diff --git a/bin/check-affected-pages.php b/bin/check-affected-pages.php
new file mode 100644
index 0000000..c5b48a2
--- /dev/null
+++ b/bin/check-affected-pages.php
@@ -0,0 +1,153 @@
+<?php
+/**
+ * Pre-flight check: list pages on this site that have
+ * `hero_style = 'default'` but are NOT Services descendants.
+ *
+ * These are the pages whose visible hero behavior changes when the
+ * Services-descendant gate is introduced in `isServicesDescendant()`
+ * (see `lib/extras.php`).
+ *
+ * Run from the WordPress root:
+ *
+ *     php bin/check-affected-pages.php
+ *
+ * Or, if the WordPress install is at a different path, point
+ * `wp-load.php` resolution accordingly (see the bootstrap below).
+ *
+ * @package CWC
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	// We are not inside WordPress. Try to bootstrap from the WordPress root.
+	// This script lives at wp-content/themes/<theme>/bin/, so the WordPress
+	// root (which contains wp-load.php) is four levels up.
+	$wp_load = dirname( __DIR__, 4 ) . '/wp-load.php';
+	if ( ! file_exists( $wp_load ) ) {
+		fwrite( STDERR, "Could not locate wp-load.php at {$wp_load}. Run this script from the WordPress root or set up ABSPATH first.\n" );
+		exit( 1 );
+	}
+	require_once $wp_load;
+}
+
+if ( ! function_exists( 'get_field' ) ) {
+	fwrite( STDERR, "ACF is not active; this script needs Advanced Custom Fields to read `hero_style`.\n" );
+	exit( 1 );
+}
+
+if ( ! function_exists( 'CWC\\isServicesDescendant' ) ) {
+	fwrite( STDERR, "CWC\\isServicesDescendant() is not loaded. Make sure the active theme is community-works-collaborative.\n" );
+	exit( 1 );
+}
+
+/**
+ * Query every published page and check whether its hero would be affected.
+ */
+function cwc_check_affected_pages() {
+	$query = new WP_Query(
+		array(
+			'post_type'      => 'page',
+			'post_status'    => 'publish',
+			'posts_per_page' => -1,
+			'orderby'        => 'menu_order title',
+			'order'          => 'ASC',
+			'no_found_rows'  => true,
+		)
+	);
+
+	$affected = array();
+	$skipped_due_to_error = 0;
+
+	while ( $query->have_posts() ) {
+		$query->the_post();
+		$post = get_post();
+
+		$hero_style = get_field( 'hero_style', $post->ID );
+
+		if ( 'default' !== $hero_style ) {
+			continue;
+		}
+
+		$is_services_descendant = \CWC\isServicesDescendant( $post );
+		if ( is_wp_error( $is_services_descendant ) ) {
+			++$skipped_due_to_error;
+			continue;
+		}
+
+		if ( $is_services_descendant ) {
+			continue;
+		}
+
+		$affected[] = array(
+			'ID'    => (int) $post->ID,
+			'title' => get_the_title( $post ),
+			'url'   => get_permalink( $post ),
+			'slug'  => $post->post_name,
+		);
+	}
+
+	wp_reset_postdata();
+
+	return array(
+		'affected'              => $affected,
+		'skipped_due_to_error'  => $skipped_due_to_error,
+	);
+}
+
+$result = cwc_check_affected_pages();
+$affected = $result['affected'];
+
+echo "Pages with hero_style = 'default' that are NOT Services descendants\n";
+echo "==================================================================\n\n";
+
+if ( empty( $affected ) ) {
+	echo "None. Every page that uses the default hero is a Services descendant (or the Services page itself).\n";
+} else {
+	printf( "Found %d affected page(s):\n\n", count( $affected ) );
+
+	$rows = array();
+	$rows[] = array( 'ID', 'Slug', 'Title', 'URL' );
+
+	foreach ( $affected as $page ) {
+		$rows[] = array(
+			(string) $page['ID'],
+			$page['slug'],
+			$page['title'],
+			$page['url'],
+		);
+	}
+
+	// Compute column widths for aligned output.
+	$widths = array();
+	foreach ( array( 0, 1, 2, 3 ) as $col ) {
+		$widths[ $col ] = 0;
+		foreach ( $rows as $row ) {
+			$widths[ $col ] = max( $widths[ $col ], strlen( $row[ $col ] ) );
+		}
+	}
+
+	$format = '| %-' . $widths[0] . 's | %-' . $widths[1] . 's | %-' . $widths[2] . 's | %-' . $widths[3] . "s |\n";
+
+	$separator = '+';
+	foreach ( $widths as $w ) {
+		$separator .= str_repeat( '-', $w + 2 ) . '+';
+	}
+	$separator .= "\n";
+
+	echo $separator;
+	foreach ( $rows as $i => $row ) {
+		printf( $format, ...$row );
+		if ( 0 === $i ) {
+			echo $separator;
+		}
+	}
+	echo $separator;
+}
+
+if ( $result['skipped_due_to_error'] > 0 ) {
+	printf(
+		"\nWarning: %d page(s) could not be evaluated due to errors. Re-run with WP_DEBUG enabled for details.\n",
+		$result['skipped_due_to_error']
+	);
+}
+
+echo "\n";