llms.txt is a plain-text file placed at a website’s root (yoursite.com/llms.txt) that describes what a business does and links to its most important pages, written in language AI models can parse quickly. It is not required for a website to function, rank, or be crawled, but it removes ambiguity for AI systems trying to understand a site’s purpose. It works alongside robots.txt and sitemap.xml, not in place of either.
Why llms.txt Exists
As AI assistants like ChatGPT, Perplexity, and Claude increasingly browse the web on a user’s behalf, they face the same problem search engines solved decades ago: a webpage is full of navigation menus, cookie banners, marketing copy, and layout markup that has nothing to do with what the business actually offers. Language models are good at extracting meaning from messy HTML, but it costs processing time and introduces room for error.
llms.txt proposes a simple fix: a short, structured, plain-language summary at a predictable location, so an AI system doesn’t have to reconstruct a site’s purpose from scratch every time. It’s a young, informally-adopted convention, not a W3C standard or something every AI company has formally committed to supporting, but it costs almost nothing to add and several major AI crawlers are known to check for it.
What to Put in an llms.txt File
A useful llms.txt file is short and specific, not a full copy of your website. Typically it includes:
- A one-line description of what the business does
- A short paragraph of context (industry, specialty, location if relevant)
- A list of core services or products, in plain language
- Links to your most important pages (services, pricing, contact, key case studies)
- Basic contact information
Skip anything that isn’t genuinely useful for understanding the business: no marketing taglines, no full navigation menu, no legal boilerplate. The file should read like a briefing note, not a homepage.
Is llms.txt Actually Required?
No. There is no penalty for not having one, no AI company currently requires it to crawl or cite a site, and it isn’t part of any official web standard the way robots.txt (via the Robots Exclusion Protocol) or sitemap.xml effectively are. It sits in the same category robots.txt and sitemap.xml occupied in their early years: an informal convention gaining adoption because it solves a real, narrow problem, before it’s formalized (if it ever is).
That said, the cost of adding one is close to zero: it’s a single static text file, no build tooling or backend changes required. For a small amount of effort, it removes one more source of ambiguity for any AI system trying to represent a business accurately.
llms.txt vs robots.txt vs sitemap.xml
These three files are often mentioned together, but they do different jobs:
- robots.txt controls access: which bots and crawlers are allowed to visit which parts of a site. It says nothing about what the content means.
- sitemap.xml lists a site’s URLs in a structured XML format, mainly to help search engines discover pages efficiently. It’s built for machines, not for reading.
- llms.txt describes the content itself, in plain language, specifically written for AI models to read and summarize quickly. It doesn’t control access or list every URL, just the ones that matter most.
A well-configured site typically has all three, each doing a distinct job.
A Minimal Example
Here’s what a short, genuinely useful llms.txt file looks like for a small business:
# Acme Design Studio > Acme Design Studio designs and builds custom websites for small businesses in Austin, Texas. ## Services - Website Design - Website Maintenance - Basic SEO Setup ## Pages - Home: https://acmedesignstudio.com/ - Services: https://acmedesignstudio.com/services/ - Contact: https://acmedesignstudio.com/contact/ ## Contact - Email: hello@acmedesignstudio.com
Notice what’s absent: no navigation menu, no legal disclaimers, no marketing language, just the facts an AI system would need to accurately describe the business to someone asking about it.
Frequently Asked Questions
Where do I put an llms.txt file?
At the root of your domain, the same location as robots.txt: yoursite.com/llms.txt. It must be publicly accessible, not behind a login or a JavaScript-rendered route.
Does llms.txt affect my search engine rankings?
Not directly. It isn't a recognized ranking signal for traditional search engines like Google. Its purpose is narrower: helping AI language models understand a site's content faster and more accurately.
What happens if I don't have an llms.txt file?
Nothing breaks. AI crawlers will still read your regular pages if robots.txt allows them to. An llms.txt file simply makes that process faster and less ambiguous, it isn't a requirement for a site to be crawled or understood.
llms.txt is one piece of a larger checklist for making a site readable by AI agents.
Want This Set Up on Your Own Site?
Unyk Web Services can add an llms.txt file and the rest of an AI-readiness pass as part of a website build or as a standalone service.
See AI Visibility FAQs