What is an LLMS.txt file? It’s the AI equivalent of a robots.txt or sitemap.xml file for SEO.
Robots.txt and sitemap.xml files provide information for search engines about the content of your website in a standard format. The robots.txt file typically tells search engines to ignore certain pages on your site for indexing purposes. They don’t have to ignore them but they usually do. As an example, WordPress sites typically have robots.txt files that include lines like “Disallow: /wp-includes/” which tells the search engines not to bother indexing files that control how the site looks or behaves because that information is rarely of use to anyone.
The sitemap.xml file tells search engines the urls of all the pages on your site that you want them to know about and index so that they might appear in search results. When you add a new page to your site, it’s important to update your sitemap.xml so that the next time a search engine crawls (scans) your site, it will find the new page.
The llms.txt file takes on this function but for llms – large language model AI systems. At this stage (December 2025) it seems fair to say that an internet-wide standard for llms.txt contents hasn’t yet been agreed and in any case everything related to LLMs is rapidly changing but the concept of an llms.txt file is something all SEO and multi engine optimisation professionals should be aware of.
Here’s the current llms.txt file for this site, generated by Yoast.
Generated by Yoast SEO v26.5, this is an llms.txt file, meant for consumption by LLMs. The XML sitemap of this website can be found by following [this link](https://virtualcaio.com/sitemap_index.xml). # virtual CAIO: AI for Business ## Pages - [Cookie Policy \(UK\)](https://virtualcaio.com/cookie-policy-uk) - [How Businesses Can Use AI for Competitor Analysis](https://virtualcaio.com/ai-competitor-analysis) - [Inventory optimisation using AI made simple](https://virtualcaio.com/inventory-optimisation) - [What is a CAIO?](https://virtualcaio.com/caio-meaning) - [Prompt Database](https://virtualcaio.com/prompt-database) ## Posts - [MultiEO \- SEO, AIEO and GEO combined](https://virtualcaio.com/multieo-multi-engine-optimisation) - [What Is a Virtual CAIO?](https://virtualcaio.com/what-is-a-virtual-caio) - [The Rise of the Virtual CAIO](https://virtualcaio.com/the-rise-of-the-virtual-caio) ## Categories - [Management](https://virtualcaio.com/category/management) - [C\-Suite](https://virtualcaio.com/category/c-suite) - [Prompting](https://virtualcaio.com/category/prompting) - [Applications](https://virtualcaio.com/category/applications) - [Marketing](https://virtualcaio.com/category/marketing)
Here’s a table setting out some pros and cons of using an llms.txt file on your on your own website.
| Aspect | Pros | Cons |
|---|---|---|
| Visibility in AI Tools | Increases chances of your content being cited or summarised accurately in AI responses (e.g., ChatGPT, Claude, Perplexity, Gemini). For an AI site, this could drive referral traffic and establish authority as AI search grows. | No guaranteed impact—many tests (e.g., server logs from 2025) show AI crawlers rarely or never access llms.txt files. Benefits are speculative and unproven at scale. |
| Control & Accuracy | Guides AI to your best content, reducing hallucinations or misrepresentations (common with complex AI topics). You can request attribution or specify usage preferences. | AI companies (OpenAI, Google, etc.) haven’t officially adopted it; they may ignore it entirely. Enforcement relies on voluntary compliance. |
| Future-Proofing | Early adoption positions your site as forward-thinking. Some tech/AI companies (Anthropic, Hugging Face, Cloudflare, Stripe) have implemented it, and crawls show increasing interest (600% adoption growth in some datasets by mid-2025). | Still a proposal, not a standard. Low overall adoption (hundreds to low thousands of sites in 2025, mostly tech/docs sites; near-zero in top 1M sites per some scans). Risk of it becoming obsolete. |
| Ease of Implementation | Simple to create (Markdown links + descriptions). Tools/plugins exist (e.g., WordPress generators, free online tools). Low server impact. | Requires manual curation and ongoing maintenance (update when content changes). If outdated, it could mislead AI. |
| SEO/Traditional Search Impact | None negative; complements robots.txt and sitemaps. May indirectly help if AI referrals grow. | Doesn’t affect Google rankings or traditional crawlers. Some experts compare it to the outdated meta keywords tag—hype without real power. |
| Specific to AI Sites | High upside: AI tools/agents (e.g., developers using Claude for coding) could better access your explanations, tutorials, or API docs. Signals you’re “AI-native.” | If your traffic is mostly human/search-driven, effort may yield zero ROI currently. |