diff --git a/src/console/PhutilConsoleFormatter.php b/src/console/PhutilConsoleFormatter.php
index 4e2e869..705dfbb 100644
--- a/src/console/PhutilConsoleFormatter.php
+++ b/src/console/PhutilConsoleFormatter.php
@@ -1,95 +1,97 @@
 <?php
 
 final class PhutilConsoleFormatter {
 
   private static $colorCodes = array(
     'black'   => 0,
     'red'     => 1,
     'green'   => 2,
     'yellow'  => 3,
     'blue'    => 4,
     'magenta' => 5,
     'cyan'    => 6,
     'white'   => 7,
     'default' => 9,
   );
 
   private static $disableANSI;
 
   public static function disableANSI($disable) {
     self::$disableANSI = $disable;
   }
 
   public static function getDisableANSI() {
     if (self::$disableANSI === null) {
       $term = phutil_utf8_strtolower(getenv('TERM'));
       // ansicon enables ANSI support on Windows
       if (!$term && getenv('ANSICON')) {
         $term = 'ansi';
       }
 
       if (phutil_is_windows() && $term !== 'cygwin' && $term !== 'ansi') {
         self::$disableANSI = true;
+      } else if (!defined('STDOUT')) {
+        self::$disableANSI = true;
       } else if (function_exists('posix_isatty') && !posix_isatty(STDOUT)) {
         self::$disableANSI = true;
       } else {
         self::$disableANSI = false;
       }
     }
     return self::$disableANSI;
   }
 
   public static function formatString($format /* ... */) {
     $colors = implode('|', array_keys(self::$colorCodes));
 
     // Sequence should be preceded by start-of-string or non-backslash
     // escaping.
     $bold_re      = '/(?<![\\\\])\*\*(.*)\*\*/sU';
     $underline_re = '/(?<![\\\\])__(.*)__/sU';
     $invert_re    = '/(?<![\\\\])##(.*)##/sU';
 
     if (self::getDisableANSI()) {
       $format = preg_replace($bold_re,      '\1',   $format);
       $format = preg_replace($underline_re, '\1',   $format);
       $format = preg_replace($invert_re,    '\1',   $format);
       $format = preg_replace(
         '@<(fg|bg):('.$colors.')>(.*)</\1>@sU',
         '\3',
         $format);
     } else {
       $esc        = chr(27);
       $bold       = $esc.'[1m'.'\\1'.$esc.'[m';
       $underline  = $esc.'[4m'.'\\1'.$esc.'[m';
       $invert     = $esc.'[7m'.'\\1'.$esc.'[m';
 
       $format = preg_replace($bold_re,      $bold,      $format);
       $format = preg_replace($underline_re, $underline, $format);
       $format = preg_replace($invert_re,    $invert,    $format);
       $format = preg_replace_callback(
         '@<(fg|bg):('.$colors.')>(.*)</\1>@sU',
         array('PhutilConsoleFormatter', 'replaceColorCode'),
         $format);
     }
 
     // Remove backslash escaping
     $format = preg_replace('/\\\\(\*\*.*\*\*|__.*__|##.*##)/sU', '\1', $format);
 
     $args = func_get_args();
     $args[0] = $format;
 
     return call_user_func_array('sprintf', $args);
   }
 
   public static function replaceColorCode($matches) {
     $codes = self::$colorCodes;
     $offset = 30 + $codes[$matches[2]];
     $default = 39;
     if ($matches[1] == 'bg') {
       $offset += 10;
       $default += 10;
     }
 
     return chr(27).'['.$offset.'m'.$matches[3].chr(27).'['.$default.'m';
   }
 
 }