Add an llms.txt file to your website

Why it matters

An AI tool that visits your website has to work out what you do from menus, banners and cookie notices. An llms.txt file gives it the short version on one page: who you are, what you offer, and which pages hold the details.

Be clear about what it does today. No major AI assistant has confirmed that it reads llms.txt when answering questions. Google says Google Search, including its AI features, ignores these files, and that having one "will neither harm nor help" your visibility there.

Some tools do look for it. Lighthouse, Google's free website testing tool, now checks the file in its "Agentic browsing" section. An AI agent is a program that browses websites on someone's behalf, for example to compare menus or book a table. Lighthouse calls llms.txt optional, does not penalise a missing file, and flags a file that causes a server error.

So the value is small but real: a clear, current summary for any tool that reads it, at almost no cost. Do it after the guides that matter more.

T4Got your Starter audit? This guide fixes T4, "llms.txt file", on page 07 (Technical and agent readiness). The free Snapshot does not check it.

Reference

llms.txt in plain words

It is a plain text file at yourcompany.lu/llms.txt, written in Markdown. Markdown is a simple way to format text with symbols: # makes a heading, > a short quote, and [text](address) a link. LLM stands for large language model, the technology behind ChatGPT, Claude and Gemini.

The format comes from a public proposal at llmstxt.org, first published in September 2024. Any site can follow it, but no standards body or AI company has made it an official rule. The proposal sets this order:

• A title with #: the name of your business. This is the only part the proposal requires.
• A summary with >: one or two sentences with the key facts.
• Optional extra text: plain paragraphs or lists, without headings.
• Sections with ##: each one a list of links, each link followed by a colon and a one-line description (the description is optional, but we recommend it).
• A section called "Optional": links an AI tool can skip when it needs a shorter version.

Your website may already have two other files for automated visitors. They do different jobs:

An llms.txt file controls nothing. It cannot let a crawler in or keep one out; only robots.txt and your security settings do that.

Before you start

Have these ready

• Guide 02: Let ChatGPT read your website done first. If AI crawlers are blocked, an llms.txt file changes nothing.
• Your fact sheet from Guide 04: name, what you do, for whom, where, languages, opening hours, contact details.
• The addresses of your 5 to 15 most important pages: menu or services, prices, booking, about, contact.
• A login to your website editor (WordPress, Webflow, Wix) or your web agency's contact.

Steps

Write, upload and check your llms.txt

1. Decide if it is worth it for you

   The file costs nothing and takes little time. It will not bring visitors on its own, and it will not change how Google ranks you.

   • Do it now if your robots.txt is in order (Guide 02) and your platform lets you add the file in a few clicks.
   • Leave it for later if crawlers are still blocked, your facts differ from site to site (Guide 04), or you would have to pay a developer just for this.

2. Write the file

   Copy the template into a plain text editor, such as Notepad on Windows or TextEdit in plain text mode on a Mac. Replace every example with your own facts from your fact sheet. Use full page addresses, starting with https://. The example is a fictional restaurant; the same shape works for a hotel, a shop or an accounting firm.

   llms.txtCopy

   # Brasserie du Parc
   
   > Brasserie in Luxembourg-Ville (Limpertsberg) serving Luxembourgish and French dishes, open Tuesday to Sunday for lunch and dinner. Private room for up to 20 guests; we speak French, Luxembourgish, German and English.
   
   Family run since 2009. Terrace open from April to October. Vegetarian dishes on every menu.
   
   ## Menu and prices
   
   - [Lunch menu](https://www.brasserieduparc.lu/en/lunch): Weekday lunch menu with two and three course prices.
   - [Dinner menu](https://www.brasserieduparc.lu/en/dinner): Full menu with prices, updated each season.
   - [Wine list](https://www.brasserieduparc.lu/en/wine): Luxembourg Moselle wines and French wines by the glass and bottle.
   
   ## Bookings and groups
   
   - [Book a table](https://www.brasserieduparc.lu/en/book): Online booking for up to 8 guests; call us for larger groups.
   - [Private room](https://www.brasserieduparc.lu/en/private-room): Room for 8 to 20 guests, business lunches and family events, set menus.
   
   ## Contact and facts
   
   - [Contact and opening hours](https://www.brasserieduparc.lu/en/contact): Address, phone, email, opening hours, parking and the nearest tram stop.
   - [About us](https://www.brasserieduparc.lu/en/about): Our story, our chef and our local suppliers.
   
   ## Optional
   
   - [Events](https://www.brasserieduparc.lu/en/events): Seasonal evenings and wine tastings.

   Illustration with a fictional business.

   • Keep the summary to one or two sentences: what you do, for whom, where, and in which languages.
   • List only public pages you want customers to find. Leave out login pages, staff areas and anything you block in robots.txt.
   • Keep every link on one line, in the form - [Page name](address): description.
   • Delete the "Optional" section if you have nothing to put there.
   • If your site has several languages, list the main language pages and say in the extra text which languages exist (see Guide 08).

   Save the file as llms.txt, all lowercase, in UTF-8 encoding. UTF-8 is the setting that keeps "à" and "é" readable. Never save it from Word, which can add hidden characters.

3. Upload it to the top of your site

   The file must open at yourcompany.lu/llms.txt, not inside a folder. How you get it there depends on your platform:

   WordPress

   Upload llms.txt to your site's main folder with your host's file manager (cPanel, DirectAdmin or Plesk) or an SFTP program such as FileZilla. Your host can tell you the folder and login. WordPress help
   
   With the Yoast SEO plugin you can instead switch on Yoast SEO → Settings → Site features → AI tools → LLMS.txt. Yoast then builds the file from your pages, so it will not follow the template word for word. Yoast help

   Webflow

   Site settings → SEO → LLMs.txt → Upload file, then Save changes. The file must be UTF-8 and under 100 KB. It goes live after you publish the site, and only on your own domain, not the staging address. Webflow help

   Wix

   Wix creates the file for you once your site is upgraded, has its own domain and allows search engines. Wix does not offer an upload option, but you can replace its text: Dashboard → SEO & GEO → Tools and settings → Go to llms.txt → More Actions → Edit file. Wix help

   • Yoast and your own file: Yoast does not overwrite an llms.txt file that is already there. It leaves your file in place and may show a warning instead.
   • Wix: once you edit the text, Wix stops updating it automatically. You then keep it current yourself (step 5). "Reset to Default" switches automatic updates back on.
   • Another platform, or a site built by an agency: ask "Can you place a plain text file at the root of our domain, at /llms.txt?" If the answer is no, skip this guide. You lose little.

4. Check that it opens as plain text

   Open a private browser window and type yourcompany.lu/llms.txt. Try it with and without www. in front. You should see one of these:

   You see	What it means
   Your text exactly as you wrote it, with # and > visible	Good, it works.
   "Page not found"	The file is in the wrong folder, has the wrong name, or the site was not published yet.
   Strange characters instead of "à" or "é"	The file was not saved as UTF-8. Save it again in UTF-8 and upload it again.
   A designed web page, a login page or another error	Send the address to your developer or platform support.

   For a second check, run your homepage through Lighthouse (in Chrome: right click, Inspect, then the Lighthouse tab) or PageSpeed Insights. Under "Agentic browsing", the llms.txt line should not show an error. Lighthouse also marks a missing file as "Not applicable", so this check only confirms the file does not break.

5. Keep it up to date

   A wrong llms.txt is worse than none, because it repeats old facts in a tidy format. Add it to the routine you already use for your website.

   • When you add, rename or delete a page, change its line in llms.txt the same day.
   • When your address, phone, prices or opening hours change, update the summary and your fact sheet together.
   • Once a month, when you repeat your check from Guide 01, click every link in the file. Each one should open a live page.

Check it worked

Confirm the file is live and correct

No AI company offers a report that shows whether it read your file. You can only check that the file is reachable, correct and current.

Common mistakes

What usually goes wrong

• Putting private pages or secrets in it. Anyone can open the file. Never list staff areas, client portals, test pages, internal documents or passwords.
• Treating it as a replacement for robots.txt. llms.txt does not allow or block anything. If robots.txt or a firewall shuts AI crawlers out, the file does not help.
• Letting it go stale. Old prices or a former address in llms.txt add one more wrong source to the internet, the problem Guide 04 fixes.
• Listing pages blocked in robots.txt. A crawler that obeys robots.txt cannot open those links. Check every address against your robots.txt file.
• Expecting visitors from it. No AI assistant has confirmed it uses the file to choose answers, and Google Search ignores it. Clear pages and correct facts come first.