Quick Answer: AGENTS.md is a Markdown document at your webroot that gives AI agents structural information about your site — URL hierarchy, key entities, constraints (areas not to crawl), schema types implemented, and content freshness. Where llms.txt is a brief manifest, AGENTS.md is the deep technical reference.

What is AGENTS.md and how does it differ from llms.txt?

llms.txt is the elevator pitch — short, friendly, summary-first. AGENTS.md is the full operating manual. AI agents that need more context after reading llms.txt will fetch AGENTS.md. It typically includes: site purpose paragraph, complete URL structure with descriptions, key entities defined, constraints (do-not-crawl paths), schema types implemented, content freshness signals, and contact for clarification.

Why do AI agents need AGENTS.md?

Modern AI agents are autonomous: they reason about what to crawl, what to cite, and what to skip. AGENTS.md gives the agent a reliable map. Without it, the agent may waste budget crawling /admin/ paths, may misidentify your primary entity, or may cite stale pages because freshness is not declared.

What sections should AGENTS.md include?

The recommended sections: Site Purpose (1 paragraph), URL Structure (table of paths and meaning), Key Entities (people, products, services with definitions), Constraints (paths to avoid, content not for citation), Schema Types (which schema you publish), Content Freshness (how often pages update), Contact (who to reach for AI partnership questions).

Where should AGENTS.md live?

At /AGENTS.md (uppercase) at the root of your domain. Some agents also check /agents.md (lowercase) as a fallback — symlinking both is best practice on case-sensitive servers like OpenLiteSpeed.

How long should AGENTS.md be?

300–800 words is the sweet spot. Long enough to be substantive, short enough that agents read the whole thing. Avoid marketing copy. Write in plain technical English the way a senior developer would document a system.

Does AGENTS.md help with traditional SEO?

Indirectly. Search engines do not index AGENTS.md as a ranking signal, but the discipline of writing it forces clarity about your site's structure that benefits every other SEO/AEO signal. Sites that have a strong AGENTS.md tend to also have stronger schema and llms.txt — and rank better across both ecosystems.