Support configuring the broadcasted client version

Author: LucaButBoring

src/mcp/client/session.py

@@ -119,6 +119,7 @@ def __init__(
         logging_callback: LoggingFnT | None = None,
         message_handler: MessageHandlerFnT | None = None,
         client_info: types.Implementation | None = None,
+        protocol_version: str | None = None,
     ) -> None:
         super().__init__(
             read_stream,
@@ -128,6 +129,7 @@ def __init__(
             read_timeout_seconds=read_timeout_seconds,
         )
         self._client_info = client_info or DEFAULT_CLIENT_INFO
+        self._protocol_version = protocol_version or types.LATEST_PROTOCOL_VERSION
         self._sampling_callback = sampling_callback or _default_sampling_callback
         self._elicitation_callback = elicitation_callback or _default_elicitation_callback
         self._list_roots_callback = list_roots_callback or _default_list_roots_callback
@@ -153,7 +155,7 @@ async def initialize(self) -> types.InitializeResult:
             types.ClientRequest(
                 types.InitializeRequest(
                     params=types.InitializeRequestParams(
-                        protocolVersion=types.LATEST_PROTOCOL_VERSION,
+                        protocolVersion=self._protocol_version,
                         capabilities=types.ClientCapabilities(
                             sampling=sampling,
                             elicitation=elicitation,

src/mcp/shared/memory.py

@@ -61,6 +61,7 @@ async def create_connected_server_and_client_session(
     client_info: types.Implementation | None = None,
     raise_exceptions: bool = False,
     elicitation_callback: ElicitationFnT | None = None,
+    protocol_version: str | None = None,
 ) -> AsyncGenerator[ClientSession, None]:
     """Creates a ClientSession that is connected to a running MCP server."""
     async with create_client_server_memory_streams() as (
@@ -92,6 +93,7 @@ async def create_connected_server_and_client_session(
                     message_handler=message_handler,
                     client_info=client_info,
                     elicitation_callback=elicitation_callback,
+                    protocol_version=protocol_version,
                 ) as client_session:
                     await client_session.initialize()
                     yield client_session