diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1260,6 +1260,8 @@
     'ManiphestDefaultEditCapability' => 'applications/maniphest/capability/ManiphestDefaultEditCapability.php',
     'ManiphestDefaultViewCapability' => 'applications/maniphest/capability/ManiphestDefaultViewCapability.php',
     'ManiphestEditAssignCapability' => 'applications/maniphest/capability/ManiphestEditAssignCapability.php',
+    'ManiphestEditConduitAPIMethod' => 'applications/maniphest/conduit/ManiphestEditConduitAPIMethod.php',
+    'ManiphestEditEngine' => 'applications/maniphest/editor/ManiphestEditEngine.php',
     'ManiphestEditPoliciesCapability' => 'applications/maniphest/capability/ManiphestEditPoliciesCapability.php',
     'ManiphestEditPriorityCapability' => 'applications/maniphest/capability/ManiphestEditPriorityCapability.php',
     'ManiphestEditProjectsCapability' => 'applications/maniphest/capability/ManiphestEditProjectsCapability.php',
@@ -1299,6 +1301,7 @@
     'ManiphestTaskDetailController' => 'applications/maniphest/controller/ManiphestTaskDetailController.php',
     'ManiphestTaskEditBulkJobType' => 'applications/maniphest/bulk/ManiphestTaskEditBulkJobType.php',
     'ManiphestTaskEditController' => 'applications/maniphest/controller/ManiphestTaskEditController.php',
+    'ManiphestTaskEditProController' => 'applications/maniphest/controller/ManiphestTaskEditProController.php',
     'ManiphestTaskHasCommitEdgeType' => 'applications/maniphest/edge/ManiphestTaskHasCommitEdgeType.php',
     'ManiphestTaskHasMockEdgeType' => 'applications/maniphest/edge/ManiphestTaskHasMockEdgeType.php',
     'ManiphestTaskHasRevisionEdgeType' => 'applications/maniphest/edge/ManiphestTaskHasRevisionEdgeType.php',
@@ -5235,6 +5238,8 @@
     'ManiphestDefaultEditCapability' => 'PhabricatorPolicyCapability',
     'ManiphestDefaultViewCapability' => 'PhabricatorPolicyCapability',
     'ManiphestEditAssignCapability' => 'PhabricatorPolicyCapability',
+    'ManiphestEditConduitAPIMethod' => 'PhabricatorEditEngineAPIMethod',
+    'ManiphestEditEngine' => 'PhabricatorEditEngine',
     'ManiphestEditPoliciesCapability' => 'PhabricatorPolicyCapability',
     'ManiphestEditPriorityCapability' => 'PhabricatorPolicyCapability',
     'ManiphestEditProjectsCapability' => 'PhabricatorPolicyCapability',
@@ -5288,6 +5293,7 @@
     'ManiphestTaskDetailController' => 'ManiphestController',
     'ManiphestTaskEditBulkJobType' => 'PhabricatorWorkerBulkJobType',
     'ManiphestTaskEditController' => 'ManiphestController',
+    'ManiphestTaskEditProController' => 'ManiphestController',
     'ManiphestTaskHasCommitEdgeType' => 'PhabricatorEdgeType',
     'ManiphestTaskHasMockEdgeType' => 'PhabricatorEdgeType',
     'ManiphestTaskHasRevisionEdgeType' => 'PhabricatorEdgeType',
diff --git a/src/applications/maniphest/application/PhabricatorManiphestApplication.php b/src/applications/maniphest/application/PhabricatorManiphestApplication.php
--- a/src/applications/maniphest/application/PhabricatorManiphestApplication.php
+++ b/src/applications/maniphest/application/PhabricatorManiphestApplication.php
@@ -69,6 +69,8 @@
         ),
         'export/(?P<key>[^/]+)/' => 'ManiphestExportController',
         'subpriority/' => 'ManiphestSubpriorityController',
+        $this->getEditRoutePattern('editpro/')
+          => 'ManiphestTaskEditProController',
       ),
     );
   }
diff --git a/src/applications/maniphest/conduit/ManiphestEditConduitAPIMethod.php b/src/applications/maniphest/conduit/ManiphestEditConduitAPIMethod.php
new file mode 100644
--- /dev/null
+++ b/src/applications/maniphest/conduit/ManiphestEditConduitAPIMethod.php
@@ -0,0 +1,19 @@
+<?php
+
+final class ManiphestEditConduitAPIMethod
+  extends PhabricatorEditEngineAPIMethod {
+
+  public function getAPIMethodName() {
+    return 'maniphest.edit';
+  }
+
+  public function newEditEngine() {
+    return new ManiphestEditEngine();
+  }
+
+  public function getMethodSummary() {
+    return pht(
+      'Apply transactions to create a new task or edit an existing one.');
+  }
+
+}
diff --git a/src/applications/maniphest/controller/ManiphestTaskEditProController.php b/src/applications/maniphest/controller/ManiphestTaskEditProController.php
new file mode 100644
--- /dev/null
+++ b/src/applications/maniphest/controller/ManiphestTaskEditProController.php
@@ -0,0 +1,11 @@
+<?php
+
+final class ManiphestTaskEditProController extends ManiphestController {
+
+  public function handleRequest(AphrontRequest $request) {
+    return id(new ManiphestEditEngine())
+      ->setController($this)
+      ->buildResponse();
+  }
+
+}
diff --git a/src/applications/maniphest/editor/ManiphestEditEngine.php b/src/applications/maniphest/editor/ManiphestEditEngine.php
new file mode 100644
--- /dev/null
+++ b/src/applications/maniphest/editor/ManiphestEditEngine.php
@@ -0,0 +1,113 @@
+<?php
+
+final class ManiphestEditEngine
+  extends PhabricatorEditEngine {
+
+  const ENGINECONST = 'maniphest.task';
+
+  public function getEngineName() {
+    return pht('Maniphest Tasks');
+  }
+
+  public function getEngineApplicationClass() {
+    return 'PhabricatorManiphestApplication';
+  }
+
+  protected function newEditableObject() {
+    return ManiphestTask::initializeNewTask($this->getViewer());
+  }
+
+  protected function newObjectQuery() {
+    return id(new ManiphestTaskQuery());
+  }
+
+  protected function getObjectCreateTitleText($object) {
+    return pht('Create New Task');
+  }
+
+  protected function getObjectEditTitleText($object) {
+    return pht('Edit %s %s', $object->getMonogram(), $object->getTitle());
+  }
+
+  protected function getObjectEditShortText($object) {
+    return $object->getMonogram();
+  }
+
+  protected function getObjectCreateShortText() {
+    return pht('Create Task');
+  }
+
+  protected function getCommentViewHeaderText($object) {
+    $is_serious = PhabricatorEnv::getEnvConfig('phabricator.serious-business');
+    if (!$is_serious) {
+      return pht('Weigh In');
+    }
+
+    return parent::getCommentViewHeaderText($object);
+  }
+
+  protected function getObjectViewURI($object) {
+    return '/'.$object->getMonogram();
+  }
+
+  protected function buildCustomEditFields($object) {
+    // See T4819.
+    $status_map = ManiphestTaskStatus::getTaskStatusMap();
+    $dup_status = ManiphestTaskStatus::getDuplicateStatus();
+    if ($object->getStatus() != $dup_status) {
+      unset($status_map[$dup_status]);
+    }
+
+    $owner_phid = $object->getOwnerPHID();
+    if ($owner_phid) {
+      $owner_value = array($owner_phid);
+    } else {
+      $owner_value = array();
+    }
+
+    $priority_map = ManiphestTaskPriority::getTaskPriorityMap();
+
+    return array(
+      id(new PhabricatorTextEditField())
+        ->setKey('title')
+        ->setLabel(pht('Title'))
+        ->setDescription(pht('Name of the paste.'))
+        ->setTransactionType(ManiphestTransaction::TYPE_TITLE)
+        ->setIsRequired(true)
+        ->setValue($object->getTitle()),
+      id(new PhabricatorSelectEditField())
+        ->setKey('status')
+        ->setLabel(pht('Status'))
+        ->setDescription(pht('Status of the task.'))
+        ->setTransactionType(ManiphestTransaction::TYPE_STATUS)
+        ->setValue($object->getStatus())
+        ->setOptions($status_map),
+      id(new PhabricatorUsersEditField())
+        ->setKey('assigned')
+        ->setAliases(array('assign', 'assignee'))
+        ->setLabel(pht('Assigned To'))
+        ->setDescription(pht('User who is responsible for the task.'))
+        ->setTransactionType(ManiphestTransaction::TYPE_OWNER)
+        ->setValue($owner_value),
+      id(new PhabricatorSelectEditField())
+        ->setKey('priority')
+        ->setLabel(pht('Priority'))
+        ->setDescription(pht('Priority of the task.'))
+        ->setTransactionType(ManiphestTransaction::TYPE_PRIORITY)
+        ->setValue($object->getPriority())
+        ->setOptions($priority_map),
+      id(new PhabricatorRemarkupEditField())
+        ->setKey('description')
+        ->setLabel(pht('Description'))
+        ->setDescription(pht('Task description.'))
+        ->setTransactionType(ManiphestTransaction::TYPE_DESCRIPTION)
+        ->setValue($object->getDescription()),
+    );
+  }
+
+  protected function getEditorURI() {
+    // TODO: Remove when cutting over.
+    return $this->getApplication()->getApplicationURI('editpro/');
+  }
+
+}
diff --git a/src/applications/maniphest/editor/ManiphestTransactionEditor.php b/src/applications/maniphest/editor/ManiphestTransactionEditor.php
--- a/src/applications/maniphest/editor/ManiphestTransactionEditor.php
+++ b/src/applications/maniphest/editor/ManiphestTransactionEditor.php
@@ -716,5 +716,34 @@
     return array($dst->getPriority(), $sub);
   }
 
+  protected function validateTransaction(
+    PhabricatorLiskDAO $object,
+    $type,
+    array $xactions) {
+
+    $errors = parent::validateTransaction($object, $type, $xactions);
+
+    switch ($type) {
+      case ManiphestTransaction::TYPE_TITLE:
+        $missing = $this->validateIsEmptyTextField(
+          $object->getTitle(),
+          $xactions);
+
+        if ($missing) {
+          $error = new PhabricatorApplicationTransactionValidationError(
+            $type,
+            pht('Required'),
+            pht('Task title is required.'),
+            nonempty(last($xactions), null));
+
+          $error->setIsMissingFieldError(true);
+          $errors[] = $error;
+        }
+        break;
+    }
+
+    return $errors;
+  }
+
 
 }