---
title: "What Is llms.txt? Definition & How to Use It"
description: "llms.txt is a proposed plain-text/Markdown file at a site root that describes the site and points AI agents to key resources. An optional bonus, not a Google requirement."
canonical: https://aiovsseo.com/glossary/llms-txt.html
date: 2026-06-07
---
# What is llms.txt?

Definition

llms.txt is a proposed Markdown file placed at a website’s root that describes the site and links to its key resources, helping AI agents navigate it. It is an optional bonus — Google says it is not required to appear in generative search.

**llms.txt** is a proposed standard file (served at `/llms.txt`) that gives AI agents a concise, Markdown-formatted map of your site: what it is and where the important content lives. Think of it as a curated table of contents written for machines.

## Should you add one?

It is cheap to add and some third-party agents may use it, so it does no harm. But Google has stated plainly that you do *not* need special AI files to appear in generative search. Treat llms.txt as optional polish after the fundamentals.

## Related files

It sits alongside `robots.txt` (which governs crawling and, via [Content-Signal](/glossary/content-signal.html), AI usage) and an optional `/.well-known/mcp.json` manifest for the [Model Context Protocol](/glossary/model-context-protocol.html).

## Frequently asked questions

**Is llms.txt required for AI search?**

No. Google has explicitly said you do not need special AI files, markup, or Markdown to appear in generative search. llms.txt is an optional convenience for third-party agents.

**What is the difference between llms.txt and robots.txt?**

robots.txt governs whether crawlers may access content (and, with Content-Signal, how AI may use it). llms.txt describes and links your content for agents. See llms.txt vs robots.txt.