What is Meta-ExternalAgent? Meta's AI crawler
Meta-ExternalAgent is the crawler Meta says it uses for purposes such as training foundation AI models or improving products by indexing content directly.
71 of the 389 major websites we measure block Meta-ExternalAgent in robots.txt (18%), making it number 8 of the 30 AI crawlers we track for how often it is blocked. 76 of those sites name it directly in their robots.txt; the rest are covered by a wildcard rule.
Key facts
| Fact | Detail |
|---|---|
| Operator | Meta |
| Used for | Meta's AI models |
| Type | Model training. Collects content that may be used to train AI models. Blocking it does not usually remove a site from AI search. |
| robots.txt token | Meta-ExternalAgent |
| Operator's documentation | Read it here |
What blocking Meta-ExternalAgent does
Meta documents robots.txt as the way to manage this crawler.
How to allow or block Meta-ExternalAgent
Add one of these groups to the robots.txt file at the root of your domain. It is a stated preference that well-behaved crawlers read, not an enforcement mechanism.
User-agent: Meta-ExternalAgent Disallow: /
User-agent: Meta-ExternalAgent Allow: /
Meta-ExternalAgent user agent string
The string Meta documents. Version numbers can change, so match on the name.
meta-externalagent/1.1
How to verify a request is really Meta-ExternalAgent
Anyone can put a crawler's name in a user agent string, so the name alone proves nothing. We did not find a published IP list or reverse DNS rule from Meta.
How to whitelist Meta-ExternalAgent in a firewall or CDN
robots.txt only states a preference. A firewall, CDN or bot protection service can still refuse the request, and the crawler then gets an error even though robots.txt allows it.
- Check that no group in your robots.txt blocks it, using the rule above.
- Add an allow rule in your firewall or CDN that matches the name in the user agent. Keep the rule narrow, because anyone can copy a name.
- Check your server logs for a 200 response from Meta-ExternalAgent afterwards.
On Cloudflare, also check AI Crawler and Agent access policies, which can block search, agent and training traffic across a site.
Why Meta-ExternalAgent gets a 403 or 405 error
A 403 means the server refused the request, which usually points to a firewall or bot rule. A 405 means the server refused the request's method, so check any rule that only permits certain methods. A crawler that obeys robots.txt won't request a page it is told to avoid, so an error in your logs points to your server's configuration. To stop it deliberately at the server, this nginx rule returns a 403:
if ($http_user_agent ~* "Meta-ExternalAgent") {
return 403;
}Which sites recently changed their rules for Meta-ExternalAgent?
| Date first seen | Site | Change |
|---|---|---|
| 2 November 2026 | metacritic.com | Started blocking |
| 19 October 2026 | howtogeek.com | Started blocking |
| 19 October 2026 | makeuseof.com | Started blocking |
| 19 October 2026 | xda-developers.com | Started blocking |
| 31 August 2026 | fastcompany.com | Stopped blocking |
| 31 August 2026 | inc.com | Stopped blocking |
See the full change log.
Who blocks Meta-ExternalAgent, by sector
| Sector | Sites measured | Blocking | Share |
|---|---|---|---|
| Technology media | 25 | 16 | 64% |
| News publishers | 44 | 26 | 59% |
| Health publishers | 16 | 5 | 31% |
| Social and media platforms | 28 | 8 | 29% |
| Travel | 19 | 4 | 21% |
| Finance and business media | 29 | 5 | 17% |
| E-commerce and retail | 19 | 3 | 16% |
| Reference and research | 25 | 3 | 12% |
| SaaS platforms | 54 | 1 | 2% |
| AI companies | 28 | 0 | 0% |
| Developer references | 34 | 0 | 0% |
| Government and institutions | 19 | 0 | 0% |
| Hosting and infrastructure | 23 | 0 | 0% |
| SEO and marketing tools | 26 | 0 | 0% |
Sites blocking Meta-ExternalAgent
academia.edu, amazon.com, androidcentral.com, arstechnica.com, asahi.com, barrons.com, bbc.co.uk, behance.net, bloomberg.com, buzzfeednews.com, canva.com, cnbc.com, cntraveler.com, corriere.it, drugs.com, dw.com, ebay.com, flickr.com, forbes.com, ft.com, gizmodo.com, globeandmail.com, hackernoon.com, healthline.com, howtogeek.com, huffpost.com, imdb.com, instacart.com, investopedia.com, lifehacker.com, makeuseof.com, marketwatch.com, mashable.com, medicalnewstoday.com, medium.com, metacritic.com, nature.com, nbcnews.com, netflix.com, newyorker.com, nytimes.com, pcmag.com, pinterest.com, reddit.com, reuters.com, sciencedirect.com, skyscanner.net, slate.com, smh.com.au, spiegel.de, strava.com, techradar.com, telegraph.co.uk, theage.com.au, theatlantic.com, theguardian.com, theregister.com, thetimes.co.uk, theverge.com, tomshardware.com, and 11 more in the full dataset.
Sites that allow Meta-ExternalAgent by name
airbnb.com, amplitude.com, delta.com, digitaltrends.com, disneyplus.com, fastcompany.com, gov.uk, hulu.com, inc.com, jasper.ai, klaviyo.com, render.com, soundcloud.com, squarespace.com, stability.ai, ulta.com.
Other Meta crawlers
Meta-ExternalFetcher (on-demand fetch).
See all 30 AI crawlers, the rule change log or the full study. Being reachable is only the first step: how AI search engines choose what to cite covers the rest.
Cite this data
You are welcome to quote or republish these figures. Please credit IndexHalo with a link to this page (CC BY 4.0). All our datasets are on the data page.
IndexHalo. "Meta-ExternalAgent block rate across major websites." Measured 3 November 2026. https://www.indexhalo.com/ai-crawlers/meta-externalagent/
<a href="https://www.indexhalo.com/ai-crawlers/meta-externalagent/">Meta-ExternalAgent block rate across major websites, IndexHalo</a>