import anyio import pytest import mcp.types as types from mcp.client.session import ClientSession from mcp.server import Server from mcp.server.lowlevel import NotificationOptions from mcp.server.models import InitializationOptions from mcp.server.session import ServerSession from mcp.shared.message import SessionMessage from mcp.shared.session import RequestResponder from mcp.types import ( ClientNotification, InitializedNotification, PromptsCapability, ResourcesCapability, ServerCapabilities, ) @pytest.mark.anyio async def test_server_session_initialize(): server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1) client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage](1) # Create a message handler to catch exceptions async def message_handler( message: RequestResponder[types.ServerRequest, types.ClientResult] | types.ServerNotification | Exception, ) -> None: if isinstance(message, Exception): raise message received_initialized = False async def run_server(): nonlocal received_initialized async with ServerSession( client_to_server_receive, server_to_client_send, InitializationOptions( server_name="mcp", server_version="0.1.0", capabilities=ServerCapabilities(), ), ) as server_session: async for message in server_session.incoming_messages: if isinstance(message, Exception): raise message if isinstance(message, ClientNotification) and isinstance(message.root, InitializedNotification): received_initialized = True return try: async with ( ClientSession( server_to_client_receive, client_to_server_send, message_handler=message_handler, ) as client_session, anyio.create_task_group() as tg, ): tg.start_soon(run_server) await client_session.initialize() except anyio.ClosedResourceError: pass assert received_initialized @pytest.mark.anyio async def test_server_capabilities(): server = Server("test") notification_options = NotificationOptions() experimental_capabilities = {} # Initially no capabilities caps = server.get_capabilities(notification_options, experimental_capabilities) assert caps.prompts is None assert caps.resources is None # Add a prompts handler @server.list_prompts() async def list_prompts(): return [] caps = server.get_capabilities(notification_options, experimental_capabilities) assert caps.prompts == PromptsCapability(listChanged=False) assert caps.resources is None # Add a resources handler @server.list_resources() async def list_resources(): return [] caps = server.get_capabilities(notification_options, experimental_capabilities) assert caps.prompts == PromptsCapability(listChanged=False) assert caps.resources == ResourcesCapability(subscribe=False, listChanged=False) @pytest.mark.anyio async def test_server_session_initialize_with_older_protocol_version(): """Test that server accepts and responds with older protocol (2024-11-05).""" server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1) client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage | Exception](1) received_initialized = False received_protocol_version = None async def run_server(): nonlocal received_initialized async with ServerSession( client_to_server_receive, server_to_client_send, InitializationOptions( server_name="mcp", server_version="0.1.0", capabilities=ServerCapabilities(), ), ) as server_session: async for message in server_session.incoming_messages: if isinstance(message, Exception): raise message if isinstance(message, types.ClientNotification) and isinstance(message.root, InitializedNotification): received_initialized = True return async def mock_client(): nonlocal received_protocol_version # Send initialization request with older protocol version (2024-11-05) await client_to_server_send.send( SessionMessage( types.JSONRPCMessage( types.JSONRPCRequest( jsonrpc="2.0", id=1, method="initialize", params=types.InitializeRequestParams( protocolVersion="2024-11-05", capabilities=types.ClientCapabilities(), clientInfo=types.Implementation(name="test-client", version="1.0.0"), ).model_dump(by_alias=True, mode="json", exclude_none=True), ) ) ) ) # Wait for the initialize response init_response_message = await server_to_client_receive.receive() assert isinstance(init_response_message.message.root, types.JSONRPCResponse) result_data = init_response_message.message.root.result init_result = types.InitializeResult.model_validate(result_data) # Check that the server responded with the requested protocol version received_protocol_version = init_result.protocolVersion assert received_protocol_version == "2024-11-05" # Send initialized notification await client_to_server_send.send( SessionMessage( types.JSONRPCMessage( types.JSONRPCNotification( jsonrpc="2.0", method="notifications/initialized", ) ) ) ) async with ( client_to_server_send, client_to_server_receive, server_to_client_send, server_to_client_receive, anyio.create_task_group() as tg, ): tg.start_soon(run_server) tg.start_soon(mock_client) assert received_initialized assert received_protocol_version == "2024-11-05"