diff --git a/src/applications/maniphest/auxiliaryfield/base/ManiphestAuxiliaryFieldSpecification.php b/src/applications/maniphest/auxiliaryfield/base/ManiphestAuxiliaryFieldSpecification.php
index 92a119b149..798f7ac5c1 100644
--- a/src/applications/maniphest/auxiliaryfield/base/ManiphestAuxiliaryFieldSpecification.php
+++ b/src/applications/maniphest/auxiliaryfield/base/ManiphestAuxiliaryFieldSpecification.php
@@ -91,6 +91,20 @@ abstract class ManiphestAuxiliaryFieldSpecification {
   }
 
 
+  /**
+   * When the user creates a task, the UI prompts them to "Create another
+   * similar task". This copies some fields (e.g., Owner and CCs) but not other
+   * fields (e.g., description). If this custom field should also be copied,
+   * return true from this method.
+   *
+   * @return bool True to copy the default value from the template task when
+   *              creating a new similar task.
+   */
+  public function shouldCopyWhenCreatingSimilarTask() {
+    return false;
+  }
+
+
   /**
    * Render a verb to appear in email titles when a transaction involving this
    * field occurs. Specifically, Maniphest emails are formatted like this:
diff --git a/src/applications/maniphest/auxiliaryfield/default/ManiphestAuxiliaryFieldDefaultSpecification.php b/src/applications/maniphest/auxiliaryfield/default/ManiphestAuxiliaryFieldDefaultSpecification.php
index 658fd1f6d3..faa341effd 100644
--- a/src/applications/maniphest/auxiliaryfield/default/ManiphestAuxiliaryFieldDefaultSpecification.php
+++ b/src/applications/maniphest/auxiliaryfield/default/ManiphestAuxiliaryFieldDefaultSpecification.php
@@ -29,6 +29,7 @@ class ManiphestAuxiliaryFieldDefaultSpecification
   private $checkboxLabel;
   private $checkboxValue;
   private $error;
+  private $shouldCopyWhenCreatingSimilarTask;
 
   const TYPE_SELECT = 'select';
   const TYPE_STRING = 'string';
@@ -178,6 +179,7 @@ class ManiphestAuxiliaryFieldDefaultSpecification
     return parent::renderForDetailView();
   }
 
+
   public function renderTransactionDescription(
     ManiphestTransaction $transaction,
     $target) {
@@ -224,4 +226,13 @@ class ManiphestAuxiliaryFieldDefaultSpecification
     return $desc;
   }
 
+  public function setShouldCopyWhenCreatingSimilarTask($copy) {
+    $this->shouldCopyWhenCreatingSimilarTask = $copy;
+    return $this;
+  }
+
+  public function shouldCopyWhenCreatingSimilarTask() {
+    return $this->shouldCopyWhenCreatingSimilarTask;
+  }
+
 }
diff --git a/src/applications/maniphest/controller/taskedit/ManiphestTaskEditController.php b/src/applications/maniphest/controller/taskedit/ManiphestTaskEditController.php
index 44b1cd84c8..fbbb31d14f 100644
--- a/src/applications/maniphest/controller/taskedit/ManiphestTaskEditController.php
+++ b/src/applications/maniphest/controller/taskedit/ManiphestTaskEditController.php
@@ -277,6 +277,15 @@ final class ManiphestTaskEditController extends ManiphestController {
           ->setURI($redirect_uri);
       }
     } else {
+      if ($aux_fields) {
+        $task->loadAndAttachAuxiliaryAttributes();
+        foreach ($aux_fields as $aux_field) {
+          $aux_key = $aux_field->getAuxiliaryKey();
+          $value = $task->getAuxiliaryAttribute($aux_key);
+          $aux_field->setValueFromStorage($value);
+        }
+      }
+
       if (!$task->getID()) {
         $task->setCCPHIDs(array(
           $user->getPHID(),
@@ -287,6 +296,19 @@ final class ManiphestTaskEditController extends ManiphestController {
             $task->setCCPHIDs($template_task->getCCPHIDs());
             $task->setProjectPHIDs($template_task->getProjectPHIDs());
             $task->setOwnerPHID($template_task->getOwnerPHID());
+
+            if ($aux_fields) {
+              $template_task->loadAndAttachAuxiliaryAttributes();
+              foreach ($aux_fields as $aux_field) {
+                if (!$aux_field->shouldCopyWhenCreatingSimilarTask()) {
+                  continue;
+                }
+
+                $aux_key = $aux_field->getAuxiliaryKey();
+                $value = $template_task->getAuxiliaryAttribute($aux_key);
+                $aux_field->setValueFromStorage($value);
+              }
+            }
           }
         }
       }
@@ -438,16 +460,6 @@ final class ManiphestTaskEditController extends ManiphestController {
           ->setDatasource('/typeahead/common/projects/'));
 
     if ($aux_fields) {
-
-      if (!$request->isFormPost()) {
-        $task->loadAndAttachAuxiliaryAttributes();
-        foreach ($aux_fields as $aux_field) {
-          $aux_key = $aux_field->getAuxiliaryKey();
-          $value = $task->getAuxiliaryAttribute($aux_key);
-          $aux_field->setValueFromStorage($value);
-        }
-      }
-
       foreach ($aux_fields as $aux_field) {
         if ($aux_field->isRequired() &&
             !$aux_field->getError() &&
diff --git a/src/applications/maniphest/extensions/task/ManiphestDefaultTaskExtensions.php b/src/applications/maniphest/extensions/task/ManiphestDefaultTaskExtensions.php
index 1ee4d049b9..d6f099f3bb 100644
--- a/src/applications/maniphest/extensions/task/ManiphestDefaultTaskExtensions.php
+++ b/src/applications/maniphest/extensions/task/ManiphestDefaultTaskExtensions.php
@@ -1,7 +1,7 @@
 <?php
 
 /*
- * Copyright 2011 Facebook, Inc.
+ * Copyright 2012 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -41,6 +41,7 @@ final class ManiphestDefaultTaskExtensions
         $spec->setSelectOptions(idx($info, 'options'));
       }
 
+      $spec->setShouldCopyWhenCreatingSimilarTask(idx($info, 'copy'));
       $specs[] = $spec;
     }
 
diff --git a/src/docs/userguide/maniphest_custom.diviner b/src/docs/userguide/maniphest_custom.diviner
index 2f433a2e9a..80e55700c6 100644
--- a/src/docs/userguide/maniphest_custom.diviner
+++ b/src/docs/userguide/maniphest_custom.diviner
@@ -53,6 +53,10 @@ the field. These options are available:
     show next to the checkbox.
   - **checkbox-value**: If type is set to **bool**, the value to show on
     the detail view when the checkbox is selected.
+  - **copy**: When a user creates a task, the UI gives them an option to
+    "Create Another Similar Task". Some fields from the original task are copied
+    into the new task, while others are not; by default, fields are not copied.
+    If you want this field to be copied, specify `true` for the `copy` property.
 
 = Advanced Field Customization =
 
@@ -63,7 +67,7 @@ rendering logic, you can do so with a little work:
     your specialized rendering, validation, storage, etc., logic.
   - Extend @{class:ManiphestTaskExtensions} and return a list of fields which
     includes your custom field objects.
-  - Set 'maniphest.custom-extensions' to the name of your new extensions
+  - Set `maniphest.custom-extensions` to the name of your new extensions
     class.
 
 This is relatively advanced but should give you significant flexibility in