If you’ve looked into getting your business mentioned by ChatGPT or Google’s AI answers, someone has probably told you that you need an llms.txt file. Some sell it as a shortcut. Others call it pointless. The truth sits in between.
We introduced the file briefly in what AEO is and how it differs from SEO. Here’s the fuller picture.
What is llms.txt?
llms.txt is a plain-text file, written in markdown, that lives at the root of your website, at an address like yourdomain.com/llms.txt. It gives AI tools a short, curated summary of your site: who you are, what you do, and links to the pages that matter most, each with a one-line note about what’s there.
Jeremy Howard of Answer.AI proposed it in September 2024 at llmstxt.org, and released a second version in August 2026. The idea is simple. Web pages are built for people, wrapped in menus, pop-ups and scripts, and an AI tool can only take in so much at once. A short file in a predictable place saves it digging through all that.
The proposal sets out the sections in a fixed order:
- A title. An H1 heading with the name of the site or business. This is the only part the proposal requires.
- A short summary. A blockquote, the markdown line that starts with a
>symbol, holding the key facts needed to make sense of the rest. - Optional detail. Paragraphs or bullet lists with more context, but no headings.
- Sections of links. Each starts with an H2 heading and holds a list. Every item is a link to a page, optionally followed by a colon and a short note about that page.
- An “Optional” section. By convention, a section called Optional holds secondary links a tool can skip when it needs to keep things short.
The proposal says it’s used most for software documentation, but the same structure works for a business describing itself.
Is llms.txt an official standard?
No. It’s a proposal, written by one person and open for comment on GitHub. It isn’t a standard set by a standards body, and we haven’t found any major AI company that has publicly committed to following it.
Here’s what the companies themselves say, as of October 2026:
- Google addresses it directly. Its guide to optimizing for generative AI features says Google Search, including its AI features, doesn’t use llms.txt files and ignores them. Having one won’t help or hurt you there.
- OpenAI and Anthropic publish pages explaining which crawlers visit sites and how to control them with robots.txt. Neither page says their crawlers or assistants read llms.txt, and we haven’t found a statement from Perplexity either way.
- Google, OpenAI, Anthropic and Perplexity all publish llms.txt files for their own developer documentation. That shows the format is taken seriously for software docs. It isn’t evidence that ChatGPT checks your file before naming a plumber.
One wrinkle: Google’s Chrome team has added an llms.txt check to Lighthouse, its free site-auditing tool, among checks for AI agents that browse websites. It only flags a file that returns a server error. A site with no file isn’t marked down.
So some tools may read your file and others ignore it, and you usually can’t confirm which. Be wary of anyone who claims to know more.
What goes in an llms.txt file?
Keep it short, with the detail one link away. For a service business, that usually means:
- Your business name as the title, written exactly as it appears on your Google Business Profile.
- A two- or three-sentence summary of what you do, for whom and where. “Residential plumbing, drain cleaning and water heater replacement for homeowners in Tampa, Brandon and Riverview” tells a tool far more than “quality service you can trust.”
- A few plain facts: service area, hours, whether you take emergency calls, licensing.
- A Services section linking each service page, with a one-line note on each.
- A Service areas section linking each town page.
- Key pages: about, case studies or reviews, FAQ, and how pricing works if you publish it.
- Contact details that match your listings exactly: phone, email, booking link.
- An Optional section for blog posts, guides and anything else a tool can skip.
Ours is a working example. Open hellionstudios.com/llms.txt and you’ll see:
- Our name as the title, then a blockquote summary: a two-person studio in Tampa, what we build, and that clients own what we build.
- A short list of facts: where we’re based, who’s on the team, that projects are fixed-fee, and that we don’t guarantee rankings or AI citations.
- Sections for services, pricing, industries, local pages, free tools, case studies, the products we own, company pages and contact.
- An Optional section linking our full-text file, our blog posts and our guides.
Notice what isn’t there: no slogans, no keyword lists, no claims nobody can check.
What about llms-full.txt?
llms-full.txt is a companion file that holds the full text of your important pages in one place, instead of links to them. It isn’t part of the llmstxt.org proposal. It’s a convention that grew up alongside it, and some documentation platforms and WordPress plugins generate both files.
llms.txt is the table of contents. llms-full.txt is the book. A tool that wants detail can read one file instead of visiting a dozen pages. Ours holds the full text of our service pages, industry pages, free tools, case studies and FAQs.
Whether it’s worth having depends on what you’d put in it:
- Worth it when you have real substance across many pages. A roofing company with detailed pages for repairs, replacements, storm damage inspections and gutters has plenty to put in.
- Not worth it when your site is five thin pages. Repeating thin copy adds nothing, and it’s one more file to keep current.
- Generate it, don’t write it by hand. A hand-assembled copy goes stale the first time someone edits a page.
Will an llms.txt file get you cited by ChatGPT?
Nobody can promise that, and anyone who does is guessing. There’s no public confirmation from the major AI companies that their assistants read the file when they answer questions, and Google says its Search ignores it.
So why bother? It costs little, Google says it won’t hurt you in Search, and some tools and browsing agents may use it. Writing one also makes you state plainly what you do, where, and which pages matter. But it’s one small part of making your business easy to understand. These matter more:
- Pages that can be crawled. If a page is blocked or carries a stray noindex tag, listing it in llms.txt doesn’t help. We cover the usual culprits in how sites accidentally hide from Google.
- Answer-first content. A service page that says in its first lines what you do, where you do it and how to book gives a tool something to quote.
- Consistent business details. Your name, phone, address, hours and services should match across your site, your Google Business Profile and your listings. When we worked with a San Antonio plumbing company, cleaning up business details across platforms was part of the job, alongside restructuring the site and adding AEO files.
- Structured data. Code on your pages that labels your business facts for machines. We explain it in structured data for AI answers.
The only way to know what AI tools say about you is to ask them. Here’s how to check whether ChatGPT recommends your business.
How do you add llms.txt to WordPress or Next.js?
Whatever the platform, the file has to end up at the root of your domain, so that yourdomain.com/llms.txt loads as plain text in a browser.
WordPress
Use a plugin. Some SEO plugins now include an llms.txt feature. Yoast SEO and All in One SEO (AIOSEO) each have a setting that generates the file from your site’s content and lets you choose what goes in it. If you already run one, check its settings before adding anything new. Then open the file and read it. A generator picks pages by its own rules, and you may need to adjust them so your service and town pages are listed, not just recent blog posts.
Or upload a static file. Write the file in a plain text editor, save it as llms.txt, and upload it through your host’s file manager or SFTP to your site’s root folder, usually the one that holds wp-config.php. You control every word, but nothing keeps it current. Change a service or your phone number and you have to update it by hand.
Pick one method. If you upload a file and also switch on a plugin’s version, one will quietly override the other.
Next.js
A static file in the public folder. Anything in public is served from the root, so public/llms.txt shows up at /llms.txt. Same trade-off as WordPress: simple, but nobody updates it for you.
A route handler that builds it from your data. This is what we do on hellionstudios.com. A route at app/llms.txt/route.ts builds the file from the same data our pages render: services, industries, case studies, blog posts and guides. It’s generated when the site is built, so when we publish a post or edit a service, the file changes on the next deploy. Our llms-full.txt works the same way. The file can’t drift from the site, because it’s made from the site.
Whichever route you take, the file is only useful while it’s true.
What mistakes should you avoid with llms.txt?
- Stale facts. An old phone number or a service you stopped offering, sitting in a file that reads as your own summary of yourself. Update it whenever your details change, or generate it.
- Links to pages that don’t exist. Dead links send a tool nowhere and waste space on a short list. Click through them after any site change, especially a redesign.
- Contradicting your own site. If the file says you serve six towns and your site lists four, a tool has to guess which is right. The file should say the same thing as your pages, in fewer words.
- Keyword stuffing. “Best plumber Tampa, cheap plumber Tampa, emergency plumber near me” helps no one. Write it the way you’d describe your business to a customer on the phone.
- Blocking it. If your robots.txt, a security plugin or your host’s firewall blocks AI crawlers, tools may never see the file. Load the address in a private browser window and check that robots.txt doesn’t disallow it. Blocking AI crawlers can be a fair business decision, but make it on purpose.
- Treating it as the whole job. A tidy llms.txt doesn’t fix thin pages or messy listings.
So, do you need one?
If your site is in decent shape, yes, add one. It’s a small job. Just keep the order right: crawlable pages, clear service pages and consistent business details first, then structured data and llms.txt on top.
Our AEO readiness checklist covers what to put in the file, along with structured data and a simple monthly test. To see what AI tools say about businesses like yours in your city, run the free AI visibility check. And if you’d rather hand off the whole job, including llms.txt and llms-full.txt generated from your own site, see our AEO work.