Googlebot may ignore general robots.txt rules for specific ones

Image credit: Abondance

Googlebot may disregard general disallow rules in a website’s robots.txt file if more specific user-agent directives are present, potentially leading to unintended indexing of pages, Google‘s Search Advocate John Mueller said.

This technical nuance can cause search engines to continue indexing content that webmasters intended to block, as observed in a recent case involving a Shopify client where spam-generated URLs were indexed despite a broad disallow rule.

The issue arose when a Shopify client’s internal search bar was exploited, generating numerous spam URLs that Google continued to index. The website owner had implemented a disallow /search rule within the robots.txt file, expecting these pages to be excluded from indexing.

Mueller identified the problem during a discussion on Reddit, explaining that the robots.txt file contained both a user-agent: Googlebot section and a more general user-agent: * section. He stated that Googlebot, when encountering a specific directive for itself, will only apply rules listed under its dedicated section.

The most specific rule in a robots.txt file always takes precedence, Mueller said. This means that if a user-agent: Googlebot block exists, any rules within the general user-agent: * section will be ignored by Googlebot.

To ensure rules apply to multiple user-agents, webmasters must either duplicate the rules within each specific user-agent section or list them once above a shared block of user-agents, according to advice from Search Engine Journal.

Mueller also emphasized that the robots.txt file primarily controls crawling, not indexing. For definitive prevention of page indexing, he recommended using a ‘noindex’ directive, typically implemented via a meta tag or HTTP header, rather than solely relying on robots.txt disallow rules.

Source: Abondance