What are roots in MCP and what problem do they solve?

Roots are a mechanism that grants MCP servers access to specific files and folders on the user's local machine. Without roots, when a user asks Claude to convert a file, Claude has no way to search the entire file system to find where that file lives. The user would need to provide the full path every time, which is not user-friendly. With roots, the client tells the server which directories are accessible. Claude can then call list_roots to discover approved directories and search within them to find the requested file automatically.