chore: import upstream snapshot with attribution

examples/stories/roots/server_lowlevel.py

@@ -0,0 +1,36 @@
+"""Roots primitive (lowlevel API): the same server→client round-trip, hand-built."""
+
+from typing import Any
+
+import mcp_types as types
+
+from mcp.server.context import ServerRequestContext
+from mcp.server.lowlevel import Server
+from stories._hosting import run_server_from_args
+
+
+def build_server() -> Server[Any]:
+    async def list_tools(
+        ctx: ServerRequestContext[Any], params: types.PaginatedRequestParams | None
+    ) -> types.ListToolsResult:
+        return types.ListToolsResult(
+            tools=[
+                types.Tool(
+                    name="show_roots",
+                    description="Return the filesystem roots the client has exposed.",
+                    input_schema={"type": "object"},
+                ),
+            ]
+        )
+
+    async def call_tool(ctx: ServerRequestContext[Any], params: types.CallToolRequestParams) -> types.CallToolResult:
+        assert params.name == "show_roots"
+        result = await ctx.session.list_roots()  # pyright: ignore[reportDeprecated]
+        lines = [f"{root.uri} ({root.name or 'unnamed'})" for root in result.roots]
+        return types.CallToolResult(content=[types.TextContent(text="\n".join(lines))])
+
+    return Server("roots-example", on_list_tools=list_tools, on_call_tool=call_tool)
+
+
+if __name__ == "__main__":
+    run_server_from_args(build_server)