LLMs.txt is a modern file designed to guide AI crawlers like ChatGPT, Claude, and Perplexity, while robots.txt is the original crawler directive file for traditional search engines like Google and Bing.
LLMs.txt helps websites define how AI models access, cite, and interpret their content — making it essential for visibility in generative search engines. In 2025, both files work together to optimize human and AI discoverability.
Introduction: Why This Matters in 2025
The rules of search have changed.
While Google, Bing, and Yahoo once ruled discoverability, AI-driven search engines like ChatGPT, Claude, Perplexity, and Google SGE now play a massive role in how users find content.
And yet, most businesses are still operating with just a robots.txt file.
To win in 2025, you need both robots.txt and the newer llms.txt — each designed for different types of crawlers, with different rules and outcomes. This article explains the difference, the purpose of each, and how to use them together for maximum visibility and AI citations.
What Is Robots.txt?
The robots.txt file has been around since 1994. It’s a simple text file that tells search engine crawlers (like Googlebot and Bingbot) what parts of your website they can access.
Key Functions of robots.txt:
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Controls access to directories or pages
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Prevents duplicate or thin content from being crawled
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Points bots to your XML sitemap
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Helps manage crawl budget
Example:
Great for technical SEO, but blind to AI crawlers like GPTBot or ClaudeBot.
What Is LLMs.txt?
Created in response to the rise of AI crawlers, llms.txt is a declaration file for Large Language Models (LLMs). It tells AI agents how they may interact with your content — and which pages should be prioritized for citation or structured extraction.
Key Functions of llms.txt:
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Grants or blocks access to AI bots like GPTBot, ClaudeBot, PerplexityBot
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Identifies “citation-worthy” content (via
Priority:declarations) -
Declares your brand entity and structured intent
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Works in harmony with
robots.txtbut speaks to a different audience
Example:
Priority: https://yourdomain.com/category/ai-seo/
Perfect for Generative Engine Optimization (GEO) and AI-first SEO.
Robots.txt vs LLMs.txt — Key Differences
| Feature | robots.txt | llms.txt |
|---|---|---|
| Audience | Search engine bots (Google, Bing) | AI crawlers (ChatGPT, Claude, Perplexity) |
| Purpose | Crawl/access control | AI citation & visibility declaration |
| Format | User-agent + allow/disallow | Access + metadata + structured discovery instructions |
| Sitemap Reference | Yes | Yes |
| Structured Signals | No | Supports E-E-A-T, entity info, citation intent |
| SEO Use Case | Index management, crawl budget | Snippet inclusion, zero-click discovery |
| Emerging Best Practice | Since 1994 | Rapid adoption since 2023 |
Do You Need Both Files?
Yes. Absolutely.
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robots.txt protects your technical SEO foundation
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llms.txt builds your AI discovery and citation foundation
Running a site without llms.txt in 2025 is like running a business without a mobile-optimized site in 2015. You’re invisible to the platforms that are shaping the future of search.
How to Use Robots.txt and LLMs.txt Together
To maximize discoverability without causing conflicts:
Best Practices:
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Don’t block important categories or content in
robots.txtif they’re listed inllms.txt -
Point both files to your sitemap
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Use
Priority:inllms.txtto flag content you want cited by AI -
Declare your business entity in
llms.txtto help LLMs link citations correctly
Real-World Example: Digital Marketing Group
At Digital Marketing Group in Marlton, NJ, we’ve implemented both files to support our AI-first SEO strategy.
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robots.txthelps us control crawl budget and eliminate duplicate content. -
llms.txthighlights key blog categories like SEO Strategies and Generative Engine Optimization, increasing our chances of being cited in AI results.
Within 60 days, we saw increased zero-click visibility in Perplexity AI and ChatGPT Web Browsing responses.
See It in Action: Who Is Using LLMs.txt?
Theories are helpful, but real-world examples are better. The following table curates a list of live llms.txt files currently deployed by major software platforms and AI researchers. Note how each organization customizes their implementation strategy to guide crawlers toward their most high-value data.
| Organization | File Location | Implementation Strategy |
|---|---|---|
| Anthropic | docs.anthropic.com/llms.txt | The “Dual-File” Method: Offers a standard navigation file and links to an llms-full.txt containing their entire documentation for single-pass AI ingestion. |
| Stripe | stripe.com/llms.txt | Product Mapping: Breaks down complex financial infrastructure into clear categories (e.g., Payments, Billing) to guide AI to documentation rather than marketing pages. |
| Cloudflare | developers.cloudflare.com/llms.txt | Developer Ecosystem: Serves as a root directory for a massive platform, linking out to distinct sub-sections for Workers, R2, and Zero Trust. |
| Vercel | vercel.com/llms.txt | Platform Architecture: Outlines frontend cloud architecture, specifically guiding AI to framework documentation (Next.js) and deployment guides. |
| Perplexity AI | docs.perplexity.ai/llms.txt | Dogfooding: As an AI search engine, they use the file to ensure their own API documentation is perfectly readable by other AI models. |
| Answer.AI | answer.ai/llms.txt | R&D Lab: A concise example for a research organization, listing projects and blog posts clearly to avoid visual clutter. |
| Zapier | docs.zapier.com/llms.txt | Integration Library: Uses the file to help AI agents understand how to connect their automation tools and specific API endpoints. |
| Digital Marketing Group | thinkdmg.com/llms.txt | Service-Based SEO: Highlights key categories (like “Generative Engine Optimization”) to increase citation probability and zero-click visibility in AI answers. |
The Future: Structured Discovery Is the New Ranking
By 2026, expect the line between “search engine” and “AI assistant” to blur entirely.
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Google SGE is already shifting how people interact with search
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ChatGPT’s web browsing uses
llms.txtas a visibility signal -
Perplexity and Claude are indexing structured content faster than Google
Having a robots.txt file isn’t enough anymore. To show up in answers, snippets, summaries, and sources, you need to communicate clearly to AI.
Conclusion
In 2025, robots.txt is your technical gatekeeper, and llms.txt is your AI handshake. Use both to control access, shape perception, and dominate both traditional and generative search engines.
Want help implementing the perfect llms.txt and robots.txt?
Contact Digital Marketing Group for a free AI SEO audit.
FAQ
Q: Do I need both robots.txt and llms.txt?
A: Yes. robots.txt governs search engine access; llms.txt manages AI crawler visibility and citation potential.
Q: Can I just add AI rules to robots.txt?
A: No. AI bots often ignore robots.txt unless they’re explicitly looking for llms.txt.
Q: Does llms.txt help my Google ranking?
A: Indirectly — it supports structured content that aligns with Google’s Helpful Content and Knowledge Graph systems.
Q: How do I deploy llms.txt?
A: Place it at https://yourdomain.com/llms.txt, just like you would with robots.txt.
