diff --git a/2meet-data-optimizer.php b/2meet-data-optimizer.php
index d6d1a18..a7fcf5d 100644
--- a/2meet-data-optimizer.php
+++ b/2meet-data-optimizer.php
@@ -234,6 +234,7 @@ require_once TMDO_PATH . 'includes/class-tmdo-rest-api.php';
 // ── v2.0.0 Engine + Adapters + Modules ───────────────────────────────────
 require_once TMDO_PATH . 'includes/engine/class-tmdo-type-caster.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-mode-manager.php';
+require_once TMDO_PATH . 'includes/engine/class-tmdo-promotion-guard.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-audit-logger.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-shadow-diff-logger.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-conflict-detector.php';
@@ -292,6 +293,8 @@ if ( is_admin() ) {
 	TMDO_Deprecated_Addons_Notice::register();
 	require_once TMDO_PATH . 'admin/class-tmdo-missing-addons-notice.php';
 	TMDO_Missing_Addons_Notice::register();
+	require_once TMDO_PATH . 'admin/class-tmdo-promotion-guard-notice.php';
+	TMDO_Promotion_Guard_Notice::register();
 }
 
 // ── WP-CLI ─────────────────────────────────────────────────────────────────
diff --git a/admin/class-tmdo-promotion-guard-notice.php b/admin/class-tmdo-promotion-guard-notice.php
new file mode 100644
index 0000000..c5e6cb9
--- /dev/null
+++ b/admin/class-tmdo-promotion-guard-notice.php
@@ -0,0 +1,63 @@
+<?php
+/**
+ * Admin notice when an entity is in aeav_only on a HivePress / WooCommerce site.
+ *
+ * Those plugins read native meta directly, so on an aeav_only entity they read
+ * stale (or, after cleanup, missing) values. The Promotion Guard refuses new
+ * promotions; sites promoted before it existed are only warned — demoting on
+ * read would leave them reading whatever native meta is left.
+ *
+ * @package WP_Data_Optimizer
+ */
+
+declare(strict_types=1);
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+/**
+ * Warns administrators about guarded entities that are already in aeav_only.
+ */
+final class TMDO_Promotion_Guard_Notice {
+
+	/**
+	 * Hook the notice.
+	 *
+	 * @return void
+	 */
+	public static function register(): void {
+		add_action( 'admin_notices', array( __CLASS__, 'render' ) );
+	}
+
+	/**
+	 * Print the notice for administrators when a guarded entity is in aeav_only.
+	 *
+	 * @return void
+	 */
+	public static function render(): void {
+		if ( ! current_user_can( 'manage_options' ) ) {
+			return;
+		}
+		$violations = TMDO_Promotion_Guard::violations();
+		if ( empty( $violations ) ) {
+			return;
+		}
+
+		$lines = array();
+		foreach ( $violations as $entity_type => $integrations ) {
+			$lines[] = sprintf( '%s（%s）：wp tmdo bridge-restore-native %s --demote', $entity_type, implode( ' / ', $integrations ), $entity_type );
+		}
+		printf(
+			'<div class="notice notice-error"><p><strong>%s</strong> %s</p></div>',
+			esc_html__( '2meet Data Optimizer：', '2meet-data-optimizer' ),
+			esc_html(
+				sprintf(
+					/* translators: %s: "entity (integrations): command" list */
+					__( '以下實體處於 aeav_only，但這些外掛會直接讀取原生 meta，可能讀到過期或遺失的資料。請先備份，再把扁平資料寫回原生並降級：%s', '2meet-data-optimizer' ),
+					implode( '；', $lines )
+				)
+			)
+		);
+	}
+}
diff --git a/includes/engine/class-tmdo-mode-manager.php b/includes/engine/class-tmdo-mode-manager.php
index 5fed59d..fa79a90 100644
--- a/includes/engine/class-tmdo-mode-manager.php
+++ b/includes/engine/class-tmdo-mode-manager.php
@@ -140,6 +140,11 @@ final class TMDO_Mode_Manager {
 			);
 		}
 
+		$guarded = TMDO_Promotion_Guard::check_promotion( $entity_type, $new_mode );
+		if ( $guarded ) {
+			return $guarded;
+		}
+
 		$all                 = self::all();
 		$all[ $entity_type ] = $new_mode;
 
diff --git a/includes/engine/class-tmdo-promotion-guard.php b/includes/engine/class-tmdo-promotion-guard.php
new file mode 100644
index 0000000..4af8dac
--- /dev/null
+++ b/includes/engine/class-tmdo-promotion-guard.php
@@ -0,0 +1,140 @@
+<?php
+/**
+ * TMDO_Promotion_Guard — keeps native meta authoritative on HivePress /
+ * WooCommerce sites (ADR-004 "search-index mode").
+ *
+ * Both plugins read native meta without going through a keyed
+ * get_*_meta() call: HivePress models load every key with get_*_meta( $id ),
+ * WooCommerce does the same for products and writes stock / sales with direct
+ * SQL. The Hook Bus cannot serve those reads from flat tables, so on these
+ * sites an entity must never reach aeav_only and native rows must never be
+ * cleaned up. Demotion always stays open.
+ *
+ * @package WP_Data_Optimizer
+ */
+
+declare(strict_types=1);
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+/**
+ * Refuses aeav_only promotion and native-meta cleanup where an integration
+ * reads native meta directly.
+ */
+final class TMDO_Promotion_Guard {
+
+	/**
+	 * Entity types each integration reads natively.
+	 *
+	 * HivePress models (Post, User, Term, Comment) all load meta with an empty
+	 * key; WooCommerce does so for products and customers.
+	 */
+	private const GUARDED = array(
+		'HivePress'   => array( 'post', 'user', 'term', 'comment' ),
+		'WooCommerce' => array( 'post', 'user' ),
+	);
+
+	/**
+	 * Check a mode change. Only promotion to aeav_only is guarded.
+	 *
+	 * @param string $entity_type Entity type.
+	 * @param string $new_mode    Target mode.
+	 * @return WP_Error|null Error when refused.
+	 */
+	public static function check_promotion( string $entity_type, string $new_mode ): ?WP_Error {
+		if ( TMDO_Mode_Manager::MODE_AEAV_ONLY !== $new_mode ) {
+			return null;
+		}
+		return self::refuse( $entity_type, TMDO_Mode_Manager::MODE_AEAV_ONLY );
+	}
+
+	/**
+	 * Check a cleanup of the entity's native managed meta rows.
+	 *
+	 * @param string $entity_type Entity type.
+	 * @return WP_Error|null Error when refused.
+	 */
+	public static function check_cleanup( string $entity_type ): ?WP_Error {
+		return self::refuse( $entity_type, 'cleanup' );
+	}
+
+	/**
+	 * Guarded entity types that are already in aeav_only (promoted before the
+	 * guard existed). Native meta may be stale there.
+	 *
+	 * @return array<string, string[]> Entity type → integration names.
+	 */
+	public static function violations(): array {
+		$out = array();
+		foreach ( TMDO_Mode_Manager::all() as $type => $mode ) {
+			if ( TMDO_Mode_Manager::MODE_AEAV_ONLY !== $mode ) {
+				continue;
+			}
+			$integrations = self::integrations_for( $type );
+			if ( ! empty( $integrations ) ) {
+				$out[ $type ] = $integrations;
+			}
+		}
+		return $out;
+	}
+
+	/**
+	 * Active integrations that read this entity type natively.
+	 *
+	 * @param string $entity_type Entity type.
+	 * @return string[]
+	 */
+	private static function integrations_for( string $entity_type ): array {
+		$active = array(
+			'HivePress'   => TMDO_Compatibility::is_hivepress_active(),
+			'WooCommerce' => TMDO_Compatibility::is_woocommerce_active(),
+		);
+
+		$names = array();
+		foreach ( self::GUARDED as $name => $types ) {
+			if ( $active[ $name ] && in_array( $entity_type, $types, true ) ) {
+				$names[] = $name;
+			}
+		}
+		return $names;
+	}
+
+	/**
+	 * Build the refusal, unless no integration applies or a filter allows it.
+	 *
+	 * @param string $entity_type Entity type.
+	 * @param string $action      'aeav_only' or 'cleanup'.
+	 * @return WP_Error|null
+	 */
+	private static function refuse( string $entity_type, string $action ): ?WP_Error {
+		$integrations = self::integrations_for( $entity_type );
+		if ( empty( $integrations ) ) {
+			return null;
+		}
+
+		/**
+		 * Allow a guarded aeav_only promotion or cleanup anyway.
+		 *
+		 * @param bool     $allow        Default false.
+		 * @param string   $entity_type  Entity type.
+		 * @param string   $action       'aeav_only' or 'cleanup'.
+		 * @param string[] $integrations Integrations that read this entity natively.
+		 */
+		if ( apply_filters( 'tmdo_promotion_guard_allow', false, $entity_type, $action, $integrations ) ) {
+			return null;
+		}
+
+		return new WP_Error(
+			'promotion_guarded',
+			sprintf(
+				/* translators: 1: integration names, 2: entity type, 3: aeav_only or cleanup */
+				__( '%1$s 直接讀取原生 meta，%2$s 不能執行 %3$s：這類站台以原生 meta 為唯一資料來源（搜尋索引模式）。', '2meet-data-optimizer' ),
+				implode( ' / ', $integrations ),
+				$entity_type,
+				$action
+			)
+		);
+	}
+}
diff --git a/includes/migration/class-tmdo-post-migration.php b/includes/migration/class-tmdo-post-migration.php
index 67b54f8..26caf95 100644
--- a/includes/migration/class-tmdo-post-migration.php
+++ b/includes/migration/class-tmdo-post-migration.php
@@ -228,6 +228,10 @@ final class TMDO_Post_Migration {
 				'Refusing post cleanup — mode is ' . esc_html( $mode ) . ', must be aeav_only'
 			);
 		}
+		$guarded = TMDO_Promotion_Guard::check_cleanup( self::ENTITY_TYPE );
+		if ( $guarded ) {
+			throw new RuntimeException( esc_html( $guarded->get_error_message() ) );
+		}
 
 		global $wpdb;
 		$keys = self::get_managed_keys();
diff --git a/includes/migration/phases/class-tmdo-phase-cleanup.php b/includes/migration/phases/class-tmdo-phase-cleanup.php
index 28b59e1..2c2a0a6 100644
--- a/includes/migration/phases/class-tmdo-phase-cleanup.php
+++ b/includes/migration/phases/class-tmdo-phase-cleanup.php
@@ -46,6 +46,10 @@ class TMDO_Phase_Cleanup extends TMDO_Migration_Phase_Base {
 		if ( TMDO_Mode_Manager::MODE_AEAV_ONLY !== $mode ) {
 			throw new \RuntimeException( "Refusing cleanup — mode is {$mode}, must be aeav_only" );
 		}
+		$guarded = TMDO_Promotion_Guard::check_cleanup( $this->entity_type );
+		if ( $guarded ) {
+			throw new \RuntimeException( $guarded->get_error_message() );
+		}
 		if ( ! empty( $job['options']['auto_backup'] ) && empty( $job['backup_path'] ) ) {
 			throw new \RuntimeException( 'Refusing cleanup — auto_backup requested but no backup_path on record' );
 		}
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 54161d5..2ab62a7 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -613,6 +613,7 @@ require_once TMDO_PATH . 'includes/class-tmdo-rest-api.php';
 // Engine (v2.0.0).
 require_once TMDO_PATH . 'includes/engine/class-tmdo-type-caster.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-mode-manager.php';
+require_once TMDO_PATH . 'includes/engine/class-tmdo-promotion-guard.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-audit-logger.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-shadow-diff-logger.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-conflict-detector.php';
diff --git a/tests/integration/bootstrap.php b/tests/integration/bootstrap.php
index c19554b..9578e92 100644
--- a/tests/integration/bootstrap.php
+++ b/tests/integration/bootstrap.php
@@ -576,6 +576,7 @@ require_once TMDO_PATH . 'includes/safety/class-tmdo-fsm-guard.php';
 require_once TMDO_PATH . 'includes/class-tmdo-rest-api.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-type-caster.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-mode-manager.php';
+require_once TMDO_PATH . 'includes/engine/class-tmdo-promotion-guard.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-audit-logger.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-shadow-diff-logger.php';
 require_once TMDO_PATH . 'includes/engine/class-tmdo-conflict-detector.php';
diff --git a/tests/unit/PromotionGuardTest.php b/tests/unit/PromotionGuardTest.php
new file mode 100644
index 0000000..7cf830e
--- /dev/null
+++ b/tests/unit/PromotionGuardTest.php
@@ -0,0 +1,163 @@
+<?php
+declare(strict_types=1);
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Promotion Guard: HivePress / WooCommerce read native meta directly
+ * (empty-key get_*_meta(), direct SQL), so on those sites native meta must
+ * stay authoritative — no aeav_only, no cleanup of native rows.
+ *
+ * Tests that declare HivePress / WooCommerce stand-in classes run in their own
+ * process so those classes do not leak into other tests.
+ */
+class PromotionGuardTest extends TestCase {
+
+	protected function setUp(): void {
+		if ( ! class_exists( 'TMDO_Promotion_Guard_Notice' ) ) {
+			require_once TMDO_PATH . 'admin/class-tmdo-promotion-guard-notice.php';
+		}
+		// Mode changes log through error_log(); in a separate process PHPUnit
+		// treats that stderr output as an error.
+		ini_set( 'error_log', '/dev/null' );
+		$GLOBALS['_wp_options']           = array();
+		$GLOBALS['_wp_filter_callbacks']  = array();
+		$GLOBALS['_wp_current_user_can']  = array( 'manage_options' => true );
+		TMDO_Mode_Manager::reset_cache();
+	}
+
+	private function modes( array $modes ): void {
+		$GLOBALS['_wp_options']['wpdo_bridge_modes'] = $modes;
+		TMDO_Mode_Manager::reset_cache();
+	}
+
+	public function test_without_integrations_aeav_only_is_allowed(): void {
+		$this->modes( array( 'post' => 'shadow_read' ) );
+
+		$this->assertTrue( TMDO_Mode_Manager::set( 'post', 'aeav_only' ) );
+		$this->assertNull( TMDO_Promotion_Guard::check_cleanup( 'post' ) );
+		$this->assertSame( array(), TMDO_Promotion_Guard::violations() );
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_hivepress_refuses_aeav_only_for_every_entity(): void {
+		eval( 'namespace HivePress; class Core {}' );
+
+		foreach ( array( 'post', 'user', 'term', 'comment' ) as $type ) {
+			$this->modes( array( $type => 'shadow_read' ) );
+
+			$result = TMDO_Mode_Manager::set( $type, 'aeav_only' );
+
+			$this->assertInstanceOf( WP_Error::class, $result, $type );
+			$this->assertSame( 'promotion_guarded', $result->get_error_code(), $type );
+			$this->assertStringContainsString( 'HivePress', $result->get_error_message(), $type );
+			$this->assertSame( 'shadow_read', TMDO_Mode_Manager::get( $type ), "{$type} mode must not change" );
+			$this->assertSame( array( $type => 'shadow_read' ), $GLOBALS['_wp_options']['wpdo_bridge_modes'], "{$type} option must not change" );
+		}
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_woocommerce_guards_post_and_user_only(): void {
+		eval( 'class WooCommerce {}' );
+
+		$this->modes( array( 'post' => 'shadow_read', 'user' => 'shadow_read', 'term' => 'shadow_read' ) );
+
+		$this->assertInstanceOf( WP_Error::class, TMDO_Mode_Manager::set( 'post', 'aeav_only' ) );
+		$this->assertInstanceOf( WP_Error::class, TMDO_Mode_Manager::set( 'user', 'aeav_only' ) );
+		$this->assertTrue( TMDO_Mode_Manager::set( 'term', 'aeav_only' ) );
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_guard_allows_lower_modes_and_demotion(): void {
+		eval( 'namespace HivePress; class Core {}' );
+
+		$this->modes( array( 'post' => 'disabled' ) );
+		$this->assertTrue( TMDO_Mode_Manager::set( 'post', 'dual_write' ) );
+		$this->assertTrue( TMDO_Mode_Manager::set( 'post', 'shadow_read' ) );
+
+		$this->modes( array( 'post' => 'aeav_only' ) );
+		$this->assertTrue( TMDO_Mode_Manager::set( 'post', 'dual_write' ), 'the way out of aeav_only stays open' );
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_filter_can_allow_a_guarded_promotion(): void {
+		eval( 'namespace HivePress; class Core {}' );
+		add_filter(
+			'tmdo_promotion_guard_allow',
+			static function ( $allow, $entity_type, $action, $integrations ) {
+				return 'user' === $entity_type && 'aeav_only' === $action && array( 'HivePress' ) === $integrations;
+			},
+			10,
+			4
+		);
+
+		$this->modes( array( 'user' => 'shadow_read', 'post' => 'shadow_read' ) );
+
+		$this->assertTrue( TMDO_Mode_Manager::set( 'user', 'aeav_only' ) );
+		$this->assertInstanceOf( WP_Error::class, TMDO_Mode_Manager::set( 'post', 'aeav_only' ) );
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_cleanup_is_refused_even_in_aeav_only(): void {
+		eval( 'namespace HivePress; class Core {}' );
+		$this->modes( array( 'post' => 'aeav_only', 'user' => 'aeav_only' ) );
+
+		$error = TMDO_Promotion_Guard::check_cleanup( 'post' );
+		$this->assertInstanceOf( WP_Error::class, $error );
+
+		try {
+			TMDO_Post_Migration::cleanup();
+			$this->fail( 'post cleanup must be refused' );
+		} catch ( RuntimeException $e ) {
+			$this->assertStringContainsString( 'HivePress', $e->getMessage() );
+		}
+
+		$job = array( 'log' => array(), 'options' => array() );
+		try {
+			( new TMDO_Phase_Cleanup( 'user' ) )->execute( $job );
+			$this->fail( 'user cleanup phase must be refused' );
+		} catch ( RuntimeException $e ) {
+			$this->assertStringContainsString( 'HivePress', $e->getMessage() );
+		}
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_sites_already_in_aeav_only_are_reported(): void {
+		eval( 'class WooCommerce {}' );
+		$this->modes( array( 'post' => 'aeav_only', 'term' => 'aeav_only' ) );
+
+		$this->assertSame( array( 'post' => array( 'WooCommerce' ) ), TMDO_Promotion_Guard::violations() );
+
+		ob_start();
+		TMDO_Promotion_Guard_Notice::render();
+		$html = (string) ob_get_clean();
+		$this->assertStringContainsString( 'post', $html );
+		$this->assertStringContainsString( 'bridge-restore-native post', $html );
+	}
+
+	public function test_notice_is_silent_without_violations(): void {
+		$this->modes( array( 'post' => 'aeav_only' ) );
+
+		ob_start();
+		TMDO_Promotion_Guard_Notice::render();
+		$this->assertSame( '', ob_get_clean() );
+	}
+}