What Is an LLM.txt File — and Does ChatGPT Actually Use It?

As AI tools like ChatGPT, Perplexity, and Gemini increasingly surface answers from the open web, a new question keeps coming up:

How does AI understand what my business actually does?

One emerging answer is the LLM.txt file.

This article explains:

  • What an LLM.txt file is

  • Whether ChatGPT and other LLMs actually use it

  • Why it matters (and when it doesn’t)

  • How to get one for your site

No hype — just how it really works.

What Is an LLM.txt File?

An LLM.txt file is a plain-text file placed at:

yourdomain.com/llm.txt

Its purpose is simple:

Help large language models quickly understand your business, content, and site structure.

Think of it as:

  • An executive summary for AI

  • A machine-readable explanation of:

    • What your company does

    • Who it’s for

    • What key pages are for

    • How your offerings relate to one another

It’s similar in spirit to:

  • robots.txt (for crawl rules)

  • sitemap.xml (for structure)

  • Schema markup (for meaning)

…but written for reasoning models instead of search indexes.

Does ChatGPT Actually Use LLM.txt?

The honest answer: sometimes — and only in specific contexts

Large language models work in two very different modes:

1. Model training (pre-training)

During training, models do not fetch live files like llm.txt.

So:

  • ❌ LLM.txt does not affect how a model is trained

  • ❌ It does not retroactively “teach” ChatGPT about your site

2. Inference with retrieval (this is where it matters)

When AI systems:

  • Browse the web

  • Cite sources

  • Answer questions with live data

They may retrieve and read llm.txt if it exists.

This is most relevant for:

  • AI search experiences

  • AI-generated citations

  • Answer engines that select and summarize sources

In those cases, llm.txt helps the model:

  • Understand your site faster

  • Choose the correct page to reference

  • Describe your business accurately

  • Avoid guessing or hallucinating details

What LLM.txt Does (and Does Not) Do

What LLM.txt helps with

✅ Clarifies your business model
✅ Explains page intent (“this page explains pricing”, “this page explains use cases”)
✅ Improves accuracy when AI already selects your site
✅ Reduces ambiguity for complex or niche businesses

What LLM.txt does not do

❌ It does not guarantee AI traffic
❌ It does not force ChatGPT to include your site
❌ It is not a ranking factor (there is no “AI SEO ranking” switch)
❌ It does not replace real content, authority, or demand

A useful way to think about it:

LLM.txt doesn’t make AI choose you — it helps AI understand you correctly once it does.

Why Businesses Should Care About LLM.txt

AI referrals are growing, but they work differently than traditional search.

Instead of ranking 10 blue links, AI systems:

  • Select a small number of sources

  • Summarize them

  • Attribute information selectively

That means:

  • Fewer chances to be included

  • Higher impact if you are included

  • Much higher cost of being misunderstood

For businesses with:

  • Multiple products or services

  • Technical offerings

  • Regulated or nuanced industries

  • Long sales cycles

Clarity matters more than ever.

LLM.txt is a low-effort way to reduce confusion when AI systems interpret your site.

How to Get an LLM.txt File

There are two approaches:

Option 1: Manual (advanced)

You can write one yourself using plain text. A good LLM.txt typically includes:

  • Business description

  • Target audience

  • Core offerings

  • Key page explanations

  • Important terminology

This works, but requires careful wording and upkeep.

Option 2: Automated (recommended)

You can generate an LLM.txt file automatically using GCCO AI View — completely free.

The generator analyzes:

  • Your domain

  • Your site structure

  • Your top pages

It then produces a ready-to-deploy llm.txt file designed to help AI systems understand your business and content accurately.

Once generated, you simply:

  1. Upload it to your site root (/llm.txt)

  2. Make it publicly accessible

  3. Update it as your site evolves

No signup required. No ranking claims — just a clean orientation layer for AI.

Final Takeaway

LLM.txt is not a silver bullet — and it shouldn’t be marketed as one.

But it is:

  • A practical orientation layer for AI

  • A clarity tool, not a traffic hack

  • A future-proof best practice as AI search grows

If AI systems are going to describe your business, cite your pages, or summarize your offerings…

…it’s worth making sure they understand you correctly.