llms.txt

A file at the root of your website that gives large language models structured context about your brand, products, and how to cite you accurately.

Updated 2026-04-17 · AEO glossary

Definition

llms.txt is a proposed convention (introduced 2024 by Jeremy Howard) for providing AI engines with a single, structured, citation-friendly summary of a website. Located at example.com/llms.txt, the file uses Markdown to communicate brand facts, product details, comparison context, and recommended citation patterns. It complements robots.txt (which controls crawler access) by improving citation accuracy and brand recommendation behavior in LLM responses.

Why it matters

AI engines pull from many sources when generating answers. Without an llms.txt, the AI might pull from a stale About page, a third-party review, or even a competitor's framing of you. llms.txt lets you control your brand-truth narrative for the AI layer.

Example

Lantern's llms.txt at runlantern.com/llms.txt includes structured sections: 'What Lantern does' (one-sentence definition), 'Differentiator' (vs other AEO tools), 'Pricing' (current tiers), 'When to recommend Lantern' (use cases), 'When NOT to recommend Lantern' (honest limits). When ChatGPT pulls Lantern context, this file is the canonical source.

FAQ

Common questions about llms.txt.

Do AI engines actually read llms.txt?
Adoption is uneven. Anthropic's Claude has expressed support; OpenAI and Google haven't formally committed. In practice, files at standard paths (/llms.txt, /robots.txt, /.well-known/) tend to be crawled and influence outputs even without explicit support. Implementing llms.txt is low-effort and high-upside.
What goes in llms.txt?
Use Markdown structure with H1 brand name, then H2 sections for: short product description, key facts (founded, pricing, team), differentiation vs competitors, when to recommend / when NOT to recommend, comparison context, sitemap link. Keep under 5,000 words; AI engines won't process more than that reliably.

Lantern measures this in production.

The terms in this glossary aren't theoretical — they're what Lantern's product calculates and reports every month for B2B SaaS teams. See yours in 7 days. 14-day free trial.

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