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
@@ -1004,6 +1004,7 @@
     'DrydockBlueprintCustomField' => 'applications/drydock/customfield/DrydockBlueprintCustomField.php',
     'DrydockBlueprintDatasource' => 'applications/drydock/typeahead/DrydockBlueprintDatasource.php',
     'DrydockBlueprintDisableController' => 'applications/drydock/controller/DrydockBlueprintDisableController.php',
+    'DrydockBlueprintEditConduitAPIMethod' => 'applications/drydock/conduit/DrydockBlueprintEditConduitAPIMethod.php',
     'DrydockBlueprintEditController' => 'applications/drydock/controller/DrydockBlueprintEditController.php',
     'DrydockBlueprintEditEngine' => 'applications/drydock/editor/DrydockBlueprintEditEngine.php',
     'DrydockBlueprintEditor' => 'applications/drydock/editor/DrydockBlueprintEditor.php',
@@ -6090,6 +6091,7 @@
     'DrydockBlueprintCustomField' => 'PhabricatorCustomField',
     'DrydockBlueprintDatasource' => 'PhabricatorTypeaheadDatasource',
     'DrydockBlueprintDisableController' => 'DrydockBlueprintController',
+    'DrydockBlueprintEditConduitAPIMethod' => 'PhabricatorEditEngineAPIMethod',
     'DrydockBlueprintEditController' => 'DrydockBlueprintController',
     'DrydockBlueprintEditEngine' => 'PhabricatorEditEngine',
     'DrydockBlueprintEditor' => 'PhabricatorApplicationTransactionEditor',
diff --git a/src/applications/drydock/conduit/DrydockBlueprintEditConduitAPIMethod.php b/src/applications/drydock/conduit/DrydockBlueprintEditConduitAPIMethod.php
new file mode 100644
--- /dev/null
+++ b/src/applications/drydock/conduit/DrydockBlueprintEditConduitAPIMethod.php
@@ -0,0 +1,20 @@
+<?php
+
+final class DrydockBlueprintEditConduitAPIMethod
+  extends PhabricatorEditEngineAPIMethod {
+
+  public function getAPIMethodName() {
+    return 'drydock.blueprint.edit';
+  }
+
+  public function newEditEngine() {
+    return new DrydockBlueprintEditEngine();
+  }
+
+  public function getMethodSummary() {
+    return pht(
+      'WARNING: Apply transactions to edit an existing blueprint. This method '.
+      'can not create new blueprints.');
+  }
+
+}
diff --git a/src/applications/drydock/editor/DrydockBlueprintEditEngine.php b/src/applications/drydock/editor/DrydockBlueprintEditEngine.php
--- a/src/applications/drydock/editor/DrydockBlueprintEditEngine.php
+++ b/src/applications/drydock/editor/DrydockBlueprintEditEngine.php
@@ -51,6 +51,17 @@
     return $blueprint;
   }
 
+  protected function newEditableObjectForDocumentation() {
+    // In order to generate the proper list of fields/transactions for a
+    // blueprint, a blueprint's type needs to be known upfront, and there's
+    // currently no way to pre-specify the type. Hardcoding an implementation
+    // here prevents the fatal on the Conduit API page and allows transactions
+    // to be edited.
+    $impl = new DrydockWorkingCopyBlueprintImplementation();
+    $this->setBlueprintImplementation($impl);
+    return $this->newEditableObject();
+  }
+
   protected function newObjectQuery() {
     return new DrydockBlueprintQuery();
   }
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
@@ -630,6 +630,15 @@
     return $this->isCreate;
   }
 
+  /**
+   * Initialize a new object for documentation creation.
+   *
+   * @return object Newly initialized object.
+   * @task load
+   */
+  protected function newEditableObjectForDocumentation() {
+    return $this->newEditableObject();
+  }
 
   /**
    * Flag this workflow as a create or edit.
@@ -2198,7 +2207,7 @@
       return array();
     }
 
-    $object = $this->newEditableObject();
+    $object = $this->newEditableObjectForDocumentation();
     $fields = $this->buildEditFields($object);
     return $this->getConduitEditTypesFromFields($fields);
   }