It seems to support your ask, as much as a protocol can. Having read all the docs and looked through some code, my mental model is:

  - A host never talks to a server directly, only via a Client (which is presumably a human). The host has or is the LLM (app).

  - A server only supplies context data (readonly), in the form of tool call, direct resource URL, or pre populated prompt. It can call back to a client directly, for example to request something from the hosts LLM.

  - A client sits in the middle, representing the human in the loop. It manages the requests bidirectionally

I look at the filesystem server and I don't see any indication of a difference between a tool that is just reading from one that is doing changes:

https://github.com/modelcontextprotocol/servers/blob/main/sr...

How can an add on that works with arbitrary "servers" tell the difference between these two tools? Without being able to tell the difference you can't really build a generic way to ask for confirmation in the application that is using the server...

      {
        name: "create_directory",
        description:
          "Create a new directory or ensure a directory exists. Can create multiple " +
          "nested directories in one operation. If the directory already exists, " +
          "this operation will succeed silently. Perfect for setting up directory " +
          "structures for projects or ensuring required paths exist. Only works within allowed directories.",
        inputSchema: zodToJsonSchema(CreateDirectoryArgsSchema) as ToolInput,
      },
      {
        name: "list_directory",
        description:
          "Get a detailed listing of all files and directories in a specified path. " +
          "Results clearly distinguish between files and directories with [FILE] and [DIR] " +
          "prefixes. This tool is essential for understanding directory structure and " +
          "finding specific files within a directory. Only works within allowed directories.",
        inputSchema: zodToJsonSchema(ListDirectoryArgsSchema) as ToolInput,
      },