diff --git a/src/applications/maniphest/editor/ManiphestEditEngine.php b/src/applications/maniphest/editor/ManiphestEditEngine.php
--- a/src/applications/maniphest/editor/ManiphestEditEngine.php
+++ b/src/applications/maniphest/editor/ManiphestEditEngine.php
@@ -81,6 +81,7 @@
         ->setLabel(pht('Status'))
         ->setDescription(pht('Status of the task.'))
         ->setTransactionType(ManiphestTransaction::TYPE_STATUS)
+        ->setIsCopyable(true)
         ->setValue($object->getStatus())
         ->setOptions($status_map)
         ->setCommentActionLabel(pht('Change Status'))
@@ -91,6 +92,7 @@
         ->setLabel(pht('Assigned To'))
         ->setDescription(pht('User who is responsible for the task.'))
         ->setTransactionType(ManiphestTransaction::TYPE_OWNER)
+        ->setIsCopyable(true)
         ->setSingleValue($object->getOwnerPHID())
         ->setCommentActionLabel(pht('Assign / Claim'))
         ->setCommentActionDefaultValue($owner_value),
@@ -99,6 +101,7 @@
         ->setLabel(pht('Priority'))
         ->setDescription(pht('Priority of the task.'))
         ->setTransactionType(ManiphestTransaction::TYPE_PRIORITY)
+        ->setIsCopyable(true)
         ->setValue($object->getPriority())
         ->setOptions($priority_map)
         ->setCommentActionLabel($priority_label),
diff --git a/src/applications/owners/editor/PhabricatorOwnersPackageEditEngine.php b/src/applications/owners/editor/PhabricatorOwnersPackageEditEngine.php
--- a/src/applications/owners/editor/PhabricatorOwnersPackageEditEngine.php
+++ b/src/applications/owners/editor/PhabricatorOwnersPackageEditEngine.php
@@ -58,6 +58,7 @@
         ->setDescription(pht('Users and projects which own the package.'))
         ->setTransactionType(PhabricatorOwnersPackageTransaction::TYPE_OWNERS)
         ->setDatasource(new PhabricatorProjectOrUserDatasource())
+        ->setIsCopyable(true)
         ->setValue($object->getOwnerPHIDs()),
       id(new PhabricatorSelectEditField())
         ->setKey('status')
@@ -74,6 +75,7 @@
             'Automatically trigger audits for commits affecting files in '.
             'this package.'))
         ->setTransactionType(PhabricatorOwnersPackageTransaction::TYPE_AUDITING)
+        ->setIsCopyable(true)
         ->setValue($object->getAuditingEnabled())
         ->setOptions(
           array(
diff --git a/src/applications/paste/editor/PhabricatorPasteEditEngine.php b/src/applications/paste/editor/PhabricatorPasteEditEngine.php
--- a/src/applications/paste/editor/PhabricatorPasteEditEngine.php
+++ b/src/applications/paste/editor/PhabricatorPasteEditEngine.php
@@ -73,6 +73,7 @@
             'title.'))
         ->setAliases(array('lang'))
         ->setTransactionType(PhabricatorPasteTransaction::TYPE_LANGUAGE)
+        ->setIsCopyable(true)
         ->setValue($object->getLanguage())
         ->setOptions($langs),
       id(new PhabricatorSelectEditField())
diff --git a/src/applications/policy/editor/PhabricatorPolicyEditEngineExtension.php b/src/applications/policy/editor/PhabricatorPolicyEditEngineExtension.php
--- a/src/applications/policy/editor/PhabricatorPolicyEditEngineExtension.php
+++ b/src/applications/policy/editor/PhabricatorPolicyEditEngineExtension.php
@@ -83,6 +83,7 @@
         ->setLabel($label)
         ->setDescription($description)
         ->setAliases($aliases)
+        ->setIsCopyable(true)
         ->setCapability($capability)
         ->setPolicies($policies)
         ->setTransactionType($type)
@@ -100,6 +101,7 @@
               ->setEditTypeKey('space')
               ->setDescription(
                 pht('Shifts the object in the Spaces application.'))
+              ->setIsCopyable(true)
               ->setIsReorderable(false)
               ->setAliases(array('space', 'policy.space'))
               ->setTransactionType($type_space)
diff --git a/src/applications/project/editor/PhabricatorProjectsEditEngineExtension.php b/src/applications/project/editor/PhabricatorProjectsEditEngineExtension.php
--- a/src/applications/project/editor/PhabricatorProjectsEditEngineExtension.php
+++ b/src/applications/project/editor/PhabricatorProjectsEditEngineExtension.php
@@ -48,6 +48,7 @@
       ->setEditTypeKey('projects')
       ->setDescription(pht('Add or remove associated projects.'))
       ->setAliases(array('project', 'projects'))
+      ->setIsCopyable(true)
       ->setUseEdgeTransactions(true)
       ->setEdgeTransactionDescriptions(
         pht('Add projects.'),
diff --git a/src/applications/subscriptions/editor/PhabricatorSubscriptionsEditEngineExtension.php b/src/applications/subscriptions/editor/PhabricatorSubscriptionsEditEngineExtension.php
--- a/src/applications/subscriptions/editor/PhabricatorSubscriptionsEditEngineExtension.php
+++ b/src/applications/subscriptions/editor/PhabricatorSubscriptionsEditEngineExtension.php
@@ -45,6 +45,7 @@
       ->setEditTypeKey('subscribers')
       ->setDescription(pht('Manage subscribers.'))
       ->setAliases(array('subscriber', 'subscribers'))
+      ->setIsCopyable(true)
       ->setUseEdgeTransactions(true)
       ->setEdgeTransactionDescriptions(
         pht('Add subscribers.'),
diff --git a/src/applications/transactions/editengine/PhabricatorEditEngine.php b/src/applications/transactions/editengine/PhabricatorEditEngine.php
--- a/src/applications/transactions/editengine/PhabricatorEditEngine.php
+++ b/src/applications/transactions/editengine/PhabricatorEditEngine.php
@@ -95,7 +95,7 @@
     }
 
     $config = $this->getEditEngineConfiguration();
-    $fields = $config->applyConfigurationToFields($this, $fields);
+    $fields = $config->applyConfigurationToFields($this, $object, $fields);
 
     foreach ($fields as $field) {
       $field
@@ -443,12 +443,16 @@
    * to make Conduit a little easier to use.
    *
    * @param wild ID, PHID, or monogram.
+   * @param list<const> List of required capability constants, or omit for
+   *   defaults.
    * @return object Corresponding editable object.
    * @task load
    */
-  private function newObjectFromIdentifier($identifier) {
+  private function newObjectFromIdentifier(
+    $identifier,
+    array $capabilities = array()) {
     if (is_int($identifier) || ctype_digit($identifier)) {
-      $object = $this->newObjectFromID($identifier);
+      $object = $this->newObjectFromID($identifier, $capabilities);
 
       if (!$object) {
         throw new Exception(
@@ -462,7 +466,7 @@
 
     $type_unknown = PhabricatorPHIDConstants::PHID_TYPE_UNKNOWN;
     if (phid_get_type($identifier) != $type_unknown) {
-      $object = $this->newObjectFromPHID($identifier);
+      $object = $this->newObjectFromPHID($identifier, $capabilities);
 
       if (!$object) {
         throw new Exception(
@@ -503,7 +507,7 @@
     // sure it's really valid, goes through standard policy check logic, and
     // picks up any `need...()` clauses we want it to load with.
 
-    $object = $this->newObjectFromPHID($target->getPHID());
+    $object = $this->newObjectFromPHID($target->getPHID(), $capabilities);
     if (!$object) {
       throw new Exception(
         pht(
@@ -536,14 +540,16 @@
    * Load an object by PHID.
    *
    * @param phid Object PHID.
+   * @param list<const> List of required capability constants, or omit for
+   *   defaults.
    * @return object|null Object, or null if no such object exists.
    * @task load
    */
-  private function newObjectFromPHID($phid) {
+  private function newObjectFromPHID($phid, array $capabilities = array()) {
     $query = $this->newObjectQuery()
       ->withPHIDs(array($phid));
 
-    return $this->newObjectFromQuery($query);
+    return $this->newObjectFromQuery($query, $capabilities);
   }
 
 
@@ -629,6 +635,9 @@
         );
         $use_default = true;
         break;
+      case 'parameters':
+        $use_default = true;
+        break;
       default:
         break;
     }
@@ -769,11 +778,43 @@
       }
     } else {
       if ($this->getIsCreate()) {
+        $template = $request->getStr('template');
+
+        if (strlen($template)) {
+          $template_object = $this->newObjectFromIdentifier(
+            $template,
+            array(
+              PhabricatorPolicyCapability::CAN_VIEW,
+            ));
+          if (!$template_object) {
+            return new Aphront404Response();
+          }
+        } else {
+          $template_object = null;
+        }
+
+        if ($template_object) {
+          $copy_fields = $this->buildEditFields($template_object);
+          $copy_fields = mpull($copy_fields, null, 'getKey');
+          foreach ($copy_fields as $copy_key => $copy_field) {
+            if (!$copy_field->getIsCopyable()) {
+              unset($copy_fields[$copy_key]);
+            }
+          }
+        } else {
+          $copy_fields = array();
+        }
+
         foreach ($fields as $field) {
           if ($field->getIsLocked() || $field->getIsHidden()) {
             continue;
           }
 
+          $field_key = $field->getKey();
+          if (isset($copy_fields[$field_key])) {
+            $field->readValueFromField($copy_fields[$field_key]);
+          }
+
           $field->readValueFromRequest($request);
         }
       }
diff --git a/src/applications/transactions/editfield/PhabricatorEditField.php b/src/applications/transactions/editfield/PhabricatorEditField.php
--- a/src/applications/transactions/editfield/PhabricatorEditField.php
+++ b/src/applications/transactions/editfield/PhabricatorEditField.php
@@ -28,6 +28,7 @@
   private $isReorderable = true;
   private $isDefaultable = true;
   private $isLockable = true;
+  private $isCopyable = false;
 
   public function setKey($key) {
     $this->key = $key;
@@ -146,6 +147,15 @@
     return $this->isHidden;
   }
 
+  public function setIsCopyable($is_copyable) {
+    $this->isCopyable = $is_copyable;
+    return $this;
+  }
+
+  public function getIsCopyable() {
+    return $this->isCopyable;
+  }
+
   public function setIsSubmittedForm($is_submitted) {
     $this->isSubmittedForm = $is_submitted;
     return $this;
@@ -366,6 +376,15 @@
     return $this->getHTTPParameterValue($request, $key);
   }
 
+  public function readValueFromField(PhabricatorEditField $other) {
+    $this->value = $this->getValueFromField($other);
+    return $this;
+  }
+
+  protected function getValueFromField(PhabricatorEditField $other) {
+    return $other->getValue();
+  }
+
 
   /**
    * Read and return the value the object had when the user first loaded the
diff --git a/src/applications/transactions/storage/PhabricatorEditEngineConfiguration.php b/src/applications/transactions/storage/PhabricatorEditEngineConfiguration.php
--- a/src/applications/transactions/storage/PhabricatorEditEngineConfiguration.php
+++ b/src/applications/transactions/storage/PhabricatorEditEngineConfiguration.php
@@ -89,12 +89,15 @@
 
   public function applyConfigurationToFields(
     PhabricatorEditEngine $engine,
+    $object,
     array $fields) {
     $fields = mpull($fields, null, 'getKey');
 
+    $is_new = !$object->getID();
+
     $values = $this->getProperty('defaults', array());
     foreach ($fields as $key => $field) {
-      if ($engine->getIsCreate()) {
+      if ($is_new) {
         if (array_key_exists($key, $values)) {
           $field->readDefaultValueFromConfiguration($values[$key]);
         }
diff --git a/src/applications/transactions/view/PhabricatorApplicationEditHTTPParameterHelpView.php b/src/applications/transactions/view/PhabricatorApplicationEditHTTPParameterHelpView.php
--- a/src/applications/transactions/view/PhabricatorApplicationEditHTTPParameterHelpView.php
+++ b/src/applications/transactions/view/PhabricatorApplicationEditHTTPParameterHelpView.php
@@ -176,6 +176,59 @@
           'wide',
         ));
 
+    $template_text = pht(<<<EOTEXT
+Template Objects
+----------------
+
+Instead of specifying each field value individually, you can specify another
+object to use as a template. Some of the initial fields will be copied from the
+template object.
+
+Specify a template object with the `template` parameter. You can use an ID,
+PHID, or monogram (for objects which have monograms). For example, you might
+use URIs like these:
+
+```
+%s?template=123
+%s?template=PHID-WXYZ-abcdef...
+%s?template=T123
+```
+
+You can combine the `template` parameter with HTTP parameters: the template
+object will be copied first, then any HTTP parameters will be read.
+
+When using `template`, these fields will be copied:
+EOTEXT
+      ,
+      $uri,
+      $uri,
+      $uri);
+
+    $yes = id(new PHUIIconView())->setIconFont('fa-check-circle green');
+    $no = id(new PHUIIconView())->setIconFont('fa-times grey');
+
+    $rows = array();
+    foreach ($fields as $field) {
+      $rows[] = array(
+        $field->getLabel(),
+        $field->getIsCopyable() ? $yes : $no,
+      );
+    }
+
+    $template_table = id(new AphrontTableView($rows))
+      ->setNoDataString(
+        pht('None of the fields on this object support templating.'))
+      ->setHeaders(
+        array(
+          pht('Field'),
+          pht('Will Copy'),
+        ))
+      ->setColumnClasses(
+        array(
+          'pri',
+          'wide',
+        ));
+
     $select_text = pht(<<<EOTEXT
 Select Fields
 -------------
@@ -243,6 +296,8 @@
       $main_table,
       $this->renderInstructions($aliases_text),
       $alias_table,
+      $this->renderInstructions($template_text),
+      $template_table,
       $this->renderInstructions($select_text),
       $select_table,
       $this->renderInstructions($types_text),
diff --git a/src/docs/user/configuration/custom_fields.diviner b/src/docs/user/configuration/custom_fields.diviner
--- a/src/docs/user/configuration/custom_fields.diviner
+++ b/src/docs/user/configuration/custom_fields.diviner
@@ -119,6 +119,8 @@
     above the control when rendered on the edit view.
   - **placeholder**: A placeholder text that appears on text boxes. Only
     supported in text, int and remarkup fields (optional).
+  - **copy**: If true, this field's value will be copied when an object is
+    created using another object as a template.
 
 The `strings` value supports different strings per control type. They are:
 
@@ -128,15 +130,6 @@
     - **search.default** Text for the search interface, defaults to "(Any)".
     - **search.require** Text for the search interface, defaults to "Require".
 
-Some applications have specific options which only work in that application.
-
-In **Maniphest**:
-
-  - **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.
-
 Internally, Phabricator implements some additional custom field types and
 options. These are not intended for general use and are subject to abrupt
 change, but are documented here for completeness:
diff --git a/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditEngineExtension.php b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditEngineExtension.php
--- a/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditEngineExtension.php
+++ b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditEngineExtension.php
@@ -35,7 +35,7 @@
 
     $field_list->setViewer($viewer);
 
-    if (!$engine->getIsCreate()) {
+    if ($object->getID()) {
       $field_list->readFieldsFromStorage($object);
     }
 
diff --git a/src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php b/src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php
--- a/src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php
+++ b/src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php
@@ -15,6 +15,7 @@
   private $fieldError;
   private $required;
   private $default;
+  private $isCopyable;
 
   abstract public function getFieldType();
 
@@ -115,6 +116,9 @@
         case 'default':
           $this->setFieldValue($value);
           break;
+        case 'copy':
+          $this->setIsCopyable($value);
+          break;
         case 'type':
           // We set this earlier on.
           break;
@@ -185,6 +189,15 @@
     return idx($this->strings, $key, $default);
   }
 
+  public function setIsCopyable($is_copyable) {
+    $this->isCopyable = $is_copyable;
+    return $this;
+  }
+
+  public function getIsCopyable() {
+    return $this->isCopyable;
+  }
+
   public function shouldUseStorage() {
     try {
       $object = $this->newStorageObject();
@@ -430,7 +443,8 @@
     $short = 'custom.'.$this->getRawStandardFieldKey();
 
     return parent::newStandardEditField()
-      ->setEditTypeKey($short);
+      ->setEditTypeKey($short)
+      ->setIsCopyable($this->getIsCopyable());
   }
 
   public function shouldAppearInConduitTransactions() {