What Is llms.txt — And Does It Actually Do Anything Yet?
llms.txt is a proposed plain-text file at your domain root that points AI models to your most useful content, in Markdown. It is a convention, not a standard: no major AI provider has committed to reading it. It costs an hour to publish and is a low-risk bet.
What llms.txt is
The idea borrows directly from robots.txt: a predictable file at
a predictable path — /llms.txt — that machines can fetch without
crawling your whole site. Where robots.txt says what not to read,
llms.txt says what's worth reading, as a curated Markdown index of your
key pages with one-line descriptions.
The pitch is that an AI model working with a limited context window benefits from a hand-written map far more than from a 4,000-URL XML sitemap.
Who actually ships one
Rather than guess, we pointed isaeo's site-level AEO check at a handful of
domains. It fetches /llms.txt and reports whether it exists:
| Domain | llms.txt |
|---|---|
| stripe.com | Present |
| vercel.com | Present |
| ahrefs.com | Absent |
| crawler-test.com | Absent |
Developer-tooling companies have adopted it; even a major SEO vendor has not. That split tells you something honest about its current status: it is an early-adopter convention, not table stakes.
What goes in it
The format is plain Markdown. An H1 with your product name, a blockquote summarising what you do, then linked sections:
# isaeo
> SEO and AEO audits for agencies — crawl a site, score every page for
> search and answer-engine readiness, export a white-label report.
## Core pages
- [Features](https://isaeo.com/features): what each audit checks
- [Pricing](https://isaeo.com/pricing): plans and limits
## Guides
- [AEO vs SEO](https://isaeo.com/blog/aeo-vs-seo): what changes when AI answers
Keep it short and keep it accurate. A stale llms.txt is worse than none — it actively misinforms anything that reads it.
See this on your own site. isaeo audits up to 10 pages free — no card, no trial timer. You get an SEO health score, an AEO score and a prioritised fix list.
Run a free audit →Is it worth doing?
Honestly: the evidence it changes model behaviour today is thin. No major provider has publicly committed to consuming it. Anyone promising you traffic from an llms.txt is overselling.
The case for publishing one anyway is that it costs about an hour, carries no downside, and forces a genuinely useful exercise — deciding which twenty pages actually represent your business. The higher-leverage work sits elsewhere: structured data, not blocking AI crawlers, and writing quotable passages.
isaeo checks for llms.txt on every crawl as part of the site-level AEO score, alongside your robots.txt AI-crawler rules — so you'll know where you stand without checking by hand.
Try it on a site you care about
isaeo checks llms.txt, AI-crawler rules and per-page AEO signals on every audit.
Start free — 10 pages, no cardNeed full-site crawls, scheduled audits and white-label reports? Compare plans →
Frequently asked questions
What is llms.txt?
llms.txt is a proposed plain-text Markdown file at a domain's root that gives AI models a curated map of the site's most useful pages. It complements robots.txt: robots.txt says what not to crawl, llms.txt says what is worth reading.
Do AI models actually read llms.txt?
No major AI provider has publicly committed to reading it, so treat it as an early convention rather than a standard. It is cheap to publish and carries no downside, but it is not a substitute for structured data and crawler access.
Where do I put llms.txt?
At the root of your domain, served as plain text at https://example.com/llms.txt — the same placement pattern as robots.txt.