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

The /llms.txt file is a plain text file you place at the root of your website that tells AI systems what your site is about and which pages are most important. Think of it as a sitemap built specifically for ChatGPT, Claude, Perplexity, and other AI engines. It was proposed by Jeremy Howard in late 2024 and is now actively read by Claude, Perplexity, and some ChatGPT implementations.

Almost nobody has one yet. That is the opportunity.

Why does it matter?

When an AI crawler visits your site, it does not browse like a human. It fetches pages, reads text, and tries to determine what your business does, what expertise you have, and which pages contain your most important content. Without guidance, it guesses. Sometimes it guesses wrong and cites your About page when your Services page would have been more useful. Sometimes it skips you entirely because it could not figure out what mattered.

An /llms.txt file removes the guesswork. It gives the AI a curated index of your most important content, organized the way you want it presented. It is the difference between handing someone a messy filing cabinet and handing them a table of contents.

What does it look like?

The format is intentionally simple. Plain text, no special encoding, no programming required. Here is an example for a roofing company:

# llms.txt — AI Content Guide for Valley Roofing Co
# https://valleyroofing.com/llms.txt

title: Valley Roofing Co
description: Commercial and residential roofing contractor
  serving the Rio Grande Valley of South Texas since 1998.
  Licensed, bonded, insured. Free estimates.

# Pages available for AI reference

/services/: Complete list of roofing services including
  commercial flat roof, residential shingle, metal roofing,
  roof repair, and emergency storm damage response.

/about/: Company history, team, licenses, insurance,
  and service area covering McAllen, Edinburg, Mission,
  Pharr, and Weslaco.

/faq/: Common questions about roofing costs, timelines,
  insurance claims, and material options.

/blog/: Articles on roof maintenance, storm preparation,
  and choosing a contractor.

Lines starting with # are comments for context. The title and description fields identify your business to AI systems. Path entries list your key pages with descriptions of what each contains. Multi-line descriptions use two-space indentation.

How to create one for your business

Open a text editor. Write out the title and description of your business in plain language. List your most important pages — your services, your about page, your FAQ, your blog. Describe what each page covers in one or two sentences. Save it as llms.txt and upload it to the root of your website so it is accessible at yoursite.com/llms.txt.

The entire process takes 10 to 15 minutes. No developer needed. No code. No special tools.

What about /llms-full.txt?

The /llms-full.txt file is an optional companion. While /llms.txt is a curated index (like a table of contents), /llms-full.txt is a full content dump — the actual text of your key pages in one file. This gives AI engines your complete content in a format they can process without crawling multiple pages.

It is not required. Start with /llms.txt. If you want to go further, add /llms-full.txt later with the full content of your most important pages.

How SiteGrader checks for /llms.txt

SiteGrader checks for both files automatically as part of the GEO (Generative Engine Optimization) category. We verify whether /llms.txt exists, whether it contains the required title and description fields, and whether /llms-full.txt is available. A missing /llms.txt costs points on your GEO score because it is one of the most impactful things you can add for AI visibility.

Related

What are AEO and GEO? — The /llms.txt file is one piece of GEO. This guide covers the full picture of AI search optimization.

What SiteGrader checks — See all 65+ checks across 12 categories, including the GEO checks that cover /llms.txt.

SPF, DKIM, and DMARC — While you are creating your /llms.txt, make sure nobody can send emails pretending to be you.