llms.txt Explained: The Machine-Readable Summary File for LLMs
llms.txt is a simple file at your site root that gives AI models a curated, machine-readable map of your most important content. Google's agentic browsing audit checks for it. Here is what it is and how to write one.
What Is llms.txt?
llms.txt is a proposed plain-text (Markdown) file placed at the root of your domain that gives large language models a curated, machine-readable summary and index of your most important content. Google's agentic browsing category includes a check for its presence at the root[1].
Think of it as a hand-drawn map for AI. Where a sitemap lists every URL for crawlers, llms.txt curates the few things you most want a model to understand about your brand, products, and key documents — in language a model can ingest directly.
How llms.txt Differs From robots.txt and Sitemaps
The three files serve different machines and purposes:
| File | Audience | Purpose |
|---|---|---|
robots.txt | Crawlers | Rules: what bots may and may not crawl |
sitemap.xml | Search engines | A complete list of indexable URLs |
llms.txt | LLMs & agents | A curated, human-readable summary of your most important content |
How Do You Create an llms.txt File?
Keep it short, in Markdown, at https://yoursite.com/llms.txt:
- Open with an H1 — your brand name — and a one-line description of what you do.
- Add a short summary of your value proposition and primary products in plain prose.
- List your most important links under headings (Docs, Products, Pricing, Key Articles), each with a short note on what it covers.
- Keep it curated. This is not a sitemap — include only what you most want a model to learn first.
Once it is live at your root, the agentic browsing audit will detect it. Indexable's own site ships an llms.txt and passes the check.
Indexable's Technical SEO Agent Fixes This Automatically
The Technical SEO Agent audits every template against Google's agentic browsing checks and hands engineering a line-level fix sheet — CLS, accessibility tree, llms.txt, and WebMCP.
Frequently Asked Questions
Where does llms.txt go?
At the root of your domain: https://yoursite.com/llms.txt, the same location pattern as robots.txt. The agentic browsing audit checks for it there.
Is llms.txt the same as a sitemap?
No. A sitemap exhaustively lists URLs for search crawlers. llms.txt is a short, curated, human-readable summary of your most important content, written for AI models to ingest directly.
Most Sites Pass 1 of 3 Agentic Checks. Yours Could Pass All Three.
Indexable's ten-agent system audits agentic browsing readiness across every template, fixes the gaps, and monitors your score as the standard evolves.
Primary Sources Cited
- Google / Chrome Developers. Lighthouse Agentic Browsing scoring documentation. Published May 5, 2026. developer.chrome.com/docs/lighthouse/agentic-browsing/scoring