[BUG] macOS EPERM on Node.js fs.open()

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

amacOS returns EPERM on Node.js fs.open() for dotfiles in user home directory despite correct permissions

Summary:
On macOS Tahoe 26.2, Node.js applications intermittently receive EPERM errors when attempting to open or create dotfiles in a user’s home directory (e.g. ~/.claude.json). This occurs even when permissions, ownership, ACLs, and FileVault state are correct, and reproduces on a freshly created admin user.

Environment:

• macOS: Tahoe 26.2
• Hardware: Apple M3 Pro
• File System: APFS
• FileVault: Enabled
• Node.js: v25.2.1
• Shell: zsh
• User Account: Fresh local admin (no Migration Assistant)

Steps to Reproduce:

1. Create a new local admin user in System Settings.
2. Log in as that user.
3. Install Node.js (e.g. via Homebrew).
4. Verify home directory permissions:

ls -ldOe $HOME
Result shows no ACLs and standard permissions.

1. Confirm atomic writes work via shell:

echo test > ~/.atomic_test.tmp
mv ~/.atomic_test.tmp ~/.atomic_test
rm ~/.atomic_test

1. Run a Node.js tool that writes a dotfile using fs.writeFileSync.

Expected Result:
The dotfile is created successfully.

Actual Result:
Node.js throws:
EPERM: operation not permitted, open '~/.tool.json'

Impact:
Breaks Node.js-based developer tools that rely on writing configuration files to the user home directory.

Notes:

• Reproduces on clean admin users.
• Not resolved by diskutil resetUserPermissions.
• Not caused by ACLs, ownership, or FileVault.
• Appears related to macOS security/TCC behavior.

Request:
Please investigate why Node.js fs.open()/fs.writeFileSync receives EPERM on dotfiles in $HOME under normal macOS configurations.

What Should Happen?

file shall be updated instead of failing the write

<img width="749" height="587" alt="Image" src="https://github.com/user-attachments/assets/cc91cca1-4091-4983-867b-d6577b0d77ea" />

Error Messages/Logs

File shall be written and application start

Steps to Reproduce

included in whats wrong

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.1 Claude Code

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_