Three Claude Code seats on one Mac, and the gotchas are all in the shared state.

Credentials are keyed by a hash of the config directory path, so each account gets its own directory with projects/, plugins/, skills/, commands/, hooks/, settings.json and CLAUDE.md symlinked back to ~/.claude. Each seat keeps its own .claude.json and history.jsonl, because the history reader rejects both symlinks and hard links. (paddo.dev) The sharp edges: /model in one seat changes all of them through shared settings, /login rewrites that seat's Keychain entry, and the Chrome bridge is scoped to the OS user, not the account. The author's ccseats zsh script polls /usage at most every two minutes and honors retry-after.