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 (common-crawlers.json, canonical path since 2026-08) + rDNS *.googlebot.com
Verify by reverse DNS: resolve the hit's source IP and confirm the hostname matches the vendor's documented pattern, then forward-resolve that hostname back to the same IP (spoofers can fake PTR records, so the forward-confirm step is load-bearing).
User-agent strings are freely spoofed, so a UA match alone proves nothing. Full step-by-step 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. robots.txt governs whether Google-CloudVertexBot may fetch; llms.txt is the separate, curated map AI assistants read once allowed in.
Vendor documentation: https://developers.google.com/search/docs/crawling-indexing/google-common-crawlers
The Google family
Google operates 5 distinct tokens in this roster, and they do not block each other: a robots.txt line for Google-CloudVertexBot does nothing to its siblings — each needs its own User-agent: entry (the robots.txt guide has combined patterns).
| Token | Role | robots.txt |
|---|---|---|
| Google-Extended | Training | honors robots.txt |
| GoogleOther | Training | honors robots.txt |
| Google-Agent | User action | ignores robots.txt |
| Google-GeminiNotebook | User action | ignores robots.txt |
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.
How do I verify Google-CloudVertexBot traffic by IP?
Reverse-resolve the hit's source IP, confirm the hostname matches Google's documented pattern, then forward-resolve that hostname back to the same IP.
Related bots
Same vendor, then other user-action fetchers — the full directory profiles all 34.