10 Common LLMs.txt Mistakes and How to Fix Them
Heads up! These 10 mistakes account for 95% of llms.txt validation failures. Learn how to avoid them and ensure your file works perfectly with AI systems.
#1: Missing H1 Header
The Problem: Starting your file without a level 1 heading or using the wrong syntax.
❌ Wrong
My Website Documentation
========================
## About Us
- [Home](https://example.com): Welcome page✅ Correct
# My Website Documentation
> Comprehensive documentation for our platform
## About Us
- [Home](https://example.com): Welcome pageFix: Always start with exactly one # followed by a space and your site name.
#2: Missing or Malformed Blockquote
The Problem: Skipping the required blockquote summary or using incorrect syntax.
❌ Wrong
# My API Documentation
This is a summary of our API documentation.
## Endpoints
- [Users API](https://api.example.com/users)✅ Correct
# My API Documentation
> Comprehensive API documentation for developers building integrations with our platform.
## Endpoints
- [Users API](https://api.example.com/users)Fix: Use > at the start of each summary line. Keep it concise but descriptive.
#3: Using Relative URLs
The Problem: Using relative paths instead of complete URLs.
❌ Wrong
## Documentation
- [Getting Started](/docs/getting-started): Start here
- [API Guide](../api/guide.html): API reference
- [FAQ](faq): Frequently asked questions✅ Correct
## Documentation
- [Getting Started](https://example.com/docs/getting-started): Start here
- [API Guide](https://example.com/api/guide): API reference
- [FAQ](https://example.com/faq): Frequently asked questionsFix: Always use complete URLs starting with https:// or http://.
#4: No H2 Sections
The Problem: Missing the required H2 sections to organize your content.
❌ Wrong
# My Website
> Great content for developers
- [Home](https://example.com): Welcome page
- [About](https://example.com/about): About us
- [Contact](https://example.com/contact): Get in touch✅ Correct
# My Website
> Great content for developers
## Main Pages
- [Home](https://example.com): Welcome page
- [About](https://example.com/about): About us
## Contact
- [Contact](https://example.com/contact): Get in touchFix: Group your links under logical H2 sections using ## syntax.
#5: Broken or Invalid URLs
The Problem: Including URLs that don't work or have typos.
Common URL Issues:
- • Typos in domain names (exampl.com instead of example.com)
- • Missing protocols (example.com/page instead of https://example.com/page)
- • Links to development/localhost URLs
- • URLs that return 404 or 500 errors
- • Password-protected or private URLs
Fix: Test every URL before adding it. Use our validator to check for broken links.
Quick Fix Reference
| Mistake | Quick Fix | Example |
|---|---|---|
| Missing H1 | Add # Title at start | # My Site |
| No blockquote | Add > summary | > Site description |
| Relative URLs | Use full https:// URLs | https://example.com |
| No H2 sections | Group links under ## | ## Documentation |
| Wrong link format | Use [Text](URL): Description | [API](https://...): Guide |
Other Common Mistakes
#6: Duplicate URLs
Including the same URL multiple times in different sections.
#7: File Too Large
Creating files larger than 500KB that may exceed AI context limits.
#8: Poor Link Descriptions
Using generic descriptions like "Click here" instead of descriptive text.
#9: Including Login-Required Pages
Linking to pages that require authentication or are behind paywalls.
#10: Inconsistent Formatting
Mixed spacing, inconsistent bullet points, or malformed Markdown.
Prevention Tips
- ✓Use our validator: Check your file with our free validator before publishing
- ✓Start with examples: Use our templates as a starting point
- ✓Test all links: Manually visit every URL to ensure it works
- ✓Keep it updated: Review and update your file regularly
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