What is llms.txt, and does your site need one?
llms.txt is a proposed file that gives AI tools a summary of your site and its key pages. Here’s who reads it, when it’s worth adding and how to write one.
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llms.txt is a short Markdown file placed at the root of your site. It contains a summary of what the site is and links to the pages you most want AI tools to read. Jeremy Howard of Answer.AI proposed it in September 2024.
Over the past year, plenty of posts have claimed that without llms.txt you’re invisible to AI. That isn’t true. llms.txt is a proposal, not a standard, and none of the major search or chat platforms has officially said it uses the file. Even so, there are cases where adding one makes sense.
What does llms.txt do?
When a language model reads a website, it has to wade through HTML full of menus, cookie banners and scripts. llms.txt offers a clean entry point instead: here is what this site is, and here are the pages that matter. It’s most common on developer documentation, where software companies publish it so coding assistants read their docs correctly.
llms.txt does not replace robots.txt. It doesn’t allow or block any bot; it only maps the content you’d like read. Access rules stay in robots.txt.
Do Google and AI answer engines use llms.txt?
Google states that you don’t need any special AI file or markup to appear in AI Overviews or AI Mode; both draw on the regular search index. OpenAI, Anthropic and Perplexity haven’t said that llms.txt plays any role in how their search crawlers rank or choose sources either.
So treat llms.txt as a cheap convenience, not a traffic lever. Crawlable, fast pages that answer questions clearly will do far more for you than any file.
When should you add one?
If you run a software, SaaS or documentation-heavy site, it’s worth adding: it helps when users point a coding assistant or chat tool at your product. For an online store it isn’t a priority. Make sure your category and product pages are crawlable and descriptive first.
We publish one ourselves at marvedo.com/llms.txt. Not because we expect traffic from it, but because it took ten minutes to write and it’s an easy way to describe our product accurately to AI tools.
How to write an llms.txt file
The file lives at your site root, at yoursite.com/llms.txt, and it’s plain Markdown. The proposal suggests this order:
- A single H1 line starting with # for the site or product name.
- A blockquote starting with > that sums up the site in one or two sentences.
- Optionally, a few paragraphs of context below it: who you serve, which languages you cover.
- Sections starting with ##, each listing links as “- [Page name](URL): short description”.
- An “## Optional” section for secondary pages, which a tool can skip when it needs a shorter context.
What to watch out for
Make sure every link works and every page exists, and update the file whenever product names, prices or features change. Never put a claim in llms.txt that your site doesn’t make: AI tools cross-check sources, and inconsistency erodes trust.
This guide was prepared with AI assistance using official sources. Examples are not customer results and do not promise performance improvements.