agentic-os: Skill for Codex

Using Git Worktrees

Overview

Git worktree allows mounting multiple working directories onto the same repository simultaneously, each mapped to a different branch. This is ideal for parallel development and hotfixes.

Workspace Selection Principles

• Manage them centrally outside the repo or in a dedicated folder (e.g., ../wt-<task>).
• Name them with task semantics (feature/hotfix + short name).
• Avoid confusing or overwriting existing workspaces.

Safety Checks

1. Detect nesting first — do not create a worktree from inside another worktree or a submodule:
   • You are already in a linked worktree if git rev-parse --git-dir differs from git rev-parse --git-common-dir (they match in the main worktree). cd to the main worktree before adding.
   • You are in a submodule if git rev-parse --show-superproject-working-tree is non-empty. Operate on the intended repo, not the submodule.
2. Ensure the primary workspace is clean (prevent taking uncommitted changes).
3. List existing worktrees first: git worktree list.
4. Check that the target directory does not exist or is empty.
5. Keep the worktree path out of the tracked tree — prefer a sibling dir (../wt-<task>). If it must live inside the repo, verify it is ignored first: git check-ignore -q <path> (exit 0 = ignored). A non-ignored in-repo worktree pollutes the parent's git status and can be committed by accident.
6. Confirm branch naming and tracking strategies.

Setup Workflow

1. Create a branch and add a worktree:
   • git worktree add ../wt-<task> -b <branch-name>
2. Switch to the new directory and run a baseline test.
3. Develop, commit, and verify independently in that directory.
4. Remove the worktree when finished (if no longer needed):
   • git worktree remove ../wt-<task>

Common Mistakes

• Committing in the wrong worktree.
• Deleting a worktree without confirming if the branch should be preserved.
• Chaotic directory naming, leading to unclear task mapping.