SemrushBot-OCOB
Semrush · Model training · robots.txt token semrushbot-ocob
4% of 30,177 measured domains disallow semrushbot-ocob in robots.txt at the site root. Separately, and independently of robots.txt, 17.4% of 30,187 reachable domains refuse an AI crawler user agent at the network edge on two consecutive probes from different locations - a refusal the site's own robots.txt does not declare and its owner often has not chosen.
Measured 2026-10-06 by direct request to every domain in the corpus. Method: how this is measured. Reuse under CC BY 4.0 with attribution.
Cite as: Crawl Census, "SemrushBot-OCOB blocking rate", measured 2026-10-06. https://crawlcensus.com/bot/semrushbot-ocob
What it is definition
Crawls pages to feed Semrush's ContentShake AI writing tool.
SemrushBot-OCOB is operated by Semrush and classified here as model training. These agents collect text and images that may end up in a training corpus. Disallowing one withholds new content from the next model. It does not withdraw anything collected before the disallow, and it does not remove the site from any answer engine.
Disallowing semrushbot-ocob withholds content crawled from that point on from Semrush's training data. It does not withdraw pages collected in earlier crawls, it does not reach copies already sitting in third-party datasets, and it does not remove the site from any answer surface.
- robots.txt token
- semrushbot-ocob
- Operator
- Semrush
- Purpose
- Model training
- Honors robots.txt
- yes
- Documentation
- https://www.semrush.com/bot/
Identity on the wire exact string
Mozilla/5.0 (compatible; SemrushBot-OCOB/1; +https://www.semrush.com/bot/)curl -A 'Mozilla/5.0 (compatible; SemrushBot-OCOB/1; +https://www.semrush.com/bot/)' https://example.com/Replace the host with your own. A 403, a challenge page or an empty body means the edge is blocking the agent whatever robots.txt says.
How to allow it, how to block it robots.txt
User-agent: semrushbot-ocob
Allow: /Absent any rule, the agent is already allowed, so this group only matters when your * group disallows something. Naming the agent replaces the * group for it entirely, so repeat here every disallow you still want to apply to it.
User-agent: semrushbot-ocob
Disallow: /Disallowing semrushbot-ocob withholds content crawled from that point on from Semrush's training data. It does not withdraw pages collected in earlier crawls, it does not reach copies already sitting in third-party datasets, and it does not remove the site from any answer surface.
Sites that block it 60 shown
See every measured domain that blocks SemrushBot-OCOB
This list is served from a cache rebuilt just now. It is discarded the moment a rescan records a policy change for this agent, so a site that has just changed its robots.txt will drop off it within one scan rather than waiting for the cache to expire.
Compare Semrush
Semrush runs no other agent in this registry.
Common questions answered
Does blocking SemrushBot-OCOB remove me from Semrush ContentShake AI?
No, not by itself. SemrushBot-OCOB collects content for training, not for the index that answers questions. Semrush operates no separate answer crawler in this registry, so there is no answer surface to lose here. Content collected before the disallow is not withdrawn.
How do I verify SemrushBot-OCOB requests are genuine?
Semrush publishes neither reverse DNS names nor address ranges for SemrushBot-OCOB, so a request carrying this user agent cannot be authenticated. The string is trivially spoofed and is routinely reused by unrelated scrapers. Treat it as a hint, rate-limit by source address, and do not grant it access you would not grant an anonymous client.
Check your own site free
See whether your robots.txt admits SemrushBot-OCOB today, and whether your edge agrees with it.