chore: import upstream snapshot with attribution

examples/stories/mrtr/server_lowlevel.py

@@ -0,0 +1,67 @@
+"""Multi-round tool result (2026 era) against the low-level Server."""
+
+from typing import Any
+
+import mcp_types as types
+
+from mcp.server.context import ServerRequestContext
+from mcp.server.lowlevel import Server
+from mcp.server.request_state import RequestStateBoundary, RequestStateSecurity
+from stories._hosting import run_server_from_args
+
+CONFIRM_SCHEMA: types.ElicitRequestedSchema = {
+    "type": "object",
+    "properties": {"confirm": {"type": "boolean", "description": "Proceed with the deployment?"}},
+    "required": ["confirm"],
+}
+DEPLOY_INPUT_SCHEMA: dict[str, Any] = {
+    "type": "object",
+    "properties": {"env": {"type": "string"}},
+    "required": ["env"],
+}
+
+
+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="deploy",
+                    description="Deploy to an environment, asking the user to confirm first.",
+                    input_schema=DEPLOY_INPUT_SCHEMA,
+                )
+            ]
+        )
+
+    async def call_tool(
+        ctx: ServerRequestContext[Any], params: types.CallToolRequestParams
+    ) -> types.CallToolResult | types.InputRequiredResult:
+        assert params.name == "deploy" and params.arguments is not None
+        env = params.arguments["env"]
+        responses = params.input_responses
+        if responses is None or "confirm" not in responses:
+            ask = types.ElicitRequest(
+                params=types.ElicitRequestFormParams(message=f"Deploy to {env}?", requested_schema=CONFIRM_SCHEMA)
+            )
+            return types.InputRequiredResult(input_requests={"confirm": ask}, request_state="awaiting-confirm")
+        assert params.request_state == "awaiting-confirm", params.request_state
+        answer = responses["confirm"]
+        if (
+            isinstance(answer, types.ElicitResult)
+            and answer.action == "accept"
+            and (answer.content or {}).get("confirm")
+        ):
+            return types.CallToolResult(content=[types.TextContent(text=f"deployed to {env}")])
+        return types.CallToolResult(content=[types.TextContent(text=f"deployment to {env} cancelled")])
+
+    server = Server("mrtr-example", on_list_tools=list_tools, on_call_tool=call_tool)
+    # Lowlevel opt-in: append the same boundary middleware MCPServer installs by
+    # default; the server name becomes the token audience.
+    server.middleware.append(RequestStateBoundary(RequestStateSecurity.ephemeral(), default_audience=server.name))
+    return server
+
+
+if __name__ == "__main__":
+    run_server_from_args(build_server)