llms.txt is a proposal for a Markdown file at the root of a site, like robots.txt, that gives language models a short, curated map: what the site is, and which pages hold the canonical facts. It is a convention some tools read, not an adopted standard.
What to put in it
llms.txt
# Acme
> Acme is a revenue forecasting platform for B2B sales teams.
## Product
- [Pricing](https://acme.io/pricing): plans and what each includes
- [Integrations](https://acme.io/integrations): Salesforce, HubSpot
## Docs
- [Quickstart](https://acme.io/docs/quickstart)Is it worth it?
It costs very little, it forces you to write down the one-sentence description of your business, and it gives any tool that reads it a cleaner path to your facts. Just do not treat it as a substitute for crawlable pages, clear copy and structured data, which matter more.