AI File Formats: llms.txt, CLAUDE.md & AGENTS.md
llms.txt gives LLMs context about your website (844,000+ sites use it). CLAUDE.md provides project context to Claude Code. AGENTS.md is the emerging universal standard for all AI coding agents. These file formats are reshaping how AI interacts with your content and codebase.
The Essential AI Files
llms.txt
Website context for LLMs
Markdown file providing LLMs with structured information about your website, products, and content.
Location: Domain root (e.g., example.com/llms.txt)
Adoption: 844,000+ websites
CLAUDE.md
Project context for Claude Code
Automatically included in every Claude Code conversation. Defines codebase structure, conventions, and requirements.
Location: Project root
Adoption: All Claude Code projects
AGENTS.md
Universal AI agent instructions
One file for all AI coding agents. Setup commands, build steps, code conventions, testing workflows.
Location: Project root
Adoption: Growing standard
llms-full.txt
Complete website context
All content in one file — no link following required. Best for comprehensive context delivery.
Location: Domain root
Adoption: Used alongside llms.txt
Tool-Specific Files
Before AGENTS.md, each tool had its own instruction file. These still work but the trend is toward unification.
.cursor/rules/
Custom rules for Cursor AI
.github/copilot-instructions.md
Instructions for Copilot
JULES.md
Guidelines for Google's coding agent
GEMINI.md
Instructions for Gemini-based tools
.junie/guidelines.md
Project-level AI guidelines
Pro Tip: Use Symlinks
Create AGENTS.md as your source of truth, then symlink to CLAUDE.md, GEMINI.md, etc.
for backward compatibility: ln -s AGENTS.md CLAUDE.md
Why These Files Matter
AI Visibility
Help LLMs understand and recommend your content accurately
Consistent Agent Behavior
Same instructions regardless of which AI tool your team uses
Reduced Hallucination
Provide authoritative context to reduce AI mistakes
Developer Experience
Onboard AI tools to your codebase conventions instantly
The Numbers
844,000+ websites have implemented llms.txt as of late 2025. Major adopters include Anthropic, Cloudflare, Stripe, Zapier, ElevenLabs, and Hugging Face. The standard is becoming foundational for AI discoverability.
Frequently Asked Questions
What is llms.txt?
llms.txt is a machine-readable file that gives LLMs context about your website. Proposed by Jeremy Howard (FastAI) in September 2024, it lives in your domain root and uses markdown formatting. Over 844,000 websites now use it, including Anthropic, Stripe, and Cloudflare.
What is CLAUDE.md?
CLAUDE.md is a file that provides project context to Claude Code. It's automatically included in every conversation, telling the agent about your codebase structure, conventions, and requirements at the start of each session.
What is AGENTS.md?
AGENTS.md is an emerging open standard for AI coding agents, started by Sourcegraph with support from OpenAI and Google. Instead of separate files for each tool (CLAUDE.md, GEMINI.md, copilot-instructions.md), projects maintain one universal AGENTS.md file.
What's the difference between llms.txt and llms-full.txt?
llms.txt is an index file with links and descriptions - agents must follow links for details. llms-full.txt includes all content directly in one file, eliminating navigation. Use llms.txt for large sites, llms-full.txt for comprehensive single-file context.
Do AI platforms actually read llms.txt?
Major platforms haven't officially confirmed they read llms.txt. However, with 844,000+ sites implementing it and adoption by Anthropic, Cloudflare, and Stripe, it's becoming a de facto standard. The SEO community sees value regardless of official confirmation.
Should I use AGENTS.md or CLAUDE.md?
AGENTS.md is the emerging universal standard with GitHub Copilot, OpenAI, and Google support. However, Claude Code still uses CLAUDE.md. Best practice: use AGENTS.md as primary, create symlinks for backward compatibility with tool-specific files.
What other AI instruction files exist?
There's .cursor/rules/ for Cursor, .github/copilot-instructions.md for Copilot, JULES.md for Google Jules, .junie/guidelines.md for JetBrains Junie, and BTT.md or AGENT.md for BetterTouchTool. AGENTS.md aims to unify these.
Can you help implement these files for my projects?
Yes. We help teams create effective llms.txt files for AI visibility and CLAUDE.md/AGENTS.md files for coding agents. This includes structuring content, writing clear instructions, and optimizing for LLM consumption.
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