Agent · Google
GoogleAgent-Mariner
The browser agent behind Google's Project Mariner and Gemini agent features, which complete tasks on websites for one user. Google lists it among user-triggered fetchers, which generally ignore robots.txt because a person initiated the request.
- Operator
- Purpose
- Agentic browsers
- Feeds
- Project Mariner (agent)
- robots.txt token
GoogleAgent-Mariner- Honours robots.txt
- Undocumented
- Documentation
- developers.google.com
What it looks like in server logs
A representative user-agent string. Version numbers change; the GoogleAgent-Mariner token does not. Paste your own log line into the user-agent checker to confirm a match.
Mozilla/5.0 (compatible; GoogleAgent-Mariner/1.0)How to block GoogleAgent-Mariner
Add this to the robots.txt at the root of your domain. Robots.txt is advisory: it works only on crawlers that choose to read it. This one is undocumented. To enforce a block, match the user agent at your CDN or web server and return 403.
User-agent: GoogleAgent-Mariner
Disallow: /
To block every agentic browser at once, or to block training while keeping AI search citations, use the robots.txt generator.
How to allow GoogleAgent-Mariner while blocking others
A more specific User-agent group wins over a wildcard. Place this above any User-agent: * block that disallows paths, and GoogleAgent-Mariner keeps full access.
User-agent: GoogleAgent-Mariner
Allow: /
How to verify a genuine hit
The user-agent string is self-asserted: anyone can send it from a laptop, and scrapers routinely impersonate well-known crawlers to slip past filters aimed at unknown ones.
Google publishes IP ranges for its user-triggered fetchers.