llms.txt vs robots.txt: Understanding the Difference

If you're familiar with robots.txt, you might wonder how llms.txt fits into the picture. While both are plain text files that live at your website's root, they serve fundamentally different purposes.

robots.txt: The Gatekeeper

The robots.txt file has been around since 1994. Its job is simple: tell web crawlers what they can't access.

User-agent: *
Disallow: /admin/
Disallow: /private/
Allow: /public/

It's a restriction mechanism. You're saying "don't crawl these pages" to search engine bots and other automated systems.

What robots.txt Does

• Prevents crawling of specific URLs or directories
• Controls crawl rate for different bots
• Points to your sitemap
• Keeps private content out of search indexes

llms.txt: The Guide

The llms.txt file takes the opposite approach. Instead of saying what AI can't see, it tells AI what it should see.

# Your Company

> Brief description of what you do.

## Documentation
- [API Docs](https://example.com/docs/api)
- [Guides](https://example.com/docs/guides)

It's a recommendation mechanism. You're saying "here's the best information about us" to AI systems.

What llms.txt Does

• Points AI to authoritative documentation
• Provides context about your product or service
• Highlights the most important resources
• Helps AI give accurate answers about you

Key Differences

| Aspect | robots.txt | llms.txt | |--------|-----------|----------| | Purpose | Restrict access | Guide to content | | Approach | Exclusion-based | Inclusion-based | | Target | Search crawlers | AI assistants | | Content | Rules and disallows | Links and descriptions | | Goal | Privacy/control | Accuracy/visibility |

Do You Need Both?

Yes. These files complement each other:

• Use robots.txt to keep sensitive areas private from all bots
• Use llms.txt to highlight your best public content for AI

A website might block its admin panel in robots.txt while pointing to its public API documentation in llms.txt. They work together, not against each other.

A Practical Example

Consider an e-commerce platform:

robots.txt:

User-agent: *
Disallow: /checkout/
Disallow: /account/
Disallow: /admin/
Sitemap: https://shop.com/sitemap.xml

llms.txt:

# ShopCo

> ShopCo is an e-commerce platform for small businesses.

## Documentation
- [Seller Guide](https://shop.com/docs/sellers)
- [API Reference](https://shop.com/docs/api)
- [Integration Tutorials](https://shop.com/docs/integrations)

## Features
- Multi-channel selling
- Inventory management
- Payment processing

The robots.txt keeps checkout flows and user accounts private. The llms.txt helps AI assistants accurately describe ShopCo's features to potential customers.

The Shift in Web Standards

For 30 years, the web has been optimized for search engines. Now, as AI assistants become a primary way people find information, we need new standards to communicate with these systems.

robots.txt was built for an era of web crawlers indexing pages. llms.txt is built for an era of AI assistants answering questions.

Both have their place. Smart website owners will use both strategically.