fix: suppress platform string output to stdout on macOS

main.py

@@ -1,3 +1,4 @@
+import io
 import argparse
 import logging
 import os
@@ -6,6 +7,13 @@ import sys
 from importlib import metadata, import_module
 from dotenv import load_dotenv
 
+# Prevent any stray output (e.g. platform identifiers like "darwin" on macOS)
+# from corrupting the MCP JSON-RPC handshake on stdout.  We capture anything
+# written to stdout during module-level initialisation and replay it to stderr
+# so that diagnostic information is not lost.
+_original_stdout = sys.stdout
+sys.stdout = io.StringIO()
+
 # Check for CLI mode early - before loading oauth_config
 # CLI mode requires OAuth 2.0 since there's no MCP session context
 _CLI_MODE = "--cli" in sys.argv
@@ -117,12 +125,21 @@ def narrow_permissions_to_services(
     }
 
 
+def _restore_stdout():
+    """Restore the real stdout and replay any captured output to stderr."""
+    captured = sys.stdout.getvalue()
+    sys.stdout = _original_stdout
+    if captured:
+        print(captured, end="", file=sys.stderr)
+
+
 def main():
     """
     Main entry point for the Google Workspace MCP server.
     Uses FastMCP's native streamable-http transport.
     Supports CLI mode for direct tool invocation without running the server.
     """
+    _restore_stdout()
     # Check if CLI mode is enabled - suppress startup messages
     if _CLI_MODE:
         # Suppress logging output in CLI mode for clean output