Guide

An llms.txt validator should judge usefulness, not just presence.

Siteline checks whether a site publishes llms.txt or llms-full.txt, but a file existing is only the starting point. The scanner asks whether the file helps an agent understand the site, important URLs, policies, APIs, and task paths.

What a useful file includes

• A concise explanation of the site or organization
• Canonical URLs for high-value pages and machine-readable resources
• Task guidance for agents: where to learn, contact, buy, book, or contribute
• Links to OpenAPI, feeds, changelogs, security contacts, or documentation where relevant
• Freshness signals, such as update dates or versioned references

What weak files look like

A thin file that only says "welcome" or repeats homepage copy gives an agent little more than it could infer from HTML. Siteline treats weak resources differently from useful resources so the grade reflects real agent support.

How it affects the grade

llms.txt can improve discovery signals, but it is not a magic pass. Siteline combines it with the rest of the agentic enablement layer: sitemap quality, agents.json, OpenAPI, feeds, changelog, MCP discovery, and security contact signals.

Validate your site

Run a Siteline scan and check the informational signals plus the Agentic Enablement level. Those two areas show whether the file was found and whether the broader machine-readable surface is strong.