How to Write an LLMs.txt File: The New Standard for AI in 2025

August 17, 2025

If the last decade of SEO was about optimizing for Google, the next decade is about building authority and trust for AI search engines. ChatGPT, Perplexity, Claude, Gemini, and DeepSeek are now pulling live data from websites and citing them in responses.

There’s only one issue, most websites aren’t LLM-friendly. Large language models struggle to interpret bloated HTML, ads, javascript-heavy pages or unstructured content.

Here’s where LLMs.txt comes in. This is a new standard that allows websites to communicate directly with AI crawlers and interface systems. If you are familiar with robots.txt or sitemap.xml, you already know why LLMs.txt will be extremely important in finding structured content.

We’ll break down a few things in this post, particularly:

• what an LLMs.txt file is
• why LLMs.txt matters for AI SEO and citations
• A step by step guide on how to write an LLMs.txt
• best practicies, real examples, and common mistakes to avoid

Let’s get started.

What is LLMs.txt?

The LLMx.txt file is a simple markdown file that is places at the root of your website, similar to robots.txt and sitemap.xml. It provides AI-friendly summaries, context, and links to structured resources so that large language models can find them quickely and reference them for content.

robots.txt - tels crawlers what not to read sitemap.xml - tells search engines where your pages are LLMs.txt - tells AI agents what matters most on your website

For businesses, that means: You can get citations in AI search engines You can help mitigate interpretations of your content It provides improved discoverability in AI-driven workflows

Why LLMs.txt Matters for Business

Let’s face it: AI-first discovery is already happening. SEO optimization will no longer just be about Google rankings. According to research:

• 30-40% of Gen Z and millennials ask AI first before searching Google
• AI search engines are growing at double-digit rates on a monthly basis
• LLMs are increasingly integrating into environments, workflows, and search assistants.

Without an LLMs.txt in your website, you risk being misunderstood by AI, getting ignored in answers where competitors are being referenced, being hidden due to bloated code.

An LLMs.txt will allow you to curate what AI sees and references.

It can give you an edge in AI SEO

How to Write an LLMs.txt File

Let’s show you the basics of a LLMs.txt flow:

1. Place the File at Root your LLMs.txt must live at

   https://yourdomain.com/llms.txt
   

   This allows you to be discoverable.

2. Start with a Project Title Use an H1 (#) to clearly state what your site is.

   Devonus Web Agency
   

3. Add a Summary use a blockquote (>) with 1-3 sentences.

   Custom websites, SEO, and digital solutions for businesses worldwide.
   

4. Provide Key Notes and Context Give AI notes or limitations if need be

   Important notes:
   - REST API only (no GraphQL support)
   - Sandbox environment available for developers
   

5. Link to Documentation in Markdown Format add H2 sections with markdown list of files.

   ## Key Pages
   - [Home](https://devonus.com/)
   - [Services – Web Development](https://devonus.com/web-development/)
   ## City Landing Pages
   - [San Diego Web Agency](https://devonus.com/san-diego-web-agency/)
   

6. Use “optional” for secondary info LLMs do have token limits. Use an “Optional” section to flag content you feel like can be skipped

   ## Optional
   - [Privacy Policy](https://devonus.com/privacy-policy/)
   

Best Practices for LLMs.txt

make sure to keep the information concise. AI doesn’t need your whole website, the essentials are enough. Use markdown consistently. Keep the formatting clear. Prioritize canonical content. link to documentation or official sources. Update it regularly. Just like SEO, stale content is bad content.

Exmaples of LLMs.txt for Your Website

# Devonus Web Agency
> Custom websites, SEO, and digital solutions for businesses worldwide.
## Key Pages
- [Home](https://devonus.com/)
- [About](https://devonus.com/about/)
- [Services – Web Design](https://devonus.com/web-design/)
- [Services – Web Development](https://devonus.com/web-development/)
## City Landing Pages
- [San Diego Web Agency](https://devonus.com/san-diego-web-agency/)
## Blog
- [How to Write an LLMs.txt File: The New Standard for AI in 2025](http://devonus.com/blog/how-to-write-an-LLMs-txt-file-step-by-step/)
## Legal
- [Privacy Policy](https://devonus.com/privacy-policy/)
- [Terms & Conditions](https://devonus.com/terms-and-conditions/)

How LLMs.txt Fits Into AI SEO

Creating the LLMs.txt is the first step in AI SEO, ensuring your brand is visible to AI search engines.

It works along robots.txt and sitemap.xml, boosts your AI citations, provides structured signals for AI crawlers, and helps control the narrative in AI answers.

While in its early stages, websites that adapt early with LLMs will win in visibility, accuracy, and trust in AI-driven accuracy.

If you’re serious about AI search vsiibility, start drafting your LLMs.txt today and make it a part of your ongoing SEO strategy.