diff --git a/mod/folder/classes/completion/custom_completion.php b/mod/folder/classes/completion/custom_completion.php
new file mode 100644
index 00000000000..b44ff3b93a3
--- /dev/null
+++ b/mod/folder/classes/completion/custom_completion.php
@@ -0,0 +1,84 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+declare(strict_types=1);
+
+namespace mod_folder\completion;
+
+use core_completion\activity_custom_completion;
+
+/**
+ * Activity custom completion subclass for the folder resource.
+ *
+ * Class for defining mod_folder's custom completion rules.
+ *
+ * @package    mod_folder
+ * @copyright  2022 David Woloszyn <david.woloszyn@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class custom_completion extends activity_custom_completion {
+
+    /**
+     * Fetches the completion state for a given completion rule.
+     *
+     * @param string $rule The completion rule.
+     * @return int The completion state.
+     */
+    public function get_state(string $rule): int {
+        return COMPLETION_UNKNOWN;
+    }
+
+    /**
+     * Fetch the list of custom completion rules that this module defines.
+     *
+     * @return array
+     */
+    public static function get_defined_custom_rules(): array {
+        // This activity/resource does not have any custom rules.
+        return [];
+    }
+
+    /**
+     * Returns an associative array of the descriptions of custom completion rules.
+     *
+     * @return array
+     */
+    public function get_custom_rule_descriptions(): array {
+        // This activity/resource does not have any custom rule descriptions.
+        return [];
+    }
+
+    /**
+     * Show the manual completion button depending on the display option set.
+     *
+     * @return bool
+     */
+    public function manual_completion_always_shown(): bool {
+        $display = $this->cm->customdata->display ?? null;
+
+        return ($display == FOLDER_DISPLAY_INLINE ?? false);
+    }
+
+    /**
+     * Returns an array of all completion rules, in the order they should be displayed to users.
+     *
+     * @return array
+     */
+    public function get_sort_order(): array {
+        // This module only supports manual completion.
+        return [];
+    }
+}
diff --git a/mod/folder/tests/behat/folder_activity_completion.feature b/mod/folder/tests/behat/folder_activity_completion.feature
index 1cbe278b0dd..04cf1332a1d 100644
--- a/mod/folder/tests/behat/folder_activity_completion.feature
+++ b/mod/folder/tests/behat/folder_activity_completion.feature
@@ -12,10 +12,12 @@ Feature: View activity completion information in the folder activity
     And the following "courses" exist:
       | fullname | shortname | enablecompletion | showcompletionconditions |
       | Course 1 | C1        | 1                | 1                        |
+      | Course 2 | C2        | 1                | 0                        |
     And the following "course enrolments" exist:
       | user | course | role           |
       | student1 | C1 | student        |
       | teacher1 | C1 | editingteacher |
+      | student1 | C2 | student        |
 
   Scenario: View automatic completion items
     Given the following "activity" exists:
@@ -52,3 +54,19 @@ Feature: View activity completion information in the folder activity
     Then the manual completion button of "Music history" is displayed as "Mark as done"
     And I toggle the manual completion state of "Music history"
     And the manual completion button of "Music history" is displayed as "Done"
+
+  @javascript
+  Scenario: The manual completion button will be shown on the course page for Inline on a course page display mode
+    Given the following "activity" exists:
+      | activity   | folder        |
+      | course     | C2            |
+      | idnumber   | mh2           |
+      | name       | Music history |
+      | section    | 1             |
+      | completion | 1             |
+      | display    | 1             |
+    When I am on the "Course 2" course page logged in as student1
+    Then the manual completion button for "Music history" should exist
+    And the manual completion button of "Music history" is displayed as "Mark as done"
+    And I toggle the manual completion state of "Music history"
+    And the manual completion button of "Music history" is displayed as "Done"