refactor: remove StdioServerParameters class

README.md

@@ -521,16 +521,9 @@ if __name__ == "__main__":
 The SDK provides a high-level client interface for connecting to MCP servers:
 
 ```python
-from mcp import ClientSession, StdioServerParameters, types
+from mcp import ClientSession, types
 from mcp.client.stdio import stdio_client
 
-# Create server parameters for stdio connection
-server_params = StdioServerParameters(
-    command="python",  # Executable
-    args=["example_server.py"],  # Optional command line arguments
-    env=None,  # Optional environment variables
-)
-
 
 # Optional: create a sampling callback
 async def handle_sampling_message(
@@ -548,7 +541,12 @@ async def handle_sampling_message(
 
 
 async def run():
-    async with stdio_client(server_params) as (read, write):
+    # Connect to server using stdio transport
+    async with stdio_client(
+        command="python",  # Executable
+        args=["example_server.py"],  # Optional command line arguments
+        env=None,  # Optional environment variables
+    ) as (read, write):
         async with ClientSession(
             read, write, sampling_callback=handle_sampling_message
         ) as session:

src/mcp/__init__.py

@@ -1,5 +1,5 @@
 from .client.session import ClientSession
-from .client.stdio import StdioServerParameters, stdio_client
+from .client.stdio import stdio_client
 from .server.session import ServerSession
 from .server.stdio import stdio_server
 from .shared.exceptions import McpError
@@ -101,7 +101,6 @@
     "ServerResult",
     "ServerSession",
     "SetLevelRequest",
-    "StdioServerParameters",
     "StopReason",
     "SubscribeRequest",
     "Tool",

src/mcp/client/stdio.py

@@ -7,7 +7,6 @@
 import anyio.lowlevel
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 from anyio.streams.text import TextReceiveStream
-from pydantic import BaseModel, Field
 
 import mcp.types as types
 
@@ -52,41 +51,19 @@ def get_default_environment() -> dict[str, str]:
     return env
 
 
-class StdioServerParameters(BaseModel):
-    command: str
-    """The executable to run to start the server."""
-
-    args: list[str] = Field(default_factory=list)
-    """Command line arguments to pass to the executable."""
-
-    env: dict[str, str] | None = None
-    """
-    The environment to use when spawning the process.
-
-    If not specified, the result of get_default_environment() will be used.
-    """
-
-    encoding: str = "utf-8"
-    """
-    The text encoding used when sending/receiving messages to the server
-
-    defaults to utf-8
-    """
-
-    encoding_error_handler: Literal["strict", "ignore", "replace"] = "strict"
-    """
-    The text encoding error handler.
-
-    See https://docs.python.org/3/library/codecs.html#codec-base-classes for
-    explanations of possible values
-    """
-
-
 @asynccontextmanager
-async def stdio_client(server: StdioServerParameters):
+async def stdio_client(
+    command: str,
+    args: list[str] | None = None,
+    env: dict[str, str] | None = None,
+    encoding: str = "utf-8",
+    encoding_error_handler: Literal["strict", "ignore", "replace"] = "strict",
+):
     """
     Client transport for stdio: this will connect to a server by spawning a
     process and communicating with it over stdin/stdout.
+
+
     """
     read_stream: MemoryObjectReceiveStream[types.JSONRPCMessage | Exception]
     read_stream_writer: MemoryObjectSendStream[types.JSONRPCMessage | Exception]
@@ -98,8 +75,8 @@ async def stdio_client(server: StdioServerParameters):
     write_stream, write_stream_reader = anyio.create_memory_object_stream(0)
 
     process = await anyio.open_process(
-        [server.command, *server.args],
-        env=server.env if server.env is not None else get_default_environment(),
+        [command] + (args or []),
+        env=env if env is not None else get_default_environment(),
         stderr=sys.stderr,
     )
 
@@ -111,8 +88,8 @@ async def stdout_reader():
                 buffer = ""
                 async for chunk in TextReceiveStream(
                     process.stdout,
-                    encoding=server.encoding,
-                    errors=server.encoding_error_handler,
+                    encoding=encoding,
+                    errors=encoding_error_handler,
                 ):
                     lines = (buffer + chunk).split("\n")
                     buffer = lines.pop()
@@ -137,8 +114,8 @@ async def stdin_writer():
                     json = message.model_dump_json(by_alias=True, exclude_none=True)
                     await process.stdin.send(
                         (json + "\n").encode(
-                            encoding=server.encoding,
-                            errors=server.encoding_error_handler,
+                            encoding=encoding,
+                            errors=encoding_error_handler,
                         )
                     )
         except anyio.ClosedResourceError:

tests/client/test_stdio.py

@@ -2,7 +2,7 @@
 
 import pytest
 
-from mcp.client.stdio import StdioServerParameters, stdio_client
+from mcp.client.stdio import stdio_client
 from mcp.types import JSONRPCMessage, JSONRPCRequest, JSONRPCResponse
 
 tee: str = shutil.which("tee")  # type: ignore
@@ -11,9 +11,7 @@
 @pytest.mark.anyio
 @pytest.mark.skipif(tee is None, reason="could not find tee command")
 async def test_stdio_client():
-    server_parameters = StdioServerParameters(command=tee)
-
-    async with stdio_client(server_parameters) as (read_stream, write_stream):
+    async with stdio_client(command=tee) as (read_stream, write_stream):
         # Test sending and receiving messages
         messages = [
             JSONRPCMessage(root=JSONRPCRequest(jsonrpc="2.0", id=1, method="ping")),