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Filipe Synthis
Filipe Synthis

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How I solved Claude Code's biggest missing feature

#claudecode #cli #opensource #javascript

If you use Claude Code with more than one account, you know the pain.

Switch from work to personal? /logout, /login, lose your session state, watch your MCP servers vanish. Do it again tomorrow. And the day after.

195+ developers https://github.com/anthropics/claude-code/issues/18435. It's been months. No native solution.

So I built one.

The problem

Claude Code stores everything in two places:

  • ~/.claude.json — your OAuth token and session
  • ~/.claude/settings.json — your preferences

One set of files. One account. Want to switch? Destroy the first session, create a new one. Every time.

For developers working with a corporate account during the day and a personal account at night, this is a daily annoyance.

The discovery

Buried in Claude Code's https://code.claude.com/docs/en/env-vars, there's a variable called CLAUDE_CONFIG_DIR. It redirects where Claude Code reads and writes its config files.

An Anthropic team member https://github.com/anthropics/claude-code/issues/261:

▎ "As an immediate workaround you can use CLAUDE_CONFIG_DIR env var to set the directory to keep your profile data in."

The variable exists. It works. But using it manually is clunky — you have to remember paths, set environment variables, and manage directories yourself.

The solution: Cloak

I built https://github.com/synth1s/cloak — a CLI addon that wraps CLAUDE_CONFIG_DIR into a friendly interface.

  npm install -g @synth1s/cloak
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Save your current session:

  cloak create work
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Log out, log in with another account, save it too:

  cloak create home
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Switch instantly:

  cloak switch work
  cloak switch home
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That's it. No logout. No login. Tokens, MCP servers, settings — all preserved.

How it works

Each account gets its own isolated directory:

  ~/.cloak/
  └── profiles/
      ├── work/
      │   ├── .claude.json
      │   ├── settings.json
      │   └── ...
      └── home/
          ├── .claude.json
          └── ...
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When you switch, Cloak sets CLAUDE_CONFIG_DIR to point to the right directory. Claude Code reads from there. Nothing is copied, moved, or overwritten.

Concurrent sessions

Different terminal, different account. At the same time.

  # Terminal A:
  claude -a work

  # Terminal B:
  claude -a home
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No conflicts. Each terminal has its own environment variable pointing to a different directory.

The shell integration story

Here's something I learned the hard way: a child process can't modify its parent's environment variables. This is an OS-level constraint.

When you run cloak switch work, the cloak binary sets the variable inside itself — but when it exits, the parent shell still has the old value.

The solution is a shell function that runs inside the shell:

  eval "$(cloak init)"
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This injects two functions — cloak() and claude() — that intercept the switch command and apply the export in the current shell. First time you run cloak switch, it offers to set this up automatically.

Built with TDD

Every feature was test-first. The project has 113 tests across 13 suites, all using Node.js native node:test runner — zero test framework dependencies.

The TDD discipline caught real bugs:

  • A shell eval was trying to execute "You're already wearing..." as bash code (the apostrophe in "You're" broke it)
  • A --print-env flag was leaking user-facing messages to stdout, corrupting the shell eval

Both would have been invisible without tests that specifically checked "stdout must contain only eval-safe shell code."

Security

The project went through a security audit before publishing:

  • Path traversal: account names validated against ^[a-zA-Z0-9][a-zA-Z0-9_-]{0,63}$
  • Credential files: created with 0o700 (dirs) and 0o600 (files) permissions
  • Shell injection: export paths are double-quoted in eval output
  • Token safety: OAuth tokens are never read, logged, or transmitted — only copied as files
  • RC file safety: .bashrc modifications include a backup file and marker comment

What's next

The tool is live on npm and solving the problem for 700+ developers who installed it in the first day. The main gap is IDE support — VSCode and JetBrains extensions don't respect CLAUDE_CONFIG_DIR yet
(https://github.com/anthropics/claude-code/issues/4739).

If you're juggling multiple Claude Code accounts, give it a try:

  npm i -g @synth1s/cloak
  cloak create work
  cloak create home
  cloak switch work
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The source is on GitHub: https://github.com/synth1s/cloak

Built because 195+ developers asked for it and nobody had built it yet.

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