Anthropic
ClaudeBot
Collects public content that may be used to improve Claude.
When you see it: Anthropic is gathering training data.
How we check it is really Anthropic
- 01
The user agent has to contain ClaudeBot.
- 02
The address is compared against Anthropic's published ranges, which we refetch every six hours.
Anthropic publishes no reverse DNS record, so an address outside the list is recorded as unverified rather than as a forgery — the list may simply be behind.
What each result means
- verified
- The address matched Anthropic's own published records. This really was them.
- unverified
- We could not confirm it, and that is all it means. The operator may publish nothing to check against, a published list may be behind the addresses actually in use, or DNS may simply have been slow. It is not an accusation.
- spoofed
- The address belongs to somebody else — its own reverse DNS record resolves to a different owner. That is positive evidence of a forgery rather than a failure to find evidence, which is why it is reported as its own result and never folded into the row above.
The distinction costs nothing to make and is the reason these numbers can be shown to someone who will ask where they came from. A report that cannot separate “we do not know” from “this was faked” invites exactly one question it cannot answer.
The lists this is checked against
Published by Anthropic and refetched every six hours. Open them; they are the same files we read.
- Operator
- Anthropic
- Token
- ClaudeBot
- Counted as
- AI training
- Verification
- Published IP ranges
- Runs JavaScript
- No
- Operator docs
- Published
User agent
ClaudeBotMatched as a token, not as a full browser string. Anthropic adds and changes the version and product text around it without notice, so a filter pinned to the whole header stops working the first time they bump a version while one matching ClaudeBot keeps working. The same string is what Anthropic names in robots.txt.
One real request
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ClaudeBot/1.0; +claudebot@anthropic.comAnthropic's other crawlers
Anthropic sends 4 crawlers, each with its own token and its own job. They are counted separately for that reason — the tokens differ by a few characters and what the fetch means does not, so folding them into one operator row would let indexing look like AI interest.
| Token | Counted as | Verification | What it fetches for |
|---|---|---|---|
ClaudeBotthis page | Training | Published IP ranges | Collects public content that may be used to improve Claude. |
| Claude-User | AI answers | Published IP ranges | Fetches a page while Claude is answering someone's question. |
| Claude-Code | AI answers | Published IP ranges | Anthropic's coding agent reading a page a developer pointed it at. |
| Claude-SearchBot | Indexing | Published IP ranges | Discovers and refreshes content for Claude's search. |
Your analytics never mentioned ClaudeBot because it cannot see it.
This crawler takes your HTML and leaves without running a line of JavaScript, so a browser tag records nothing. TrueStat reads it server-side, checks the address, and shows you which pages it fetched — including the ones that returned a 404.