Giving each project its own account, its own standing instructions, and its own memory.
Every tool that scopes configuration per project eventually discovers that its scoping has a seam. Claude Code's seam sits exactly where you would not look for it: in the mechanisms you leave alone rather than the one you configure.
I run several Claude Code projects that have no business sharing a login, a set of standing instructions, or a session history. Claude Code supports this through the CLAUDE_CONFIG_DIR environment variable, and it does what it says. What surprised me is that turning it on exposes two further mechanisms that stayed invisible for as long as everything lived in one place. An Ancestor Walk quietly hands your global instructions back to the project you just isolated. Account Sync refills that project with the skills and connectors attached to your account. Three Surfaces, near the end, takes both apart; the steps below only close them.
Both are clo