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
@@ -4174,16 +4174,22 @@
     'PhabricatorProjectTransactionType' => 'applications/project/xaction/PhabricatorProjectTransactionType.php',
     'PhabricatorProjectTrigger' => 'applications/project/storage/PhabricatorProjectTrigger.php',
     'PhabricatorProjectTriggerController' => 'applications/project/controller/trigger/PhabricatorProjectTriggerController.php',
+    'PhabricatorProjectTriggerCorruptionException' => 'applications/project/exception/PhabricatorProjectTriggerCorruptionException.php',
     'PhabricatorProjectTriggerEditController' => 'applications/project/controller/trigger/PhabricatorProjectTriggerEditController.php',
     'PhabricatorProjectTriggerEditor' => 'applications/project/editor/PhabricatorProjectTriggerEditor.php',
+    'PhabricatorProjectTriggerInvalidRule' => 'applications/project/trigger/PhabricatorProjectTriggerInvalidRule.php',
     'PhabricatorProjectTriggerListController' => 'applications/project/controller/trigger/PhabricatorProjectTriggerListController.php',
+    'PhabricatorProjectTriggerManiphestStatusRule' => 'applications/project/trigger/PhabricatorProjectTriggerManiphestStatusRule.php',
     'PhabricatorProjectTriggerNameTransaction' => 'applications/project/xaction/trigger/PhabricatorProjectTriggerNameTransaction.php',
     'PhabricatorProjectTriggerPHIDType' => 'applications/project/phid/PhabricatorProjectTriggerPHIDType.php',
     'PhabricatorProjectTriggerQuery' => 'applications/project/query/PhabricatorProjectTriggerQuery.php',
+    'PhabricatorProjectTriggerRule' => 'applications/project/trigger/PhabricatorProjectTriggerRule.php',
+    'PhabricatorProjectTriggerRuleRecord' => 'applications/project/trigger/PhabricatorProjectTriggerRuleRecord.php',
     'PhabricatorProjectTriggerSearchEngine' => 'applications/project/query/PhabricatorProjectTriggerSearchEngine.php',
     'PhabricatorProjectTriggerTransaction' => 'applications/project/storage/PhabricatorProjectTriggerTransaction.php',
     'PhabricatorProjectTriggerTransactionQuery' => 'applications/project/query/PhabricatorProjectTriggerTransactionQuery.php',
     'PhabricatorProjectTriggerTransactionType' => 'applications/project/xaction/trigger/PhabricatorProjectTriggerTransactionType.php',
+    'PhabricatorProjectTriggerUnknownRule' => 'applications/project/trigger/PhabricatorProjectTriggerUnknownRule.php',
     'PhabricatorProjectTriggerViewController' => 'applications/project/controller/trigger/PhabricatorProjectTriggerViewController.php',
     'PhabricatorProjectTypeTransaction' => 'applications/project/xaction/PhabricatorProjectTypeTransaction.php',
     'PhabricatorProjectUIEventListener' => 'applications/project/events/PhabricatorProjectUIEventListener.php',
@@ -10300,16 +10306,22 @@
       'PhabricatorDestructibleInterface',
     ),
     'PhabricatorProjectTriggerController' => 'PhabricatorProjectController',
+    'PhabricatorProjectTriggerCorruptionException' => 'Exception',
     'PhabricatorProjectTriggerEditController' => 'PhabricatorProjectTriggerController',
     'PhabricatorProjectTriggerEditor' => 'PhabricatorApplicationTransactionEditor',
+    'PhabricatorProjectTriggerInvalidRule' => 'PhabricatorProjectTriggerRule',
     'PhabricatorProjectTriggerListController' => 'PhabricatorProjectTriggerController',
+    'PhabricatorProjectTriggerManiphestStatusRule' => 'PhabricatorProjectTriggerRule',
     'PhabricatorProjectTriggerNameTransaction' => 'PhabricatorProjectTriggerTransactionType',
     'PhabricatorProjectTriggerPHIDType' => 'PhabricatorPHIDType',
     'PhabricatorProjectTriggerQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
+    'PhabricatorProjectTriggerRule' => 'Phobject',
+    'PhabricatorProjectTriggerRuleRecord' => 'Phobject',
     'PhabricatorProjectTriggerSearchEngine' => 'PhabricatorApplicationSearchEngine',
     'PhabricatorProjectTriggerTransaction' => 'PhabricatorModularTransaction',
     'PhabricatorProjectTriggerTransactionQuery' => 'PhabricatorApplicationTransactionQuery',
     'PhabricatorProjectTriggerTransactionType' => 'PhabricatorModularTransactionType',
+    'PhabricatorProjectTriggerUnknownRule' => 'PhabricatorProjectTriggerRule',
     'PhabricatorProjectTriggerViewController' => 'PhabricatorProjectTriggerController',
     'PhabricatorProjectTypeTransaction' => 'PhabricatorProjectTransactionType',
     'PhabricatorProjectUIEventListener' => 'PhabricatorEventListener',
diff --git a/src/applications/project/controller/PhabricatorProjectBoardViewController.php b/src/applications/project/controller/PhabricatorProjectBoardViewController.php
--- a/src/applications/project/controller/PhabricatorProjectBoardViewController.php
+++ b/src/applications/project/controller/PhabricatorProjectBoardViewController.php
@@ -1270,6 +1270,7 @@
         array(
           'items' => hsprintf('%s', $trigger_menu),
           'tip' => $trigger_tip,
+          'size' => 300,
         ));
 
     return $trigger_button;
diff --git a/src/applications/project/controller/PhabricatorProjectMoveController.php b/src/applications/project/controller/PhabricatorProjectMoveController.php
--- a/src/applications/project/controller/PhabricatorProjectMoveController.php
+++ b/src/applications/project/controller/PhabricatorProjectMoveController.php
@@ -70,6 +70,7 @@
     $columns = id(new PhabricatorProjectColumnQuery())
       ->setViewer($viewer)
       ->withProjectPHIDs(array($project->getPHID()))
+      ->needTriggers(true)
       ->execute();
 
     $columns = mpull($columns, null, 'getPHID');
@@ -110,6 +111,19 @@
       $xactions[] = $header_xaction;
     }
 
+    if ($column->canHaveTrigger()) {
+      $trigger = $column->getTrigger();
+      if ($trigger) {
+        $trigger_xactions = $trigger->newDropTransactions(
+          $viewer,
+          $column,
+          $object);
+        foreach ($trigger_xactions as $trigger_xaction) {
+          $xactions[] = $trigger_xaction;
+        }
+      }
+    }
+
     $editor = id(new ManiphestTransactionEditor())
       ->setActor($viewer)
       ->setContinueOnMissingFields(true)
diff --git a/src/applications/project/exception/PhabricatorProjectTriggerCorruptionException.php b/src/applications/project/exception/PhabricatorProjectTriggerCorruptionException.php
new file mode 100644
--- /dev/null
+++ b/src/applications/project/exception/PhabricatorProjectTriggerCorruptionException.php
@@ -0,0 +1,4 @@
+<?php
+
+final class PhabricatorProjectTriggerCorruptionException
+  extends Exception {}
diff --git a/src/applications/project/storage/PhabricatorProjectTrigger.php b/src/applications/project/storage/PhabricatorProjectTrigger.php
--- a/src/applications/project/storage/PhabricatorProjectTrigger.php
+++ b/src/applications/project/storage/PhabricatorProjectTrigger.php
@@ -11,6 +11,8 @@
   protected $ruleset = array();
   protected $editPolicy;
 
+  private $triggerRules;
+
   public static function initializeNewTrigger() {
     $default_edit = PhabricatorPolicies::POLICY_USER;
 
@@ -60,11 +62,182 @@
     return pht('Trigger %d', $this->getID());
   }
 
+  public function getTriggerRules() {
+    if ($this->triggerRules === null) {
+
+      // TODO: Temporary hard-coded rule specification.
+      $rule_specifications = array(
+        array(
+          'type' => 'status',
+          'value' => ManiphestTaskStatus::getDefaultClosedStatus(),
+        ),
+        // This is an intentionally unknown rule.
+        array(
+          'type' => 'quack',
+          'value' => 'aaa',
+        ),
+        // This is an intentionally invalid rule.
+        array(
+          'type' => 'status',
+          'value' => 'quack',
+        ),
+      );
+
+      // NOTE: We're trying to preserve the database state in the rule
+      // structure, even if it includes rule types we don't have implementations
+      // for, or rules with invalid rule values.
+
+      // If an administrator adds or removes extensions which add rules, or
+      // an upgrade affects rule validity, existing rules may become invalid.
+      // When they do, we still want the UI to reflect the ruleset state
+      // accurately and "Edit" + "Save" shouldn't destroy data unless the
+      // user explicitly modifies the ruleset.
+
+      // When we run into rules which are structured correctly but which have
+      // types we don't know about, we replace them with "Unknown Rules". If
+      // we know about the type of a rule but the value doesn't validate, we
+      // replace it with "Invalid Rules". These two rule types don't take any
+      // actions when a card is dropped into the column, but they show the user
+      // what's wrong with the ruleset and can be saved without causing any
+      // collateral damage.
+
+      $rule_map = PhabricatorProjectTriggerRule::getAllTriggerRules();
+
+      // If the stored rule data isn't a list of rules (or we encounter other
+      // fundamental structural problems, below), there isn't much we can do
+      // to try to represent the state.
+      if (!is_array($rule_specifications)) {
+        throw new PhabricatorProjectTriggerCorruptionException(
+          pht(
+            'Trigger ("%s") has a corrupt ruleset: expected a list of '.
+            'rule specifications, found "%s".',
+            $this->getPHID(),
+            phutil_describe_type($rule_specifications)));
+      }
+
+      $trigger_rules = array();
+      foreach ($rule_specifications as $key => $rule) {
+        if (!is_array($rule)) {
+          throw new PhabricatorProjectTriggerCorruptionException(
+            pht(
+              'Trigger ("%s") has a corrupt ruleset: rule (with key "%s") '.
+              'should be a rule specification, but is actually "%s".',
+              $this->getPHID(),
+              $key,
+              phutil_describe_type($rule)));
+        }
+
+        try {
+          PhutilTypeSpec::checkMap(
+            $rule,
+            array(
+              'type' => 'string',
+              'value' => 'wild',
+            ));
+        } catch (PhutilTypeCheckException $ex) {
+          throw new PhabricatorProjectTriggerCorruptionException(
+            pht(
+              'Trigger ("%s") has a corrupt ruleset: rule (with key "%s") '.
+              'is not a valid rule specification: %s',
+              $this->getPHID(),
+              $key,
+              $ex->getMessage()));
+        }
+
+        $record = id(new PhabricatorProjectTriggerRuleRecord())
+          ->setType(idx($rule, 'type'))
+          ->setValue(idx($rule, 'value'));
+
+        if (!isset($rule_map[$record->getType()])) {
+          $rule = new PhabricatorProjectTriggerUnknownRule();
+        } else {
+          $rule = clone $rule_map[$record->getType()];
+        }
+
+        try {
+          $rule->setRecord($record);
+        } catch (Exception $ex) {
+          $rule = id(new PhabricatorProjectTriggerInvalidRule())
+            ->setRecord($record);
+        }
+
+        $trigger_rules[] = $rule;
+      }
+
+      $this->triggerRules = $trigger_rules;
+    }
+
+    return $this->triggerRules;
+  }
+
   public function getRulesDescription() {
-    // TODO: Summarize the trigger rules in human-readable text.
-    return pht('Does things.');
+    $rules = $this->getTriggerRules();
+    if (!$rules) {
+      return pht('Does nothing.');
+    }
+
+    $things = array();
+
+    $count = count($rules);
+    $limit = 3;
+
+    if ($count > $limit) {
+      $show_rules = array_slice($rules, 0, ($limit - 1));
+    } else {
+      $show_rules = $rules;
+    }
+
+    foreach ($show_rules as $rule) {
+      $things[] = $rule->getDescription();
+    }
+
+    if ($count > $limit) {
+      $things[] = pht(
+        '(Applies %s more actions.)',
+        new PhutilNumber($count - $limit));
+    }
+
+    return implode("\n", $things);
   }
 
+  public function newDropTransactions(
+    PhabricatorUser $viewer,
+    PhabricatorProjectColumn $column,
+    $object) {
+
+    $trigger_xactions = array();
+    foreach ($this->getTriggerRules() as $rule) {
+      $rule
+        ->setViewer($viewer)
+        ->setTrigger($this)
+        ->setColumn($column)
+        ->setObject($object);
+
+      $xactions = $rule->getDropTransactions(
+        $object,
+        $rule->getRecord()->getValue());
+
+      if (!is_array($xactions)) {
+        throw new Exception(
+          pht(
+            'Expected trigger rule (of class "%s") to return a list of '.
+            'transactions from "newDropTransactions()", but got "%s".',
+            get_class($rule),
+            phutil_describe_type($xactions)));
+      }
+
+      $expect_type = get_class($object->getApplicationTransactionTemplate());
+      assert_instances_of($xactions, $expect_type);
+
+      foreach ($xactions as $xaction) {
+        $trigger_xactions[] = $xaction;
+      }
+    }
+
+    return $trigger_xactions;
+  }
+
+
 
 /* -(  PhabricatorApplicationTransactionInterface  )------------------------- */
 
diff --git a/src/applications/project/trigger/PhabricatorProjectTriggerInvalidRule.php b/src/applications/project/trigger/PhabricatorProjectTriggerInvalidRule.php
new file mode 100644
--- /dev/null
+++ b/src/applications/project/trigger/PhabricatorProjectTriggerInvalidRule.php
@@ -0,0 +1,22 @@
+<?php
+
+final class PhabricatorProjectTriggerInvalidRule
+  extends PhabricatorProjectTriggerRule {
+
+  const TRIGGERTYPE = 'invalid';
+
+  public function getDescription() {
+    return pht(
+      'Invalid rule (of type "%s").',
+      $this->getRecord()->getType());
+  }
+
+  protected function assertValidRuleValue($value) {
+    return;
+  }
+
+  protected function newDropTransactions($object, $value) {
+    return array();
+  }
+
+}
diff --git a/src/applications/project/trigger/PhabricatorProjectTriggerManiphestStatusRule.php b/src/applications/project/trigger/PhabricatorProjectTriggerManiphestStatusRule.php
new file mode 100644
--- /dev/null
+++ b/src/applications/project/trigger/PhabricatorProjectTriggerManiphestStatusRule.php
@@ -0,0 +1,41 @@
+<?php
+
+final class PhabricatorProjectTriggerManiphestStatusRule
+  extends PhabricatorProjectTriggerRule {
+
+  const TRIGGERTYPE = 'task.status';
+
+  public function getDescription() {
+    $value = $this->getValue();
+
+    return pht(
+      'Changes status to "%s".',
+      ManiphestTaskStatus::getTaskStatusName($value));
+  }
+
+  protected function assertValidRuleValue($value) {
+    if (!is_string($value)) {
+      throw new Exception(
+        pht(
+          'Status rule value should be a string, but is not (value is "%s").',
+          phutil_describe_type($value)));
+    }
+
+    $map = ManiphestTaskStatus::getTaskStatusMap();
+    if (!isset($map[$value])) {
+      throw new Exception(
+        pht(
+          'Rule value ("%s") is not a valid task status.',
+          $value));
+    }
+  }
+
+  protected function newDropTransactions($object, $value) {
+    return array(
+      $this->newTransaction()
+        ->setTransactionType(ManiphestTaskStatusTransaction::TRANSACTIONTYPE)
+        ->setNewValue($value),
+    );
+  }
+
+}
diff --git a/src/applications/project/trigger/PhabricatorProjectTriggerRule.php b/src/applications/project/trigger/PhabricatorProjectTriggerRule.php
new file mode 100644
--- /dev/null
+++ b/src/applications/project/trigger/PhabricatorProjectTriggerRule.php
@@ -0,0 +1,89 @@
+<?php
+
+abstract class PhabricatorProjectTriggerRule
+  extends Phobject {
+
+  private $record;
+  private $viewer;
+  private $column;
+  private $trigger;
+  private $object;
+
+  final public function getTriggerType() {
+    return $this->getPhobjectClassConstant('TRIGGERTYPE', 64);
+  }
+
+  final public static function getAllTriggerRules() {
+    return id(new PhutilClassMapQuery())
+      ->setAncestorClass(__CLASS__)
+      ->setUniqueMethod('getTriggerType')
+      ->execute();
+  }
+
+  final public function setRecord(PhabricatorProjectTriggerRuleRecord $record) {
+    $value = $record->getValue();
+
+    $this->assertValidRuleValue($value);
+
+    $this->record = $record;
+    return $this;
+  }
+
+  final public function getRecord() {
+    return $this->record;
+  }
+
+  final protected function getValue() {
+    return $this->getRecord()->getValue();
+  }
+
+  abstract public function getDescription();
+  abstract protected function assertValidRuleValue($value);
+  abstract protected function newDropTransactions($object, $value);
+
+  final public function getDropTransactions($object, $value) {
+    return $this->newDropTransactions($object, $value);
+  }
+
+  final public function setViewer(PhabricatorUser $viewer) {
+    $this->viewer = $viewer;
+    return $this;
+  }
+
+  final public function getViewer() {
+    return $this->viewer;
+  }
+
+  final public function setColumn(PhabricatorProjectColumn $column) {
+    $this->column = $column;
+    return $this;
+  }
+
+  final public function getColumn() {
+    return $this->column;
+  }
+
+  final public function setTrigger(PhabricatorProjectTrigger $trigger) {
+    $this->trigger = $trigger;
+    return $this;
+  }
+
+  final public function getTrigger() {
+    return $this->trigger;
+  }
+
+  final public function setObject(
+    PhabricatorApplicationTransactionInterface $object) {
+    $this->object = $object;
+    return $this;
+  }
+
+  final public function getObject() {
+    return $this->object;
+  }
+
+  final protected function newTransaction() {
+    return $this->getObject()->getApplicationTransactionTemplate();
+  }
+
+}
diff --git a/src/applications/project/trigger/PhabricatorProjectTriggerRuleRecord.php b/src/applications/project/trigger/PhabricatorProjectTriggerRuleRecord.php
new file mode 100644
--- /dev/null
+++ b/src/applications/project/trigger/PhabricatorProjectTriggerRuleRecord.php
@@ -0,0 +1,27 @@
+<?php
+
+final class PhabricatorProjectTriggerRuleRecord
+  extends Phobject {
+
+  private $type;
+  private $value;
+
+  public function setType($type) {
+    $this->type = $type;
+    return $this;
+  }
+
+  public function getType() {
+    return $this->type;
+  }
+
+  public function setValue($value) {
+    $this->value = $value;
+    return $this;
+  }
+
+  public function getValue() {
+    return $this->value;
+  }
+
+}
diff --git a/src/applications/project/trigger/PhabricatorProjectTriggerUnknownRule.php b/src/applications/project/trigger/PhabricatorProjectTriggerUnknownRule.php
new file mode 100644
--- /dev/null
+++ b/src/applications/project/trigger/PhabricatorProjectTriggerUnknownRule.php
@@ -0,0 +1,22 @@
+<?php
+
+final class PhabricatorProjectTriggerUnknownRule
+  extends PhabricatorProjectTriggerRule {
+
+  const TRIGGERTYPE = 'unknown';
+
+  public function getDescription() {
+    return pht(
+      'Unknown rule (of type "%s").',
+      $this->getRecord()->getType());
+  }
+
+  protected function assertValidRuleValue($value) {
+    return;
+  }
+
+  protected function newDropTransactions($object, $value) {
+    return array();
+  }
+
+}