Crawler directory · AI training crawler
Meta-ExternalAgent: user agent, robots.txt rules, and how to allow or block it
Meta-ExternalAgent crawls public pages for Meta’s AI products and model training. It is separate from facebookexternalhit, which builds link previews when someone shares your URL on Meta platforms.
- Operator
- Meta
- Feeds
- Meta AI and Llama training
- Type
- AI training crawler
- robots.txt token
- Meta-ExternalAgent
Meta-ExternalAgent user agent
Requests from Meta-ExternalAgent carry a User-Agent header like this (example — vendors change version numbers, so match on the token Meta-ExternalAgent, not the whole string):
meta-externalagent/1.1 (+https://developers.facebook.com/docs/sharing/webmasters/crawler)
To see how often it visits, filter your access log with grep -i "Meta-ExternalAgent" access.log. A User-Agent can be faked, so treat it as a claim, not proof.
Official documentation: developers.facebook.com. Vendors change their crawlers, so check it for the current details.
Should you allow or block Meta-ExternalAgent?
Blocking stops future crawls from being used for model training. It does not remove content already collected, and it does not stop you being cited in live answers, which use separate retrieval bots.
robots.txt rules for Meta-ExternalAgent
Put these in the robots.txt at the root of your domain.
Block Meta-ExternalAgent
User-agent: Meta-ExternalAgent Disallow: /
Explicitly allow Meta-ExternalAgent
User-agent: Meta-ExternalAgent Allow: /
Block only part of your site
User-agent: Meta-ExternalAgent Disallow: /private/ Allow: /
robots.txt states your policy; it does not enforce it. A CDN or firewall can block a bot your robots.txt allows, which is why it is worth testing rather than assuming.
Check what your site does today
The free AI bot checker reads your robots.txt and tells you whether GPTBot, ClaudeBot, PerplexityBot and nine other AI crawlers are allowed, blocked or crawling by default, then runs a live GPTBot fetch to prove your content is actually served.
Check my site free →Questions, answered
What is Meta-ExternalAgent?+
Meta-ExternalAgent crawls public pages for Meta’s AI products and model training. It is separate from facebookexternalhit, which builds link previews when someone shares your URL on Meta platforms.
How do I block Meta-ExternalAgent in robots.txt?+
Add these two lines to the robots.txt at the root of your domain: User-agent: Meta-ExternalAgent Disallow: / User-agent tokens are matched case-insensitively. The rule applies from the crawler's next visit; it does not delete anything already collected.
Will blocking Meta-ExternalAgent affect my Google rankings?+
No. Meta-ExternalAgent is separate from Googlebot, so blocking it does not change how Google Search indexes or ranks you. Blocking stops future crawls from being used for model training. It does not remove content already collected, and it does not stop you being cited in live answers, which use separate retrieval bots.
What does the Meta-ExternalAgent user agent look like?+
An example User-Agent header is: meta-externalagent/1.1 (+https://developers.facebook.com/docs/sharing/webmasters/crawler). Vendors change version numbers, so match on the token Meta-ExternalAgent rather than the whole string. A User-Agent can be spoofed, so verify important traffic against the vendor's published details before trusting it.
Related crawlers
More on the trade-offs in the AI bot policies guide and the robots.txt guide.