# meta-externalagent

## In short

meta-externalagent is an AI crawler operated by Meta. Its robots.txt token is meta-externalagent, and the vendor documentation we fetched on 2026-09-06 is the source for every statement on this page.

| Fact | Value |
| --- | --- |
| Robots token | meta-externalagent |
| Vendor | Meta |
| Purpose | training corpus, search index |
| Documented verification | none published |
| Vendor documentation last verified | 2026-09-06 |
| Share of read domains disallowing it for / | 16.0% of 131 |
| Last verified | 2026-09-06 |

## Does meta-externalagent obey robots.txt?

The vendor documentation at https://developers.facebook.com/docs/sharing/webmasters/web-crawlers/ states that meta-externalagent respects robots.txt. We fetched that page and it answered our checker on 2026-09-06. This records what the vendor documents, not what any individual request did.

## How do I allow meta-externalagent in robots.txt?

Add this group to the robots.txt at the root of the host: User-agent: meta-externalagent
Allow: /. The token is matched case insensitively as a substring of the user agent by RFC 9309, and the longest matching rule wins.

## How do I disallow meta-externalagent in robots.txt?

Add this group to the robots.txt at the root of the host: User-agent: meta-externalagent
Disallow: /. A robots.txt rule is a request that a well behaved crawler honours; it is not an access control.

## How do I verify a request really came from meta-externalagent?

We have not found a documented verification method for meta-externalagent: the vendor publishes neither an IP range file nor a reverse DNS convention that we could fetch. Without one, a user agent string is not evidence of origin.

## Source

- https://developers.facebook.com/docs/sharing/webmasters/web-crawlers/ (HTTP 200, Verified 2026-09-06)
- https://darkvisitors.com/agents/meta-externalagent (HTTP 200, Verified 2026-09-06)

AEO Watch is an independent, factual monitor. It is not affiliated with, endorsed by or speaking for any crawler vendor. Every statement is an observation with the date it was made and the raw evidence behind it: a robots.txt line, an HTTP status code, a header. There are no scores, no grades and no verdicts here, and nothing on this page is advice. A site opts out at any time and the opt out is honoured automatically and permanently.