diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 91d5a3cc7b..2040568496 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -458,6 +458,7 @@ phutil_register_library_map(array(
     'DifferentialGetWorkingCopy' => 'applications/differential/DifferentialGetWorkingCopy.php',
     'DifferentialGitSVNIDCommitMessageField' => 'applications/differential/field/DifferentialGitSVNIDCommitMessageField.php',
     'DifferentialHarbormasterField' => 'applications/differential/customfield/DifferentialHarbormasterField.php',
+    'DifferentialHeraldStateReasons' => 'applications/differential/herald/DifferentialHeraldStateReasons.php',
     'DifferentialHiddenComment' => 'applications/differential/storage/DifferentialHiddenComment.php',
     'DifferentialHostField' => 'applications/differential/customfield/DifferentialHostField.php',
     'DifferentialHovercardEngineExtension' => 'applications/differential/engineextension/DifferentialHovercardEngineExtension.php',
@@ -1328,6 +1329,7 @@ phutil_register_library_map(array(
     'HeraldApplicationActionGroup' => 'applications/herald/action/HeraldApplicationActionGroup.php',
     'HeraldApplyTranscript' => 'applications/herald/storage/transcript/HeraldApplyTranscript.php',
     'HeraldBasicFieldGroup' => 'applications/herald/field/HeraldBasicFieldGroup.php',
+    'HeraldBuildableState' => 'applications/herald/state/HeraldBuildableState.php',
     'HeraldCommitAdapter' => 'applications/diffusion/herald/HeraldCommitAdapter.php',
     'HeraldCondition' => 'applications/herald/storage/HeraldCondition.php',
     'HeraldConditionTranscript' => 'applications/herald/storage/transcript/HeraldConditionTranscript.php',
@@ -1351,6 +1353,7 @@ phutil_register_library_map(array(
     'HeraldGroup' => 'applications/herald/group/HeraldGroup.php',
     'HeraldInvalidActionException' => 'applications/herald/engine/exception/HeraldInvalidActionException.php',
     'HeraldInvalidConditionException' => 'applications/herald/engine/exception/HeraldInvalidConditionException.php',
+    'HeraldMailableState' => 'applications/herald/state/HeraldMailableState.php',
     'HeraldManageGlobalRulesCapability' => 'applications/herald/capability/HeraldManageGlobalRulesCapability.php',
     'HeraldManiphestTaskAdapter' => 'applications/maniphest/herald/HeraldManiphestTaskAdapter.php',
     'HeraldNewController' => 'applications/herald/controller/HeraldNewController.php',
@@ -1388,6 +1391,8 @@ phutil_register_library_map(array(
     'HeraldSchemaSpec' => 'applications/herald/storage/HeraldSchemaSpec.php',
     'HeraldSelectFieldValue' => 'applications/herald/value/HeraldSelectFieldValue.php',
     'HeraldSpaceField' => 'applications/spaces/herald/HeraldSpaceField.php',
+    'HeraldState' => 'applications/herald/state/HeraldState.php',
+    'HeraldStateReasons' => 'applications/herald/state/HeraldStateReasons.php',
     'HeraldSubscribersField' => 'applications/subscriptions/herald/HeraldSubscribersField.php',
     'HeraldSupportActionGroup' => 'applications/herald/action/HeraldSupportActionGroup.php',
     'HeraldSupportFieldGroup' => 'applications/herald/field/HeraldSupportFieldGroup.php',
@@ -5467,6 +5472,7 @@ phutil_register_library_map(array(
     'DifferentialGetWorkingCopy' => 'Phobject',
     'DifferentialGitSVNIDCommitMessageField' => 'DifferentialCommitMessageField',
     'DifferentialHarbormasterField' => 'DifferentialCustomField',
+    'DifferentialHeraldStateReasons' => 'HeraldStateReasons',
     'DifferentialHiddenComment' => 'DifferentialDAO',
     'DifferentialHostField' => 'DifferentialCustomField',
     'DifferentialHovercardEngineExtension' => 'PhabricatorHovercardEngineExtension',
@@ -6458,6 +6464,7 @@ phutil_register_library_map(array(
     'HeraldApplicationActionGroup' => 'HeraldActionGroup',
     'HeraldApplyTranscript' => 'Phobject',
     'HeraldBasicFieldGroup' => 'HeraldFieldGroup',
+    'HeraldBuildableState' => 'HeraldState',
     'HeraldCommitAdapter' => array(
       'HeraldAdapter',
       'HarbormasterBuildableAdapterInterface',
@@ -6487,6 +6494,7 @@ phutil_register_library_map(array(
     'HeraldGroup' => 'Phobject',
     'HeraldInvalidActionException' => 'Exception',
     'HeraldInvalidConditionException' => 'Exception',
+    'HeraldMailableState' => 'HeraldState',
     'HeraldManageGlobalRulesCapability' => 'PhabricatorPolicyCapability',
     'HeraldManiphestTaskAdapter' => 'HeraldAdapter',
     'HeraldNewController' => 'HeraldController',
@@ -6531,6 +6539,8 @@ phutil_register_library_map(array(
     'HeraldSchemaSpec' => 'PhabricatorConfigSchemaSpec',
     'HeraldSelectFieldValue' => 'HeraldFieldValue',
     'HeraldSpaceField' => 'HeraldField',
+    'HeraldState' => 'Phobject',
+    'HeraldStateReasons' => 'Phobject',
     'HeraldSubscribersField' => 'HeraldField',
     'HeraldSupportActionGroup' => 'HeraldActionGroup',
     'HeraldSupportFieldGroup' => 'HeraldFieldGroup',
diff --git a/src/applications/differential/editor/DifferentialTransactionEditor.php b/src/applications/differential/editor/DifferentialTransactionEditor.php
index 5e013eff43..9ab30c3f06 100644
--- a/src/applications/differential/editor/DifferentialTransactionEditor.php
+++ b/src/applications/differential/editor/DifferentialTransactionEditor.php
@@ -1003,26 +1003,7 @@ final class DifferentialTransactionEditor
   protected function shouldApplyHeraldRules(
     PhabricatorLiskDAO $object,
     array $xactions) {
-
-    if ($this->getIsNewObject()) {
-      return true;
-    }
-
-    foreach ($xactions as $xaction) {
-      switch ($xaction->getTransactionType()) {
-        case DifferentialTransaction::TYPE_UPDATE:
-          if (!$this->getIsCloseByCommit()) {
-            return true;
-          }
-          break;
-        case DifferentialRevisionCommandeerTransaction::TRANSACTIONTYPE:
-          // When users commandeer revisions, we may need to trigger
-          // signatures or author-based rules.
-          return true;
-      }
-    }
-
-    return parent::shouldApplyHeraldRules($object, $xactions);
+    return true;
   }
 
   protected function didApplyHeraldRules(
@@ -1211,6 +1192,33 @@ final class DifferentialTransactionEditor
       $revision,
       $revision->getActiveDiff());
 
+    // If the object is still a draft, prevent "Send me an email" and other
+    // similar rules from acting yet.
+    if (!$object->shouldBroadcast()) {
+      $adapter->setForbiddenAction(
+        HeraldMailableState::STATECONST,
+        DifferentialHeraldStateReasons::REASON_DRAFT);
+    }
+
+    // If this edit didn't actually change the diff (for example, a user
+    // edited the title or changed subscribers), prevent "Run build plan"
+    // and other similar rules from acting yet, since the build results will
+    // not (or, at least, should not) change unless the actual source changes.
+    $has_update = false;
+    $type_update = DifferentialTransaction::TYPE_UPDATE;
+    foreach ($xactions as $xaction) {
+      if ($xaction->getTransactionType() == $type_update) {
+        $has_update = true;
+        break;
+      }
+    }
+
+    if (!$has_update) {
+      $adapter->setForbiddenAction(
+        HeraldBuildableState::STATECONST,
+        DifferentialHeraldStateReasons::REASON_UNCHANGED);
+    }
+
     return $adapter;
   }
 
diff --git a/src/applications/differential/herald/DifferentialHeraldStateReasons.php b/src/applications/differential/herald/DifferentialHeraldStateReasons.php
new file mode 100644
index 0000000000..d3259560d5
--- /dev/null
+++ b/src/applications/differential/herald/DifferentialHeraldStateReasons.php
@@ -0,0 +1,22 @@
+<?php
+
+final class DifferentialHeraldStateReasons
+  extends HeraldStateReasons {
+
+  const REASON_DRAFT = 'differential.draft';
+  const REASON_UNCHANGED = 'differential.unchanged';
+
+  public function explainReason($reason) {
+    $reasons = array(
+      self::REASON_DRAFT => pht(
+        'This revision is still an unsubmitted draft, so mail will not '.
+        'be sent yet.'),
+      self::REASON_UNCHANGED => pht(
+        'The update which triggered Herald did not update the diff for '.
+        'this revision, so builds will not run.'),
+    );
+
+    return idx($reasons, $reason);
+  }
+
+}
diff --git a/src/applications/harbormaster/herald/HarbormasterRunBuildPlansHeraldAction.php b/src/applications/harbormaster/herald/HarbormasterRunBuildPlansHeraldAction.php
index 76bdf9ccc3..8c718e5f5d 100644
--- a/src/applications/harbormaster/herald/HarbormasterRunBuildPlansHeraldAction.php
+++ b/src/applications/harbormaster/herald/HarbormasterRunBuildPlansHeraldAction.php
@@ -7,6 +7,12 @@ final class HarbormasterRunBuildPlansHeraldAction
 
   const ACTIONCONST = 'harbormaster.build';
 
+  public function getRequiredAdapterStates() {
+    return array(
+      HeraldBuildableState::STATECONST,
+    );
+  }
+
   public function getActionGroupKey() {
     return HeraldSupportActionGroup::ACTIONGROUPKEY;
   }
diff --git a/src/applications/herald/action/HeraldAction.php b/src/applications/herald/action/HeraldAction.php
index 091f3e9bc2..a2d589f9f2 100644
--- a/src/applications/herald/action/HeraldAction.php
+++ b/src/applications/herald/action/HeraldAction.php
@@ -17,6 +17,7 @@ abstract class HeraldAction extends Phobject {
   const DO_STANDARD_PERMISSION = 'do.standard.permission';
   const DO_STANDARD_INVALID_ACTION = 'do.standard.invalid-action';
   const DO_STANDARD_WRONG_RULE_TYPE = 'do.standard.wrong-rule-type';
+  const DO_STANDARD_FORBIDDEN = 'do.standard.forbidden';
 
   abstract public function getHeraldActionName();
   abstract public function supportsObject($object);
@@ -25,6 +26,10 @@ abstract class HeraldAction extends Phobject {
 
   abstract public function renderActionDescription($value);
 
+  public function getRequiredAdapterStates() {
+    return array();
+  }
+
   protected function renderActionEffectDescription($type, $data) {
     return null;
   }
@@ -336,6 +341,11 @@ abstract class HeraldAction extends Phobject {
         'color' => 'red',
         'name' => pht('Wrong Rule Type'),
       ),
+      self::DO_STANDARD_FORBIDDEN => array(
+        'icon' => 'fa-ban',
+        'color' => 'violet',
+        'name' => pht('Forbidden'),
+      ),
     );
   }
 
@@ -381,6 +391,8 @@ abstract class HeraldAction extends Phobject {
         return pht(
           'This action does not support rules of type "%s".',
           $data);
+      case self::DO_STANDARD_FORBIDDEN:
+        return HeraldStateReasons::getExplanation($data);
     }
 
     return null;
diff --git a/src/applications/herald/adapter/HeraldAdapter.php b/src/applications/herald/adapter/HeraldAdapter.php
index 78ce862945..1c50c0b5ee 100644
--- a/src/applications/herald/adapter/HeraldAdapter.php
+++ b/src/applications/herald/adapter/HeraldAdapter.php
@@ -37,6 +37,7 @@ abstract class HeraldAdapter extends Phobject {
   private $fieldMap;
   private $actionMap;
   private $edgeCache = array();
+  private $forbiddenActions = array();
 
   public function getEmailPHIDs() {
     return array_values($this->emailPHIDs);
@@ -1116,4 +1117,38 @@ abstract class HeraldAdapter extends Phobject {
     return $this->edgeCache[$type];
   }
 
+
+/* -(  Forbidden Actions  )-------------------------------------------------- */
+
+
+  final public function getForbiddenActions() {
+    return array_keys($this->forbiddenActions);
+  }
+
+  final public function setForbiddenAction($action, $reason) {
+    $this->forbiddenActions[$action] = $reason;
+    return $this;
+  }
+
+  final public function getRequiredFieldStates($field_key) {
+    return $this->requireFieldImplementation($field_key)
+      ->getRequiredAdapterStates();
+  }
+
+  final public function getRequiredActionStates($action_key) {
+    return $this->requireActionImplementation($action_key)
+      ->getRequiredAdapterStates();
+  }
+
+  final public function getForbiddenReason($action) {
+    if (!isset($this->forbiddenActions[$action])) {
+      throw new Exception(
+        pht(
+          'Action "%s" is not forbidden!',
+          $action));
+    }
+
+    return $this->forbiddenActions[$action];
+  }
+
 }
diff --git a/src/applications/herald/controller/HeraldTranscriptController.php b/src/applications/herald/controller/HeraldTranscriptController.php
index a9509beb33..dc7ca676e3 100644
--- a/src/applications/herald/controller/HeraldTranscriptController.php
+++ b/src/applications/herald/controller/HeraldTranscriptController.php
@@ -273,7 +273,11 @@ final class HeraldTranscriptController extends HeraldController {
           ->setTarget(phutil_tag('strong', array(), pht('Conditions'))));
 
       foreach ($cond_xscripts as $cond_xscript) {
-        if ($cond_xscript->getResult()) {
+        if ($cond_xscript->isForbidden()) {
+          $icon = 'fa-ban';
+          $color = 'indigo';
+          $result = pht('Forbidden');
+        } else if ($cond_xscript->getResult()) {
           $icon = 'fa-check';
           $color = 'green';
           $result = pht('Passed');
@@ -284,12 +288,17 @@ final class HeraldTranscriptController extends HeraldController {
         }
 
         if ($cond_xscript->getNote()) {
+          $note_text = $cond_xscript->getNote();
+          if ($cond_xscript->isForbidden()) {
+            $note_text = HeraldStateReasons::getExplanation($note_text);
+          }
+
           $note = phutil_tag(
             'div',
             array(
               'class' => 'herald-condition-note',
             ),
-            $cond_xscript->getNote());
+            $note_text);
         } else {
           $note = null;
         }
@@ -310,7 +319,12 @@ final class HeraldTranscriptController extends HeraldController {
         $cond_list->addItem($cond_item);
       }
 
-      if ($rule_xscript->getResult()) {
+      if ($rule_xscript->isForbidden()) {
+        $last_icon = 'fa-ban';
+        $last_color = 'indigo';
+        $last_result = pht('Forbidden');
+        $last_note = pht('Object state prevented rule evaluation.');
+      } else if ($rule_xscript->getResult()) {
         $last_icon = 'fa-check-circle';
         $last_color = 'green';
         $last_result = pht('Passed');
diff --git a/src/applications/herald/engine/HeraldEngine.php b/src/applications/herald/engine/HeraldEngine.php
index df81117b80..b8e1db5626 100644
--- a/src/applications/herald/engine/HeraldEngine.php
+++ b/src/applications/herald/engine/HeraldEngine.php
@@ -12,6 +12,9 @@ final class HeraldEngine extends Phobject {
   protected $object;
   private $dryRun;
 
+  private $forbiddenFields = array();
+  private $forbiddenActions = array();
+
   public function setDryRun($dry_run) {
     $this->dryRun = $dry_run;
     return $this;
@@ -76,39 +79,42 @@ final class HeraldEngine extends Phobject {
           // This is not a dry run, and this rule is only supposed to be
           // applied a single time, and it's already been applied...
           // That means automatic failure.
-          $xscript = id(new HeraldRuleTranscript())
-            ->setRuleID($rule->getID())
+          $this->newRuleTranscript($rule)
             ->setResult(false)
-            ->setRuleName($rule->getName())
-            ->setRuleOwner($rule->getAuthorPHID())
             ->setReason(
               pht(
                 'This rule is only supposed to be repeated a single time, '.
                 'and it has already been applied.'));
-          $this->transcript->addRuleTranscript($xscript);
+
           $rule_matches = false;
         } else {
-          $rule_matches = $this->doesRuleMatch($rule, $object);
+          if ($this->isForbidden($rule, $object)) {
+            $this->newRuleTranscript($rule)
+              ->setResult(HeraldRuleTranscript::RESULT_FORBIDDEN)
+              ->setReason(
+                pht(
+                  'Object state is not compatible with rule.'));
+
+            $rule_matches = false;
+          } else {
+            $rule_matches = $this->doesRuleMatch($rule, $object);
+          }
         }
       } catch (HeraldRecursiveConditionsException $ex) {
         $names = array();
-        foreach ($this->stack as $rule_id => $ignored) {
-          $names[] = '"'.$rules[$rule_id]->getName().'"';
+        foreach ($this->stack as $rule_phid => $ignored) {
+          $names[] = '"'.$rules[$rule_phid]->getName().'"';
         }
         $names = implode(', ', $names);
-        foreach ($this->stack as $rule_id => $ignored) {
-          $xscript = new HeraldRuleTranscript();
-          $xscript->setRuleID($rule_id);
-          $xscript->setResult(false);
-          $xscript->setReason(
-            pht(
-              "Rules %s are recursively dependent upon one another! ".
-              "Don't do this! You have formed an unresolvable cycle in the ".
-              "dependency graph!",
-              $names));
-          $xscript->setRuleName($rules[$rule_id]->getName());
-          $xscript->setRuleOwner($rules[$rule_id]->getAuthorPHID());
-          $this->transcript->addRuleTranscript($xscript);
+        foreach ($this->stack as $rule_phid => $ignored) {
+          $this->newRuleTranscript($rules[$rule_phid])
+            ->setResult(false)
+            ->setReason(
+              pht(
+                "Rules %s are recursively dependent upon one another! ".
+                "Don't do this! You have formed an unresolvable cycle in the ".
+                "dependency graph!",
+                $names));
         }
         $rule_matches = false;
       }
@@ -309,14 +315,9 @@ final class HeraldEngine extends Phobject {
       }
     }
 
-    $rule_transcript = new HeraldRuleTranscript();
-    $rule_transcript->setRuleID($rule->getID());
-    $rule_transcript->setResult($result);
-    $rule_transcript->setReason($reason);
-    $rule_transcript->setRuleName($rule->getName());
-    $rule_transcript->setRuleOwner($rule->getAuthorPHID());
-
-    $this->transcript->addRuleTranscript($rule_transcript);
+    $this->newRuleTranscript($rule)
+      ->setResult($result)
+      ->setReason($reason);
 
     return $result;
   }
@@ -327,16 +328,7 @@ final class HeraldEngine extends Phobject {
     HeraldAdapter $object) {
 
     $object_value = $this->getConditionObjectValue($condition, $object);
-    $test_value   = $condition->getValue();
-
-    $cond = $condition->getFieldCondition();
-
-    $transcript = new HeraldConditionTranscript();
-    $transcript->setRuleID($rule->getID());
-    $transcript->setConditionID($condition->getID());
-    $transcript->setFieldName($condition->getFieldName());
-    $transcript->setCondition($cond);
-    $transcript->setTestValue($test_value);
+    $transcript = $this->newConditionTranscript($rule, $condition);
 
     try {
       $result = $object->doesConditionMatch(
@@ -351,8 +343,6 @@ final class HeraldEngine extends Phobject {
 
     $transcript->setResult($result);
 
-    $this->transcript->addConditionTranscript($transcript);
-
     return $result;
   }
 
@@ -446,4 +436,136 @@ final class HeraldEngine extends Phobject {
     return false;
   }
 
+  private function newRuleTranscript(HeraldRule $rule) {
+    $xscript = id(new HeraldRuleTranscript())
+      ->setRuleID($rule->getID())
+      ->setRuleName($rule->getName())
+      ->setRuleOwner($rule->getAuthorPHID());
+
+    $this->transcript->addRuleTranscript($xscript);
+
+    return $xscript;
+  }
+
+  private function newConditionTranscript(
+    HeraldRule $rule,
+    HeraldCondition $condition) {
+
+    $xscript = id(new HeraldConditionTranscript())
+      ->setRuleID($rule->getID())
+      ->setConditionID($condition->getID())
+      ->setFieldName($condition->getFieldName())
+      ->setCondition($condition->getFieldCondition())
+      ->setTestValue($condition->getValue());
+
+    $this->transcript->addConditionTranscript($xscript);
+
+    return $xscript;
+  }
+
+  private function newApplyTranscript(
+    HeraldAdapter $adapter,
+    HeraldRule $rule,
+    HeraldActionRecord $action) {
+
+    $effect = id(new HeraldEffect())
+      ->setObjectPHID($adapter->getPHID())
+      ->setAction($action->getAction())
+      ->setTarget($action->getTarget())
+      ->setRule($rule);
+
+    $xscript = new HeraldApplyTranscript($effect, false);
+
+    $this->transcript->addApplyTranscript($xscript);
+
+    return $xscript;
+  }
+
+  private function isForbidden(
+    HeraldRule $rule,
+    HeraldAdapter $adapter) {
+
+    $forbidden = $adapter->getForbiddenActions();
+    if (!$forbidden) {
+      return false;
+    }
+
+    $forbidden = array_fuse($forbidden);
+
+    $is_forbidden = false;
+
+    foreach ($rule->getConditions() as $condition) {
+      $field_key = $condition->getFieldName();
+
+      if (!isset($this->forbiddenFields[$field_key])) {
+        $reason = null;
+
+        try {
+          $states = $adapter->getRequiredFieldStates($field_key);
+        } catch (Exception $ex) {
+          $states = array();
+        }
+
+        foreach ($states as $state) {
+          if (!isset($forbidden[$state])) {
+            continue;
+          }
+          $reason = $adapter->getForbiddenReason($state);
+          break;
+        }
+
+        $this->forbiddenFields[$field_key] = $reason;
+      }
+
+      $forbidden_reason = $this->forbiddenFields[$field_key];
+      if ($forbidden_reason !== null) {
+        $this->newConditionTranscript($rule, $condition)
+          ->setResult(HeraldConditionTranscript::RESULT_FORBIDDEN)
+          ->setNote($forbidden_reason);
+
+        $is_forbidden = true;
+      }
+    }
+
+    foreach ($rule->getActions() as $action_record) {
+      $action_key = $action_record->getAction();
+
+      if (!isset($this->forbiddenActions[$action_key])) {
+        $reason = null;
+
+        try {
+          $states = $adapter->getRequiredActionStates($action_key);
+        } catch (Exception $ex) {
+          $states = array();
+        }
+
+        foreach ($states as $state) {
+          if (!isset($forbidden[$state])) {
+            continue;
+          }
+          $reason = $adapter->getForbiddenReason($state);
+          break;
+        }
+
+        $this->forbiddenActions[$action_key] = $reason;
+      }
+
+      $forbidden_reason = $this->forbiddenActions[$action_key];
+      if ($forbidden_reason !== null) {
+        $this->newApplyTranscript($adapter, $rule, $action_record)
+          ->setAppliedReason(
+            array(
+              array(
+                'type' => HeraldAction::DO_STANDARD_FORBIDDEN,
+                'data' => $forbidden_reason,
+              ),
+            ));
+
+        $is_forbidden = true;
+      }
+    }
+
+    return $is_forbidden;
+  }
+
 }
diff --git a/src/applications/herald/field/HeraldField.php b/src/applications/herald/field/HeraldField.php
index 2abed0ff1d..408a76f7fb 100644
--- a/src/applications/herald/field/HeraldField.php
+++ b/src/applications/herald/field/HeraldField.php
@@ -20,6 +20,10 @@ abstract class HeraldField extends Phobject {
     return null;
   }
 
+  public function getRequiredAdapterStates() {
+    return array();
+  }
+
   protected function getHeraldFieldStandardType() {
     throw new PhutilMethodNotImplementedException();
   }
diff --git a/src/applications/herald/state/HeraldBuildableState.php b/src/applications/herald/state/HeraldBuildableState.php
new file mode 100644
index 0000000000..d19ae87c36
--- /dev/null
+++ b/src/applications/herald/state/HeraldBuildableState.php
@@ -0,0 +1,7 @@
+<?php
+
+final class HeraldBuildableState extends HeraldState {
+
+  const STATECONST = 'buildable';
+
+}
diff --git a/src/applications/herald/state/HeraldMailableState.php b/src/applications/herald/state/HeraldMailableState.php
new file mode 100644
index 0000000000..78f0600f00
--- /dev/null
+++ b/src/applications/herald/state/HeraldMailableState.php
@@ -0,0 +1,7 @@
+<?php
+
+final class HeraldMailableState extends HeraldState {
+
+  const STATECONST = 'mailable';
+
+}
diff --git a/src/applications/herald/state/HeraldState.php b/src/applications/herald/state/HeraldState.php
new file mode 100644
index 0000000000..9d11f8bcb6
--- /dev/null
+++ b/src/applications/herald/state/HeraldState.php
@@ -0,0 +1,3 @@
+<?php
+
+abstract class HeraldState extends Phobject {}
diff --git a/src/applications/herald/state/HeraldStateReasons.php b/src/applications/herald/state/HeraldStateReasons.php
new file mode 100644
index 0000000000..d85e8b713f
--- /dev/null
+++ b/src/applications/herald/state/HeraldStateReasons.php
@@ -0,0 +1,26 @@
+<?php
+
+abstract class HeraldStateReasons extends Phobject {
+
+  abstract public function explainReason($reason);
+
+  final public static function getAllReasons() {
+    return id(new PhutilClassMapQuery())
+      ->setAncestorClass(__CLASS__)
+      ->execute();
+  }
+
+  final public static function getExplanation($reason) {
+    $reasons = self::getAllReasons();
+
+    foreach ($reasons as $reason_implementation) {
+      $explanation = $reason_implementation->explainReason($reason);
+      if ($explanation !== null) {
+        return $explanation;
+      }
+    }
+
+    return pht('Unknown reason ("%s").', $reason);
+  }
+
+}
diff --git a/src/applications/herald/storage/transcript/HeraldConditionTranscript.php b/src/applications/herald/storage/transcript/HeraldConditionTranscript.php
index 36a534e6b0..a7096b6880 100644
--- a/src/applications/herald/storage/transcript/HeraldConditionTranscript.php
+++ b/src/applications/herald/storage/transcript/HeraldConditionTranscript.php
@@ -10,6 +10,8 @@ final class HeraldConditionTranscript extends Phobject {
   protected $note;
   protected $result;
 
+  const RESULT_FORBIDDEN = 'forbidden';
+
   public function setRuleID($rule_id) {
     $this->ruleID = $rule_id;
     return $this;
@@ -72,4 +74,9 @@ final class HeraldConditionTranscript extends Phobject {
   public function getResult() {
     return $this->result;
   }
+
+  public function isForbidden() {
+    return ($this->getResult() === self::RESULT_FORBIDDEN);
+  }
+
 }
diff --git a/src/applications/herald/storage/transcript/HeraldRuleTranscript.php b/src/applications/herald/storage/transcript/HeraldRuleTranscript.php
index d12f1f9dd9..8928a74cf6 100644
--- a/src/applications/herald/storage/transcript/HeraldRuleTranscript.php
+++ b/src/applications/herald/storage/transcript/HeraldRuleTranscript.php
@@ -9,6 +9,12 @@ final class HeraldRuleTranscript extends Phobject {
   protected $ruleName;
   protected $ruleOwner;
 
+  const RESULT_FORBIDDEN = 'forbidden';
+
+  public function isForbidden() {
+    return ($this->getResult() === self::RESULT_FORBIDDEN);
+  }
+
   public function setResult($result) {
     $this->result = $result;
     return $this;
diff --git a/src/applications/metamta/herald/PhabricatorMetaMTAEmailHeraldAction.php b/src/applications/metamta/herald/PhabricatorMetaMTAEmailHeraldAction.php
index 2b29fe2443..74fb879fe7 100644
--- a/src/applications/metamta/herald/PhabricatorMetaMTAEmailHeraldAction.php
+++ b/src/applications/metamta/herald/PhabricatorMetaMTAEmailHeraldAction.php
@@ -6,6 +6,12 @@ abstract class PhabricatorMetaMTAEmailHeraldAction
   const DO_SEND = 'do.send';
   const DO_FORCE = 'do.force';
 
+  public function getRequiredAdapterStates() {
+    return array(
+      HeraldMailableState::STATECONST,
+    );
+  }
+
   public function supportsObject($object) {
     // NOTE: This implementation lacks generality, but there's no great way to
     // figure out if something generates email right now.