chore: import upstream snapshot with attribution

examples/stories/standalone_get/client.py

@@ -0,0 +1,40 @@
+"""Receive `notifications/resources/list_changed` over the standalone GET stream, then re-list."""
+
+import anyio
+import mcp_types as types
+
+from mcp.client import Client
+from stories._harness import Target, run_client
+
+
+async def main(target: Target, *, mode: str = "auto") -> None:
+    # `message_handler` is constructor-only on `Client`, so the event it sets
+    # has to exist before the connection does.
+    received: list[types.ResourceListChangedNotification] = []
+    seen = anyio.Event()
+
+    async def on_message(message: object) -> None:
+        if isinstance(message, types.ResourceListChangedNotification):
+            received.append(message)
+            seen.set()
+
+    async with Client(target, mode=mode, message_handler=on_message) as client:
+        before = await client.list_resources()
+        assert len(before.resources) >= 1, before
+
+        result = await client.call_tool("add_note", {"content": "hello"})
+        assert not result.is_error, result
+
+        # The notification rides the standalone GET stream, not the call's POST stream —
+        # delivery order vs the tool result is not guaranteed, so wait.
+        with anyio.fail_after(5):
+            await seen.wait()
+        assert len(received) == 1, received
+
+        after = await client.list_resources()
+        assert len(after.resources) == len(before.resources) + 1, after
+        assert {r.name for r in after.resources} >= {"initial", "note-1"}
+
+
+if __name__ == "__main__":
+    run_client(main)