YandexAdditionalBot

YandexAdditionalBot exists so that robots.txt can be applied to Yandex AI answers rather than to the search index.^[1] It works over pages the main crawler has already indexed and does not request indexing itself.^[2]

Yandex publishes the user agent string the token sends.^[3] Verification is by reverse DNS: take the address from the server log, resolve it back to a host name, and check that the host ends in a Yandex domain before resolving forward again to confirm the pair.^[4]

Disallowing the token is the documented route to keeping a page out of Yandex AI answers while leaving ordinary Yandex search indexing alone. Blocking the main crawler instead removes the site from both at once.

There is no documentation page or IP range list from Yandex that we can point at for this token.

A user agent is a claim, not a proof: any client can send any name. Where an operator publishes IP ranges, a reverse lookup is the only way to tell a real visit from an impersonation.