The LLMS.txt Domain Dilemma: Where Should You Actually Put Your File?

Here's a question that's been nagging at me since I started researching LLMS.txt files: If Anthropic puts theirs at docs.anthropic.com/llms.txt and Shopify uses shopify.dev/llms.txt, why isn't anyone talking about the fact that anthropic.com/llms.txt and shopify.com/llms.txt don't exist?

This isn't just a technical nitpick–it reveals a fundamental strategic challenge that could make or break your AI visibility. And for online business owners with courses on subdomains, membership sites, or multiple brand properties, getting this wrong could mean AI systems never find your most valuable content.

Let me break down what's really happening here and give you the strategic framework to make the right choice for your business.

Why Major Companies Are Splitting Their LLMS.txt Files

When I discovered that some of the biggest names in tech aren't putting their LLMS.txt files on their main domains, I had to dig deeper. Here's what I found:

The Content-Location Logic

Companies like Anthropic and Shopify are following a “content lives where content lives” approach:

• Anthropic's API docs live at docs.anthropic.com, so that's where their LLMS.txt goes
• Shopify's developer resources are at shopify.dev, so that gets the file
• It makes logical sense from a technical perspective

The Problem Nobody's Talking About

But here's the issue: if an AI system (or a human) looks for anthropic.com/llms.txt first, they hit a dead end. There's no standard for where to look, which creates a discoverability nightmare.

This fragmentation is happening because we're in the Wild West phase of LLMS.txt adoption. The big players are experimenting, but there's no consensus on best practices yet.

The Real-World Impact for Your Business

For most small to medium businesses, this domain confusion is actually an opportunity. While enterprise companies figure out their complex subdomain strategies, you can move faster and more decisively.

But first, you need to understand your business model and content structure.

The Four Business Models and Where Your LLMS.txt Should Live

The Simple Business (Most Website HQ Clients)

Your situation: One main website, all important content on your primary domain Strategy: Put your LLMS.txt file at yourdomain.com/llms.txt Why this works: AI systems will naturally check your main domain first, and all your content is there anyway

Example structure:

yourbusiness.com/llms.txt
- About your services
- Contact information  
- Key service pages
- Case studies or testimonials
- Blog highlights

This is the cleanest, most discoverable approach for most businesses.

The Course Creator with Subdomains

Your situation: Main business site at yourbusiness.com, but courses at learn.yourbusiness.com or academy.yourbusiness.com Strategy: Multi-file approach with cross-references Why this matters: Your courses might be your highest-value offering, but they're “hidden” from AI on a subdomain.

Recommended approach:

1. Main domain file (yourbusiness.com/llms.txt): Business overview with clear references to your course platform
2. Course subdomain file (learn.yourbusiness.com/llms.txt): Detailed course catalog and learning resources
3. Cross-link everything: Each file should reference the other

Example main file entry:

## Educational Resources
- [Complete Course Catalog](https://learn.yourbusiness.com): Our comprehensive training programs
- [Course Documentation](https://learn.yourbusiness.com/llms.txt): Detailed course information for AI systems

The Multi-Brand Business

Your situation: Multiple brands or distinct business lines on different domains Strategy: Separate LLMS.txt files for each brand, with strategic cross-references where appropriate Why this works: Each brand can speak with its own voice while maintaining discoverability.

The Complex Enterprise (Shopify/Anthropic Model)

Your situation: Main corporate site, developer portal, documentation site, community platform Strategy: Specialized LLMS.txt files for each audience, coordinated strategy Why this complexity exists: Different audiences need different information depth and focus.

How to Decide Your Domain Strategy

Ask yourself these three questions:

1. Where is your most valuable content? If your courses, tools, or key resources live on a subdomain, that subdomain needs its own LLMS.txt file. But don't abandon your main domain—use it to guide AI systems to your specialized content.

2. How do people naturally discover you? Most people will start at yourbusiness.com, so that's where your “front door” LLMS.txt should be, even if it primarily directs traffic elsewhere.

3. What's your growth strategy? If you plan to expand into multiple subdomains or business lines, design your LLMS.txt architecture now to accommodate this growth.

The Cross-Reference Strategy That Actually Works

Here's how to handle multiple domains without confusing AI systems:

Your main domain LLMS.txt should include:

## Platform Resources
- [Course Platform](https://learn.yourbusiness.com): Access our complete training library
- [Course Documentation](https://learn.yourbusiness.com/llms.txt): Detailed AI-readable course information
- [Community](https://community.yourbusiness.com): Join our member discussions

Your subdomain LLMS.txt should include:

## About [Your Business Name]
This is the course platform for [Your Business Name]. For complete business information, see [yourbusiness.com/llms.txt].

## Available Courses
[Detailed course listings...]

This creates a navigation web that helps AI systems understand your complete ecosystem.

The Technical Implementation

For the single-domain approach (recommended for most businesses):

1. Create one comprehensive LLMS.txt file
2. Place it at yourdomain.com/llms.txt
3. Include everything important about your business
4. Update it whenever you expand to new domains

For the multi-domain approach:

1. Start with a “hub” file on your main domain
2. Create specialized files for subdomains with significant content
3. Use clear cross-references between files
4. Maintain consistency in your business description across files

Future-Proofing Your Strategy

The LLMS.txt standard is still evolving, so design for flexibility:

Start simple: Begin with a single file on your main domain, even if you have subdomains Plan for growth: Structure your content so you can easily split it later if needed Monitor usage: Track which domains AI systems are actually checking (we'll cover this in a future article) Stay consistent: Whatever approach you choose, be consistent in how you describe your business across all files

What This Means for Your Competitive Advantage

While larger companies wrestle with complex domain architectures, smaller businesses can:

• Move faster with simpler, more discoverable implementations
• Be more comprehensive by putting everything in one place
• Create better user experiences because AI systems find your content immediately
• Adapt quickly as standards evolve

Your Domain Strategy Action Plan

If you have one main website: Put your LLMS.txt at yourdomain.com/llms.txt and include everything important about your business.

If you have courses on a subdomain: Create files on both domains with clear cross-references. Your main domain file should highlight your courses and point to the detailed course information.

If you have multiple business lines: Start with separate files for each domain, but ensure they're discoverable from your main brand domain.

If you're planning to expand: Design your main domain file to accommodate future growth, with sections you can later split into specialized subdomain files.

Your Domain Questions Answered

In this series:

1. Why Your Website Needs an LLMS.txt File (And What the Heck That Even Means)
2. What Industry Leaders Put in Their LLMS.txt Files (And How to Steal Their Strategies)
3. How to Create Your First LLMS.txt File: A Step-by-Step Guide
4. The LLMS.txt Domain Dilemma: Where Should You Actually Put Your File? –This article!