diff --git a/lib/private/Remote/Api/ApiBase.php b/lib/private/Remote/Api/ApiBase.php
index 64153a9311..70292a977f 100644
--- a/lib/private/Remote/Api/ApiBase.php
+++ b/lib/private/Remote/Api/ApiBase.php
@@ -57,6 +57,7 @@ class ApiBase {
 	 * @param array $query
 	 * @param array $headers
 	 * @return resource|string
+	 * @throws \InvalidArgumentException
 	 */
 	protected function request($method, $url, array $body = [], array $query = [], array $headers = []) {
 		$fullUrl = trim($this->instance->getFullUrl(), '/') . '/' . $url;
diff --git a/lib/private/Remote/Api/ApiCollection.php b/lib/private/Remote/Api/ApiCollection.php
index 41b1bac0e0..5ce97621db 100644
--- a/lib/private/Remote/Api/ApiCollection.php
+++ b/lib/private/Remote/Api/ApiCollection.php
@@ -28,8 +28,11 @@ use OCP\Remote\ICredentials;
 use OCP\Remote\IInstance;
 
 class ApiCollection implements IApiCollection {
+	/** @var IInstance */
 	private $instance;
+	/** @var ICredentials */
 	private $credentials;
+	/** @var IClientService */
 	private $clientService;
 
 	public function __construct(IInstance $instance, ICredentials $credentials, IClientService $clientService) {
diff --git a/lib/private/Remote/Api/ApiFactory.php b/lib/private/Remote/Api/ApiFactory.php
index ea084c188f..19b8e8eb50 100644
--- a/lib/private/Remote/Api/ApiFactory.php
+++ b/lib/private/Remote/Api/ApiFactory.php
@@ -28,6 +28,7 @@ use OCP\Remote\ICredentials;
 use OCP\Remote\IInstance;
 
 class ApiFactory implements IApiFactory {
+	/** @var IClientService */
 	private $clientService;
 
 	public function __construct(IClientService $clientService) {
diff --git a/lib/private/Remote/Instance.php b/lib/private/Remote/Instance.php
index ab0081d86c..0ed301ae86 100644
--- a/lib/private/Remote/Instance.php
+++ b/lib/private/Remote/Instance.php
@@ -39,6 +39,7 @@ class Instance implements IInstance {
 	/** @var IClientService */
 	private $clientService;
 
+	/** @var array|null */
 	private $status;
 
 	/**
@@ -93,6 +94,10 @@ class Instance implements IInstance {
 		return $status['installed'] && !$status['maintenance'];
 	}
 
+	/**
+	 * @return array
+	 * @throws NotFoundException
+	 */
 	private function getStatus() {
 		if ($this->status) {
 			return $this->status;
@@ -120,6 +125,10 @@ class Instance implements IInstance {
 		return $status;
 	}
 
+	/**
+	 * @param string $url
+	 * @return bool|string
+	 */
 	private function downloadStatus($url) {
 		try {
 			$request = $this->clientService->newClient()->get($url);
diff --git a/lib/private/Remote/InstanceFactory.php b/lib/private/Remote/InstanceFactory.php
index 3b99bc6182..72baa43361 100644
--- a/lib/private/Remote/InstanceFactory.php
+++ b/lib/private/Remote/InstanceFactory.php
@@ -27,7 +27,9 @@ use OCP\ICache;
 use OCP\Remote\IInstanceFactory;
 
 class InstanceFactory implements IInstanceFactory {
+	/** @var ICache */
 	private $cache;
+	/** @var IClientService */
 	private $clientService;
 
 	public function __construct(ICache $cache, IClientService $clientService) {
diff --git a/lib/public/Remote/IInstanceFactory.php b/lib/public/Remote/IInstanceFactory.php
index 22ac85563f..6aae463a89 100644
--- a/lib/public/Remote/IInstanceFactory.php
+++ b/lib/public/Remote/IInstanceFactory.php
@@ -26,7 +26,7 @@ namespace OCP\Remote;
  */
 interface IInstanceFactory {
 	/**
-	 * @param $url
+	 * @param string $url
 	 * @return IInstance
 	 *
 	 * @since 13.0.0