Tools · tku

tku: Run Claude as Another Account, Just Once

A one-shot exec that runs Claude Code under a different subscription without touching your active login, so your work session keeps going while you fire off one thing as your personal account.

By Franz Geffke 08 Jul 2026 4 min read #tku #rust #claude-code #cli #tooling

A while back I wrote about tku, my little Rust CLI for tracking token usage and swapping between my work and personal Claude subscriptions. The swap part (tku account use work) does a global switch: it rewrites your login and everything from then on runs as that account. Good for changing context for a while, but overkill when you just want to run one thing as the other account and keep going.

That’s the gap tku account exec fills.

One session, one account, no global switch

Say I’m deep in a work session and I want to run a single Claude Code session on my personal subscription, maybe to keep the side-project tokens off the company plan. I don’t want to log out, swap, do the thing, and swap back. I just want:

tku account exec personal -- claude

That runs claude as personal in an isolated config dir, leaving your active ~/.claude untouched. Your current work session (and any other claude you have open) keeps running exactly as it was. When the exec session exits, nothing about your global login has changed.

Like sudo or env, it runs whatever you put after --. It doesn’t launch claude for you, so a one-shot prompt works the same way:

tku account exec personal -- claude -p "summarise this repo"

Or drop into a shell with the right CLAUDE_CONFIG_DIR already set, and run your own launcher from there:

tku account exec personal -- bash -i

What it does under the hood

It seeds a private dir from the account’s stashed credentials, then symlinks your shared skills/, plugins/, agents/, commands/, and CLAUDE.md so the session behaves like your normal setup, just with a different login. It copies and patches .claude.json and settings.json, and syncs any refreshed credentials back to the stash on exit. The dir lives under $XDG_RUNTIME_DIR (tmpfs, cleared on logout), never in your persistent config.

A few flags if you want to shape that: --ephemeral for a throwaway dir deleted on exit, --clean for a bare instance with none of the shared skills/plugins, and --copy to copy the shared dirs instead of symlinking them.

The honest caveats

• Token usage inside an exec session is written to the isolated dir, so it does not show up in tku reports. That’s the trade for isolation.
• It refuses to run if the account is already live, whether as your active login or another exec. Claude’s OAuth refresh tokens are single-use, so two live sessions on one login invalidate each other and brick both. To run two of the same account at once, add a second login with fresh credentials as a separate stash entry.
• Credentials have to be file-based (~/.claude/.credentials.json), so this is Linux, not macOS, where Claude keeps them in the Keychain that CLAUDE_CONFIG_DIR doesn’t relocate.

It turns out this is the account command I reach for most now. The global swap is for changing gears; exec is for the quick detour without leaving the road you’re on.

It’s on GitHub. If you juggle more than one Claude subscription the way I do, it’s a nice one to have.