What is a user agent (and how do AI agents identify themselves)?
Updated By Akkrev
A user agent is the name a browser or bot sends with each web request. AI crawlers and agents use names like GPTBot, ChatGPT-User and Google-Agent.
A user agent is a short text string that every browser, crawler and bot sends with each request to a website, saying what it is. A Chrome browser on a Mac sends one string; Googlebot sends another; OpenAI’s crawler sends one containing “GPTBot”.
How AI systems identify themselves
- Training crawlers: GPTBot, ClaudeBot, Google-Extended (a robots.txt token rather than a separate crawler).
- Search crawlers: OAI-SearchBot, Claude-SearchBot, PerplexityBot.
- User-triggered fetchers: ChatGPT-User, Claude-User, Perplexity-User, and Google-Agent for agents on Google’s infrastructure.
Some agentic browsers use an ordinary browser user agent and can’t be told apart from people this way.
Why it matters for hotels
User agents are what robots.txt rules and many bot management settings act on. They’re also easy to fake, which is why AI companies publish IP ranges and why signed requests such as Web Bot Auth are being adopted. Checking your server logs for these names shows which AI systems already visit your site.
Why it matters for AI visibility
User agents tell you which AI crawlers and assistants are reading your site. That’s an early signal of AI visibility.