Fix Windows compatibility and deprecated -p flag by cj-elevate · Pull Request #43 · jamubc/gemini-mcp-tool

cj-elevate · 2025-12-01T02:48:14Z

Summary

Set shell: true in spawn() to support Windows .cmd executables
Replace deprecated -p/--prompt flag with positional prompt
Add -y flag for non-interactive YOLO mode
NEW: Add workingDirectory parameter for cross-drive access on Windows

Problem

Issue 1: Windows spawn fails
On Windows, gemini is installed as gemini.cmd which requires shell: true to execute properly via Node's spawn(). Without this, the MCP fails with:

Error executing ask-gemini: Failed to spawn command: spawn gemini ENOENT

Issue 2: Deprecated flag conflict
The -p flag is deprecated and causes conflicts when used with positional prompts in newer Gemini CLI versions (v0.18+):

Cannot use both a positional prompt and the --prompt (-p) flag together

Issue 3: Windows multi-drive limitation
Gemini CLI locks workspace to the launch directory. On Windows with multiple drives (C:/, D:/, E:/), users couldn't access files across drives.

Solution

Changed shell: false to shell: true in commandExecutor.ts
Replaced -p flag usage with positional prompt argument
Added -y flag for YOLO mode (required for non-interactive use)
Added workingDirectory parameter that sets cwd in spawn, allowing users to specify which drive to access

Usage

// Access C: drive
ask-gemini({ prompt: "List files in C:/Users", workingDirectory: "C:/" })

// Access D: drive  
ask-gemini({ prompt: "Analyze D:/project/code.ts", workingDirectory: "D:/" })

Testing

Tested on Windows 11 with Gemini CLI v0.18.4 via Claude Code MCP integration.

- Set shell: true in spawn() to support Windows .cmd executables - Replace deprecated -p/--prompt flag with positional prompt - Add -y flag for non-interactive YOLO mode On Windows, gemini is installed as gemini.cmd which requires shell: true to execute properly. The -p flag is deprecated and causes conflicts when used with positional prompts in newer Gemini CLI versions. Tested on Windows 11 with Gemini CLI v0.18.4

gemini-code-assist · 2025-12-01T02:48:25Z

Summary of Changes

Hello @cj-elevate, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly improves the robustness and cross-platform compatibility of the Gemini CLI integration. It addresses critical issues for Windows users by enabling proper execution of .cmd files and updates the command argument handling to accommodate changes in the Gemini CLI, specifically replacing a deprecated prompt flag with a positional argument. Additionally, it ensures non-interactive operation by including the -y flag, making the integration more reliable across different environments and CLI versions.

Highlights

Windows Compatibility: The spawn() function now uses shell: true to correctly execute .cmd executables on Windows, resolving ENOENT errors that previously prevented the Gemini CLI from running.
Deprecated Flag Replacement: The -p/--prompt flag has been replaced with a positional prompt argument to align with changes in newer Gemini CLI versions (v0.18+) and avoid conflicts.
Non-interactive Mode: The -y flag (YOLO mode) is now consistently added to command arguments to support non-interactive use of the Gemini CLI.

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Code Review

This pull request correctly addresses Windows compatibility issues by enabling a shell for command execution and updates the code to use a positional prompt instead of the deprecated -p flag, which is a good improvement. My review includes a critical security suggestion to limit the use of shell: true to Windows only, reducing the risk of command injection on other platforms. I've also pointed out an opportunity to refactor some duplicated code to improve the long-term maintainability of the geminiExecutor.

gemini-code-assist · 2025-12-01T02:49:35Z

    const childProcess = spawn(command, args, {
      env: process.env,
-      shell: false,
+      shell: true,


Enabling shell: true unconditionally can introduce security vulnerabilities if the command or arguments are not properly sanitized, especially on non-Windows platforms where it might not be necessary. Since this change is intended for Windows compatibility, it's safer to enable the shell only when running on Windows. This minimizes the potential attack surface of command injection.

Suggested change

shell: true,

shell: process.platform === "win32",

gemini-code-assist · 2025-12-01T02:49:35Z

+  const args = ['-y']; // YOLO mode for non-interactive
  if (model) { args.push(CLI.FLAGS.MODEL, model); }
  if (sandbox) { args.push(CLI.FLAGS.SANDBOX); }
-
-  // Ensure @ symbols work cross-platform by wrapping in quotes if needed
-  const finalPrompt = prompt_processed.includes('@') && !prompt_processed.startsWith('"') 
-    ? `"${prompt_processed}"` 
-    : prompt_processed;
-
-  args.push(CLI.FLAGS.PROMPT, finalPrompt);
+
+  // Use positional prompt (not -p flag which is deprecated)
+  args.push(prompt_processed);


The logic for constructing the arguments array is nearly identical here and in the catch block (lines 104-111). This duplication can lead to maintenance issues, where a change in one place might not be reflected in the other. To improve maintainability and reduce redundancy, consider extracting this logic into a single helper function.

- Add workingDirectory parameter to ask-gemini tool - Pass cwd to spawn() to control Gemini's workspace directory - Enables accessing files on any Windows drive (C:/, D:/, E:/, etc.) This solves the Windows multi-drive limitation where Gemini workspace is locked to the launch directory. Users can now specify which drive root to use as the working directory, giving full read access to that drive. Example: workingDirectory: "C:/" → access C: drive files workingDirectory: "D:/" → access D: drive files

- Change package name to @joeytheman/gemini-mcp-tool - Bump version to 1.2.0 - Add PR jamubc#43 changelog entries (Windows fixes)

Sundeepg98 · 2026-03-01T06:54:52Z

Hey @cj-elevate! Your PR correctly identifies both issues (Windows .cmd resolution and deprecated -p flag). However, using shell: true without arg escaping means prompts with spaces can still break — the shell splits them into multiple positional args.

I've submitted an alternative approach in #57 that uses cross-spawn instead of shell: true. It's a drop-in replacement for child_process.spawn that handles .cmd resolution and argument escaping transparently, while keeping shell: false (avoiding any shell injection surface).

The key difference:

	This PR (`shell: true`)	#57 (`cross-spawn`)
`.cmd` resolution	✅	✅
Arg escaping	❌ needs manual quoting	✅ automatic
Security	⚠️ shell injection surface	✅ `shell: false` preserved
Dependency	None	`cross-spawn` (40M+/week, used by npm)

Either approach solves the core issue — just wanted to share the cross-spawn option since it's what npm itself uses for this exact problem. Cheers!

jamubc · 2026-05-30T09:06:13Z

Thanks — the Windows word-splitting is fixed in #76/#77; the -p→positional migration stays tracked in #48. Closing as largely superseded.

gemini-code-assist Bot reviewed Dec 1, 2025

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Sundeepg98 mentioned this pull request Mar 1, 2026

fix: use cross-spawn for Windows compatibility #57

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jamubc closed this May 30, 2026

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Fix Windows compatibility and deprecated -p flag#43

Fix Windows compatibility and deprecated -p flag#43
cj-elevate wants to merge 2 commits into
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cj-elevate:fix/windows-compatibility-and-deprecated-prompt-flag

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cj-elevate commented Dec 1, 2025 •

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