diff --git a/src/Parser/Tokenizer/Tokenizer.php b/src/Parser/Tokenizer/Tokenizer.php
index bb67fd38..a3571d7a 100644
--- a/src/Parser/Tokenizer/Tokenizer.php
+++ b/src/Parser/Tokenizer/Tokenizer.php
@@ -250,7 +250,7 @@ public static function period(\Iterator $fragments): \Iterator
 
     public static function symbol(\Iterator $fragments, ?Buffer $buffer = null): \Iterator
     {
-        $buffer = $buffer ?? Buffer::empty();
+        $buffer ??= Buffer::empty();
         $capture = true;
 
         while ($capture && $fragments->valid()) {
@@ -324,7 +324,7 @@ public static function angle(\Iterator $fragments): \Iterator
      */
     public static function tag(\Iterator $fragments, ?Buffer $buffer = null): \Iterator
     {
-        $buffer = $buffer ?? Buffer::empty();
+        $buffer ??= Buffer::empty();
         $isClosing = false;
 
         while ($fragments->valid()) {
@@ -410,16 +410,19 @@ public static function tagContent(\Iterator $fragments): \Iterator
                     yield from $buffer->flush(TokenType::STRING);
                     yield from self::block($fragments);
                     break;
+                case $fragment->value === '>':
+                    throw new \Exception(sprintf('@TODO: Illegal Character "%s"', $fragment->value));
                 case $fragment->value === '<':
                     $fragments->next();
-                    if ($fragments->current()?->value === '/') {
+                    if (!$fragments->valid()) {
+                        throw new \Exception("@TODO: Unexpected end of input");
+                    }
+                    if ($fragments->current()->value === '/') {
                         yield from $buffer->flush(TokenType::STRING);
                         return Buffer::empty()->append($fragment);
-                    } else if (!ctype_space($fragments->current()?->value)) {
-                        yield from self::tag($fragments, Buffer::empty()->append($fragment));
-                    } else {
-                        $buffer->append($fragment);
                     }
+                    yield from self::tag($fragments, Buffer::empty()->append($fragment));
+                    break;
                 case ctype_space($fragment->value):
                     yield from $buffer->flush(TokenType::STRING);
                     yield from self::space($fragments);
diff --git a/test/Unit/Parser/Tokenizer/TokenizerTest.php b/test/Unit/Parser/Tokenizer/TokenizerTest.php
new file mode 100644
index 00000000..d25c1a58
--- /dev/null
+++ b/test/Unit/Parser/Tokenizer/TokenizerTest.php
@@ -0,0 +1,48 @@
+<?php
+
+namespace PackageFactory\ComponentEngine\Test\Unit\Parser\Tokenizer;
+
+use PackageFactory\ComponentEngine\Parser\Source\Source;
+use PackageFactory\ComponentEngine\Parser\Tokenizer\Tokenizer;
+
+class TokenizerTest extends \PHPUnit\Framework\TestCase
+{
+    public function examplesInvalidTagContentsSyntax(): \Iterator
+    {
+        yield "> inside text" => [
+            '<p>acd>def<p>',
+            '@TODO: Illegal Character ">"'
+        ];
+
+        yield "> between tags" => [
+            '<p>><p>',
+            '@TODO: Illegal Character ">"'
+        ];
+        
+        /*
+         * @todo no exception is thrown on tokenizer level ...
+         * 
+         * <p>abc<def</p>
+         * <p>< </p>
+         * <p><</p>
+         */
+    }
+    
+    /**
+     * @test
+     * @dataProvider examplesInvalidTagContentsSyntax
+     */
+    public function invalidTagContents(string $sourceCode, string $expectedMessage): void
+    {
+        $tokenizer = Tokenizer::fromSource(
+            Source::fromString($sourceCode)
+        );
+        
+        $this->expectException(\Exception::class);
+        $this->expectExceptionMessage($expectedMessage);
+        
+        foreach ($tokenizer as $token) {
+            continue;
+        }
+    }
+}