diff --git a/src/Lib/Core.php b/src/Lib/Core.php
index ba1ec74..1d160eb 100644
--- a/src/Lib/Core.php
+++ b/src/Lib/Core.php
@@ -75,6 +75,14 @@ class Core implements ILib
             ));
         }
 
+        $env->set('php-sapi', new CoreFunc('php-sapi', 'Get the name of the PHP SAPI.', 0, 0,
+            fn () => php_sapi_name()
+        ));
+
+        $env->set('php-version', new CoreFunc('php-version', 'Get the PHP version.', 0, 0,
+            fn () => phpversion()
+        ));
+
         if (!$this->safemode) {
             $env->set('print', new CoreFunc('print', 'Print arguments.', 0, -1,
                 function (...$args) {
diff --git a/src/Lib/IO.php b/src/Lib/IO.php
index 47d1641..0e99259 100644
--- a/src/Lib/IO.php
+++ b/src/Lib/IO.php
@@ -18,6 +18,13 @@ class IO implements ILib
         $env->set('DIRSEP', \DIRECTORY_SEPARATOR);
         $env->set('HOME', $_SERVER['HOME'] . \DIRECTORY_SEPARATOR);
 
+        if (php_sapi_name() == 'cli') {
+            // Define standard I/O streams
+            $env->set('STDIN', STDIN);
+            $env->set('STDOUT', STDOUT);
+            $env->set('STDERR', STDERR);
+        }
+
         $env->set('wd', new CoreFunc('wd', 'Get the current working directory.', 0, 0,
             fn () => getcwd() . \DIRECTORY_SEPARATOR
         ));
@@ -34,6 +41,10 @@ class IO implements ILib
             fn (string $dir) => is_dir($dir)
         ));
 
+        $env->set('tty?', new CoreFunc('tty?', 'Return true if the given file descriptor is a TTY.', 1, 1,
+            fn ($stream) => stream_isatty($stream)
+        ));
+
         $env->set('fsize', new CoreFunc('fsize', 'Return the size of a file.', 1, 1,
             fn (string $file) => @filesize($file)
         ));