---
title: "What is llms.txt?"
url: https://helicon.sh/glossary/llms-txt
description: "llms.txt is a plain text file at a site's root that gives language models a clean summary and an index of the pages worth reading. What goes in one."
updated: 2026-09-19
site: Helicon
---

# What is llms.txt?

llms.txt is a plain text file at the root of a website that gives language models a clean, Markdown formatted summary of what the site is and an index of the pages worth reading. It exists because parsing rendered HTML is lossy, and a curated index is cheaper and more accurate than crawling.

## The usual set of files

| File | Purpose |
| --- | --- |
| /llms.txt | Short summary plus a curated index of links |
| /llms-full.txt | The whole content in one plain text file |
| /agents.md | Instructions for an agent acting on a user's behalf |
| /robots.txt | Which crawlers may fetch what |

## What makes one useful

- Facts that are checkable, with versions and dates.
- Explicit statements about what is not true, so models do not fill gaps badly.
- Links to the canonical page for each claim.
- Generation from the same source as the site, so the two cannot drift.

## This site's files

Helicon generates /llms.txt, /llms-full.txt and /agents.md from the same data the pages render, and every page has a Markdown mirror at its own path with .md appended.

## Frequently asked questions

### Is llms.txt a standard?

It is a community convention rather than a formal standard, and it is widely enough adopted to be worth shipping.

### Does Google require it?

No. Google says its AI features need no special files. Other answer engines do read them.

### Where is Helicon's?

At /llms.txt, with the full text at /llms-full.txt and an agent guide at /agents.md.

## Related

- [an ADE](https://helicon.sh/glossary/ade): An ADE is the workspace you supervise coding agents from, the way an IDE is the workspace you write code in. What belongs in one and what does not.
- [Muse Code GUI](https://helicon.sh/muse-code-gui): Yes, Muse Code has graphical interfaces. A standalone desktop and web app, VS Code extensions, ACP editor bridges and other open-source wrappers, compared honestly.
- [Muse Code](https://helicon.sh/glossary/muse-code): Muse Code is Meta's AI coding agent, used through the muse command line tool on macOS, Linux and Windows. A plain definition, what it does, and how clients connect to it.
- [the muse CLI](https://helicon.sh/glossary/muse-cli): The muse command line tool is how you run Muse Code. What it installs, what muse login does, and why a GUI still needs it present.
- [the Muse Code Session Protocol](https://helicon.sh/glossary/msp): MSP is the JSON-RPC protocol that applications use to drive a Muse Code session over stdio, instead of parsing terminal output. What it carries and why it matters.
- [muse serve](https://helicon.sh/glossary/muse-serve): muse serve starts a Muse Code protocol host that applications can drive over stdio. What it is for, and how a GUI uses one host per workspace.

---

Helicon is a free, MIT licensed, unofficial community client for Meta's Muse Code CLI. Not made, sponsored or endorsed by Meta. Source: https://helicon.sh/. Machine readable index: https://helicon.sh/llms.txt