Fixing 'The path argument must be of type string' Error in Copilot CLI

If you've been using GitHub Copilot CLI and suddenly find yourself unable to run any commands, encountering the error message The "path" argument must be of type string. Received undefined with every command you try, you're not alone. This frustrating issue can bring your AI-assisted development workflow to a complete halt.

The Problem

The error manifests itself consistently across all Copilot CLI commands. Whether you're trying to check your current directory with pwd, list files, or execute any other command through the CLI, you'll see the same error message:

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1✗ Check current directory
2  $ pwd
3  The "path" argument must be of type string. Received undefined

This error essentially renders the Copilot CLI unusable, as every operation fails before it can even begin. The CLI appears to be unable to properly handle path arguments internally, which is a critical issue since path handling is fundamental to almost every file system operation.

Understanding the Root Cause

This issue typically occurs due to a compatibility problem between the Copilot CLI version and your Node.js runtime. Specifically, older versions of Node.js may not be fully compatible with the way newer versions of Copilot CLI handle path operations internally.

The error suggests that somewhere in the code, a function expecting a string path argument is receiving undefined instead. This could happen if:

1. Environment variables aren't being read correctly
2. Path resolution methods have changed between Node.js versions
3. The CLI is using newer Node.js APIs that aren't available or work differently in older versions

The Solution: Update Node.js

The fix for this issue is surprisingly straightforward: upgrade your Node.js version. Users have reported that updating from Node.js 18.19.1 to Node.js 24.9.0 (or any recent stable version) resolves the issue completely.

Here's how to fix the problem:

Step 1: Check Your Current Node.js Version

First, verify which version of Node.js you're currently running:

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1node --version

If you're on Node.js 18 or earlier, you'll likely encounter this issue with recent Copilot CLI versions.

Step 2: Update Node.js

There are several ways to update Node.js depending on your operating system and how you originally installed it:

Using Node Version Manager (nvm) - Recommended:

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1# Install the latest LTS version
2nvm install --lts
3
4# Or install a specific version
5nvm install 24.9.0
6
7# Set it as your default
8nvm alias default 24.9.0

macOS with Homebrew:

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1brew update
2brew upgrade node

Windows:

Download and install the latest version from the official Node.js website.

Linux (using NodeSource):

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1# For Node.js 24.x
2curl -fsSL https://deb.nodesource.com/setup_24.x | sudo -E bash -
3sudo apt-get install -y nodejs

Step 3: Verify the Installation

After updating, confirm that you're running the new version:

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1node --version

Step 4: Test Copilot CLI

Now try running your Copilot CLI commands again. They should work without the path argument error:

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1# The commands should now execute successfully
2github-copilot-cli "your command here"

Why This Works

The fix works because newer versions of Node.js include:

• Better path handling APIs
• Improved compatibility with modern CLI tools
• Bug fixes in the core path module
• Enhanced environment variable handling

By upgrading Node.js, you ensure that the Copilot CLI has access to all the APIs and features it expects, allowing it to properly resolve and handle path arguments.

Prevention Tips

To avoid similar issues in the future:

1. Keep Node.js Updated: Regularly update your Node.js installation to the latest LTS (Long Term Support) version.

2. Use Node Version Manager: Tools like nvm (Node Version Manager) make it easy to switch between Node.js versions and keep multiple versions installed for different projects.

3. Check Compatibility: Before installing CLI tools or updating them, check the documentation for minimum Node.js version requirements.

4. Monitor Deprecation Notices: Pay attention to deprecation warnings in your Node.js applications, as they can signal upcoming compatibility issues.

Conclusion

The The "path" argument must be of type string. Received undefined error in GitHub Copilot CLI can be completely resolved by upgrading to a newer version of Node.js. This simple update restores full functionality to the CLI and ensures compatibility with modern development tools.

If you're still experiencing issues after upgrading Node.js, consider:

• Reinstalling the Copilot CLI
• Checking for any conflicting environment variables
• Verifying your system's PATH configuration

By keeping your development environment up to date, you can avoid these types of compatibility issues and maintain a smooth, productive workflow with AI-assisted development tools like GitHub Copilot CLI.