Google Suggests Noindex Header for LLMs: Key Insights
▼ Summary
– Google’s John Mueller stated that llms.txt wouldn’t be considered duplicate content unless it matches an HTML page, but suggested using noindex to prevent indexing.
– Llms.txt is a proposed standard to provide large language models with a Markdown-formatted version of a webpage’s main content, excluding non-essential elements like ads and navigation.
– Unlike robots.txt, which controls robot behavior, llms.txt is designed to deliver curated content specifically for large language models.
– Concerns were raised that external links to llms.txt might lead Google to index it alongside or instead of the original HTML content.
– Adding a noindex header to llms.txt is recommended to prevent it from appearing in Google’s index, while blocking it via robots.txt is unnecessary.
Google recently addressed concerns about whether llms.txt files could be flagged as duplicate content, suggesting webmasters consider using a noindex header to prevent unintended indexing. During a discussion, Google’s John Mueller clarified that while these files aren’t inherently duplicate content, taking precautions to keep them out of search results might be wise.
The llms.txt proposal aims to streamline how large language models access core webpage content by stripping away non-essential elements like ads, navigation, and other peripheral data. Positioned at the root of a domain (e.g., example.com/llms.txt), this file provides a clean, Markdown-formatted version of a page’s primary content. Unlike robots.txt, which dictates crawler behavior, llms.txt serves as a content delivery mechanism specifically for AI models.
A question arose on Bluesky about whether Google might mistakenly treat llms.txt as duplicate content if external sources linked to it, potentially causing the file to appear in search results alongside the original HTML page. Mueller responded that duplicate content issues would only arise if the file mirrored an existing HTML page, which defeats its purpose. However, he acknowledged that accidental indexing could occur if the file gained backlinks, leading to a confusing experience for users.
To avoid this scenario, Mueller recommended applying a noindex directive to llms.txt files. This approach ensures search engines won’t include them in their indexes while still allowing crawlers to access the content. Blocking Google via robots.txt isn’t necessary, and could backfire, as it would prevent the noindex instruction from being detected.
For publishers leveraging llms.txt, proactively managing how search engines interact with these files helps maintain clarity in search results. While the format itself isn’t problematic, taking simple steps like adding a noindex header can prevent unintended consequences down the line.
(Source: Search Engine Journal)
