devpit
An account is optional and free. "Today the account signs you in on this computer and tells devpit your name and address. That is all it does: nothing is uploaded and nothing is synced, and sync between machines is not built yet." Your projects, boards, conversations, terminal history and files are on this computer either way.
Signing in
From Sign in at the foot of the sidebar — "Optional — nothing is synced yet" — from Settings → Account, or on first run, where Not now skips it.
devpit opens your browser at devpit.app and shows a dialog, Approve this code: "Your browser is open at <host>. Check that it shows this code, then approve it there." The code is printed large in the dialog so you can compare the two. devpit waits while you do, and signs you in once you have approved it.
Signing in creates the account the first time. devpit never sees your password. Copies installed before devpit moved to devpit.app may still ask the old address, and keep working.
What it keeps
One token, in ~/.devpit/account-token, readable only by you. It is sent as a header to the account server and never shown on screen. A token the server refuses is deleted rather than retried forever.
Signing out
Sign out, in the sidebar's account menu or in Settings → Account. It "Clears the signed-in state on this computer."
What it is not
It is not your Claude sign-in. The plan limits on the Usage page are read with the sign-in the Claude CLI saved for itself, and signing in to devpit, or out of it, does not touch them.
It is not what sends error reports either. Those are a separate switch in Settings → General, off unless you turn it on, and they carry no account even when you are signed in.
It is also not where your work lives. See Where your data lives.