What is llms.txt, and should your website have one?
By Dawid Makowski · 5 June 2026 · 6 min read
llms.txt in one paragraph
llms.txt is a markdown-formatted text file placed at a website's root (yoursite.com/llms.txt) that gives AI engines and agents a structured, plain-language summary of the business: what it does, what it offers, and where its key content lives. It helps large language models represent the site accurately.
Websites are written for humans and styled for browsers. AI crawlers have to reverse-engineer meaning from navigation, marketing copy and markup, and they often get it wrong or give up. llms.txt addresses this directly: one file, at a predictable address, that says in plain structured text what the site is and where the important things are.
How does llms.txt differ from robots.txt?
robots.txt controls access: which crawlers may fetch which paths. llms.txt provides understanding: what the content means and how it fits together. They complement rather than compete. A third file, ai.txt, is sometimes deployed alongside to state usage permissions for AI systems, whether and how content may be used in AI-generated responses.
| File | Purpose | Audience |
|---|---|---|
| robots.txt | Crawl permissions and sitemap location | All crawlers |
| llms.txt | Structured description of the business and content map | AI engines and agents |
| ai.txt | Usage permissions for AI training and answers | AI systems |
What goes in a good llms.txt?
The convention is markdown: an H1 with the site name, a blockquote summary, then sections of annotated links. For a business site, the file should cover:
- Identity. Company name, location, founding context and a one-paragraph description of what the business does.
- Services. Each service line with a one-line description and its URL.
- Audience. Who the business serves: sectors, company sizes, regions.
- People. Leadership names, roles and credentials, since AI engines weigh who is behind a firm.
- Content map. Key pages and articles with one-line annotations so an agent can route to the right resource.
- Contact. How to reach the business, including the official email and profiles.
Does llms.txt actually get read?
Adoption is growing and uneven, which is normal for a young convention. Some AI crawlers fetch it routinely; others do not yet. The cost of deployment is an hour of writing and a file upload, and the file doubles as the canonical plain-language description of your business, useful well beyond AI crawlers. Low cost, growing upside, no downside: deploy it.
Common deployment mistakes
- Serving HTML instead of text. If your server routes unknown URLs to the homepage, yoursite.com/llms.txt returns a webpage with a 200 status and AI agents read garbage. The file must be served as plain text from the actual path. This catch-all routing problem is one of the most common failures we find in audits.
- Writing marketing copy. The file is for machines that summarise. Adjectives dilute it; facts concentrate it. State what the business does, for whom, where.
- Letting it rot. An llms.txt that contradicts the live site erodes the trust it was meant to build. Update it when services or pages change.
How to deploy it
Write the file in markdown, name it llms.txt, place it in your web root, and confirm that fetching yoursite.com/llms.txt returns the raw text with a text/plain or text/markdown content type. Pair it with ai.txt if you want to state usage terms. Then verify your robots.txt and sitemap are also served correctly, the three files fail together when server routing is broken. You can see a live example at i12ai.com/llms.txt.
Quick answers
Where does llms.txt go?
At the web root, so it resolves at yoursite.com/llms.txt, the same location pattern as robots.txt. It must be served as plain text, not routed to an HTML page.
Is llms.txt an official standard?
It is a community convention rather than a ratified standard, proposed in 2024 and adopted incrementally by AI crawlers and site owners since. Conventions of this kind (robots.txt included) typically harden through adoption.
Do I need both llms.txt and ai.txt?
llms.txt is the higher-value file: it describes your business. ai.txt adds usage permissions for AI systems. Deploying both takes little extra effort, and together they cover description and permission.
Want your llms.txt, schema and entity stack done properly?
Our GEO service deploys the full AI-discovery layer and verifies every file serves correctly.