Your site has an /llms.txt. A retrieval engine just fetched it. Did it parse cleanly, or did the engine silently skip half of it because the structure was broken? This validator checks every structural signal in the llmstxt.org spec — H1 title, blockquote description, H2 sections, link-list formatting, absolute HTTPS URLs — and tells you exactly what to fix.
Option A: fetch /llms.txt from a live URL. Option B: paste the file contents. Both work; fetch mode also reports the HTTP status + content-type.