Meta-ExternalAgent: user agent, IP verification and robots.txt
Meta-ExternalAgent is operated by Meta. It is classified here as Training (AI training and indexing crawler). Verification method: None available.
Exact user-agent string
meta-externalagent/1.1 (+/documentation/sharing/webmasters/web-crawlers)
robots.txt token: Meta-ExternalAgent. The user-agent string is self-asserted and can be
forged by anyone. It is a claim, not proof.
How to verify Meta-ExternalAgent is genuine
Meta publishes no IP range file and no reverse DNS method for Meta-ExternalAgent. There is no way for anyone, including us, to prove a request claiming this identity is genuine.
How to block or allow Meta-ExternalAgent
User-agent: Meta-ExternalAgent
Disallow: /Replace Disallow with Allow to permit it explicitly.
What blocking Meta-ExternalAgent costs you
Meta describes this crawler as serving both foundation model training and direct content indexing, bundled under one token. That bundling is the cost: there is no published way to opt out of the training use while keeping the indexing use, so blocking is all or nothing.
What is specific to Meta-ExternalAgent
Meta publishes no IP range file for its crawlers, so a Meta-ExternalAgent request cannot be verified the way an OpenAI or Google request can. Its own documentation points site owners to allowlisting either the user-agent strings or the IP addresses, describing the latter as more secure, but the addresses are not published as a machine-readable list the way every other major operator's are. The user-agent itself is also unusually thin: the shorter published form is just meta-externalagent/1.1 with no browser prefix, which makes it trivially cheap to forge and easy to miss in log filters written to expect a Mozilla/5.0 prefix.
Verify a request claiming to be Meta-ExternalAgent
Check a Meta-ExternalAgent request against Meta's published ranges
Source
Primary documentation: https://developers.facebook.com/docs/sharing/webmasters/web-crawlers/. Last verified 2026-08-02.
Other Meta crawlers
- Meta-ExternalFetcher - User-triggered fetch
- Meta-WebIndexer - Meta AI search index
- Meta-ExternalAds - Advertising and business products
- FacebookExternalHit - Link preview fetch