Fix Error: calling "initialize": invalid trailing data at the end of stream.

Server/src/main.py

@@ -1,12 +1,21 @@
 import argparse
 import asyncio
 import logging
-from contextlib import asynccontextmanager
+from contextlib import asynccontextmanager, redirect_stdout
 import os
+import sys
 import threading
 import time
 from typing import AsyncIterator, Any
 from urllib.parse import urlparse
+import io
+from utils.cr_stripper import CRStripper
+
+if sys.platform == 'win32':
+    import msvcrt
+    # Set binary mode on stdout to prevent automatic translation at the FD level
+    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
+
 
 from fastmcp import FastMCP
 from logging.handlers import RotatingFileHandler
@@ -402,8 +411,16 @@ def main():
         mcp.run(transport=transport, host=host, port=port)
     else:
         # Use stdio transport for traditional MCP
-        logger.info("Starting FastMCP with stdio transport")
-        mcp.run(transport='stdio')
+        removed_crlf = io.TextIOWrapper(
+            CRStripper(sys.stdout.buffer),
+            encoding=sys.stdout.encoding or 'utf-8',
+            newline='\n',
+            line_buffering=True,
+        )
+
+        with redirect_stdout(removed_crlf):
+            logger.info("Starting FastMCP with stdio transport")
+            mcp.run(transport='stdio')
 
 
 # Run the server

Server/src/utils/__init__.py

@@ -0,0 +1,6 @@
+"""
+SUMMARY: Utils package initialization.
+"""
+from .cr_stripper import CRStripper
+
+__all__ = ["CRStripper"]

Server/src/utils/cr_stripper.py

@@ -0,0 +1,75 @@
+"""
+Provides a utility to strip carriage return characters from output streams.
+
+This module implements the `CRStripper` class, which wraps a file-like object
+to filter out carriage return (\r) characters during write operations.
+
+Usage of this wrapper is essential for Model Context Protocol (MCP) communication
+over stdio, as it ensures consistent line endings and safeguards against 
+protocol errors, particularly in Windows environments.
+"""
+
+from typing import Any, BinaryIO
+
+class CRStripper:
+    """
+    A file-like wrapper that strips carriage return (\r) characters from data before writing.
+
+    This class intercepts write calls to the underlying stream and removes all 
+    instances of '\r', ensuring that output is clean and consistent across 
+    different platforms.
+    """
+    def __init__(self, stream: BinaryIO) -> None:
+        """
+        Initialize the stripper with an underlying stream.
+
+        Args:
+            stream (BinaryIO): The underlying file-like object or buffer to wrap (e.g., sys.stdout.buffer).
+        """
+        self._stream = stream
+
+    def write(self, data: bytes | bytearray | str) -> int:
+        """
+        Write data to the underlying stream after stripping all carriage return characters.
+
+        Args:
+            data (bytes | bytearray | str): The data to be written.
+
+        Returns:
+            int: The number of bytes or characters processed (matches input length if successful).
+        """
+        if isinstance(data, (bytes, bytearray)):
+            stripped = data.replace(b'\r', b'')
+            written = self._stream.write(stripped)
+        elif isinstance(data, str):
+            stripped = data.replace('\r', '')
+            written = self._stream.write(stripped)
+        else:
+            return self._stream.write(data)
+
+        # If the underlying stream wrote all the stripped data, we report
+        # that we wrote all the ORIGINAL data.
+        # This prevents callers (like TextIOWrapper) from seeing a "partial write"
+        # mismatch when we intentionally removed characters.
+        if written == len(stripped):
+            return len(data)
+
+        return written
+
+    def flush(self) -> None:
+        """
+        Flush the underlying stream.
+        """
+        return self._stream.flush()
+
+    def __getattr__(self, name: str) -> Any:
+        """
+        Delegate any attribute or method access to the underlying stream.
+
+        Args:
+            name (str): The name of the attribute to access.
+
+        Returns:
+            Any: The attribute or method from the wrapped stream.
+        """
+        return getattr(self._stream, name)