# llms.txt validator

_Source: https://seomatrix.ai/tools/llms-validator/_

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## What it does

llms.txt is a plain-Markdown file at your site root (/llms.txt) that gives AI crawlers a curated map of your most important pages, and this check confirms it both exists and follows the llmstxt.org format — an H1 title, a summary, section headings, and link lists. A missing or malformed file means any AI crawler that looks for an llms.txt index finds nothing and has only your raw HTML to infer site structure from, so a clean, valid llms.txt makes your key content easier to find, read, and cite.

## What it checks

- **File exists at root** — The validator requests /llms.txt at your domain root and confirms it returns HTTP 200 as plain text/Markdown — AI crawlers only look there, so a file buried in a subfolder is invisible.
- **H1 title line** — The spec requires the first line to be a single H1 (# Site name) naming the project — it's the anchor an engine reads to identify whose content this is.
- **Blockquote summary** — A short `>` summary directly under the title tells the model what the site is about in one sentence, priming it to summarize and cite you accurately.
- **H2 section headings** — Content is grouped under `##` sections (Docs, Guides, API), giving the file a scannable structure the crawler can navigate by topic.
- **Link lists** — Each section lists `- [title](url): description` entries pointing to your key pages; well-formed links are what actually route the AI to citable source material.
- **File size / conciseness** — llms.txt is meant to be a lean index, not a dump — an oversized file risks truncation or being ignored, so the check flags files that blow past a sensible size.

## How to use it

1. Paste your site URL (or the direct /llms.txt link) and run the check.
2. Review the flagged items — missing file, absent title or summary, sections with no links, or an oversized file.
3. Fix the gaps in your llms.txt (or regenerate it with the paired generator) and re-run until it validates clean.

## FAQ

### Where should llms.txt live?

At your domain root, reachable at https://yourdomain.com/llms.txt. AI crawlers only check that exact path, so placing it in a subfolder makes it invisible.

### What makes an llms.txt 'well-formed'?

It follows the llmstxt.org format: a single H1 title, an optional blockquote summary, one or more H2 sections, and Markdown link lists under them. This validator checks each of those parts plus overall size.

### Is llms.txt the same as llms-full.txt or robots.txt?

No. robots.txt controls crawler access, llms.txt is a curated Markdown index of your best pages, and llms-full.txt bundles the full page bodies into one file. This tool validates the llms.txt index.

### Does a valid llms.txt guarantee I'll be cited?

No — it removes a technical barrier by making your content easy to find and parse, but citation still depends on the quality and relevance of the pages you link to.