E2 · GEO / LLM Readiness

    llms.txt Checker — is your llms.txt published and valid?

    An `llms.txt` file is like `robots.txt` for large language models — a Markdown map that tells AI systems what your site is and which pages are authoritative. This check confirms yours is published at your site root, returns a 200, is served as real Markdown (not an HTML error page), and contains a summary plus links to your key URLs. A clean llms.txt helps AI engines represent and cite you accurately.
    Updated June 2026 · Technical SEO & GEO · Part of GEO / LLM Readiness

    Check & validate your llms.txt

    Paste a URL — GEObubbly fetches your /llms.txt and confirms it returns a 200, is valid Markdown, and includes a summary plus key links.

    ✓ Free check✓ 1 signal✓ No signup required
    In short: An llms.txt file — an emerging standard, like robots.txt for LLMs — tells AI systems what your site is and points them to your authoritative content, reducing misrepresentation.

    What does the llms.txt check validate?

    It fetches yourdomain.com/llms.txt and confirms it's a usable file for AI systems. Specifically:

    • Reachable — it returns a 200 at the site root and isn't blocked by robots.txt or your CDN.
    • Markdown, not HTML — it's served as plain Markdown, not an HTML page or a custom 404.
    • Has a summary — a short title (H1) and a one-paragraph description of what the site is.
    • Curated links — Markdown links to your most important, authoritative pages.

    A valid, well-formed file passes; one that exists but is thin or malformed is a warning; no llms.txt at all is a fail.

    How is it evaluated, and how is it scored?

    GEObubbly fetches /llms.txt, confirms a 200 response, checks that the content is Markdown rather than an HTML error page, and looks for a summary and links. It's a core GEO / LLM Readiness check worth 3 points — a cheap, high-leverage signal because so few sites have one yet.

    Why llms.txt matters for GEO

    When an AI engine answers a question about your product or company, it stitches together whatever it can find — and without guidance, that can be stale, scattered or wrong. An llms.txt gives those systems a curated, high-signal map: here's what we do, and here are the canonical pages to trust. That reduces misrepresentation and steers engines toward your best content rather than letting them guess from fragments. Adoption is still early, which is precisely the opportunity: publishing a clean llms.txt now is a cheap, low-risk edge while most competitors don't have one. It won't rescue a site that's blocked or unindexable, but paired with answer-first content, fast server-rendered pages and accurate structured data, it measurably improves how correctly ChatGPT, Perplexity and other engines describe and cite you. Think of it as the guided tour you hand the AI — one of the most actionable wins in GEO / LLM Readiness.

    How this check scores
    Pass: A valid /llms.txt is published (Markdown, with a summary and key URLs).
    Warning: An llms.txt exists but is thin, empty or malformed.
    Fail: No llms.txt file.

    FAQ

    An llms.txt is a Markdown file placed at your site root (/llms.txt) that gives AI systems a curated summary of what your site is and links to your most authoritative pages. It works like a guided tour for large language models — the opposite of making them crawl and guess. When an AI engine describes or cites your brand, it can anchor to this authoritative source instead of stitching together stale or scattered fragments, which reduces misquoting and helps it represent you accurately.

    Related checks in GEO / LLM Readiness

    E1
    AI bot access in robots.txt
    E12
    Author / expert E-E-A-T signals
    E13
    Entity clarity & consistency

    Audit your page across all 15 checks in GEO / LLM Readiness

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