diff --git a/src/phage/agent/PhagePHPAgent.php b/src/phage/agent/PhagePHPAgent.php
index 67552ec..39a74e8 100644
--- a/src/phage/agent/PhagePHPAgent.php
+++ b/src/phage/agent/PhagePHPAgent.php
@@ -1,103 +1,104 @@
 <?php
 
 final class PhagePHPAgent extends Phobject {
 
   private $stdin;
   private $master;
   private $exec = array();
 
   public function __construct($stdin) {
     $this->stdin = $stdin;
   }
 
   public function execute() {
     while (true) {
       if ($this->exec) {
         $iterator = new FutureIterator($this->exec);
         $iterator->setUpdateInterval(0.050);
         foreach ($iterator as $key => $future) {
           if ($future === null) {
             break;
           }
           $this->resolveFuture($key, $future);
           break;
         }
       } else {
         PhutilChannel::waitForAny(array($this->getMaster()));
       }
 
       $this->processInput();
     }
   }
 
   private function getMaster() {
     if (!$this->master) {
       $raw_channel = new PhutilSocketChannel(
         $this->stdin,
         fopen('php://stdout', 'w'));
 
       $json_channel = new PhutilJSONProtocolChannel($raw_channel);
       $this->master = $json_channel;
     }
 
     return $this->master;
   }
 
   private function processInput() {
     $channel = $this->getMaster();
 
     $open = $channel->update();
     if (!$open) {
       throw new Exception(pht('Channel closed!'));
     }
 
     while (true) {
       $command = $channel->read();
       if ($command === null) {
         break;
       }
       $this->processCommand($command);
     }
   }
 
   private function processCommand(array $spec) {
     switch ($spec['type']) {
       case 'EXEC':
         $key = $spec['key'];
         $cmd = $spec['command'];
 
         $future = new ExecFuture('%C', $cmd);
         $this->exec[$key] = $future;
         break;
       case 'EXIT':
         $this->terminateAgent();
         break;
     }
   }
 
   private function resolveFuture($key, Future $future) {
     $result = $future->resolve();
     $master = $this->getMaster();
 
     $master->write(
       array(
         'type'    => 'RSLV',
         'key'     => $key,
         'err'     => $result[0],
         'stdout'  => $result[1],
         'stderr'  => $result[2],
       ));
+    unset($this->exec[$key]);
   }
 
   public function __destruct() {
     $this->terminateAgent();
   }
 
   private function terminateAgent() {
     foreach ($this->exec as $key => $future) {
       $future->resolveKill();
     }
     exit(0);
   }
 
 }