diff --git a/auth/oauth2/classes/api.php b/auth/oauth2/classes/api.php
index 5bf053cfcf5..1192b5f0bf9 100644
--- a/auth/oauth2/classes/api.php
+++ b/auth/oauth2/classes/api.php
@@ -55,7 +55,7 @@ class api {
      * Requires auth/oauth2:managelinkedlogins capability at the user context.
      *
      * @param int $userid (defaults to $USER->id)
-     * @return boolean
+     * @return linked_login[]
      */
     public static function get_linked_logins($userid = false) {
         global $USER;
@@ -79,7 +79,7 @@ class api {
      *
      * @param string $username as returned from an oauth client.
      * @param \core\oauth2\issuer $issuer
-     * @return stdClass User record if found.
+     * @return linked_login|false record if found and user exists, false otherwise.
      */
     public static function match_username_to_user($username, $issuer) {
         $params = [
@@ -106,7 +106,7 @@ class api {
      * @param \core\oauth2\issuer $issuer
      * @param int $userid (defaults to $USER->id)
      * @param bool $skippermissions During signup we need to set this before the user is setup for capability checks.
-     * @return bool
+     * @return linked_login
      */
     public static function link_login($userinfo, $issuer, $userid = false, $skippermissions = false) {
         global $USER;
@@ -234,7 +234,7 @@ class api {
         $expires = $login->get('confirmtokenexpires');
         if (time() > $expires) {
             $login->delete();
-            return;
+            return false;
         }
         $login->set('confirmtokenexpires', 0);
         $login->set('confirmtoken', '');
@@ -247,7 +247,7 @@ class api {
      *
      * @param array $userinfo as returned from an oauth client.
      * @param \core\oauth2\issuer $issuer
-     * @return bool
+     * @return stdClass
      */
     public static function create_new_confirmed_account($userinfo, $issuer) {
         global $CFG, $DB;
@@ -284,7 +284,7 @@ class api {
      * @param array $userinfo as returned from an oauth client.
      * @param \core\oauth2\issuer $issuer
      * @param int $userid (defaults to $USER->id)
-     * @return bool
+     * @return stdClass
      */
     public static function send_confirm_account_email($userinfo, $issuer) {
         global $CFG, $DB;
@@ -356,7 +356,6 @@ class api {
      * Requires auth/oauth2:managelinkedlogins capability at the user context.
      *
      * @param int $linkedloginid
-     * @return boolean
      */
     public static function delete_linked_login($linkedloginid) {
         global $USER;
@@ -405,7 +404,7 @@ class api {
      *
      * @param array $userinfo
      * @param object $user
-     * @return object
+     * @return stdClass
      */
     private static function save_user(array $userinfo, object $user): object {
         // Map supplied issuer user info to Moodle user fields.