Do I need both llms.txt and llms-full.txt?

No — most sites only need llms.txt. llms-full.txt is a supplement for content-heavy sites (documentation, long articles, JS-rendered pages) where the curated index alone doesn't give AI agents enough material. Start with llms.txt, add llms-full.txt when agents need more than your 5–15 best pages.

Where does llms-full.txt live and how do agents find it?

It lives at your site root by convention — https://your-domain.com/llms-full.txt — and you link to it from llms.txt using a relative Markdown link ([llms-full.txt](llms-full.txt)). Agents that follow the convention check both files.

Does llms-full.txt cause duplicate content problems for SEO?

No. Google has stated it does not read llms.txt at all, so neither file affects Google rankings or triggers duplicate-content penalties. The files are for AI engines (ChatGPT, Claude, Perplexity, Gemini), not search crawlers.

llms.txt spec · AI content strategy · Updated 2026

llms.txt vs llms-full.txt: What's the Difference and Which Do You Need?

llms.txt is a curated index of your best pages. llms-full.txt is the entire site content in one Markdown file. Different jobs, different sizes — here's how to choose.

The Short Answer

llms.txt gives AI agents a map of your site: a small, curated Markdown list of the pages that matter most. llms-full.txt gives them the territory: the full text of your content, formatted as Markdown, in a single file. The spec at llmstxt.org treats llms.txt as the primary file — llms-full.txt is an optional companion for sites where the map alone isn't enough.

What llms.txt Is (and Isn't)

An llms.txt file is a short Markdown document at your site root. It opens with an H1 (your site name) and a one-line > blockquote summary, followed by a curated list of links — usually your 5 to 15 most important pages, grouped under ## headings.

# Example Site

> A concise description of what the site is and who it's for.

## Documentation

- [Getting Started](https://example.com/docs/getting-started)
- [API Reference](https://example.com/docs/api)

## Blog

- [How We Built X](https://example.com/blog/how-we-built-x)

The job of llms.txt is prioritization. An agent that lands on your site can read this file in milliseconds and know exactly which pages are worth fetching — instead of guessing from a crawl or landing on your marketing pages.

What llms-full.txt Is

llms-full.txt is the same idea scaled up: your site's full content, converted to Markdown and merged into one file, served from https://your-domain.com/llms-full.txt. It's meant for situations where the curated index isn't enough material for the agent:

Documentation sites — an agent needs the actual API docs, not just a link to them.
Long-form content — tutorials and guides that span thousands of words.
JS-rendered pages — content that doesn't exist in the raw HTML an agent fetches.
Research-heavy sites — papers, data pages, reference material agents should read in full.

You link to it from your llms.txt with a relative Markdown link:

# Example Site

> A concise description of what the site is and who it's for.

## Documentation

- [Getting Started](https://example.com/docs/getting-started)
- [API Reference](https://example.com/docs/api)

[llms-full.txt](llms-full.txt)

Key Differences at a Glance

	llms.txt	llms-full.txt
Content	Curated link list	Full site content as Markdown
Typical size	1–5 KB	10 KB – several MB
Purpose	Prioritize what agents read	Give agents everything at once
Required?	Yes (the primary file)	Optional
Best for	Every site	Docs, long-form, JS-heavy sites

Which One Do You Need?

Start with llms.txt alone. It's the file every AI engine checks first, it's trivial to maintain, and for most sites the curated list is exactly what an agent needs. Add llms-full.txt when you observe that agents need more material — typically once your site has substantial documentation or long-form content, or when you want AI engines to be able to answer from your content without fetching every page.

There's no penalty for having both, and no penalty for having just llms.txt. The only real mistake is treating llms-full.txt as a replacement for the curated index — an agent expects the index first, and llms-full.txt is reached through it.

Validate Both Files

After publishing either file, run it through our free llms.txt validator — it checks the H1, absolute URLs, Markdown formatting, and structure, and gives you an AI Readiness Score so you know the file will parse cleanly for agents. Then use the generator to produce a fresh llms.txt from your sitemap in seconds.