The idea: one config folder per account

Each CLI keeps everything that identifies you in a single folder:

Settings, session history and the login all hang off that folder. Point the variable at a different folder and the tool behaves like a fresh install: you sign in once, and from then on that folder stays signed in to that account. The default folder keeps your first account, untouched.

Claude Code

Create the folder and start Claude Code with it:

mkdir -p ~/.claude-work
CLAUDE_CONFIG_DIR=~/.claude-work claude

Log in with your work account when asked. Now a plain claude in one tab uses your personal account, and the command above uses your work account in another. Both can run at the same time.

Codex CLI

Same pattern:

mkdir -p ~/.codex-work
CODEX_HOME=~/.codex-work codex

Sign in with the second account once. Plain codex keeps using ~/.codex. If the folder doesn't exist, Codex stops with an error saying the CODEX_HOME path does not exist, so create it first.

Make it one word

Typing variables gets old fast. Add aliases to ~/.zshrc (or ~/.bashrc):

alias claude-work='CLAUDE_CONFIG_DIR="$HOME/.claude-work" claude'
alias codex-work='CODEX_HOME="$HOME/.codex-work" codex'

Open a new tab or run source ~/.zshrc, and claude-work / codex-work start in the work account. Add one pair per account (claude-client, codex-client, and so on).

If you'd rather switch a whole tab at once, export both variables there:

export CLAUDE_CONFIG_DIR="$HOME/.claude-work"
export CODEX_HOME="$HOME/.codex-work"

Every claude and codex command in that tab now uses the work account until you close it.

What to copy between folders, and what not to

• Copy your settings if you want the same setup in both accounts. For Codex that's config.toml (including MCP servers): cp ~/.codex/config.toml ~/.codex-work/. For Claude Code, copy settings.json and your global CLAUDE.md if you use one.

• Don't copy login files. In Codex that's auth.json. Copying it puts the first account into the second folder, which defeats the point.

• Leave history alone. Each folder keeps its own sessions, so each account's history stays with that account.

Three mistakes I made so you don't have to

1. Wrong account in a tab. Run echo $CLAUDE_CONFIG_DIR $CODEX_HOME. Empty output means the tab is on the default folders.

2. Logging out everywhere. codex logout clears the login of the current CODEX_HOME. If everything shares ~/.codex, that includes other terminals and the Codex inside the ChatGPT desktop app. Separate folders avoid it.

3. Forgetting the desktop apps. These variables only affect the command line. Claude Desktop and the ChatGPT app still keep one account each, and by default the ChatGPT app's Codex shares ~/.codex with plain codex.

What about the desktop apps?

That last point is where the free setup ends. The desktop apps need their own data folder per account, which means a separate copy of each app. There's a manual way to do it, with rough edges such as one shared Dock icon and Google sign-in landing in the wrong copy. I wrote up every option, free and paid, in How to Use Multiple Claude and ChatGPT Accounts on One Computer.

Full disclosure: I build two apps that handle the desktop side. Claude Sessions Pro turns each Claude account into its own app on a Mac, or its own window on Windows. Sessions Pro for Codex does the same for the ChatGPT app: its own app on a Mac, or its own window on Windows. In both, every profile has an "open in Terminal" button that starts the CLI with that profile's own CLAUDE_CONFIG_DIR or CODEX_HOME, so the terminal and the app are always signed in to the same account.

For the terminal alone, though, the two variables above are all you need. Set them up once and you'll stop logging in and out for good.