As artificial intelligence (AI) and large language models (LLMs) like ChatGPT, Claude, and Gemini grow more powerful, websites face new challenges and opportunities. One important tool for websites is the llms.txt file—a simple, standardized text file designed to help AI understand and use website content better. This guide explains what llms.txt is, why it matters, how it’s being adopted, and best practices for creating one. It also shows how platforms like Spotlight lead the way in making websites more visible in AI chat conversations.

What Is llms.txt and Why Was It Created?

llms.txt is a file placed in a website’s root directory (similar to the well-known robots.txt file). Its purpose is to provide clear, structured information specifically for large language models and AI agents. Unlike regular HTML or sitemap files, llms.txt is meant to be both machine-readable and human-friendly.

The idea behind llms.txt is to help AI systems better understand the website’s purpose, key resources, and content structure. This helps reduce errors or “hallucinations”—when AI gives wrong or misleading answers—and improves the accuracy of responses that mention your site.

The concept is still fairly new and evolving, but it was created in response to how AI models increasingly rely on web content to answer user questions and provide recommendations. By offering a standardized file, website owners can guide AI to their most important content and clarify usage terms.

How Does llms.txt Work in Practice?

When an LLM or AI agent visits a website—either to crawl, index, or fetch data—it looks for files that help it understand the site. If llms.txt is present at the root URL (for example, https://get-spotlight.com/llms.txt), the AI reads it to get:

A summary of what the website offers and who it serves
A list of key pages with descriptions (like documentation, blog, or API)
Metadata such as content update dates or version numbers
Optional instructions or license terms for using the content

This information helps the AI decide which parts of the site are most relevant to a user’s query. It improves the chances the AI will cite the site correctly and with helpful context.

For example, if a user asks an AI about the API of a cloud service, the AI can quickly find the API reference page from the llms.txt file, rather than guessing or relying on incomplete data.

Example of a Well-Formatted llms.txt

Here is a sample llms.txt file based on best practices recommended Anthropic, who established the standard:

# Spotlight - Brand Visibility in AI Conversations

## What is Spotlight?

Spotlight (get-spotlight.com) is a SaaS platform that helps brands monitor, measure, and improve their visibility within AI chat conversations. Spotlight tracks how brands appear across major AI platforms and provides actionable insights to improve AI-generated visibility.

## Supported AI Platforms

Spotlight currently monitors 8 major AI platforms:
- ChatGPT
- Google AI Overviews
- Google AI Mode
- Grok
- Gemini
- Claude
- Perplexity
- Copilot

## Core Capabilities

### Prompt Discovery & Analysis
Spotlight discovers the most searched prompts that brands would want to appear in—queries their potential customers ask when searching for products or services the brand offers. Prompts are grouped by topics aligned with the brand's marketing objectives, and Spotlight measures each prompt's search volume to help prioritize actions.

### Weekly Monitoring
All discovered prompts are sent to all 8 AI models weekly using local IPs to get geographically relevant responses. This ensures brands understand how they appear to users in different regions.

### Brand Mention Analysis
Spotlight analyzes AI responses to:
- Identify brand mentions across all platforms
- Evaluate sentiment around brand mentions
- Compare positioning against competitors
- Track visibility rankings over time

### Citation & Source Tracking
The platform captures and analyzes:
- All citations and data sources used by AI models in their responses
- The queries ChatGPT uses to fetch fresh data from the web
- How often each piece of brand-owned content is cited by each model over time
- What types of websites each model prefers to cite

### Competitive Intelligence
Spotlight provides:
- Visibility rankings showing how brands compare to competitors
- Sentiment breakdowns for brand mentions
- Analysis of what makes high-visibility brands successful
- Reverse engineering of successful content strategies

### Content Optimization
Spotlight includes tools to improve visibility:
- Content grading system that evaluates existing webpages
- Optimization guidance for both technical and content aspects
- Gap analysis identifying prompts where brands don't appear
- Content suggestions that directly address missing prompt coverage

### Traffic Attribution
Spotlight integrates with Google Analytics to:
- Track traffic coming from LLMs
- Identify which LLM drove the traffic
- Show which pages received LLM traffic
- Close the loop between AI visibility and actual website traffic

### Reputation Monitoring
Spotlight has a dedicated section for brand reputation on AI chatbots:
- Sends prompts directly asking models about brand quality, value, and key metrics
- Analyzes and scores how the brand is perceived by each model
- Includes data sources used by models, allowing users to manage negative inputs

## Use Cases

- Marketing teams monitoring brand visibility in AI search results
- SEO professionals optimizing for Generative Engine Optimization (GEO)
- Brand managers tracking reputation across AI platforms
- Content teams creating AI-optimized content
- Competitive intelligence professionals benchmarking against competitors
- Product teams understanding how their offerings are described by AI

## Target Audience

Spotlight is designed for:
- Brands seeking to improve visibility in AI-generated responses
- Marketing teams focused on GEO (Generative Engine Optimization)
- Companies monitoring how AI platforms present their brand
- Organizations optimizing content for AI citations
- Businesses tracking competitor positioning in AI conversations

## Technology

Spotlight is built by AI agents, enabling rapid development of new features and adaptation to the fast-changing landscape of AI search and visibility.

For more information, visit https://get-spotlight.com

Why Are More LLMs and AI Tools Starting to Use llms.txt?

Adoption of llms.txt is growing as AI developers realize the benefits of structured site info. Several reasons explain this trend:

Improved Accuracy: AI models that access llms.txt can reduce hallucinations by relying on verified site descriptions.
Efficient Data Access: AI can quickly focus on relevant pages rather than crawling the entire site.
Better User Experience: End users get more precise answers with proper citations.
Standardization: Having a common file format simplifies integration across different AI platforms.

Currently, only 2 LLMs are official using llms.txt – Claude and Grok. However the rest of the LLMs are considering reading the file when analyzing a website. Server logs show evidence that ChatGPT is accessing the llms.txt files, but there is no evidence that the files’ content is currently considered in OpenAI’s responses.

What Are the Best Practices for Creating an Effective llms.txt File?

Creating a useful llms.txt file means balancing clarity, completeness, and usability. Here are expert recommendations:

1. Where and How Should You Place the File?

Put llms.txt in the root directory of your website (https://yourdomain.com/llms.txt).
Use plain text format, but include Markdown-style headings and bullet points for readability.
Ensure it’s accessible without login or special permissions.
Set content-type HTTP header to text/plain.

2. What Should the Structure and Content Include?

Header/Title: One-line description of the website.
Summary: 2-4 sentences explaining site purpose, audience, and offerings.
Key Resources: List of important URLs with short, clear descriptions.
Metadata: Dates, version numbers, content types (tutorial, reference, blog).
Optional Sections: Sitemap link, contact info, license terms, update frequency, special instructions.

3. How Should You Write the Content?

Be concise but informative.
Prioritize your most valuable pages first.
Avoid marketing fluff or vague language.
Don’t list every page—focus on key content.
Use absolute URLs, not relative ones.

4. What Are Technical Tips to Remember?

Keep file size small (under 100KB).
Update regularly to reflect site changes.
Use proper HTTP headers.
Add a “last updated” timestamp.

5. What Should You Avoid?

Avoid listing internal or private URLs.
Skip broken or outdated links.
Don’t use the file to manipulate AI outputs unethically.
Avoid excessive promotional language.

What Is the Current State of llms.txt Adoption Across AI Models?

Adoption of llms.txt is still in early stages but growing steadily. Here’s what we know from industry observations:

✅ Claude: Actively supports llms.txt as part of its web browsing and citation process.
✅ Grok: Considers llms.txt for content prioritization.
❌ ChatGPT: Not currently using llms.txt , however server logs show their bots accessing the file.
❌ Perplexity: Not currently using llms.txt.
❌ Gemini: Not currently using llms.txt .
❌ Google AI Overviews: Not currently using llms.txt.
❌ Google AI Mode: Not currently using llms.txt.
❌ Microsoft Copilot: Official not currently using llms.txt.

While most models do not yet fully support it today, it is likely to see growth in adoption in the near future.

How Can Website Teams Create and Maintain an Effective llms.txt File Step by Step?

Follow these steps to build a strong llms.txt file:

Plan Your Content: Identify your site’s main purpose, target audience, and key pages.
Write a Clear Header and Summary: Keep it simple and informative.
List Key Resources: Choose your top pages (documentation, blog, API, etc.). Write concise descriptions.
Add Metadata: Include dates, version info, and content types for clarity.
Include Optional Details: Sitemap URL, contact info, usage license, update notes.
Format Using Plain Text and Markdown Style: Use headings, bullet points, and line breaks.
Place the File at Your Root URL: Upload to https://yourdomain.com/llms.txt.
Set HTTP Headers: Ensure content-type is text/plain.
Test Accessibility: Check that AI crawlers and humans can access the file.
Update Regularly: Review and revise as your site changes.

What Are Some Authoritative Views on the Importance of Structured Files Like llms.txt?

AI and SEO experts emphasize that structured site metadata is critical for AI-powered search and discovery.

John Mueller, a Webmaster Trends Analyst at Google, has stressed the importance of clear site structure and metadata for search engines to understand content. While not specifically about llms.txt, his insights apply: “Structured data helps search engines and AI better understand your site, which can lead to better visibility and user experience.”

Additionally, researchers at Stanford University’s AI Lab highlight that AI systems benefit significantly from explicit, standardized signals about content origin and purpose to reduce misinformation.

These expert opinions underline why tools like llms.txt will become a standard part of website optimization in the AI era.

FAQ

What is the difference between llms.txt and robots.txt?

robots.txt tells search engine bots which pages to crawl or avoid, mainly to control indexing. llms.txt provides structured, descriptive information to help AI language models understand and use your website content better. Both live in the root directory but serve different purposes.

How does llms.txt reduce AI hallucinations?

By giving AI clear, authoritative descriptions and links to key resources, llms.txt helps prevent the AI from guessing or inventing answers based on incomplete data. This leads to more accurate and trustworthy AI responses.

Can I generate llms.txt files automatically?

You can copy the example in this post as a reference, add a description of your website, and have an LLM generate a llms.txt file automatically. However, manual review and customization ensure the file accurately reflects your site’s content and strategy.

Should llms.txt replace sitemaps or structured data?

No. llms.txt complements sitemaps and structured data by providing a human-readable, AI-focused overview. Use it alongside other SEO tools for best results.

How often should I update my llms.txt file?

Update it whenever you make significant changes to your website’s content, structure, or key resources. At minimum, review quarterly to keep it current.

Does Spotlight support llms.txt optimization?

Yes. Spotlight offers insights and recommendations related to llms.txt as part of its comprehensive AI visibility platform. It tracks how LLMs use site information and suggests improvements to maximize AI-driven traffic and brand mentions.

Conclusion

llms.txt is an emerging but powerful tool that helps websites communicate clearly with AI language models. It provides structured, concise information that improves AI understanding, reduces errors, and boosts your site’s chances of being cited accurately. Adoption is growing among major AI platforms, making it an important part of future-proofing your website for AI-driven search.

Brands and website owners looking to lead in this space should consider creating and maintaining a strong llms.txt file. Platforms like Spotlight offer advanced support for monitoring and optimizing AI visibility, helping brands stay ahead in this fast-evolving landscape.

By following best practices for llms.txt, you can help AI systems find, understand, and use your content effectively—enhancing your brand’s presence in the AI-powered web of tomorrow.

References

Google Search Central – robots.txt specifications
Stanford AI Lab
John Mueller, Google Webmaster Trends Analyst, Twitter
Anthropic Blog on Claude AI https://www.anthropic.com/blog
OpenAI API Documentation https://platform.openai.com/docs

What Is llms.txt and How Can It Help Your Website Be Seen by AI?