What it does
Google-CloudVertexBot is Google's user action crawler. A live fetch made because a human asked the assistant about your page right now. Closest thing to a real visitor; several of these (Perplexity-User, meta-externalfetcher) ignore robots.txt by design because the request is user-initiated.
Crawls only when a site owner requests ingestion for building Vertex AI Agents; no effect on Search.
Full UA: not captured in our July 2026 roster review — match log hits on the token Google-CloudVertexBot (case-insensitive substring) and verify by IP before acting.
How to verify a hit is really Google-CloudVertexBot
Verification method (July 2026): Google common-crawler IP ranges + rDNS *.googlebot.com
User-agent strings are freely spoofed, so a UA match alone proves nothing. Confirm the source IP belongs to Google — published IP-range JSON where available, otherwise RDAP/rDNS on the IP. Full method: verify by IP.
Allow or block in robots.txt
Match the exact token Google-CloudVertexBot in robots.txt:
# Block Google-CloudVertexBot site-wide
User-agent: Google-CloudVertexBot
Disallow: /# Explicitly allow Google-CloudVertexBot
User-agent: Google-CloudVertexBot
Allow: /For the allow-search-block-training combined pattern (and the Allow-directive gotcha that silently kills carve-outs), see the robots.txt guide.
Vendor documentation: https://developers.google.com/search/docs/crawling-indexing/google-common-crawlers
Frequently asked questions
What is Google-CloudVertexBot?
Google-CloudVertexBot is Google's user action crawler. A live fetch made because a human asked the assistant about your page right now. Closest thing to a real visitor; several of these (Perplexity-User, meta-externalfetcher) ignore robots.txt by design because the request is user-initiated.
Does Google-CloudVertexBot respect robots.txt?
Yes — Google documents robots.txt compliance for Google-CloudVertexBot (vendor docs reviewed July 2026).
How do I block Google-CloudVertexBot?
Add 'User-agent: Google-CloudVertexBot' followed by 'Disallow: /' to your robots.txt. Use the exact token — substring variants of other tokens will not match.