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AI crawler profile

What is Meta-ExternalAgent? How to allow or block Meta's crawler

User-agent string to match in robots.txt and server logs: Meta-ExternalAgent

Operator

Meta

Purpose

AI model training

robots.txt

Respects robots.txt

Official docs

Meta documentation ↗

Meta-ExternalAgent is Meta's crawler for collecting training data for its Llama models and Meta AI products. It is distinct from facebookexternalhit (which fetches link previews), so you can block AI training without breaking how your links render on Facebook and Instagram.

Does Meta-ExternalAgent respect robots.txt?

Meta documents the agent and states it respects robots.txt rules.

Verify it's really Meta-ExternalAgent

Meta publishes no IP-range file for Meta-ExternalAgent, so it can only be identified by its user-agent string — which anything can send. Treat traffic claiming this agent as unverified, and prefer a reverse-DNS check where the operator documents one before acting on it.

Block Meta-ExternalAgent with robots.txt

robots.txt — block
User-agent: Meta-ExternalAgent
Disallow: /

Explicitly allow Meta-ExternalAgent

robots.txt — allow
User-agent: Meta-ExternalAgent
Allow: /

Block Meta-ExternalAgent at the server or CDN

robots.txt is the right first step for Meta-ExternalAgent, since Meta honors it. Use these only if you want the block enforced rather than requested — for example to stop agents spoofing the user agent. Matching on the user-agent string still trusts a self-declared header — and no IP-range file exists for this agent, so treat it as best-effort.

nginx
if ($http_user_agent ~* "Meta-ExternalAgent") {
    return 403;
}
apache — .htaccess
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Meta-ExternalAgent [NC]
RewriteRule .* - [F,L]
cloudflare — WAF expression
(http.user_agent contains "Meta-ExternalAgent")

Find Meta-ExternalAgent in your server logs

shell
grep -i "Meta-ExternalAgent" /var/log/nginx/access.log | wc -l

Should you block Meta-ExternalAgent?

Blocking Meta-ExternalAgent opts your content out of Meta's model training — a legitimate choice for original content you don't want reproduced by AI. The trade-off: models trained without your content are less likely to know your brand or recommend it unprompted. There is no direct traffic loss today, since training crawlers don't send visitors. See our guide on whether to block AI bots for the full decision framework.

Check and monitor Meta-ExternalAgent on your site

Related reading

Frequently asked questions

What is Meta-ExternalAgent?

Meta-ExternalAgent is Meta's web crawler for collecting AI training data. Crawls content to train Meta's AI models.

Does Meta-ExternalAgent respect robots.txt?

Meta documents the agent and states it respects robots.txt rules.

How do I block Meta-ExternalAgent?

Add "User-agent: Meta-ExternalAgent" followed by "Disallow: /" to your robots.txt file. The change takes effect the next time the bot fetches your robots.txt.

Does blocking Meta-ExternalAgent hurt my Google rankings?

No. Meta-ExternalAgent is separate from Googlebot, which handles Google Search indexing. Blocking Meta-ExternalAgent has no effect on your traditional search rankings.

How can I tell if Meta-ExternalAgent is crawling my site?

Search your server access logs for the string "Meta-ExternalAgent" — for example: grep -i "Meta-ExternalAgent" /var/log/nginx/access.log | wc -l. Our free AI Bot Log Analyzer does this in your browser: paste a log file and it counts hits per AI crawler, including Meta-ExternalAgent, with per-path breakdowns.

How do I use Meta-ExternalAgent?

You don't — Meta-ExternalAgent isn't a tool you run. It's Meta's own crawler, operated by Meta, that visits your site from their infrastructure. The only control you have over it is whether you allow or block it, via robots.txt or a server rule. If you're looking to crawl other sites yourself, you'd write your own crawler or use a crawling library; sending "Meta-ExternalAgent" as your user agent would be impersonating Meta.

Where is the official Meta documentation for Meta-ExternalAgent?

Meta publishes it at https://developers.facebook.com/docs/sharing/webmasters/web-crawlers/. That page is the authoritative source for the user-agent string and Meta's stated crawling policy.

More Meta agents

Part of our directory of every known AI crawler, refreshed monthly. Last verified: 2026-08-14.