What is the llms.txt file?

llms.txt is a proposal published by Jeremy Howard. Placed at a website's root (https://yoursite.com/llms.txt), it presents a selection of resources and context in Markdown. Support depends on each tool: presence alone proves neither retrieval, indexing, nor use.

robots.txt controls access for crawlers that respect its directives. llms.txt has no such control function and should not be described as its equivalent.

A merchant may reference public UCP documentation and URLs in the file. Technical discovery of a UCP implementation should still follow the mechanisms specified by UCP and by the agent involved.

Structure and syntax of llms.txt

The file uses lightweight Markdown syntax. Here is the recommended structure for an e-commerce site:

# [Your Store Name]

> [One-sentence description of your store and what it sells]

## About
[More detailed description in 2-3 sentences: who you are, what you sell, your values]

## Catalog and Categories
- [Category 1 URL](https://yoursite.com/category-1/): [Short description]
- [Category 2 URL](https://yoursite.com/category-2/): [Short description]

## Featured Products
- [Product 1 URL](https://yoursite.com/products/product-1/): [Name, price, key feature]
- [Product 2 URL](https://yoursite.com/products/product-2/): [Name, price, key feature]

## Merchant Information
- Return policy: [URL], free returns within [X] days
- Shipping: [URL], free shipping over $[threshold]
- Customer service: [email or URL]
- Shipping zones: USA, Canada, UK

## UCP Endpoints (Universal Commerce Protocol)
- Catalog: https://yoursite.com/catalog/search
- Inventory: https://yoursite.com/catalog/lookup
- Checkout: https://yoursite.com/checkout-sessions
- Orders: https://yoursite.com/orders/{id}

Key sections for an e-commerce merchant

"About" section

Write a factual, precise description of your store. Avoid marketing jargon. If a tool retrieves the file, this section provides immediately usable context. For a gardening supply store: "Specialist in professional and amateur gardening equipment. We sell tools, irrigation systems, greenhouses, and garden accessories. Shipping across the US and Canada."

"UCP Endpoints" section

This section may reference documentation for endpoints that are actually operational. Do not assume that a UCP agent will discover them from this file alone: verify the discovery mechanism supported by its implementation.

"Merchant Information" section

Reference the canonical pages for returns, delivery times, and coverage areas. The file should point to those sources, not replace them.

llms.txt vs robots.txt: the differences

Aspect	robots.txt	llms.txt
Audience	Crawlers that respect the protocol	AI tools that choose to support the convention
Main function	Allow or disallow crawling of paths	Present selected resources and context
Format	Structured text directives	Free Markdown
Status	Standardized protocol, with crawler-specific support	Optional proposal, with variable support
Google Search effect	Can restrict crawling, without guaranteeing indexing	No positive or negative effect stated by Google

Where to submit your llms.txt

No central submission is required: publish the file on your own domain and keep it aligned with canonical pages.
llmstxt.org documents the proposal and its format.

Best practices and mistakes to avoid

Update llms.txt regularly. A file with broken links or outdated information is counterproductive. Plan a minimum quarterly review.

Don't list non-operational endpoints. A broken or premature URL makes the file inaccurate and reduces its documentary value.

Be factual, not marketing. "Best headphones in America" tells an AI agent nothing. "Bluetooth headphones $50-400, Sony, Bose, Jabra, US shipping" is actionable.

llms.txt for e-commerce: a publishing guide and its real limits