diff --git a/completion/classes/external.php b/completion/classes/external.php
index 6bb4ece1a3a..3dc1af84471 100644
--- a/completion/classes/external.php
+++ b/completion/classes/external.php
@@ -339,6 +339,7 @@ class core_completion_external extends external_api {
                                         )
                                     ]
                                 ),
+                                'Completion status details',
                                 VALUE_DEFAULT,
                                 []
                             ),
diff --git a/course/externallib.php b/course/externallib.php
index 0397a8d9ed1..0a374127f5b 100644
--- a/course/externallib.php
+++ b/course/externallib.php
@@ -483,6 +483,7 @@ class core_course_external extends external_api {
                                                 'dataid' => new external_value(PARAM_NOTAGS, 'cm data id', VALUE_OPTIONAL),
                                             )
                                         ),
+                                        'Course dates',
                                         VALUE_DEFAULT,
                                         []
                                     ),
@@ -514,7 +515,7 @@ class core_course_external extends external_api {
                                                             VALUE_OPTIONAL
                                                    ),
                                               )
-                                          ), VALUE_DEFAULT, array()
+                                          ), 'Course contents', VALUE_DEFAULT, array()
                                       ),
                                     'contentsinfo' => new external_single_structure(
                                         array(
@@ -1305,7 +1306,7 @@ class core_course_external extends external_api {
                                 'value' => new external_value(PARAM_RAW, 'the value for the option 1 (yes) or 0 (no)'
                             )
                         )
-                    ), VALUE_DEFAULT, array()
+                    ), 'Course duplication options', VALUE_DEFAULT, array()
                 ),
             )
         );
@@ -1532,7 +1533,7 @@ class core_course_external extends external_api {
                                 'value' => new external_value(PARAM_RAW, 'the value for the option 1 (yes) or 0 (no)'
                             )
                         )
-                    ), VALUE_DEFAULT, array()
+                    ), 'Course import options', VALUE_DEFAULT, array()
                 ),
             )
         );
diff --git a/lib/tests/externallib_test.php b/lib/tests/externallib_test.php
index 68fb84280d9..ff09d856a18 100644
--- a/lib/tests/externallib_test.php
+++ b/lib/tests/externallib_test.php
@@ -95,7 +95,8 @@ class externallib_test extends \advanced_testcase {
         $this->assertSame('666', $result['scalar']);
 
         $params = array('text'=>'aaa');
-        $description = new \external_function_parameters(array('someid' => new \external_value(PARAM_INT, 'Some int value', false),
+        $description = new \external_function_parameters(array(
+            'someid' => new \external_value(PARAM_INT, 'Some int value', VALUE_DEFAULT),
             'text'   => new \external_value(PARAM_ALPHA, 'Some text value')));
         $result = \external_api::validate_parameters($description, $params);
         $this->assertCount(2, $result);
@@ -105,7 +106,8 @@ class externallib_test extends \advanced_testcase {
         $this->assertSame('aaa', $result['text']);
 
         $params = array('text'=>'aaa');
-        $description = new \external_function_parameters(array('someid' => new \external_value(PARAM_INT, 'Some int value', false, 6),
+        $description = new \external_function_parameters(array(
+            'someid' => new \external_value(PARAM_INT, 'Some int value', VALUE_DEFAULT, 6),
             'text'   => new \external_value(PARAM_ALPHA, 'Some text value')));
         $result = \external_api::validate_parameters($description, $params);
         $this->assertCount(2, $result);
diff --git a/mod/page/classes/external.php b/mod/page/classes/external.php
index 01566bb0418..76bf14d3696 100644
--- a/mod/page/classes/external.php
+++ b/mod/page/classes/external.php
@@ -188,7 +188,7 @@ class mod_page_external extends external_api {
                         helper_for_get_mods_by_courses::standard_coursemodule_elements_returns(),
                         [
                             'content' => new external_value(PARAM_RAW, 'Page content'),
-                            'contentformat' => new external_format_value('content', 'Content format'),
+                            'contentformat' => new external_format_value('content', VALUE_REQUIRED, 'Content format'),
                             'contentfiles' => new external_files('Files in the content'),
                             'legacyfiles' => new external_value(PARAM_INT, 'Legacy files flag'),
                             'legacyfileslast' => new external_value(PARAM_INT, 'Legacy files last control flag'),
diff --git a/tag/classes/external.php b/tag/classes/external.php
index 6214f86ac02..128023fd94b 100644
--- a/tag/classes/external.php
+++ b/tag/classes/external.php
@@ -247,7 +247,7 @@ class core_tag_external extends external_api {
                         'name' => new external_value(PARAM_TAG, 'name'),
                         'rawname' => new external_value(PARAM_RAW, 'tag raw name (may contain capital letters)'),
                         'description' => new external_value(PARAM_RAW, 'tag description'),
-                        'descriptionformat' => new external_format_value(PARAM_INT, 'tag description format'),
+                        'descriptionformat' => new external_format_value(PARAM_INT, VALUE_REQUIRED, 'tag description format'),
                         'flag' => new external_value(PARAM_INT, 'flag', VALUE_OPTIONAL),
                         'official' => new external_value(PARAM_INT,
                             'whether this flag is standard (deprecated, use isstandard)', VALUE_OPTIONAL),