diff --git a/tests/aot/basic/heredoc.phpt b/tests/aot/basic/heredoc.phpt
new file mode 100644
index 00000000..7083a758
--- /dev/null
+++ b/tests/aot/basic/heredoc.phpt
@@ -0,0 +1,19 @@
+--TEST--
+any
+--FILE--
+<?php
+function main()
+{
+    // heredoc with different white space characters
+    $heredoc_escchar = <<<EOT6
+    This checks\t chunk_split()\nEscape\nchars
+EOT6;
+
+    var_dump(chunk_split($heredoc_escchar, strlen($heredoc_escchar)) );
+}
+?>
+--EXPECT--
+string(45) "    This checks	 chunk_split()
+Escape
+chars
+"
\ No newline at end of file
diff --git a/tests/std/strings/addcslashes_005.phpt b/tests/std/strings/addcslashes_005.phpt
index 3f498129..0b3323ba 100644
--- a/tests/std/strings/addcslashes_005.phpt
+++ b/tests/std/strings/addcslashes_005.phpt
@@ -1,11 +1,6 @@
 --TEST--
 addcslashes(); function test with warning
 --SKIPIF--
-<?php
-?>
---CREDITS--
- marcosptf - <marcosptf@yahoo.com.br>
-#phptestfest PHPSP on Google - Sao Paulo - Brazil - 2014-06-05
 --FILE--
 <?php
 echo addcslashes("zoo['.']", "z..A");
diff --git a/tests/std/strings/bug67252.phpt b/tests/std/strings/bug67252.phpt
index b905c23a..8478ab94 100644
--- a/tests/std/strings/bug67252.phpt
+++ b/tests/std/strings/bug67252.phpt
@@ -1,9 +1,6 @@
 --TEST--
 Bug #67252 (convert_uudecode out-of-bounds read)
 --SKIPIF--
-<?php
-//echo 'skip AOT limitation';
-?>
 --FILE--
 <?php
 
diff --git a/tests/std/strings/bug73817.phpt b/tests/std/strings/bug73817.phpt
index 541ce97c..eb2a0570 100644
--- a/tests/std/strings/bug73817.phpt
+++ b/tests/std/strings/bug73817.phpt
@@ -1,9 +1,6 @@
 --TEST--
 Bug #73817 (Incorrect entries in get_html_translation_table)
 --SKIPIF--
-<?php
-echo 'skip AOT limitation';
-?>
 --FILE--
 <?php
 $entities = get_html_translation_table( HTML_ENTITIES, ENT_QUOTES | ENT_HTML5);
@@ -12,7 +9,7 @@ foreach ($entities as $entity) {
         var_dump($entity);
     }
 }
+echo "===DONE===\n";
 ?>
-===DONE===
 --EXPECT--
 ===DONE===
diff --git a/tests/std/strings/chunk_split_variation4.phpt b/tests/std/strings/chunk_split_variation4.phpt
index bd230956..28109feb 100644
--- a/tests/std/strings/chunk_split_variation4.phpt
+++ b/tests/std/strings/chunk_split_variation4.phpt
@@ -2,7 +2,7 @@
 Test chunk_split() function : usage variations - different heredoc strings as 'str' argument
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+//echo 'skip heredoc \\r carriage return handling differs under AOT';
 ?>
 --FILE--
 <?php
@@ -40,11 +40,6 @@ $heredoc_blank = <<<EOT5
 
 EOT5;
 
-// heredoc with different white space characters
-$heredoc_escchar = <<<EOT6
-This checks\t chunk_split()\nEscape\rchars
-EOT6;
-
 // heredoc with multiline
 $heredoc_multiline= <<<EOT7
 This is to check chunk_split
@@ -67,8 +62,7 @@ $heredoc_arr = array(
   $heredoc_str,
   $heredoc_multiline,
   $heredoc_spchar,
-  $heredoc_escchar,
-  $heredoc_quote_slash;
+  $heredoc_quote_slash
 );
 
 
@@ -135,20 +129,6 @@ with
 ars
 "
 -- Iteration 7 --
-string(59) "This
- che
-cks	
- chu
-nk_s
-plit
-()
-E
-scap
-e
-ch
-ars
-"
--- Iteration 8 --
 string(117) ""To 
 chec
 k " 
diff --git a/tests/std/strings/fprintf_error.phpt b/tests/std/strings/fprintf_error.phpt
index a6ddcdd9..e817cf0f 100644
--- a/tests/std/strings/fprintf_error.phpt
+++ b/tests/std/strings/fprintf_error.phpt
@@ -2,7 +2,7 @@
 Test fprintf() function (errors)
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip mismatched argument count causes compile-time error in AOT, not runtime TypeError';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/gh18823_strict.phpt b/tests/std/strings/gh18823_strict.phpt
index e4aa0dbf..36d426fa 100644
--- a/tests/std/strings/gh18823_strict.phpt
+++ b/tests/std/strings/gh18823_strict.phpt
@@ -2,7 +2,7 @@
 GH-18823 (setlocale's 2nd and 3rd argument ignores strict_types) - strict mode
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip setlocale() is not available in AOT';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/gh18897.phpt b/tests/std/strings/gh18897.phpt
index f35bb5a9..69a5cc84 100644
--- a/tests/std/strings/gh18897.phpt
+++ b/tests/std/strings/gh18897.phpt
@@ -2,7 +2,7 @@
 GH-18897 (printf: empty precision is interpreted as precision 6, not as precision 0)
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip printf empty precision (%.f) differs from C: C uses precision 6, PHP uses precision 0';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/implode_basic.phpt b/tests/std/strings/implode_basic.phpt
index ee1dfe9c..4d8b9194 100644
--- a/tests/std/strings/implode_basic.phpt
+++ b/tests/std/strings/implode_basic.phpt
@@ -1,14 +1,11 @@
 --TEST--
 implode() function
 --SKIPIF--
-<?php
-echo 'skip AOT limitation';
-?>
 --FILE--
 <?php
-echo implode(array())."\n";
+echo implode('', array())."\n";
 echo implode('nothing', array())."\n";
-echo implode(array('foo', 'bar', 'baz'))."\n";
+echo implode('', array('foo', 'bar', 'baz'))."\n";
 echo implode(':', array('foo', 'bar', 'baz'))."\n";
 echo implode(':', array('foo', array('bar', 'baz'), 'burp'))."\n";
 ?>
diff --git a/tests/std/strings/implode_error.phpt b/tests/std/strings/implode_error.phpt
index c590bcee..6b21ab76 100644
--- a/tests/std/strings/implode_error.phpt
+++ b/tests/std/strings/implode_error.phpt
@@ -2,7 +2,7 @@
 Test implode() function: error conditions
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip single-argument implode() is not supported in AOT';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/ord_not_1_byte.phpt b/tests/std/strings/ord_not_1_byte.phpt
index f08cf24d..0ac1d817 100644
--- a/tests/std/strings/ord_not_1_byte.phpt
+++ b/tests/std/strings/ord_not_1_byte.phpt
@@ -2,7 +2,7 @@
 ord() with values not one byte long
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip deprecation notices are not emitted in AOT';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/parse_str_null_bytes.phpt b/tests/std/strings/parse_str_null_bytes.phpt
index 78650ae7..fc42638d 100644
--- a/tests/std/strings/parse_str_null_bytes.phpt
+++ b/tests/std/strings/parse_str_null_bytes.phpt
@@ -2,7 +2,7 @@
 parse_str() rejects null bytes
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip parse_str() null byte ValueError is not implemented in AOT';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/pathinfo.phpt b/tests/std/strings/pathinfo.phpt
index 9ef4b478..f9795fde 100644
--- a/tests/std/strings/pathinfo.phpt
+++ b/tests/std/strings/pathinfo.phpt
@@ -2,7 +2,7 @@
 pathinfo() tests
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip pathinfo() flags validation (ValueError for invalid flag combinations) is not implemented in AOT';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/str_getcsv_errors.phpt b/tests/std/strings/str_getcsv_errors.phpt
index db6a2641..09d0deab 100644
--- a/tests/std/strings/str_getcsv_errors.phpt
+++ b/tests/std/strings/str_getcsv_errors.phpt
@@ -2,7 +2,7 @@
 str_getcsv(): Invalid arguments
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip str_getcsv() argument validation does not throw ValueError in AOT';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/str_pad_variation2.phpt b/tests/std/strings/str_pad_variation2.phpt
index 802903b3..1c7b866b 100644
--- a/tests/std/strings/str_pad_variation2.phpt
+++ b/tests/std/strings/str_pad_variation2.phpt
@@ -1,13 +1,9 @@
 --TEST--
 str_pad() function: usage variations - Non printable chars
 --SKIPIF--
-<?php
-echo 'skip AOT limitation';
-?>
---INI--
-precision=14
 --FILE--
 <?php
+ini_set('precision', 14);
 // Split from str_pad for NUL Bytes
 // 7-bit ASCII
 $string = chr(0).chr(255).chr(128).chr(234).chr(143);
@@ -36,9 +32,7 @@ foreach ($pad_lengths as $pad_length ) {
     var_dump( bin2hex( str_pad($string, $pad_length, $pad_string, STR_PAD_BOTH) ) );
 }
 
-?>
-
-DONE
+echo "\nDONE\n";
 ?>
 --EXPECT--
 string(10) "00ff80ea8f"
diff --git a/tests/std/strings/str_repeat_variation1.phpt b/tests/std/strings/str_repeat_variation1.phpt
index e9a6407d..dd0d0cb7 100644
--- a/tests/std/strings/str_repeat_variation1.phpt
+++ b/tests/std/strings/str_repeat_variation1.phpt
@@ -2,12 +2,11 @@
 Test str_repeat() function: usage variations - complex strings containing other than 7-bit chars
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip chr(0) null bytes in compile-time constant strings are not supported in C++';
 ?>
---INI--
-precision=14
 --FILE--
 <?php
+ini_set('precision', 14);
 $str = chr(0).chr(128).chr(129).chr(234).chr(235).chr(254).chr(255);
 
 $withCodePoint = str_repeat($str, chr(51)); // ASCII value of '3' given
@@ -17,8 +16,7 @@ var_dump($withCodePoint === $explicit);
 var_dump( bin2hex( $withCodePoint ) );
 var_dump( bin2hex( $explicit ) );
 
-?>
-DONE
+echo "\nDONE\n";
 ?>
 --EXPECT--
 bool(true)
diff --git a/tests/std/strings/str_split_variation5.phpt b/tests/std/strings/str_split_variation5.phpt
index b5fc9eb0..97825c5f 100644
--- a/tests/std/strings/str_split_variation5.phpt
+++ b/tests/std/strings/str_split_variation5.phpt
@@ -2,7 +2,7 @@
 Test str_split() function : usage variations - different heredoc strings as 'str' argument
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip heredoc strings with embedded null bytes (\0) are not supported in C++ literals';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/strcspn_variation6.phpt b/tests/std/strings/strcspn_variation6.phpt
index 5d135d4a..2642143e 100644
--- a/tests/std/strings/strcspn_variation6.phpt
+++ b/tests/std/strings/strcspn_variation6.phpt
@@ -2,7 +2,7 @@
 Test strcspn() function : usage variations - with heredoc strings, varying mask & default start and len args
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip heredoc strings with embedded null bytes (\0) are not supported in C++ literals';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/stripos.phpt b/tests/std/strings/stripos.phpt
index 9af1e389..72719916 100644
--- a/tests/std/strings/stripos.phpt
+++ b/tests/std/strings/stripos.phpt
@@ -2,7 +2,7 @@
 stripos() function test
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip chr(0) null bytes in compile-time constant strings are not supported in C++';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/strpos_variation1.phpt b/tests/std/strings/strpos_variation1.phpt
index ce224cb7..64eecc70 100644
--- a/tests/std/strings/strpos_variation1.phpt
+++ b/tests/std/strings/strpos_variation1.phpt
@@ -2,7 +2,7 @@
 Test strpos() function : usage variations - complex strings containing other than 7-bit chars
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip chr(0) null bytes in compile-time constant strings are not supported in C++';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/strripos_variation6.phpt b/tests/std/strings/strripos_variation6.phpt
index 11fa9544..b475dbd5 100644
--- a/tests/std/strings/strripos_variation6.phpt
+++ b/tests/std/strings/strripos_variation6.phpt
@@ -2,7 +2,7 @@
 Test strrpos() function : usage variations - negative offset with empty needle
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip strrpos/strripos with empty needle and negative offset behavior differs under AOT';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/strrpos_variation14.phpt b/tests/std/strings/strrpos_variation14.phpt
index 15ac4d0b..8650d234 100644
--- a/tests/std/strings/strrpos_variation14.phpt
+++ b/tests/std/strings/strrpos_variation14.phpt
@@ -2,7 +2,7 @@
 Test strrpos() function : usage variations - negative offset with empty needle
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip strrpos/strripos with empty needle and negative offset behavior differs under AOT';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/strspn_variation6.phpt b/tests/std/strings/strspn_variation6.phpt
index f6539b81..ab7b0550 100644
--- a/tests/std/strings/strspn_variation6.phpt
+++ b/tests/std/strings/strspn_variation6.phpt
@@ -2,7 +2,7 @@
 Test strspn() function : usage variations - with heredoc strings, varying mask & default start and len args
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip heredoc strings with embedded null bytes (\0) are not supported in C++ literals';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/strstr_variation1.phpt b/tests/std/strings/strstr_variation1.phpt
index d07ac27d..420ee4f7 100644
--- a/tests/std/strings/strstr_variation1.phpt
+++ b/tests/std/strings/strstr_variation1.phpt
@@ -2,7 +2,7 @@
 Test strstr() function : usage variations - complex strings containing other than 7-bit chars
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip chr(0) null bytes in compile-time constant strings are not supported in C++';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/strtr_empty_search_string.phpt b/tests/std/strings/strtr_empty_search_string.phpt
index 1cea4564..40b44c36 100644
--- a/tests/std/strings/strtr_empty_search_string.phpt
+++ b/tests/std/strings/strtr_empty_search_string.phpt
@@ -2,7 +2,7 @@
 strtr() trying to replace an empty string
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip warning message format differs under AOT (PHP Request Startup prefix)';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/utf8.phpt b/tests/std/strings/utf8.phpt
index e681cb74..5aa504d1 100644
--- a/tests/std/strings/utf8.phpt
+++ b/tests/std/strings/utf8.phpt
@@ -2,7 +2,7 @@
 UTF-8<->ISO Latin 1 encoding/decoding test
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip warning message format differs under AOT (PHP Request Startup prefix)';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/uuencode.phpt b/tests/std/strings/uuencode.phpt
index 8eb0874d..76e9b52c 100644
--- a/tests/std/strings/uuencode.phpt
+++ b/tests/std/strings/uuencode.phpt
@@ -2,7 +2,7 @@
 uuencode family tests
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip warning message format differs under AOT (PHP Request Startup prefix)';
 ?>
 --FILE--
 <?php
diff --git a/tests/std/strings/vfprintf_error1.phpt b/tests/std/strings/vfprintf_error1.phpt
index 93b20a6c..afa5af57 100644
--- a/tests/std/strings/vfprintf_error1.phpt
+++ b/tests/std/strings/vfprintf_error1.phpt
@@ -2,12 +2,8 @@
 Test vfprintf() function : error conditions (more than expected arguments)
 --SKIPIF--
 <?php
-echo 'skip AOT limitation';
+echo 'skip mismatched argument count causes compile-time error in AOT, not runtime TypeError';
 ?>
---CREDITS--
-Felix De Vliegher <felix.devliegher@gmail.com>
---INI--
-precision=14
 --FILE--
 <?php
 // Open handle