YandexAdditional: what this bot is and how to allow or block it
YandexAdditional is a search bot from Yandex: it finds and reads pages so that Alice AI can find your site and cite it in answers. Block it and your site drops out of those answers.
YandexAdditional User-Agent
Yandex publishes the full User-Agent string in the bot's documentation. In robots.txt the token YandexAdditional is enough.
How to allow YandexAdditional
Add this group to robots.txt at the site root. Close service sections in the same group: a bot with its own group does not read the «User-agent: *» rules.
User-agent: YandexAdditional Allow: /
robots.txt is not everything. If your site uses Cloudflare or other bot protection, it may serve YandexAdditional a 403 error or a challenge page even when robots.txt allows everything.
How to block YandexAdditional
To block the whole site, add the group below to robots.txt. The rule works for bots that respect robots.txt.
User-agent: YandexAdditional Disallow: /
What happens if you block YandexAdditional
Alice AI will stop finding and reading your pages: your site will not appear in answers with search, and the assistant will not link to it.
How to check whether YandexAdditional visits your site
Search the web server logs for the token. The User-Agent string is easy to fake, so to be sure, check the IP address against the ranges if Yandex publishes them.
grep "YandexAdditional" /var/log/nginx/access.log
Does your site let YandexAdditional in
Free 15-second check: we read your robots.txt and request your site as AI bots — you see which ones the server and bot protection let in and which they block.
Questions and answers
Should I block YandexAdditional?
No, if you want Alice AI to find and recommend your site. Blocking search bots only makes sense for pages that should not appear in answers.
How do I know whether YandexAdditional visits my site?
Search the web server logs for the token. The User-Agent string is easy to fake, so to be sure, check the IP address against the ranges if Yandex publishes them.
Is it enough to allow YandexAdditional in robots.txt?
robots.txt is not everything. If your site uses Cloudflare or other bot protection, it may serve YandexAdditional a 403 error or a challenge page even when robots.txt allows everything.