Free tool
llms.txt validator: test or generate your AI index
Paste a domain to verify your /llms.txt and /llms-full.txt files against the standard, check headers and link syntax, or generate a clean starter file tailored to your website.
What this llms.txt tool checks
- /llms.txt HTTP status & headers — Probes /llms.txt and verifies whether it returns 200 OK with text/markdown or text/plain (not an HTML fallback).
- Standard H1 project title & summary — Checks for the required # Project Title header and > blockquote summary line describing the project.
- Markdown section & link hierarchy — Parses ## Section headings and validates link formats (- [Title](url): Description).
- Absolute vs relative URL checks — Warns if links use relative paths rather than absolute URLs, which can confuse downstream LLMs.
- Companion /llms-full.txt check — Probes whether an optional full-text documentation companion file is published.
- Auto-starter generation — If no file exists, extracts your real page metadata and nav links to produce a valid starter file.
Frequently Asked Questions
What is an llms.txt file and who uses it?
llms.txt is an open markdown standard proposed to help Large Language Models (LLMs) and AI coding tools (such as Claude, Cursor, ChatGPT Search, and Perplexity) easily discover and read structured documentation about a project or website. Instead of traversing noisy HTML with navigation bars and cookies, AI systems fetch /llms.txt to get clean summaries and curated markdown links to key pages.
How does llms.txt differ from robots.txt?
robots.txt specifies permissions and crawler access rules (who is allowed to crawl which paths). In contrast, llms.txt is a curated index for AI models — providing high-signal summaries, links to core documentation, and context on what your product or library does. robots.txt governs access; llms.txt guides comprehension.
What is the difference between llms.txt and llms-full.txt?
llms.txt is a concise index containing a project title, short summary, and structured links to documentation pages. llms-full.txt (or llms-ctx.txt) is an optional consolidated file that bundles the complete full-text documentation into one file for LLMs with large context windows (like Claude 3.5 Sonnet or Gemini 1.5 Pro) to consume in a single read.
Where should I host my llms.txt file?
Place it at the root of your web server so it is publicly accessible at https://yourdomain.com/llms.txt. In modern frameworks like Next.js, Astro, Remix, Nuxt, or Vite, placing it in the /public folder (public/llms.txt) will automatically serve it from the root path upon deployment.
What Content-Type header should /llms.txt return?
The specification recommends serving llms.txt with Content-Type: text/markdown; charset=utf-8 or text/plain; charset=utf-8. Avoid returning text/html or redirecting 404s to a single-page app index.html shell.
Does having an llms.txt help with AI search visibility?
Yes. When an AI search engine or developer agent seeks authoritative context on your product, APIs, or pricing, checking /llms.txt allows it to ingest exact, curated links rather than guessing page structures from cluttered HTML. It acts as an authoritative sitemap for LLMs.
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