Anthropic

Claude-Code

AI answersPublished IP ranges

Anthropic's coding agent reading a page a developer pointed it at.

When you see it: A developer working with Claude Code asked it to read your documentation or an article.

How we check it is really Anthropic

  1. 01

    The user agent has to contain Claude-Code.

  2. 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
Claude-Code
Counted as
AI assistant
Verification
Published IP ranges
Runs JavaScript
No
Operator docs
Published

User agent

Claude-Code

Matched 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 Claude-Code keeps working. The same string is what Anthropic names in robots.txt.

Anthropic'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.

TokenCounted asVerificationWhat it fetches for
Claude-Codethis pageAI answersPublished IP rangesAnthropic's coding agent reading a page a developer pointed it at.
Claude-UserAI answersPublished IP rangesFetches a page while Claude is answering someone's question.
Claude-SearchBotIndexingPublished IP rangesDiscovers and refreshes content for Claude's search.
ClaudeBotTrainingPublished IP rangesCollects public content that may be used to improve Claude.

Your analytics never mentioned Claude-Code 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.