From 18d5492523231e5b51b0e967637ef140318afca5 Mon Sep 17 00:00:00 2001
From: KevinTran3011 <112609054+KevinTran3011@users.noreply.github.com>
Date: Mon, 24 Aug 2026 10:48:04 +1000
Subject: [PATCH] fix: avoid shell interpretation in MCP dev launcher

---
 src/mcp/cli/cli.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/mcp/cli/cli.py b/src/mcp/cli/cli.py
index 203034c6ef..69908e092a 100644
--- a/src/mcp/cli/cli.py
+++ b/src/mcp/cli/cli.py
@@ -45,7 +45,7 @@ def _get_npx_command():
         # Try both npx.cmd and npx.exe on Windows
         for cmd in ["npx.cmd", "npx.exe", "npx"]:
             try:
-                subprocess.run([cmd, "--version"], check=True, capture_output=True, shell=True)
+                subprocess.run([cmd, "--version"], check=True, capture_output=True)
                 return cmd
             except subprocess.CalledProcessError:
                 continue
@@ -271,12 +271,13 @@ def dev(
             )
             sys.exit(1)
 
-        # Run the MCP Inspector command with shell=True on Windows
-        shell = sys.platform == "win32"
+        # Pass an argv list directly to the process. Using cmd.exe on Windows
+        # makes every argument part of a shell command and can reinterpret
+        # repository/file-controlled values.
         process = subprocess.run(
             [npx_cmd, "@modelcontextprotocol/inspector"] + uv_cmd,
             check=True,
-            shell=shell,
+            shell=False,
             env=dict(os.environ.items()),  # Copy the environment for subprocess launch
         )
         sys.exit(process.returncode)