ClaudeBot vs Google-Extended: Which AI Crawler Should You Allow or Block?
Complete side-by-side comparison of ClaudeBot (Anthropic) and Google-Extended (Google): user-agent strings, safety ratings, SEO impact, and copy-paste blocking rules. Updated August 2026.
Quick Verdict
Both ClaudeBot and Google-Extended carry the same safety rating (Safe). Your decision should come down to whether you want your content used by Anthropic versus Google, and whether each bot's purpose (training, search, or user requests) aligns with your content strategy.
| Attribute | ClaudeBot | Google-Extended |
|---|---|---|
| Operator | Anthropic | |
| User-agent string | ClaudeBot |
Google-Extended |
| Category | AI & LLM Bots | AI & LLM Bots |
| Safety rating | Safe | Safe |
| SEO impact if blocked | Low - No SEO ranking impact | Low - No SEO ranking impact |
| Recommendation | Generally safe to allow; provides legitimate crawling value. | Generally safe to allow; provides legitimate crawling value. |
| Official docs | ClaudeBot docs | Google-Extended docs |
What is ClaudeBot?
ClaudeBot is Anthropic's training crawler. The full profile covers the rest.
What is Google-Extended?
Google-Extended is not a crawler. The full profile covers the rest.
ClaudeBot vs Google-Extended by the numbers
ClaudeBot is a training crawler and Google-Extended is an opt-out token rather than a crawler. They do different jobs, so a sensible policy often treats them differently.
| Measure | ClaudeBot | Google-Extended |
|---|---|---|
| robots.txt token | ClaudeBot | Google-Extended |
| What it does | collects pages to train AI models | collects pages to train AI models |
| Crawler type | a training crawler | an opt-out token rather than a crawler |
| Priority tier | Tier 1 | Tier 1 |
| Follows robots.txt | Yes, per operator | Not applicable (token) |
| Top-10k robots.txt files | 858 named (15.4%), 805 blocked (14.4%) | 801 named (14.3%), 723 blocked (13%) |
| Blocked by top 1k / middle / tail | 20.4% / 14.6% / 13.3% | 18.6% / 13.1% / 11.9% |
In our robots.txt study of the Tranco top 10,000 (5,583 valid files, fetched October 20, 2026), ClaudeBot is blocked more often than Google-Extended: 805 files against 723. The counts are close, which suggests most sites that think about one also think about the other.
Writing rules for both
Because each crawler reads only the group that names it, you can give ClaudeBot and Google-Extended different answers in the same file. A common pattern, refusing training while allowing search and assistant fetches, looks like this for these two:
User-agent: ClaudeBot
Disallow: /
User-agent: Google-Extended
Allow: /- One group each. Do not rely on
User-agent: *to cover either crawler if you have named the other; name both. - Copy shared rules. Any
Disallowlines from the*group that should still apply must be repeated in each named group. - Mind the edge. A bot manager can refuse one and admit the other regardless of robots.txt.
- Verify both. The crawlability checker for AI search shows how each is treated on your live site.
Test yourself: if you write User-agent: ClaudeBot and User-agent: Google-Extended on consecutive lines above one Disallow: /, are both blocked?
Yes. Several User-agent lines in a row form one group, and the rules below apply to every name in it.
Test yourself: does blocking ClaudeBot also block Google-Extended?
No. Each token is matched separately.
Which to allow, by goal
| Your goal | ClaudeBot | Google-Extended |
|---|---|---|
| You want AI answers to cite you | Optional | Allow |
| You want to stop AI training | Block | No effect |
| Your server is under load | Rate-limit | Rate-limit |
| You need search traffic | No effect | No effect |
Related: how AI engines choose their sources
Block ClaudeBot if you do not want your content used for training. Set Google-Extended to control how content is used, not whether it is fetched.
The rest of each operator's family
Anthropic also runs anthropic-ai, Claude-Code, Claude-SearchBot, Claude-User, Claude-Web. Rules for ClaudeBot do not cover them. Google also runs AdsBot-Google, AdsBot-Google-Mobile, APIs-Google, Chrome-Lighthouse, FeedFetcher-Google. Rules for Google-Extended do not cover them.
Read the full profiles for both crawlers, linked in the table above, for documentation links, user-agent strings and server-side rules.
Mistakes when writing rules for ClaudeBot and Google-Extended together
ClaudeBot is named in 15.4% of the top-site robots.txt files in our study and blocked in 14.4%; Google-Extended is named in 14.3% of the top-site robots.txt files in our study and blocked in 13%. Large sites block ClaudeBot more often, which usually reflects a decision about training rather than about Google-Extended.
- They are different kinds of agent (a training crawler versus an opt-out token rather than a crawler), so the usual error is giving them the same rule out of habit. Blocking both to stop training only needs the ClaudeBot line; the other one changes something else entirely.
- They come from different operators (Anthropic and Google), with different documentation and different update cycles. Do not assume a change one of them announces applies to the other.
- Putting
User-agent: ClaudeBotandUser-agent: Google-Extendedin separate groups and then editing only one. Two groups drift apart over time; keep a comment above each that says why it differs from the other.
Each crawler's own profile lists the mistakes that apply to it alone; this list is only about combining the two.
Why Google-Extended never shows up next to ClaudeBot in your logs
Google-Extended is a control token from Google, not a crawler: nothing with that name ever requests a page. ClaudeBot is a a training crawler from Anthropic that does send requests, so it is the only one of the two you can count, verify or rate-limit.
- A firewall rule can act on ClaudeBot but not on Google-Extended. The token only works as a robots.txt line.
- Blocking Google-Extended does not slow Google's crawling. It changes what Google may do with pages its other crawlers already fetch.
- In our study of top sites, 13% block Google-Extended and 14.4% block ClaudeBot. Blocking the crawler is the more common choice here.
How ClaudeBot and Google-Extended moved in our latest scans
Between our scans of October 17, 2026 and October 20, 2026, files naming ClaudeBot went from 800 to 858 (+58) and files blocking it from 745 to 805 (+60), so more sites wrote a rule for ClaudeBot and more of those rules block it. For comparison, 2026 and October 20, 2026, files naming Google-Extended went from 743 to 801 (+58) and files blocking it from 666 to 723 (+57), so more sites wrote a rule for Google-Extended and more of those rules block it.
Over the 3 days between those scans, blocking of ClaudeBot moved +60 files and blocking of Google-Extended moved +57. Owners are acting faster on ClaudeBot, which is the one to recheck first if you have not touched your file this month.
We first recorded ClaudeBot on March 17, 2026. Anthropic documents it on support.claude.com, and we recheck that page before each release. We first recorded Google-Extended on March 17, 2026. Google documents it on developers.google.com, and we recheck that page before each release.
Among the 104 AI and LLM crawlers in our database, ClaudeBot sits seventh by priority (Tier 1), level with ChatGPT Agent, ChatGPT Operator, ChatGPT-User, ChatGPT-User/2.0. 81 of the 104 share its safe rating. On the Google-Extended side: Among the 104 AI and LLM crawlers in our database, Google-Extended sits eighth by priority (Tier 1), level with ChatGPT Agent, ChatGPT Operator, ChatGPT-User, ChatGPT-User/2.0. 81 of the 104 share its safe rating.
How top sites treat ClaudeBot and Google-Extended
From our robots.txt study of the Tranco top 10,000 (5,583 valid files, fetched October 20, 2026):
ClaudeBot, the most blocked of the ClaudeBot and Google-Extended tokens: blocked in 14.4% of files (594 with its own group, 211 throughUser-agent: *), more often by the top 1,000 (20.4%) than the long tail (13.3%).Google-Extended, second of the ClaudeBot and Google-Extended tokens: blocked in 13% of files (519 with its own group, 204 throughUser-agent: *), more often by the top 1,000 (18.6%) than the long tail (11.9%).
For scale, 20.1% of all files block at least one AI training crawler. ClaudeBot is one of the tokens driving that figure.
More questions about ClaudeBot and Google-Extended
- Can I allow one and block the other?
- Yes. Give each its own
User-agentgroup with its own rules. Each crawler reads only the group that names it. - Which of the two visits more often?
- It depends on your site, your audience and how often your content changes. Your access logs are the reliable answer; the commands above count both.
- How long until a change applies?
- Crawlers commonly cache robots.txt for up to a day, so allow about 24 hours and confirm in your logs.
- Do I need to update my rules when either operator launches a new crawler?
- Often, yes. A new token is not covered by rules written for the old ones. Check this comparison and both profiles periodically, or rerun the AI crawlability checker after any announcement.
Frequently asked questions
What is the difference between ClaudeBot and Google-Extended?
ClaudeBot is operated by Anthropic (ClaudeBot is Anthropic's training crawler. Anthropic says it collects "web content that could potentially contribute to" model training.) while Google-Extended is operated by Google (Google-Extended is not a crawler. It is a robots.txt token: disallowing it tells Google not to use content crawled by Googlebot for Gemini training and grounding.). They use different user-agent strings (ClaudeBot vs Google-Extended) and must be blocked separately in robots.txt.
Should I block ClaudeBot or Google-Extended?
Both ClaudeBot and Google-Extended carry the same safety rating (Safe). Your decision should come down to whether you want your content used by Anthropic versus Google, and whether each bot's purpose (training, search, or user requests) aligns with your content strategy.
Does blocking ClaudeBot or Google-Extended hurt SEO?
ClaudeBot: Low - No SEO ranking impact. Google-Extended: Low - No SEO ranking impact. Neither is a traditional search-ranking crawler, so blocking them does not affect Google or Bing rankings, but it may reduce your visibility in AI-generated answers.
How do I block both ClaudeBot and Google-Extended?
Add both user-agent groups to your robots.txt: "User-agent: ClaudeBot" with "Disallow: /" and "User-agent: Google-Extended" with "Disallow: /". Remember robots.txt is voluntary; combine with server-level rules for enforcement.
How to block each bot
Block ClaudeBot in robots.txt
User-agent: ClaudeBot Disallow: /
Block Google-Extended in robots.txt
User-agent: Google-Extended Disallow: /
Setting ClaudeBot, Google-Extended and the rest in one go? Tick both in the robots.txt generator (265+ presets), then confirm the result with the AI crawler checker.
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