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In order to modify the output of robots.txt, a site’s environment (production or non-production) must be accessible at a custom domain that is set as the primary domain.

To replace the convenience domain with a custom primary domain, complete the steps to launch a WordPress single site, or by launching the main site (ID 1) of a WordPress multisite.


A site on a WordPress environment that is only accessible via a convenience domain has a hard-coded robots.txt output that returns:

User-agent: *
Disallow: /

Requests to any URLs on that environment will also return an x-robots-tag: noindex, nofollow header. These settings are intended to prevent search engines from indexing content hosted on non-production sites, or unlaunched production sites.

Modify the robots.txt file

To modify robots.txt for a site, hook into the do_robotstxt action or filter the output by hooking into the robots_txt filter.

In most cases, custom code to override the robots.txt file can be added to a theme’s functions.php file. For sites that require more tailored search engine crawling directives, custom code can be selectively added and enabled with a site-specific plugin.



In this code example, the do_robotstxt action is used to mark a specific directory as nofollow for all User Agents:

function my_robotstxt_disallow_directory() {
    echo 'User-agent: *' . PHP_EOL;
    echo 'Disallow: /path/to/your/directory/' . PHP_EOL;
add_action( 'do_robotstxt', 'my_robotstxt_disallow_directory' );



In this code example, the output of robots.txt is modified using the robots_txt filter:

function my_robots_txt_disallow_private_directory( $output, $public ) {
    $output .= 'Disallow: /wp-admin/' . PHP_EOL;
    $output .= 'Allow: /wp-admin/admin-ajax.php' . PHP_EOL;

    // Add custom rules here
    $output .= 'Disallow: /private-directory/' . PHP_EOL;
    $output .= 'Allow: /public-directory/' . PHP_EOL;

    return $output;
add_filter( 'robots_txt', 'my_robots_txt_disallow_private_directory', 10, 2 );

Disallow AI crawlers

Use the robots_txt filter to configure a site’s robots.txt to disallow artificial intelligence (AI) crawlers from crawling a site.


Additional restriction to a site’s content can be put in place for AI crawlers with the VIP_Request_Block utility class.

In this code example, a site’s robots.txt is configured to disallow requests from User-Agents of well-known AI crawlers (e.g. OpenAI’s GPTBot).

Only 4 AI crawlers are included in this code example, though far more exist. Customers should research which AI crawler User-Agents should be disallowed for their site and include them in a modified version of this code example.

function my_robots_txt_block_ai_crawlers( $output, $public ) {
	$output .= '
## OpenAI GPTBot crawler (
User-agent: GPTbot
Disallow: /

## OpenAI ChatGPT service (
User-agent: ChatGPT-User
Disallow: /

## Common Crawl crawler (
User-agent: CCBot
Disallow: /

## Google Bard / Gemini crawler (
User-agent: Google-Extended
Disallow: /

    return $output;
add_filter( 'robots_txt', 'my_robots_txt_block_ai_crawlers', 10, 2 );

Test modifications

Modifications made to robots.txt should be tested on a non-production environment first. If the non-production environment is in an unlaunched state with a convenience domain, the environment’s hard-coded robots.txt must be temporarily overridden to allow for testing.

Add the following code to override the environment’s hard-coded robots.txt:

remove_filter( 'robots_txt', 'Automattic\VIP\Core\Privacy\vip_convenience_domain_robots_txt' );


The /robots.txt file is cached for long periods of time by the page cache. After changes are made to /robots.txt, the cached version can be purged by using the VIP Dashboard or VIP-CLI.

The cached version of /robots.txt can also be cleared from within the WordPress Admin dashboard.

  1. In the WP Admin, select Settings -> Reading from the lefthand navigation menu.
  2. Toggle the setting of Search engine visibility, and select the button labeled “Save Changes” each time the setting is changed.

Last updated: March 01, 2024

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