diff --git a/src/Extension/Autolink/UrlAutolinkParser.php b/src/Extension/Autolink/UrlAutolinkParser.php
index 6b4290a994..f44da3357e 100644
--- a/src/Extension/Autolink/UrlAutolinkParser.php
+++ b/src/Extension/Autolink/UrlAutolinkParser.php
@@ -58,7 +58,11 @@ final class UrlAutolinkParser implements InlineParserInterface
      */
     private array $prefixes = ['www'];
 
-    /** @psalm-readonly */
+    /**
+     * @psalm-var non-empty-string
+     *
+     * @psalm-readonly
+     */
     private string $finalRegex;
 
     /**
@@ -66,6 +70,9 @@ final class UrlAutolinkParser implements InlineParserInterface
      */
     public function __construct(array $allowedProtocols = ['http', 'https', 'ftp'])
     {
+        /**
+         * @psalm-suppress PropertyTypeCoercion
+         */
         $this->finalRegex = \sprintf(self::REGEX, \implode('|', $allowedProtocols));
 
         foreach ($allowedProtocols as $protocol) {
diff --git a/src/Extension/CommonMark/Parser/Block/ListBlockStartParser.php b/src/Extension/CommonMark/Parser/Block/ListBlockStartParser.php
index 74b0c2bb99..65b4535b82 100644
--- a/src/Extension/CommonMark/Parser/Block/ListBlockStartParser.php
+++ b/src/Extension/CommonMark/Parser/Block/ListBlockStartParser.php
@@ -28,7 +28,11 @@ final class ListBlockStartParser implements BlockStartParserInterface, Configura
     /** @psalm-readonly-allow-private-mutation */
     private ?ConfigurationInterface $config = null;
 
-    /** @psalm-readonly-allow-private-mutation */
+    /**
+     * @psalm-var non-empty-string|null
+     *
+     * @psalm-readonly-allow-private-mutation
+     */
     private ?string $listMarkerRegex = null;
 
     public function setConfiguration(ConfigurationInterface $configuration): void
@@ -131,6 +135,9 @@ private static function calculateListMarkerPadding(Cursor $cursor, int $markerLe
         return $markerLength + $spacesAfterMarker;
     }
 
+    /**
+     * @psalm-return non-empty-string
+     */
     private function generateListMarkerRegex(): string
     {
         // No configuration given - use the defaults
diff --git a/src/Extension/Embed/DomainFilteringAdapter.php b/src/Extension/Embed/DomainFilteringAdapter.php
index 69dc096f35..d150764aa4 100644
--- a/src/Extension/Embed/DomainFilteringAdapter.php
+++ b/src/Extension/Embed/DomainFilteringAdapter.php
@@ -17,6 +17,7 @@ class DomainFilteringAdapter implements EmbedAdapterInterface
 {
     private EmbedAdapterInterface $decorated;
 
+    /** @psalm-var non-empty-string */
     private string $regex;
 
     /**
@@ -40,6 +41,8 @@ public function updateEmbeds(array $embeds): void
 
     /**
      * @param string[] $allowedDomains
+     *
+     * @psalm-return non-empty-string
      */
     private static function createRegex(array $allowedDomains): string
     {
diff --git a/src/Extension/ExternalLink/ExternalLinkProcessor.php b/src/Extension/ExternalLink/ExternalLinkProcessor.php
index 125053575c..0f1852070a 100644
--- a/src/Extension/ExternalLink/ExternalLinkProcessor.php
+++ b/src/Extension/ExternalLink/ExternalLinkProcessor.php
@@ -95,7 +95,7 @@ private function applyRelAttribute(Link $link, bool $isExternal): void
     /**
      * @internal This method is only public so we can easily test it. DO NOT USE THIS OUTSIDE OF THIS EXTENSION!
      *
-     * @param mixed $compareTo
+     * @param non-empty-string|list<non-empty-string> $compareTo
      */
     public static function hostMatches(string $host, $compareTo): bool
     {
diff --git a/src/Extension/FrontMatter/Data/SymfonyYamlFrontMatterParser.php b/src/Extension/FrontMatter/Data/SymfonyYamlFrontMatterParser.php
index b21e9f78e0..8d99d336aa 100644
--- a/src/Extension/FrontMatter/Data/SymfonyYamlFrontMatterParser.php
+++ b/src/Extension/FrontMatter/Data/SymfonyYamlFrontMatterParser.php
@@ -30,6 +30,7 @@ public function parse(string $frontMatter)
         }
 
         try {
+            /** @psalm-suppress ReservedWord */
             return Yaml::parse($frontMatter);
         } catch (ParseException $ex) {
             throw InvalidFrontMatterException::wrap($ex);
diff --git a/src/Parser/Cursor.php b/src/Parser/Cursor.php
index f2b6c96c55..d6d76b3a92 100644
--- a/src/Parser/Cursor.php
+++ b/src/Parser/Cursor.php
@@ -393,6 +393,8 @@ public function isAtEnd(): bool
      * Try to match a regular expression
      *
      * Returns the matching text and advances to the end of that match
+     *
+     * @psalm-param non-empty-string $regex
      */
     public function match(string $regex): ?string
     {
diff --git a/src/Parser/Inline/InlineParserMatch.php b/src/Parser/Inline/InlineParserMatch.php
index 516a2c293f..e433ed27e8 100644
--- a/src/Parser/Inline/InlineParserMatch.php
+++ b/src/Parser/Inline/InlineParserMatch.php
@@ -36,6 +36,8 @@ public function caseSensitive(): self
 
     /**
      * @internal
+     *
+     * @psalm-return non-empty-string
      */
     public function getRegex(): string
     {
diff --git a/src/Parser/InlineParserEngine.php b/src/Parser/InlineParserEngine.php
index da5c25e323..b91a63f72f 100644
--- a/src/Parser/InlineParserEngine.php
+++ b/src/Parser/InlineParserEngine.php
@@ -36,8 +36,8 @@ final class InlineParserEngine implements InlineParserEngineInterface
 
     /**
      * @var array<int, InlineParserInterface|string|bool>
-     * @psalm-var list<array{0: InlineParserInterface, 1: string, 2: bool}>
-     * @phpstan-var array<int, array{0: InlineParserInterface, 1: string, 2: bool}>
+     * @psalm-var list<array{0: InlineParserInterface, 1: non-empty-string, 2: bool}>
+     * @phpstan-var array<int, array{0: InlineParserInterface, 1: non-empty-string, 2: bool}>
      */
     private array $parsers = [];
 
diff --git a/src/Util/RegexHelper.php b/src/Util/RegexHelper.php
index 8ead731e2b..44e7e3ade5 100644
--- a/src/Util/RegexHelper.php
+++ b/src/Util/RegexHelper.php
@@ -98,6 +98,8 @@ public static function isLetter(?string $character): bool
     /**
      * Attempt to match a regex in string s at offset offset
      *
+     * @psalm-param non-empty-string $regex
+     *
      * @return int|null Index of match, or null
      *
      * @psalm-pure
@@ -119,6 +121,8 @@ public static function matchAt(string $regex, string $string, int $offset = 0):
     /**
      * Functional wrapper around preg_match_all which only returns the first set of matches
      *
+     * @psalm-param non-empty-string $pattern
+     *
      * @return string[]|null
      *
      * @psalm-pure
@@ -162,6 +166,8 @@ public static function unescape(string $string): string
      *
      * @phpstan-param HtmlBlock::TYPE_* $type
      *
+     * @psalm-return non-empty-string
+     *
      * @throws InvalidArgumentException if an invalid type is given
      *
      * @psalm-pure
@@ -197,6 +203,8 @@ public static function getHtmlBlockOpenRegex(int $type): string
      *
      * @phpstan-param HtmlBlock::TYPE_* $type
      *
+     * @psalm-return non-empty-string
+     *
      * @throws InvalidArgumentException if an invalid type is given
      *
      * @psalm-pure