Meta-ExternalAgent

What Meta-ExternalAgent does

Meta-ExternalAgent crawls public pages for uses Meta describes as training AI models or improving products by indexing content directly. It is separate from the link-preview fetcher (facebookexternalhit), which means blocking AI training no longer breaks link previews on Facebook and Instagram. Its 2024 introduction was widely covered precisely because of that split: before it, refusing Meta's AI harvesting risked degrading your links across the largest social platforms - a coupling site owners had complained about since Meta's AI training disclosures began.

Why it visits your site

Meta trains its Llama family and assistant features on public web data; your text is raw material. Volume reports place it among the more active AI crawlers since launch.

The bigger picture: AI training crawlers

Training crawlers are the most economically lopsided visitors your server has. A search crawler takes your content and pays you back in ranked listings and click-throughs; a training crawler takes the same content to improve a commercial model and, by design, sends nothing in return. The visit itself is the entire transaction. That asymmetry is why training bots - not AI in general - are where most of the blocking debate actually lives, and why the publishing industry's response has split between refusal and negotiation: several large publishers block these crawlers outright, while others have signed licensing deals with the same operators. Both strategies start from the same place - knowing, concretely, how much of your archive is being read and by whom.

The norms here are young and still hardening. The better operators now publish user agents, IP ranges, and opt-out tokens, and honor robots.txt; others publish nothing and, by widely credited reports, crawl through disallow rules. Treat each crawler on its record rather than assuming the category behaves uniformly - and remember that a robots.txt line only ever governs the polite end of the spectrum.

Should you block it?

The dedicated token makes this a clean decision: blocking meta-externalagent stops Meta's AI harvesting without affecting how your links render when humans share them. Meta operates no search product that sends you traffic, so the referral cost of blocking is effectively zero. If you block AI training crawlers generally, include it.

Block via robots.txt

Add these lines to the robots.txt at your site root to ask Meta-ExternalAgent to stay away:

User-agent: meta-externalagent
Disallow: /

Remember that robots.txt is a request, not a lock - compliance is voluntary, and enforcement happens at the server. Viz's AI Control pairs robots.txt rules with server-level 403 responses and then probes your site to verify the block is actually holding.

How to see Meta-ExternalAgent traffic on your site

You have three windows onto it, each with a catch. Raw hosting access logs contain every Meta-ExternalAgent request, but many managed WordPress hosts don't expose them, and when they do you are grepping text files by hand. A CDN dashboard sees the traffic at the edge, but it lives outside WordPress and speaks in totals, not in your site's terms. And JavaScript analytics - GA4 and friends - will never show it at all, because Meta-ExternalAgent doesn't run scripts.

Viz's answer is the request log: filter to Meta-ExternalAgent and read exactly which URLs it fetched and when, right inside wp-admin - then watch the same filter after any blocking decision to see whether the visits stopped, slowed, or kept coming.