diff --git a/structarmed.php b/structarmed.php
index fc5c799b13c3..88932d17cdd0 100644
--- a/structarmed.php
+++ b/structarmed.php
@@ -10,7 +10,7 @@
  * For the full copyright and license information, please view
  * the LICENSE file that was distributed with this source code.
  */
-
+use Boundwize\StructArmed\Rule\Rules\Function_\MustHaveReturnTypeFunctionRule;
 use Boundwize\StructArmed\Preset\Presets\CodeQualityPreset;
 use CodeIgniter\Cache\ResponseCache;
 use CodeIgniter\HTTP\CLIRequest;
@@ -52,6 +52,10 @@
     ])
     ->cacheDirectory(is_dir('/tmp') ? '/tmp/structarmed' : null)
     ->withPresets(Preset::PSR4(), Preset::CODEQUALITY())
+
+    ->layer('Helpers', __DIR__ . '/system/Helpers')
+    ->rule('helpers.functions_must_have_return_type', new MustHaveReturnTypeFunctionRule('Helpers'))
+
     // Resolve CodeIgniter layers from class names because several layers share directories.
     ->layerPattern('API', '/^CodeIgniter\\\\API\\\\.*$/')
     ->layerPattern('Cache', '/^CodeIgniter\\\\Cache\\\\.*$/')
@@ -110,7 +114,7 @@
         'Security'      => ['Cookie', 'HTTP', 'I18n', 'Session'],
         'Session'       => ['Cookie', 'Database', 'HTTP', 'I18n'],
         'Throttle'      => ['Cache', 'I18n'],
-        'Validation'    => ['Database', 'HTTP'],
+        'Validation'    => ['Database', 'HTTP', 'Helpers'],
         'View'          => ['Cache'],
     ])
     ->skipPathsForRuleset(['*test*'])
diff --git a/system/Helpers/array_helper.php b/system/Helpers/array_helper.php
index f0ea0637c545..c5ccde761544 100644
--- a/system/Helpers/array_helper.php
+++ b/system/Helpers/array_helper.php
@@ -21,10 +21,8 @@
      * wildcard searches, like foo.*.bar
      *
      * @param array<array-key, mixed> $array
-     *
-     * @return mixed
      */
-    function dot_array_search(string $index, array $array)
+    function dot_array_search(string $index, array $array): mixed
     {
         return ArrayHelper::dotSearch($index, $array);
     }
@@ -36,10 +34,8 @@ function dot_array_search(string $index, array $array)
      *
      * @param int|string              $key
      * @param array<array-key, mixed> $array
-     *
-     * @return mixed
      */
-    function array_deep_search($key, array $array)
+    function array_deep_search($key, array $array): mixed
     {
         if (isset($array[$key])) {
             return $array[$key];
diff --git a/system/Helpers/cookie_helper.php b/system/Helpers/cookie_helper.php
index e3b10a1b60f6..3d3758278b8d 100644
--- a/system/Helpers/cookie_helper.php
+++ b/system/Helpers/cookie_helper.php
@@ -79,7 +79,7 @@ function set_cookie(
      *
      * @see \CodeIgniter\HTTP\IncomingRequest::getCookie()
      */
-    function get_cookie($index, bool $xssClean = false, ?string $prefix = '')
+    function get_cookie($index, bool $xssClean = false, ?string $prefix = ''): array|string|null
     {
         if ($prefix === '') {
             $cookie = config(CookieConfig::class);
diff --git a/system/Helpers/filesystem_helper.php b/system/Helpers/filesystem_helper.php
index f9a04dd142df..7c42bd5c65f8 100644
--- a/system/Helpers/filesystem_helper.php
+++ b/system/Helpers/filesystem_helper.php
@@ -326,7 +326,7 @@ function get_dir_file_info(string $sourceDir, bool $topLevelOnly = true, bool $r
      *  fileperms?: int
      * }|null
      */
-    function get_file_info(string $file, $returnedValues = ['name', 'server_path', 'size', 'date'])
+    function get_file_info(string $file, $returnedValues = ['name', 'server_path', 'size', 'date']): ?array
     {
         if (! is_file($file)) {
             return null;
diff --git a/system/Helpers/form_helper.php b/system/Helpers/form_helper.php
index 1cf120acb78a..dee1f001365b 100644
--- a/system/Helpers/form_helper.php
+++ b/system/Helpers/form_helper.php
@@ -558,7 +558,7 @@ function form_close(string $extra = ''): string
      *
      * @return list<string>|string
      */
-    function set_value(string $field, $default = '', bool $htmlEscape = true)
+    function set_value(string $field, $default = '', bool $htmlEscape = true): array|string
     {
         $request = service('request');
 
@@ -695,7 +695,7 @@ function set_radio(string $field, string $value = '', bool $default = false): st
      *
      * @return array<string, string>
      */
-    function validation_errors()
+    function validation_errors(): array
     {
         $errors = session('_ci_validation_errors');
 
diff --git a/system/Helpers/html_helper.php b/system/Helpers/html_helper.php
index 9f0b86470aa8..67441f935c11 100644
--- a/system/Helpers/html_helper.php
+++ b/system/Helpers/html_helper.php
@@ -540,10 +540,8 @@ function embed(string $src, string $type = 'unknown', string $attributes = '', b
 if (! function_exists('_has_protocol')) {
     /**
      * Test the protocol of a URI.
-     *
-     * @return false|int
      */
-    function _has_protocol(string $url)
+    function _has_protocol(string $url): false|int
     {
         return preg_match('#^([a-z]+:)?//#i', $url);
     }
diff --git a/system/Helpers/kint_helper.php b/system/Helpers/kint_helper.php
index 02d180328e92..e311d9ff7cc8 100644
--- a/system/Helpers/kint_helper.php
+++ b/system/Helpers/kint_helper.php
@@ -39,10 +39,8 @@ function dd(...$vars): void
          * dd function
          *
          * @param mixed ...$vars
-         *
-         * @return int
          */
-        function dd(...$vars)
+        function dd(...$vars): int
         {
             return 0;
         }
@@ -55,10 +53,8 @@ function dd(...$vars)
      * d function
      *
      * @param mixed ...$vars
-     *
-     * @return int
      */
-    function d(...$vars)
+    function d(...$vars): int
     {
         return 0;
     }
@@ -77,10 +73,8 @@ function trace(): void
     } else {
         /**
          * Generic trace function in case that Kint is not loaded.
-         *
-         * @return int
          */
-        function trace()
+        function trace(): int
         {
             return 0;
         }
diff --git a/system/Helpers/number_helper.php b/system/Helpers/number_helper.php
index a737428706bd..2f4f6f9bed74 100644
--- a/system/Helpers/number_helper.php
+++ b/system/Helpers/number_helper.php
@@ -21,10 +21,8 @@
      *
      * @param float|int|string      $num    Will be cast as int
      * @param non-empty-string|null $locale [optional]
-     *
-     * @return bool|string
      */
-    function number_to_size($num, int $precision = 1, ?string $locale = null)
+    function number_to_size($num, int $precision = 1, ?string $locale = null): bool|string
     {
         try {
             // Strip any formatting & ensure numeric input
@@ -76,10 +74,8 @@ function number_to_size($num, int $precision = 1, ?string $locale = null)
      * @param int|string            $num       Will be cast as int
      * @param int                   $precision [optional] The optional number of decimal digits to round to.
      * @param non-empty-string|null $locale    [optional]
-     *
-     * @return bool|string
      */
-    function number_to_amount($num, int $precision = 0, ?string $locale = null)
+    function number_to_amount($num, int $precision = 0, ?string $locale = null): bool|string
     {
         // Strip any formatting & ensure numeric input
         try {
diff --git a/system/Helpers/test_helper.php b/system/Helpers/test_helper.php
index b455aa301e2f..b8cbe0462350 100644
--- a/system/Helpers/test_helper.php
+++ b/system/Helpers/test_helper.php
@@ -28,7 +28,7 @@
      *
      * @return array<string, mixed>|object
      */
-    function fake($model, ?array $overrides = null, $persist = true)
+    function fake($model, ?array $overrides = null, $persist = true): array|object
     {
         $fabricator = new Fabricator($model);
 
@@ -49,10 +49,8 @@ function fake($model, ?array $overrides = null, $persist = true)
      * Used within our test suite to mock certain system tools.
      *
      * @param string $className Fully qualified class name
-     *
-     * @return object
      */
-    function mock(string $className)
+    function mock(string $className): object
     {
         $mockClass   = $className::$mockClass;
         $mockService = $className::$mockServiceName ?? '';
diff --git a/system/Helpers/text_helper.php b/system/Helpers/text_helper.php
index f8ea0c15447c..cf9459100dfb 100644
--- a/system/Helpers/text_helper.php
+++ b/system/Helpers/text_helper.php
@@ -458,7 +458,7 @@ function ellipsize(string $str, int $maxLength, $position = 1, string $ellipsis
      *
      * @return array<array-key, mixed>|string string or array
      */
-    function strip_slashes($str)
+    function strip_slashes($str): array|string
     {
         if (! is_array($str)) {
             return stripslashes($str);
diff --git a/system/Helpers/url_helper.php b/system/Helpers/url_helper.php
index 884354a1254e..e43954909d65 100644
--- a/system/Helpers/url_helper.php
+++ b/system/Helpers/url_helper.php
@@ -71,7 +71,7 @@ function base_url($relativePath = '', ?string $scheme = null): string
      * @return string|URI When returning string, the query and fragment parts are removed.
      *                    When returning URI, the query and fragment parts are preserved.
      */
-    function current_url(bool $returnObject = false, ?IncomingRequest $request = null)
+    function current_url(bool $returnObject = false, ?IncomingRequest $request = null): string|URI
     {
         $request ??= service('request');
         /** @var CLIRequest|IncomingRequest $request */
@@ -87,10 +87,8 @@ function current_url(bool $returnObject = false, ?IncomingRequest $request = nul
      * we first check in a saved session variable, if it exists, and use that.
      * If that's not available, however, we'll use a sanitized url from $_SERVER['HTTP_REFERER']
      * which can be set by the user so is untrusted and not set by certain browsers/servers.
-     *
-     * @return string|URI
      */
-    function previous_url(bool $returnObject = false)
+    function previous_url(bool $returnObject = false): string|URI
     {
         // Grab from the session first, if we have it,
         // since it's more reliable and safer.