Cursor runs it as a coding agent, which means it reads documentation while a developer is building something against your API, usually with the developer watching. What it cannot fetch, the developer gets as a guess from the model instead.
What blocking it costs you: The editor a large share of developers now write in cannot pull up your reference page while they are building against you. A developer building against your API reads whatever they can get instead of your documentation, and integrates against a guess.
The user agent, and the token a rule matches on
These are two different strings and confusing them is why a rule that looks right does nothing.
A robots.txt rule matches on the product token, case-insensitively, and
ignores the rest of the user-agent header entirely.
robots.txt token
Cursor
Operator
Cursor
Category
Coding agent
Full user agent
Not published by Cursor. Match on the token above.
Where an operator has not published the exact string, this page says so rather than
inventing a plausible one. A user agent you can grep your logs for is worth nothing if it is a guess.
Allowing Cursor
Paste this into robots.txt at the root of your domain.
An empty Disallow: and Allow: / mean the same thing to a crawler. What does
not mean the same thing is having no rule at all: absence is permission by default, but it is
permission nobody wrote down, and it survives only until somebody adds a blanket
User-agent: * block without thinking about this crawler.
Blocking Cursor
User-agent: Cursor
Disallow: /
Before you paste that: the editor a large share of developers now write in cannot pull up your reference page while they are building against you. That is the cost, and it is paid silently — no error appears in your logs, no report tells you, and the traffic you lose was traffic you never saw arrive.
How the web actually treats Cursor
Measured on 2026-09-06, by reading the robots.txt of
292 public websites and resolving each one against this crawler specifically.
Verdict
Sites
Share
Blocked
6
2%
Explicitly allowed
232
79%
No rule either way
54
18%
No site is named, here or anywhere else on this domain. The count is the useful part; a league table of
businesses that never asked to be measured is not.
The row worth reading twice is the last one. 54 of 292 sites have written no rule about
Cursor at all, which means their position on it is an accident rather than a decision — whatever
their User-agent: * block happens to say.
Checking what your site does right now
Reading your own robots.txt is not the same as knowing what a crawler concludes from it.
Precedence between a User-agent: * group and a named one, the longest-match rule between
overlapping paths, and a token you spelled slightly wrong all produce a file that looks correct and
behaves otherwise.
npx axray-cli your-site.com
The scan resolves your file against all 54 crawlers on this list individually and reports
which ones are allowed, blocked, or covered by nothing. It is free, needs no account, and installs nothing.
Questions people ask about Cursor
What is Cursor?
Cursor is a coding agent operated by Cursor: it reads documentation while a developer is building something against your API, usually with the developer watching. What it cannot fetch, the developer gets as a guess from the model instead.
Should I block Cursor in robots.txt?
Only if you are willing to pay what it costs. The editor a large share of developers now write in cannot pull up your reference page while they are building against you. A developer building against your API reads whatever they can get instead of your documentation, and integrates against a guess.
What is the Cursor user agent string?
Cursor does not publish a full user-agent string for this crawler. The robots.txt product token is Cursor, and that is what a rule matches on; matching is case-insensitive.
How do I check whether my site is blocking Cursor right now?
Scan your site with AXRAY. It resolves your robots.txt against 54 named AI crawlers individually rather than reporting one verdict for all of them, so it will tell you whether this specific crawler is allowed, blocked, or covered by no rule at all. It is free and needs no account.