MistralAI-User: what it is, what it does with your content, and what blocking it costs
What MistralAI-User is
MistralAI-User fetches a page because a person asked for it. They pasted your URL, or followed a link, and asked the assistant to read it. There is no crawl schedule and no training corpus involved. Blocking it means failing a visitor who explicitly asked for your page.
Operator: Mistral AI
robots.txt token: MistralAI-User
User-agent on the wire: not published by the operator
Category: User-triggered fetch
What blocking it actually costs
Le Chat cannot fetch your page when a user asks about a specific URL.
How to block MistralAI-User
Add this to your robots.txt:
User-agent: MistralAI-User
Disallow: /
The token must appear on its own User-agent: line. A named group replaces the User-agent: * group rather than adding to it, so anything you also want disallowed for this crawler has to be repeated inside its group.
How to allow MistralAI-User
User-agent: MistralAI-User
Allow: /
An explicit allow is worth writing even when you have no blanket block: it documents the decision, and it survives someone later adding a restrictive User-agent: * rule without thinking about AI crawlers.
robots.txt is not the only thing that can block it
A permissive robots.txt does not mean MistralAI-User can reach you. WAF rules, Cloudflare's bot-management settings, rate limits and country blocks all sit in front of robots.txt and answer first. A site whose robots.txt welcomes MistralAI-User and whose edge returns 403 to it is blocked in every way that matters, and nothing in robots.txt will tell you so.
This is the gap the AI Crawler Access Checker was built to close: it reads robots.txt and sends a real request carrying the crawler's user-agent, so you see what the crawler sees.
Common questions
- What user-agent does MistralAI-User send?
Mistral AI does not publish an exact user-agent string for MistralAI-User. Match on the
MistralAI-Usertoken in robots.txt rather than on a full string you found elsewhere.- How do I block MistralAI-User?
Add a group to robots.txt naming the token exactly:
User-agent: MistralAI-User Disallow: /The group must name
MistralAI-Useron its own line. AUser-agent: *group does not combine with a named one. Under RFC 9309, the most specific matching group replaces the wildcard entirely, it does not inherit from it.- What does blocking MistralAI-User cost me?
Le Chat cannot fetch your page when a user asks about a specific URL.
- Can I tell a real MistralAI-User request from a fake one?
Not reliably. Mistral AI does not publish verified IP ranges for MistralAI-User, so the user-agent string is the only signal, and anyone can send it. Treat robots.txt as a statement of policy rather than as enforcement.
Is MistralAI-User blocked on your site right now?
Reading your own robots.txt only answers half of it, because a firewall rule can block MistralAI-User while robots.txt says it is welcome. The checker tests both.
Check your site free