An SEO email lands in your inbox: "Your website is missing an llms.txt file, so AI tools like ChatGPT can't understand your business." It offers to set one up for a fee. Or your web designer mentions it, or a website audit tool flags it.

Here's what the file is, what it can and can't do for a small business, and how to add one yourself in about 20 minutes if you want it.

The quick answer

llms.txt is a short text file that summarizes your website for AI tools. It lives at yourbusiness.com/llms.txt.
It's optional. Google says you don't need it to appear in AI Overviews or AI Mode.
It's cheap to add, so it's fine to have one. Just don't pay much for it, and don't expect it to bring in customers by itself.
The things that do matter more: letting AI search bots read your site, a complete Google Business Profile, and clear pages.

What llms.txt is

llms.txt is a proposal by Jeremy Howard, first published in September 2024 and updated in August 2026. "LLM" stands for large language model, the technology behind ChatGPT, Claude and Gemini.

The idea: web pages are built for people, wrapped in menus, pop-ups and scripts. An AI tool reading your site has to dig through all that to find the useful part. An llms.txt file hands it a clean summary instead: who you are, what you do, and links to your most useful pages.

The format is plain Markdown (simple text formatting with # for headings and - for lists). The proposal sets out the order:

A heading with your business name. This is the only required part.
A short summary, written as a quote (a line starting with >).
Optional extra detail.
Sections of links, each under its own ## heading, with a short note on each link.

A small business version looks like this:

# Riverside Plumbing

> Licensed plumbing repair and installation for homes and small businesses in Augusta, GA. Same team since 2009.

- Phone: (555) 555-0123
- Hours: Monday to Friday, 8am to 5pm

## Services

- [Drain cleaning](https://riversideplumbing.example/drain-cleaning): Blocked sinks, showers and main lines
- [Water heaters](https://riversideplumbing.example/water-heaters): Repair and replacement, tank and tankless

## Company

- [About us](https://riversideplumbing.example/about): Who we are and our service area
- [Contact](https://riversideplumbing.example/contact): Call or book online

What llms.txt isn't

It isn't robots.txt. robots.txt tells bots what they're allowed to read. llms.txt is a guide, not a permission slip. Blocking or allowing AI bots is still done in robots.txt; see Should My Small Business Block AI Bots From Its Website?
It isn't a sitemap. Your sitemap lists every page for search engines. llms.txt is a short, hand-picked overview.
It isn't required by Google. Google's AI features documentation says: "You don't need to create new machine readable files, AI text files, or markup to appear in these features."

Does it actually help?

Honestly, it depends on who's reading.

Where it's used today: the proposal says llms.txt files are "used most heavily for software documentation," where coding assistants follow them to find the right instructions. Plenty of tech companies publish one for their developer docs, including OpenAI, Cloudflare and Perplexity, whose documentation pages point AI tools to their llms.txt index.

Where it isn't proven: we haven't found an AI search company that says it uses llms.txt to decide which local businesses to recommend. Google says plainly that AI Overviews don't need it.

Where it's heading: Google's Chrome team added an llms.txt check to Lighthouse, its free website testing tool, describing the file as "an emerging convention." If your site doesn't have one, the check is marked "Not Applicable," because providing the file is "optional at the moment."

So it's a reasonable bit of housekeeping, not a growth plan. We publish one on our own site at /llms.txt: it costs nothing to keep up and puts our services, contact details and best articles in one tidy place.

How to add one

Step 1: Check whether you already have one

Type your domain followed by /llms.txt into a browser. Some website platforms and SEO plugins create one automatically. If you see a page of text, you already have one; read it to make sure it's accurate. If you get a "page not found" error, you don't.

Step 2: Write it

Open a plain text editor (Notepad on Windows, TextEdit in plain text mode on a Mac) and fill in:

# Your business name
> One or two sentences: what you do, for whom, and where.
Your phone, hours and service area as a short list.
A ## Services section linking your main service pages, each with a one-line note.
A ## Company section linking About and Contact.
Optionally, a ## Blog posts section with your three to five most useful articles.

Keep it short. The proposal's point is a file "small enough to fit in context," so the detail stays on your actual pages. Only list pages that are already public.

Step 3: Put it on your site

The file must be reachable at exactly yourbusiness.com/llms.txt:

WordPress: check whether your SEO plugin has an llms.txt option first. If not, upload the file to your site's main folder with your host's file manager.
Squarespace, Wix and other site builders: search their help pages for "llms.txt" to see whether they offer a setting for it.
Custom sites: ask whoever maintains the site to add it. It's a five-minute job.

Step 4: Check it

Open yourbusiness.com/llms.txt in a private browser window. You should see your text exactly as written, not an error page or your homepage.

Keeping it right

The one real risk with llms.txt is that it goes stale. A file that lists an old phone number or a service you dropped is worse than none, because AI tools may repeat it.

Update it whenever your phone number, address, hours or services change, the same day you update your website and Google Business Profile.
Check it twice a year, and click every link.
Make sure it matches what your website and Google Business Profile say. Mismatched details confuse people and machines alike.

When to call someone

Your site builder won't let you add a file at the site's root and you still want one.
Someone quoted you a large fee for "AI optimization" built around an llms.txt file. Get a second opinion first.
You're not showing up in AI answers at all. The cause is almost always elsewhere: blocked bots, a thin Business Profile, or pages that don't say clearly what you do.

If any of that sounds familiar, get in touch.

What Is llms.txt, and Does My Business Website Need One?

The quick answer

What llms.txt is

What llms.txt isn't

Does it actually help?

How to add one