diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index c8d6739317493cc91f390766b29be94c47aae72f..53fc41e2b33b924f92e27828c3912e88fc7d660d 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -938,6 +938,8 @@ function request_uri() {
  * @param $type
  *   The category to which this message belongs. Can be any string, but the
  *   general practice is to use the name of the module calling watchdog().
+ *   The $type parameter is limited to 16 characters; anything longer is
+ *   truncated.
  * @param $message
  *   The message to store in the log. See t() for documentation
  *   on how $message and $variables interact. Keep $message
@@ -947,8 +949,16 @@ function request_uri() {
  *   NULL if message is already translated or not possible to
  *   translate.
  * @param $severity
- *   The severity of the message, as per RFC 3164. Possible values are
- *   WATCHDOG_ERROR, WATCHDOG_WARNING, etc.
+ *   The severity of the message; one of the following values as defined in
+ *   @link http://www.faqs.org/rfcs/rfc3164.html RFC 3164: @endlink
+ *   - WATCHDOG_EMERGENCY: Emergency, system is unusable.
+ *   - WATCHDOG_ALERT: Alert, action must be taken immediately.
+ *   - WATCHDOG_CRITICAL: Critical conditions.
+ *   - WATCHDOG_ERROR: Error conditions.
+ *   - WATCHDOG_WARNING: Warning conditions.
+ *   - WATCHDOG_NOTICE: (default) Normal but significant conditions.
+ *   - WATCHDOG_INFO: Informational messages.
+ *   - WATCHDOG_DEBUG: Debug-level messages.
  * @param $link
  *   A link to associate with the message.
  *