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
@@ -1430,6 +1430,8 @@
     'HarbormasterBuildStep' => 'applications/harbormaster/storage/configuration/HarbormasterBuildStep.php',
     'HarbormasterBuildStepCoreCustomField' => 'applications/harbormaster/customfield/HarbormasterBuildStepCoreCustomField.php',
     'HarbormasterBuildStepCustomField' => 'applications/harbormaster/customfield/HarbormasterBuildStepCustomField.php',
+    'HarbormasterBuildStepEditAPIMethod' => 'applications/harbormaster/conduit/HarbormasterBuildStepEditAPIMethod.php',
+    'HarbormasterBuildStepEditEngine' => 'applications/harbormaster/editor/HarbormasterBuildStepEditEngine.php',
     'HarbormasterBuildStepEditor' => 'applications/harbormaster/editor/HarbormasterBuildStepEditor.php',
     'HarbormasterBuildStepGroup' => 'applications/harbormaster/stepgroup/HarbormasterBuildStepGroup.php',
     'HarbormasterBuildStepImplementation' => 'applications/harbormaster/step/HarbormasterBuildStepImplementation.php',
@@ -7636,6 +7638,8 @@
       'PhabricatorStandardCustomFieldInterface',
     ),
     'HarbormasterBuildStepCustomField' => 'PhabricatorCustomField',
+    'HarbormasterBuildStepEditAPIMethod' => 'PhabricatorEditEngineAPIMethod',
+    'HarbormasterBuildStepEditEngine' => 'PhabricatorEditEngine',
     'HarbormasterBuildStepEditor' => 'PhabricatorApplicationTransactionEditor',
     'HarbormasterBuildStepGroup' => 'Phobject',
     'HarbormasterBuildStepImplementation' => 'Phobject',
diff --git a/src/applications/harbormaster/conduit/HarbormasterBuildStepEditAPIMethod.php b/src/applications/harbormaster/conduit/HarbormasterBuildStepEditAPIMethod.php
new file mode 100644
--- /dev/null
+++ b/src/applications/harbormaster/conduit/HarbormasterBuildStepEditAPIMethod.php
@@ -0,0 +1,20 @@
+<?php
+
+final class HarbormasterBuildStepEditAPIMethod
+  extends PhabricatorEditEngineAPIMethod {
+
+  public function getAPIMethodName() {
+    return 'harbormaster.step.edit';
+  }
+
+  public function newEditEngine() {
+    return new HarbormasterBuildStepEditEngine();
+  }
+
+  public function getMethodSummary() {
+    return pht(
+      'Apply transactions to create a new build step or edit an existing '.
+      'one.');
+  }
+
+}
diff --git a/src/applications/harbormaster/editor/HarbormasterBuildStepEditEngine.php b/src/applications/harbormaster/editor/HarbormasterBuildStepEditEngine.php
new file mode 100644
--- /dev/null
+++ b/src/applications/harbormaster/editor/HarbormasterBuildStepEditEngine.php
@@ -0,0 +1,107 @@
+<?php
+
+final class HarbormasterBuildStepEditEngine
+  extends PhabricatorEditEngine {
+
+  const ENGINECONST = 'harbormaster.buildstep';
+
+  private $buildPlan;
+
+  public function setBuildPlan(HarbormasterBuildPlan $build_plan) {
+    $this->buildPlan = $build_plan;
+    return $this;
+  }
+
+  public function getBuildPlan() {
+    if ($this->buildPlan === null) {
+      throw new PhutilInvalidStateException('setBuildPlan');
+    }
+
+    return $this->buildPlan;
+  }
+
+  public function isEngineConfigurable() {
+    return false;
+  }
+
+  public function getEngineName() {
+    return pht('Harbormaster Build Steps');
+  }
+
+  public function getSummaryHeader() {
+    return pht('Edit Harbormaster Build Step Configurations');
+  }
+
+  public function getSummaryText() {
+    return pht('This engine is used to edit Harbormaster build steps.');
+  }
+
+  public function getEngineApplicationClass() {
+    return 'PhabricatorHarbormasterApplication';
+  }
+
+  protected function newEditableObject() {
+    $viewer = $this->getViewer();
+
+
+    $plan = HarbormasterBuildPlan::initializeNewBuildPlan($viewer);
+    $this->setBuildPlan($plan);
+
+    $plan = $this->getBuildPlan();
+
+    $step = HarbormasterBuildStep::initializeNewStep($viewer);
+
+    $step->setBuildPlanPHID($plan->getPHID());
+    $step->attachBuildPlan($plan);
+
+    return $step;
+  }
+
+  protected function newObjectQuery() {
+    return new HarbormasterBuildStepQuery();
+  }
+
+  protected function getObjectCreateTitleText($object) {
+    return pht('Create Build Step');
+  }
+
+  protected function getObjectCreateButtonText($object) {
+    return pht('Create Build Step');
+  }
+
+  protected function getObjectEditTitleText($object) {
+    return pht('Edit Build Step: %s', $object->getName());
+  }
+
+  protected function getObjectEditShortText($object) {
+    return pht('Edit Build Step');
+  }
+
+  protected function getObjectCreateShortText() {
+    return pht('Create Build Step');
+  }
+
+  protected function getObjectName() {
+    return pht('Build Step');
+  }
+
+  protected function getEditorURI() {
+    return '/harbormaster/step/edit/';
+  }
+
+  protected function getObjectCreateCancelURI($object) {
+    return '/harbormaster/step/';
+  }
+
+  protected function getObjectViewURI($object) {
+    $id = $object->getID();
+    return "/harbormaster/step/{$id}/";
+  }
+
+  protected function buildCustomEditFields($object) {
+    $fields = array();
+
+    return $fields;
+  }
+
+}