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Drop RootModel from JSONRPCMessage (#1908)

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This commit is contained in:
Marcelo Trylesinski 2026-01-19 14:04:15 +01:00 • committed by GitHub
commit f4672c5084
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4 changed files with 314 additions and 476 deletions
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6
src/mcp/client/sse.py
View file

@ -73,9 +73,7 @@ async def sse_client(
event_source.response.raise_for_status()
logger.debug("SSE connection established")
async def sse_reader(
task_status: TaskStatus[str] = anyio.TASK_STATUS_IGNORED,
):
async def sse_reader(task_status: TaskStatus[str] = anyio.TASK_STATUS_IGNORED):
try:
async for sse in event_source.aiter_sse(): # pragma: no branch
logger.debug(f"Received SSE event: {sse.event}")
@ -108,7 +106,7 @@ async def sse_client(
if not sse.data:
continue
try:
message = types.JSONRPCMessage.model_validate_json( # noqa: E501
message = types.jsonrpc_message_adapter.validate_json(
sse.data, by_name=False
)
logger.debug(f"Received server message: {message}")

2
src/mcp/client/stdio/__init__.py
View file

@ -150,7 +150,7 @@ async def stdio_client(server: StdioServerParameters, errlog: TextIO = sys.stder
for line in lines:
try:
message = types.JSONRPCMessage.model_validate_json(line, by_name=False)
message = types.jsonrpc_message_adapter.validate_json(line, by_name=False)
except Exception as exc: # pragma: no cover
logger.exception("Failed to parse JSONRPC message from server")
await read_stream_writer.send(exc)

44
src/mcp/client/streamable_http.py
View file

@ -25,6 +25,7 @@ from mcp.types import (
JSONRPCRequest,
JSONRPCResponse,
RequestId,
jsonrpc_message_adapter,
)
logger = logging.getLogger(__name__)
@ -95,11 +96,11 @@ class StreamableHTTPTransport:
def _is_initialization_request(self, message: JSONRPCMessage) -> bool:
"""Check if the message is an initialization request."""
return isinstance(message.root, JSONRPCRequest) and message.root.method == "initialize"
return isinstance(message, JSONRPCRequest) and message.method == "initialize"
def _is_initialized_notification(self, message: JSONRPCMessage) -> bool:
"""Check if the message is an initialized notification."""
return isinstance(message.root, JSONRPCNotification) and message.root.method == "notifications/initialized"
return isinstance(message, JSONRPCNotification) and message.method == "notifications/initialized"
def _maybe_extract_session_id_from_response(self, response: httpx.Response) -> None:
"""Extract and store session ID from response headers."""
@ -110,15 +111,15 @@ class StreamableHTTPTransport:
def _maybe_extract_protocol_version_from_message(self, message: JSONRPCMessage) -> None:
"""Extract protocol version from initialization response message."""
if isinstance(message.root, JSONRPCResponse) and message.root.result: # pragma: no branch
if isinstance(message, JSONRPCResponse) and message.result: # pragma: no branch
try:
# Parse the result as InitializeResult for type safety
init_result = InitializeResult.model_validate(message.root.result, by_name=False)
init_result = InitializeResult.model_validate(message.result, by_name=False)
self.protocol_version = str(init_result.protocol_version)
logger.info(f"Negotiated protocol version: {self.protocol_version}")
except Exception: # pragma: no cover
logger.warning("Failed to parse initialization response as InitializeResult", exc_info=True)
logger.warning(f"Raw result: {message.root.result}")
logger.warning(f"Raw result: {message.result}")
async def _handle_sse_event(
self,
@ -137,7 +138,7 @@ class StreamableHTTPTransport:
await resumption_callback(sse.id)
return False
try:
message = JSONRPCMessage.model_validate_json(sse.data, by_name=False)
message = jsonrpc_message_adapter.validate_json(sse.data, by_name=False)
logger.debug(f"SSE message: {message}")
# Extract protocol version from initialization response
@ -145,8 +146,8 @@ class StreamableHTTPTransport:
self._maybe_extract_protocol_version_from_message(message)
# If this is a response and we have original_request_id, replace it
if original_request_id is not None and isinstance(message.root, JSONRPCResponse | JSONRPCError):
message.root.id = original_request_id
if original_request_id is not None and isinstance(message, JSONRPCResponse | JSONRPCError):
message.id = original_request_id
session_message = SessionMessage(message)
await read_stream_writer.send(session_message)
@ -157,7 +158,7 @@ class StreamableHTTPTransport:
# If this is a response or error return True indicating completion
# Otherwise, return False to continue listening
return isinstance(message.root, JSONRPCResponse | JSONRPCError)
return isinstance(message, JSONRPCResponse | JSONRPCError)
except Exception as exc: # pragma: no cover
logger.exception("Error parsing SSE message")
@ -222,8 +223,8 @@ class StreamableHTTPTransport:
# Extract original request ID to map responses
original_request_id = None
if isinstance(ctx.session_message.message.root, JSONRPCRequest): # pragma: no branch
original_request_id = ctx.session_message.message.root.id
if isinstance(ctx.session_message.message, JSONRPCRequest): # pragma: no branch
original_request_id = ctx.session_message.message.id
async with aconnect_sse(ctx.client, "GET", self.url, headers=headers) as event_source:
event_source.response.raise_for_status()
@ -257,12 +258,9 @@ class StreamableHTTPTransport:
return
if response.status_code == 404: # pragma: no branch
if isinstance(message.root, JSONRPCRequest):
await self._send_session_terminated_error( # pragma: no cover
ctx.read_stream_writer, # pragma: no cover
message.root.id, # pragma: no cover
) # pragma: no cover
return # pragma: no cover
if isinstance(message, JSONRPCRequest): # pragma: no branch
await self._send_session_terminated_error(ctx.read_stream_writer, message.id)
return
response.raise_for_status()
if is_initialization:
@ -270,7 +268,7 @@ class StreamableHTTPTransport:
# Per https://modelcontextprotocol.io/specification/2025-06-18/basic#notifications:
# The server MUST NOT send a response to notifications.
if isinstance(message.root, JSONRPCRequest):
if isinstance(message, JSONRPCRequest):
content_type = response.headers.get("content-type", "").lower()
if content_type.startswith("application/json"):
await self._handle_json_response(response, ctx.read_stream_writer, is_initialization)
@ -291,7 +289,7 @@ class StreamableHTTPTransport:
"""Handle JSON response from the server."""
try:
content = await response.aread()
message = JSONRPCMessage.model_validate_json(content, by_name=False)
message = jsonrpc_message_adapter.validate_json(content, by_name=False)
# Extract protocol version from initialization response
if is_initialization:
@ -365,8 +363,8 @@ class StreamableHTTPTransport:
# Extract original request ID to map responses
original_request_id = None
if isinstance(ctx.session_message.message.root, JSONRPCRequest): # pragma: no branch
original_request_id = ctx.session_message.message.root.id
if isinstance(ctx.session_message.message, JSONRPCRequest): # pragma: no branch
original_request_id = ctx.session_message.message.id
try:
async with aconnect_sse(ctx.client, "GET", self.url, headers=headers) as event_source:
@ -416,7 +414,7 @@ class StreamableHTTPTransport:
id=request_id,
error=ErrorData(code=32600, message="Session terminated"),
)
session_message = SessionMessage(JSONRPCMessage(jsonrpc_error))
session_message = SessionMessage(jsonrpc_error)
await read_stream_writer.send(session_message)
async def post_writer(
@ -463,7 +461,7 @@ class StreamableHTTPTransport:
await self._handle_post_request(ctx)
# If this is a request, start a new task to handle it
if isinstance(message.root, JSONRPCRequest):
if isinstance(message, JSONRPCRequest):
tg.start_soon(handle_request_async)
else:
await handle_request_async()

2
src/mcp/client/websocket.py
View file

@ -51,7 +51,7 @@ async def websocket_client(
async with read_stream_writer:
async for raw_text in ws:
try:
message = types.JSONRPCMessage.model_validate_json(raw_text, by_name=False)
message = types.jsonrpc_message_adapter.validate_json(raw_text, by_name=False)
session_message = SessionMessage(message)
await read_stream_writer.send(session_message)
except ValidationError as exc: # pragma: no cover