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

By Bill Stilwell · Last reviewed October 16, 2026

The short answer

llms.txt is a proposed text file that lists a site’s most useful pages for large language models (LLMs), the kind of artificial intelligence (AI) behind tools like ChatGPT. Google’s official guide says Google Search doesn’t use it and you don’t need it, though keeping one for other services is fine. For most local businesses, it’s optional and low priority. Your time is better spent on crawl access, clear pages, and accurate listings.

What this means

The llms.txt idea was proposed by Jeremy Howard in September 2024. The file sits at yoursite.com/llms.txt and is written in Markdown, a simple text format. It starts with your site’s name as a heading, can include a short summary, and then lists links to your key pages in sections.

It’s different from robots.txt. Robots.txt tells crawlers what they may visit. llms.txt is a suggested reading list. It doesn’t allow or block anything.

Say a plumbing company’s llms.txt lists its home page, its five service pages, its service area page, and its pricing page, each with a one-line description. That’s the whole file.

Why it matters

You’ll hear people say every business needs an llms.txt file to show up in AI answers. The official record doesn’t back that up.

Google’s guide to its generative AI features says you can ignore AI text files like llms.txt, and that Google Search doesn’t use them.
Google’s “AI features and your website” page says you don’t need new machine-readable files or AI text files to appear in AI Overviews or AI Mode.
As of this page’s review date, we found no official document from OpenAI, Anthropic, Perplexity, or Microsoft saying their search tools read llms.txt.
Google’s Lighthouse testing tool now checks llms.txt, but only flags server errors. A missing file is marked “not applicable.”

So the risk of skipping it is low. The cost of adding a simple one is also low. The real risk is paying someone for it as if it will change your results.

Who this applies to

Anyone deciding whether to add the file. It may be more useful for sites with lots of documentation, like software companies, than for a local service business with 10 to 20 pages.

How to do it

Decide whether you want one. Write down your reason. “My developer offered it and it took 10 minutes” is a fine reason. “It will get me into ChatGPT” is not supported by official sources.
If you add one, keep it simple. Start with a top heading line (a line that begins with one # sign) with your business name. Add a one-paragraph summary of what you do and where.
List your key pages under headings like “Services” and “About,” one link per line with a short description.
Upload it to the root of your site so it loads at yoursite.com/llms.txt.
Keep it in sync. When you add, rename, or remove a page, update the file. An out-of-date list is worse than none.
Don’t put anything in it you wouldn’t publish. It’s a public file.
Spend most of your effort elsewhere: crawl access (19.13.2), Bing (19.13.3), and clear, accurate pages (19.9 Writing Answer-First Content).

What proof to keep

A note in your website records with your decision and the date
If you publish one, a dated copy of the file
The page list it was built from, so you can update it later

Common mistakes

Paying for llms.txt as an “AI ranking” service. No official source says it affects rankings or citations.
Treating it like robots.txt. It doesn’t block or allow anything.
Letting it go stale. Broken links and old pages send the wrong message.
Making dozens of extra Markdown copies of every page without a reason. That’s more to maintain.
Skipping the basics because “we have an llms.txt now.”

When to get help from a pro

A web developer: if your platform doesn’t let you upload a file to the site root. Questions to ask:

Can we add a file at the root without breaking anything?
How will the file stay updated when pages change?

Bill’s note

[Bill: add your opinion here. For example, what you tell clients who ask about llms.txt, and whether you added one to SiteSmarty or BillStilwell.com and why.]

If you’d rather have this done for you, SiteSmarty builds and maintains websites for local businesses.

How I did this for SiteSmarty

[Date I did this:]
[What I actually did, step by step: whether I added llms.txt to SiteSmarty and what I put in it]
[What it cost and how long it took:]
[What surprised me or what I’d do differently:]
[Screenshot or photo to add, with private info blurred: the llms.txt file, or the note explaining the decision]
[Result so far:]

Questions people ask

Does Google use llms.txt? No. Google’s official guide says Google Search doesn’t use it and you don’t need it.

Does llms.txt help with ChatGPT? We found no official OpenAI document saying ChatGPT search reads it. OpenAI says to allow its OAI-SearchBot crawler if you want to show in ChatGPT search.

How do I make an llms.txt file? Write a plain text file in Markdown with your business name as a heading, a short summary, and links to your key pages. Upload it to your site’s root.

Is llms.txt the same as robots.txt? No. Robots.txt controls crawler access. llms.txt is only a suggested list of pages.

Audit check

Question: Is there a written decision about llms.txt, and if the file exists, is it accurate and current?
Pass looks like: A dated decision in the website records. If published, a short file at the root with working links to current key pages.
Fail looks like: Money spent on llms.txt as a ranking tactic. A file with broken or outdated links. A file used in place of fixing crawl or content problems.
Evidence to collect: The decision note, a dated copy of the file if it exists, and a link check.

Where this fits

Do this first: 19.13.1 How AI Tools Choose Sources, 19.13.2 AI Crawler Access

Do this next: 19.13.6 Tracking Traffic from AI Tools

Sources

llmstxt.org, "The /llms.txt file" (checked October 16, 2026)
Google Search Central, "Optimizing your website for generative AI features on Google Search" (checked October 16, 2026)
Google Search Central, "AI features and your website" (checked October 16, 2026)
Chrome for Developers, "llms.txt" (Lighthouse audit) (checked October 16, 2026)
OpenAI Help Center, "Publishers and Developers FAQ" (checked October 16, 2026)

This page explains general rules and Bill's own experience. It is not legal, tax, or insurance advice. Talk to a qualified professional about your situation.