diff --git a/AGENTS.md b/AGENTS.md
index c4b3e044b..9c78bd3c5 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -91,7 +91,7 @@ assets/                  # JS, CSS, images, fonts
   classes or interfaces** — external addons extend these classes and PHP will fatal if
   the child class doesn't declare the same return type. Use `@return` PHPDoc tags instead.
   This applies to all classes in `inc/gateways/`, `inc/ui/class-base-element.php`,
-  `inc/models/class-base-model.php`, `inc/integrations/`, and `inc/checkout/signup-fields/`.
+  `inc/models/class-base-model.php`, `inc/integrations/`, and `inc/checkout/`.
   Private and final methods may use PHP return types freely.
 - **PHPDoc**: Required on classes and public methods in `inc/`. Not required in `tests/`.
   Every file header: `@package WP_Ultimo`, `@subpackage`, `@since`.
diff --git a/inc/gateways/class-base-gateway.php b/inc/gateways/class-base-gateway.php
index 65cf58bb5..a03981b5a 100644
--- a/inc/gateways/class-base-gateway.php
+++ b/inc/gateways/class-base-gateway.php
@@ -594,7 +594,7 @@ public function supports_payment_polling() {
 	 * @param int $payment_id The local payment ID to verify.
 	 * @return array{success: bool, status: string, message: string}
 	 */
-	public function verify_and_complete_payment($payment_id) {
+	public function verify_and_complete_payment(int $payment_id) {
 
 		unset($payment_id);
 
@@ -823,7 +823,7 @@ public function get_confirm_url() {
 	 * @param string $message The error message.
 	 * @return void
 	 */
-	public function redirect_with_error($message) {
+	public function redirect_with_error(string $message) {
 
 		$url = remove_query_arg(['wu-confirm', 'payment', 'token', 'PayerID', 'ba_token', 'subscription_id', 'status'], $this->return_url ?: wu_get_current_url());
 
diff --git a/inc/integrations/host-providers/class-cloudflare-host-provider.php b/inc/integrations/host-providers/class-cloudflare-host-provider.php
index 3e373fd7e..acf404baa 100644
--- a/inc/integrations/host-providers/class-cloudflare-host-provider.php
+++ b/inc/integrations/host-providers/class-cloudflare-host-provider.php
@@ -144,7 +144,7 @@ public function add_cloudflare_dns_entries($dns_records, $domain) {
 	 *
 	 * @since 2.0.0
 	 */
-	public function detect(): bool {
+	public function detect() {
 		/**
 		 * As Cloudflare recently enabled wildcards for all customers, this integration is no longer required.
 		 * https://blog.cloudflare.com/wildcard-proxy-for-everyone/
diff --git a/inc/integrations/host-providers/class-cpanel-host-provider.php b/inc/integrations/host-providers/class-cpanel-host-provider.php
index 929bdbf1b..12e83afe6 100644
--- a/inc/integrations/host-providers/class-cpanel-host-provider.php
+++ b/inc/integrations/host-providers/class-cpanel-host-provider.php
@@ -97,7 +97,7 @@ class CPanel_Host_Provider extends Base_Host_Provider {
 	 *
 	 * @since 2.0.0
 	 */
-	public function detect(): bool {
+	public function detect() {
 
 		return false;
 	}
@@ -262,7 +262,7 @@ public function load_api() {
 	 * @since  1.6.2
 	 * @param null|int $site_id The site id.
 	 */
-	public function get_site_url($site_id = null): string {
+	public function get_site_url($site_id = null) {
 
 		return trim(preg_replace('#^https?://#', '', get_site_url($site_id)), '/');
 	}
diff --git a/inc/integrations/interface-capability-module.php b/inc/integrations/interface-capability-module.php
index 4107bec5b..2741ded2e 100644
--- a/inc/integrations/interface-capability-module.php
+++ b/inc/integrations/interface-capability-module.php
@@ -56,7 +56,7 @@ public function get_supported_features();
 	 * @param string $feature Feature identifier to check.
 	 * @return bool
 	 */
-	public function supports($feature);
+	public function supports(string $feature);
 
 	/**
 	 * Registers WordPress hooks for this capability.
diff --git a/inc/ui/class-billing-info-element.php b/inc/ui/class-billing-info-element.php
index 1f8da7b74..e073b7b2c 100644
--- a/inc/ui/class-billing-info-element.php
+++ b/inc/ui/class-billing-info-element.php
@@ -266,7 +266,7 @@ public function setup_preview() {
 	 *
 	 * @param array       $atts Parameters of the block/shortcode.
 	 * @param string|null $content The content inside the shortcode.
-	 * @return string
+	 * @return void
 	 */
 	public function output($atts, $content = null) {