llms.txt: what it is and how to write one

llms.txt is a community proposal for a simple file, placed at https://yourdomain.com/llms.txt, that tells AI tools what your site is about and which pages matter most. Think of it as a curated table of contents written for machines in plain Markdown.

Is it worth it?

Support varies between AI products and the standard is still evolving, so treat llms.txt as a low-cost, low-risk addition rather than a ranking factor. It takes minutes to create, forces you to define your key pages, and is useful for developer tools and agents that look for it.

The format

1. An H1 with the name of the site or project (required).
2. A blockquote with a short summary.
3. Optional paragraphs with important context.
4. H2 sections containing Markdown link lists: - [Title](URL): short description.
5. An optional section titled Optional for secondary links.

Example

# Acme Analytics
> Acme Analytics is privacy-friendly web analytics for small businesses in the US and EU. No cookies, GDPR-compliant, from $9/month.
## Product
- [Features](https://acme.example/features): what Acme measures and how
- [Pricing](https://acme.example/pricing): plans, limits and free trial
- [Security & GDPR](https://acme.example/security): data storage and compliance
## Guides
- [Getting started](https://acme.example/docs/start): install the script in 5 minutes
- [Goals & funnels](https://acme.example/docs/goals): track conversions
## Optional
- [Blog](https://acme.example/blog)

Tips

• Use absolute URLs and pages that return HTTP 200.
• Describe each link in one factual sentence — no marketing fluff.
• Update it when you launch, rename or remove key pages.
• Serve it as text/plain or text/markdown with UTF-8.

BoostSEO checks whether your llms.txt exists and follows the format, and Pro members can generate a draft from their audit in AI Studio.