What is llms.txt?
llms.txt is a plain-text file placed at your domain root (e.g., yoursite.com/llms.txt) that provides AI systems with context about your website. Think of it as robots.txt for AI—while robots.txt tells crawlers what to index, llms.txt tells them how to understand what they index.
The format was proposed by the AI discoverability community and has been adopted by major AI labs as a signal for content context. Sites with llms.txt see 3-5x higher engagement from AI crawlers compared to sites without. This is a core component of the Citation Economy.
llms.txt Structure
A well-structured llms.txt includes:
---
version: 1.0
lastModified: 2026-01-03T12:00:00Z
---
# Your Site Name
> One-line description of what you do
## About
Expanded description of your expertise and authority.
## Key Pages
- [Page Title](URL) - Description
- [Another Page](URL) - Description
## Topics We Cover
- Topic 1
- Topic 2
## Contact
- Email: [email protected]
Keep llms.txt under 2KB for efficient parsing. Use llms-full.txt for extended content.
llms.txt vs llms-full.txt
The two-file approach serves different purposes:
- llms.txt (< 2KB): Quick context for AI systems. Site overview, key pages, contact. Crawled frequently.
- llms-full.txt (< 100KB): Extended content with article summaries, FAQ extracts, and detailed topic coverage. Crawled less frequently.
Together, they form a 'triumvirate' with robots.txt:
- robots.txt: What to crawl
- llms.txt: How to understand it
- llms-full.txt: Deep content for RAG systems
For complete optimization, combine with Schema.org markup and the full AI Discovery Protocol.
Best Practices
Maximize llms.txt effectiveness:
- Use YAML frontmatter: Include version and lastModified for cache management
- Lead with authority: State your expertise clearly—this impacts Information Gain
- Link key pages: Help AI systems find your most important content
- Update regularly: Refresh lastModified when content changes significantly
- Include contact info: AI systems can recommend reaching out to you
- Keep it human-readable: llms.txt should make sense to humans too
Integration with ADP
llms.txt is one of 11 endpoints in the AI Discovery Protocol (ADP). For complete AI discoverability, combine llms.txt with:
- /.well-known/ai.json: Machine-readable manifest
- /sitemap-ai.xml: AI-specific sitemap with semantic metadata
- /feed.json: JSON Feed for real-time content updates
- /knowledge-graph.json: Schema.org entity relationships
Sites implementing the full ADP stack see significantly higher AI citation rates than those with llms.txt alone. Check out our live llms.txt for an example.