append to the URL.