What Is llms-full.txt and Why It Matters

If llms.txt is the executive summary of your website for AI models, llms-full.txt is the full briefing document. Both live at the root of your site, both are plain Markdown, and both are read by large language model crawlers — but they serve different purposes.

The short version

• /llms.txt: a concise, curated index of what matters on your site. Typically 100–300 words. Good for telling LLMs what is here.
• /llms-full.txt: the extended version with real content — descriptions, FAQs, details, context. Typically 500+ words. Good for telling LLMs what this site is actually about.

Together they give LLM crawlers both a map (llms.txt) and the territory (llms-full.txt).

Why the two-file split exists

LLM crawlers have limits on how much content they can process per domain. llms.txt gives them a cheap, fast way to understand the shape of your site without parsing the whole thing. When a model wants deeper context — say, to answer a specific question or summarize your offering — it can pull llms-full.txt.

Think of it like robots.txt + a sitemap, but in Markdown, and with real prose instead of URL lists.

What goes in llms-full.txt

A useful llms-full.txt has:

1. A clear H1 — your site or product name
2. A blockquote summary — one paragraph describing what you do
3. About / overview section — 100–200 words of honest description
4. Key pages — linked list of the pages that matter, with a short sentence each
5. FAQ section — 5+ real questions and answers about your product or service
6. Contact or links — pointers to critical destinations (docs, pricing, contact)

Aim for at least 500 words. Longer is fine if the content is genuinely useful — 1000–1500 is a good sweet spot for many sites. Avoid padding or filler: LLMs notice.

Who reads it today

The llms.txt standard was proposed in late 2024 by Jeremy Howard and is being adopted by an increasing number of AI crawlers, including those operated by OpenAI, Anthropic, and Perplexity. Adoption is still early and uneven, but the cost of adding the file is tiny and the upside keeps growing.

Do you need both?

If your site is small (a landing page, a simple SaaS homepage), a good llms.txt might be enough. For anything more substantial — a product site with multiple pages, a SaaS with real documentation, a fintech or e-commerce — the full version gives LLMs the context they need to cite you accurately.

The lazy way to get one

If you do not want to write llms-full.txt from scratch, run your site through LLCrawler and we generate a draft for you based on your actual content — pages, FAQs, descriptions, the works. Copy, review, upload.

That is the whole point of llms-full.txt: give LLMs the truth about your site, in plain text, once — and stop guessing whether they understood.