What is llms.txt, and does your website need one?

By PHP Site Manager team · Updated Oct 22, 2026 · How it works

Short answer: llms.txt is a plain text file at the root of a website (yoursite.com/llms.txt) that summarises the site and links to its most useful pages, written for AI tools rather than people. It is optional, cheap to add and harmless, but it is not a ranking factor, and Google has said it does not use it.

Where llms.txt came from

The format was proposed in September 2024 by Jeremy Howard, co-founder of Answer.AI. The idea is simple: web pages are full of menus, scripts and layout that make it harder for a language model to find the useful content, so give it a clean summary instead.

What goes in the file

An llms.txt file is written in Markdown:

A main heading with the name of the business or project
A short summary in a quote block
Optional plain notes with key facts
Headed lists of links to important pages, each with a one-line description
An "Optional" section for pages a tool can skip if it is short on space

Here is a short example for a plumbing business:

# Clearline Plumbing

> Licensed plumbers in Westmere and nearby towns. Leak repair, drain cleaning, water heaters and repiping. Same-day appointments.

## Services
- [Drain cleaning](https://example.com/drains): kitchen, bath and main line clogs
- [Water heaters](https://example.com/water-heaters): repair and replacement

## Contact
- [Book a plumber](https://example.com/contact): phone, hours and service area

You can see a live one at phpsitemanager.com/llms.txt.

Who uses it

Support is uneven. Some AI tools and developer platforms read llms.txt files, and many documentation sites publish them. Google is the notable exception. Gary Illyes of Google has said Google does not support llms.txt and has no plans to, and John Mueller has compared it to the old keywords meta tag. Google's own guidance on AI features says you do not need new machine readable files, AI text files or special markup to appear in AI Overviews or AI Mode.

Should a small business bother?

It costs nothing to include if your website platform writes it for you, and it gives a tidy, accurate summary to any tool that does read it. Just do not expect it to change rankings. The things that move the needle are much older:

Let search crawlers in (check your robots.txt)
Put real facts in real text: services, prices, hours, area, phone
Add structured data for your business type
Keep your Google Business Profile complete and accurate
Earn reviews and mentions on sites your customers trust

Every PHP Site Manager site gets an llms.txt file written and updated automatically from its pages, alongside the fundamentals above. Want to see where your current site stands? Try our free AI readiness check.

Sources: Google Search Central: AI features and your website; The Agile Brand Guide: llms.txt. Checked 22 October 2026.