Free tools / llms.txt checker
Does your site have a valid llms.txt?
llms.txt is a convention for coding agents reading documentation sites. No search or answer engine reads it; Google says it neither helps nor harms, and in a 137,000-domain study 97 percent of these files received no request in a month. The check reports whether yours exists and is well-formed, and frames it for what it is.
Questions
Does llms.txt help SEO or AI visibility?
Not by any published evidence. Half of the 400 most popular npm packages' sites publish one, and the share tracks the tools people use to build agents, not any ranking lever. It is useful for coding agents reading your docs.
What should llms.txt contain?
An H1 with the project name, a one-paragraph summary, and sections of Markdown links to the pages an agent should read, with a line on each. llms-full.txt is the full documentation in one Markdown file.
Should a product site publish one?
If the site is documentation that agents read, yes; it costs little. A marketing site gains nothing from it. RankCLI reports a missing file as a notice framed for docs sites, never as an error.
The other free checks
- AI crawler access checker
- robots.txt AI crawler checker
- Sitemap checker
- Structured data checker
- Security headers checker
- Full SEO and AI-search audit
- AI visibility checker
All of them run locally too: npx @rankcli/cli audit --url yoursite.com.