Make SDK work on Windows without additional arguments

[JonasHelming]

Is your feature request related to a problem? Please describe.
We experienced that to start MCP servers via the SDK on Windows, you need to start a command interpreter (e.g. cmd.exe) as the server command in order for path lookups to work as expected
e.g. like this:

"filesystem": {
    "command": "cmd",
    "args": ["/C", "npx -y @modelcontextprotocol/server-filesystem /Users/YOUR_USERNAME/Desktop"],
    "env": {
      "CUSTOM_ENV_VAR": "custom-value"
    }
  }

Describe the solution you'd like

Would be nice to hide this in the client SDK to hide the complexity from the user, at least with a sensible default for Windows.

Describe alternatives you've considered
none

Additional context
We have documented this work around for our users: https://theia-ide.org/docs/user_ai/#mcp-integration
See also: https://eclipsesource.com/blogs/2024/12/19/theia-ide-and-theia-ai-support-mcp/

[aiqlcom]

I also encounter the same issue, and I noticed that there is an ongoing pull request addressing it: #95

This pull request aims to replace spawn with cross-spawn to resolve the issue.

ad6ea75#diff-cf9cf0e16fe93b95e6cc378c616f4cf5e884677337106dec23f740caee8707c3R1-R2

My workaround:

I am currently employing an alternative method as a temporary workaround to address this issue:

typescript-sdk/src/client/stdio.ts

Lines 107 to 118 in 3164da6

	return new Promise((resolve, reject) => {
	this._process = spawn(
	this._serverParams.command,
	this._serverParams.args ?? [],
	{
	env: this._serverParams.env ?? getDefaultEnvironment(),
	stdio: ["pipe", "pipe", this._serverParams.stderr ?? "inherit"],
	shell: false,
	signal: this._abortController.signal,
	windowsHide: process.platform === "win32" && isElectron(),
	}
	);

On Linux or macOS, shell: true is usually not required because command-line tools (such as npx) are typically standalone executables.

However, on Windows, shell: true is necessary to ensure that commands are executed correctly through the command interpreter.

Thus, I replaced it with shell: process.platform === "win32" ? true : false to temporarily avoid this issue.