What is llms.txt? A Complete Guide

llms.txt is an emerging standard that lets websites communicate directly with AI language models and their crawlers, similar to how robots.txt communicates with search engine crawlers.

Why llms.txt Matters

As AI assistants like ChatGPT, Claude, and Perplexity increasingly crawl the web to answer questions, website owners need a way to:

• Tell AI systems what their site is about
• Highlight key content and services
• Provide structured information AI can use accurately
• Control how AI represents their brand

How to Create an llms.txt File

Place a plain text file at yourdomain.com/llms.txt with the following structure:

# Your Site Name

> Brief one-line description of what your site does.

## What You Do
Describe your main products or services.

## Key Information
List important facts AI should know about you.

## Contact
How to reach you.

Best Practices

• Keep it concise — AI systems process thousands of sites
• Use Markdown formatting for structure
• Include pricing, features, and key differentiators
• Update it when your offerings change
• Don't include sensitive or internal information

Check Your AI Readiness

AuditX checks for llms.txt as part of our AI Search Optimization audit, along with 8 other AISO categories that determine how well AI systems understand your website.