Migrating from older cac - cac

If you used cac before the environment manager update, here’s what changed.

Command mapping

Old command	New command	Notes
`cac setup`	—	No longer needed. Auto-initializes on first use.
`cac add us1 proxy`	`cac env create us1 -p proxy`	Proxy is now a `-p` flag, not a positional arg.
`cac us1`	`cac us1`	Unchanged — shortcut for `cac env activate us1`.
`cac ls`	`cac ls`	Unchanged — shortcut for `cac env ls`.
`cac check`	`cac env check`	Moved under `env` subcommand.
`cac stop`	`cac env deactivate`	Renamed. Deactivates the environment entirely.
`cac -c`	`cac env activate <name>`	Re-activate by name instead.
`cac relay on/off`	—	Relay is now automatic (TUN auto-detected).
`cac delete`	`cac self delete`	Moved under `self` subcommand.

Deprecation warnings

All old commands still work but print a warning with the new equivalent:

$ cac add us1 proxy
warning: 'cac add' → 'cac env create <name> -p <proxy>'

$ cac stop
warning: 'cac stop' → 'cac env deactivate'

New capabilities

Feature	Command
Install Claude Code versions	`cac claude install latest`
Pin environment to a version	`cac claude pin 2.1.81`
Create env without proxy	`cac env create personal`
Auto-install versions	`cac env create work -c 2.1.81`
Update cac	`cac self update`

Existing environments

Your existing ~/.cac/envs/ environments continue to work. They will show claude: system in cac ls since they don’t have a pinned version. You can pin them:

cac us1                      # activate old env
cac claude pin 2.1.81        # pin to a managed version

The .claude isolation directory (~/.cac/envs/<name>/.claude/) is created automatically on next activation if it doesn’t exist yet.