What is meta-externalagent?
meta-externalagent is a training crawler operated by Meta: it collects text to train a model on. It sends nobody to your site, now or later, and it is the only category on this list where that is true.
Training crawler
Should you block meta-externalagent?
meta-externalagent is operated by Meta. Collects content for model training. Blocking it is a legitimate business choice with no traffic cost.
What meta-externalagent is
Meta runs it as a training crawler, which means it collects text to train a model on. It sends nobody to your site, now or later, and it is the only category on this list where that is true.
What blocking it costs you: Excluded from Meta AI training. Nothing, in traffic terms. This is the one group where blocking has a real argument behind it and no visitor cost.
The user agent, and the token a rule matches on
These are two different strings and confusing them is why a rule that looks right does nothing.
A robots.txt rule matches on the product token, case-insensitively, and
ignores the rest of the user-agent header entirely.
| robots.txt token | meta-externalagent |
|---|---|
| Operator | Meta |
| Category | Training crawler |
| Full user agent | meta-externalagent/1.1 (+https://developers.facebook.com/docs/sharing/webmasters/crawler) |
Allowing meta-externalagent
Paste this into robots.txt at the root of your domain.
User-agent: meta-externalagent
Allow: /
Sitemap: https://axray.online/sitemap.xml
An empty Disallow: and Allow: / mean the same thing to a crawler. What does
not mean the same thing is having no rule at all: absence is permission by default, but it is
permission nobody wrote down, and it survives only until somebody adds a blanket
User-agent: * block without thinking about this crawler.
Blocking meta-externalagent
User-agent: meta-externalagent
Disallow: /This one is a fair decision to make. A training crawler sends you no visitors, so blocking it costs you nothing in traffic and is a position you are entitled to take. Be clear about what it achieves: robots.txt is honoured by operators who choose to honour it, and does nothing about your text reaching a model through a third-party copy, a screenshot, or somebody pasting it into a chat window.
How the web actually treats meta-externalagent
Measured on 2026-09-06, by reading the robots.txt of
292 public websites and resolving each one against this crawler specifically.
| Verdict | Sites | Share |
|---|---|---|
| Blocked | 34 | 12% |
| Explicitly allowed | 204 | 70% |
| No rule either way | 54 | 18% |
No site is named, here or anywhere else on this domain. The count is the useful part; a league table of businesses that never asked to be measured is not.
The row worth reading twice is the last one. 54 of 292 sites have written no rule about
meta-externalagent at all, which means their position on it is an accident rather than a decision — whatever
their User-agent: * block happens to say.
What meta-externalagent is not
Meta runs 2 other crawlers with different jobs, and this is where the expensive mistake happens. Somebody means “do not train on my content”, writes one rule against the operator’s name as they remember it, and blocks the crawler that would have sent them a customer instead.
| Crawler | What it does instead |
|---|---|
meta-webindexer |
Indexes you so an assistant can cite and link you. Blocking it removes you from AI answers. |
meta-externalfetcher |
Fetches your page because a human asked an assistant to open it right now. Blocking it breaks a live request. |
Rules are matched per token. Blocking one of these says nothing about the others, which is the point: you can refuse training and keep every crawler that puts your link in front of a person.
Checking what your site does right now
Reading your own robots.txt is not the same as knowing what a crawler concludes from it.
Precedence between a User-agent: * group and a named one, the longest-match rule between
overlapping paths, and a token you spelled slightly wrong all produce a file that looks correct and
behaves otherwise.
npx axray-cli your-site.comThe scan resolves your file against all 54 crawlers on this list individually and reports which ones are allowed, blocked, or covered by nothing. It is free, needs no account, and installs nothing.
Questions people ask about meta-externalagent
Should I block meta-externalagent in robots.txt?
Blocking meta-externalagent costs you no visitors, because it collects content for model training rather than sending anyone to your site. That makes it the one group where the decision is genuinely yours to make on principle. What it does not do is keep your content out of models — it applies only to operators who read robots.txt, and does nothing about a copy reached through somebody else.
What is the meta-externalagent user agent string?
meta-externalagent/1.1 (+https://developers.facebook.com/docs/sharing/webmasters/crawler) — and the robots.txt product token, which is what a rule actually matches on, is meta-externalagent.
How do I check whether my site is blocking meta-externalagent right now?
Scan your site with AXRAY. It resolves your robots.txt against 54 named AI crawlers individually rather than reporting one verdict for all of them, so it will tell you whether this specific crawler is allowed, blocked, or covered by no rule at all. It is free and needs no account.
Other training crawlers
GPTBot— OpenAIClaudeBot— AnthropicGoogle-Extended— GoogleApplebot-Extended— AppleCCBot— Common CrawlBytespider— ByteDanceDeepSeekBot— DeepSeekAI2Bot— Ai2
The full reference: all 54 AI crawlers, and who blocks each one.
See which of these 54 crawlers your own site is blocking, and what each one costs you. One scan, no account.