diff --git a/plugins/af_comics/filter_base.php b/plugins/af_comics/filter_base.php
index 5c82bc870..83bc48184 100644
--- a/plugins/af_comics/filter_base.php
+++ b/plugins/af_comics/filter_base.php
@@ -1,20 +1,38 @@
 <?php
 abstract class Af_ComicFilter {
+	/** @return array<string> */
 	public abstract function supported();
+
+	/**
+	 * @param array<string,mixed> $article
+	 * @return bool
+	 */
 	public abstract function process(&$article);
 
 	public function __construct(/*PluginHost $host*/) {
 
 	}
 
+	/**
+	 * @param string $url
+	 * @return string|false
+	 */
 	public function on_subscribe($url) {
 		return false;
 	}
 
+	/**
+	 * @param string $url
+	 * @return array{"title": string, "site_url": string}|false
+	 */
 	public function on_basic_info($url) {
 		return false;
 	}
 
+	/**
+	 * @param string $url
+	 * @return string|false
+	 */
 	public function on_fetch($url) {
 		return false;
 	}
diff --git a/plugins/af_comics/filters/af_comics_tfd.php b/plugins/af_comics/filters/af_comics_tfd.php
index 19ca43a24..2010da37e 100644
--- a/plugins/af_comics/filters/af_comics_tfd.php
+++ b/plugins/af_comics/filters/af_comics_tfd.php
@@ -12,7 +12,7 @@ class Af_Comics_Tfd extends Af_ComicFilter {
 				false, false, 0,
 				"Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0)");
 
-			if (!$res) return $article;
+			if (!$res) return false;
 
 			$doc = new DOMDocument();