How does an MCP client recognize when a user wants a resource?

In a typical implementation, your client recognizes resource requests through user input patterns. For example, when a user types something like what is in the at sign followed by a document name, your code parses that input, recognizes the at-mention as a resource request, and sends a read resource request to the MCP server with the appropriate URI. The server returns a read resource result containing the actual content. Your client then injects that content into the prompt before sending it to Claude. The user just sees the natural at-mention syntax, while behind the scenes the resource protocol does all the work of fetching the data.