# User Agent In [computing](https://en.wikipedia.org/wiki/Computing), a user agent is any software, acting on behalf of a [user](https://en.wikipedia.org/wiki/User_\(computing\)), which "retrieves, renders and facilitates end-user interaction with Web content". A user agent is therefore a special kind of [software agent](https://en.wikipedia.org/wiki/Software_agent). Some prominent examples of user agents are [web browsers](https://en.wikipedia.org/wiki/Web_browsers) and [email readers](https://en.wikipedia.org/wiki/Email_client). Often, a user agent acts as the [client](https://en.wikipedia.org/wiki/Client_\(computing\)) in a [client–server system](https://en.wikipedia.org/wiki/Client%E2%80%93server_model). In some contexts, such as within the [Session Initiation Protocol](https://en.wikipedia.org/wiki/Session_Initiation_Protocol) (SIP), the term *user agent* refers to both end points of a communications session. Source: --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://doc.bitbrowser.net/fingerprint/18.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.