using-git-worktrees

Run `git worktree add <path> -b <branch-name>` to create a linked worktree on a new branch. Prefer placing it in a `.worktrees/` directory at the project root, and verify that directory is listed in .gitignore before creating it.

Compare `git rev-parse --git-dir` with `git rev-parse --git-common-dir`. If the resolved paths differ, you are in a linked worktree. Also run `git rev-parse --show-superproject-working-tree` to rule out being inside a submodule, which produces the same difference.

Use a native tool such as EnterWorktree or a /worktree command whenever one is available, since it manages directory placement, branching, and cleanup automatically. Manual `git worktree add` is only a fallback and can create state the harness cannot track.

An unignored worktree directory causes git to track the entire nested worktree contents, accidentally committing them into the repository. Verify with `git check-ignore` and commit the .gitignore update before creating the worktree.

A permission error usually means the sandbox blocked worktree creation. In that case, report the restriction and continue working in the current directory, running dependency setup and baseline tests in place instead.