## Filter: wpd_ai_child_page_register

Register or modify child (sub) pages under the Alpha Insights admin menu.

### Description

The admin menu builder collects child pages (submenu items) and sorts them by `menu_position`. This filter receives the array of child page definitions so you can add new subpages or change existing ones. Each child page must have at least `page_title`, `menu_title`, `menu_slug`, and `page_callback`.

#### Location

File: `includes/classes/WPDAI_Admin_Menu.php`

Context: When building the admin menu (before sorting and loading child pages).

### Parameters

Parameter | Type | Description
--- | --- | ---
$child_pages | array | Array of child page arrays. Each item typically has `page_title`, `menu_title`, `menu_slug`, `page_callback`, and optionally `menu_position` (numeric; lower first).

#### Return

Type: array

The (possibly modified) array of child page definitions.

### Example Usage

#### Add a custom subpage

    add_filter( 'wpd_ai_child_page_register', 'add_my_alpha_child_page' );
    function add_my_alpha_child_page( $child_pages ) {
        $child_pages[] = array(
            'page_title'    => __( 'My Extension', 'alpha-insights-pro' ),
            'menu_title'    => __( 'My Extension', 'alpha-insights-pro' ),
            'menu_slug'     => 'alpha-insights-my-extension',
            'page_callback' => 'my_extension_render_page',
            'menu_position' => 50,
        );
        return $child_pages;
    }

    function my_extension_render_page() {
        echo '<p>' . esc_html__( 'My custom page content.', 'alpha-insights-pro' ) . '</p>';
    }

#### Remove a built-in subpage

    add_filter( 'wpd_ai_child_page_register', 'remove_alpha_child_page' );
    function remove_alpha_child_page( $child_pages ) {
        return array_filter( $child_pages, function( $page ) {
            return ( isset( $page['menu_slug'] ) && $page['menu_slug'] !== 'page-to-remove' );
        } );
    }

### Related Filters

- wpd_alpha_insights_menu_items – Modify menu items structure
- wpd_alpha_insights_menu_html – Modify menu HTML output