diff --git a/src/ConfigInspectorManager.php b/src/ConfigInspectorManager.php
index d1331ae..d234a4f 100644
--- a/src/ConfigInspectorManager.php
+++ b/src/ConfigInspectorManager.php
@@ -124,7 +124,7 @@ class ConfigInspectorManager extends DefaultPluginManager {
   /**
    * Check schema compliance in configuration object.
    *
-   * @param $config_name
+   * @param string $config_name
    *   Configuration name.
    *
    * @throws Drupal\Core\Config\Schema\SchemaIncompleteException
diff --git a/src/Controller/ConfigInspectorController.php b/src/Controller/ConfigInspectorController.php
index ac585e6..02c0215 100644
--- a/src/Controller/ConfigInspectorController.php
+++ b/src/Controller/ConfigInspectorController.php
@@ -23,6 +23,8 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
 class ConfigInspectorController extends ControllerBase {
 
   /**
+   * The config storage.
+   *
    * @var \Drupal\Core\Config\StorageInterface
    */
   protected $configStorage;
@@ -223,6 +225,14 @@ class ConfigInspectorController extends ControllerBase {
 
   /**
    * Format config schema as list table.
+   *
+   * @param string $config_name
+   *   The config name.
+   * @param array|object $config_schema
+   *   An array of config elements with key.
+   *
+   * @return array
+   *   The list table as a render array.
    */
   protected function formatList($config_name, $config_schema) {
     $rows = array();
@@ -260,8 +270,18 @@ class ConfigInspectorController extends ControllerBase {
 
   /**
    * Format config schema as a tree.
+   *
+   * @param array $schema
+   *   The schema.
+   * @param bool $collapsed
+   *   (Optional) Indicates whether the fieldset is collapsed by default.
+   * @param string $base_key
+   *   Prefix used in the description.
+   *
+   * @return array
+   *   The tree in the form of a render array.
    */
-  public function formatTree($schema, $collapsed = FALSE, $base_key = '') {
+  public function formatTree(array $schema, $collapsed = FALSE, $base_key = '') {
     $build = array();
     foreach ($schema as $key => $element) {
       $definition = $element->getDataDefinition();
@@ -313,6 +333,14 @@ class ConfigInspectorController extends ControllerBase {
 
   /**
    * Helper function to dump data in a reasonably reviewable fashion.
+   *
+   * @param string $data
+   *   The displayed data.
+   * @param string $title
+   *   (Optional) The title. Defaults to "Data'.
+   *
+   * @return array
+   *   The render array.
    */
   protected function formatData($data, $title = 'Data') {
     $output = '<h2>' . $title . '</h2>';