using-git-worktrees

name	using-git-worktrees
description	Use when starting feature work that needs isolation from the current workspace, or before executing an implementation plan in a separate git worktree

Using Git Worktrees

Overview

Git worktrees create isolated workspaces sharing the same repository, allowing work on multiple branches simultaneously without switching.

Core principle: Directory choice is not enough. Project-local worktrees are safe only when the path is both ignored by git and not tracked in the repository.

Announce at start: "I'm using the using-git-worktrees skill to set up an isolated workspace."

Directory Selection Process

Follow this priority order:

1. Check Existing Directories

# Check in priority order
ls -d .worktrees 2>/dev/null     # Preferred (hidden)
ls -d worktrees 2>/dev/null      # Alternative

If found: Treat them as candidates, not automatic choices. Reuse only after safety verification. If both exist, check .worktrees first.

2. Check CLAUDE.md

grep -i "worktree" CLAUDE.md 2>/dev/null

If preference specified: Use it without asking, but still run safety verification for project-local directories.

3. Ask User

If no directory exists and no CLAUDE.md preference:

No worktree directory found. Where should I create worktrees?

1. .worktrees/ (project-local, hidden)
2. ~/.config/superpowers/worktrees/<project-name>/ (global location)

Which would you prefer?

Safety Verification

For Project-Local Directories (.worktrees or worktrees)

MUST verify two things before creating a worktree:

1. The directory is ignored by git
2. The directory is not already tracked in the repository

# Ignored?
git check-ignore -q .worktrees 2>/dev/null || git check-ignore -q worktrees 2>/dev/null

# Tracked already?
git ls-files --stage .worktrees worktrees

Expected result:

• git check-ignore succeeds for the directory you plan to use
• git ls-files --stage ... prints nothing

If NOT ignored:

1. Add the directory to .gitignore
2. Commit that change
3. Re-run safety verification
4. Only then create the worktree

If tracked:

1. Stop
2. Do not reuse that project-local directory yet
3. Fix the tracked path first, or fall back to the global directory

Why this matters: A tracked .worktrees/<branch> path can appear as a gitlink/submodule-like entry and leak into normal commits. Existing directory != safe directory.

Post-Creation Verification

Immediately after git worktree add, verify the new path did not appear in the main worktree's tracked state:

git status --short .worktrees worktrees
git ls-files --stage .worktrees worktrees

Expected result: No new tracked entry for the worktree path.

If you see .worktrees/<branch> or worktrees/<branch> in status or as a 160000 gitlink entry:

1. Stop
2. Do not continue implementation yet
3. Remove/fix the tracked entry or move the worktree outside the repo

For Global Directory (~/.config/superpowers/worktrees)

No .gitignore verification needed; the worktree lives outside the repository.

Creation Steps

1. Detect Project Name

project=$(basename "$(git rev-parse --show-toplevel)")

2. Create Worktree

# Determine full path
case "$LOCATION" in
  .worktrees|worktrees)
    mkdir -p "$LOCATION"
    path="$LOCATION/$BRANCH_NAME"
    ;;
  "$HOME"/.config/superpowers/worktrees/*)
    mkdir -p "$HOME/.config/superpowers/worktrees/$project"
    path="$HOME/.config/superpowers/worktrees/$project/$BRANCH_NAME"
    ;;
esac

# Create worktree with new branch
git worktree add "$path" -b "$BRANCH_NAME"
cd "$path"

3. Run Project Setup

Auto-detect and run appropriate setup:

# Node.js
if [ -f package.json ]; then npm install; fi

# Rust
if [ -f Cargo.toml ]; then cargo build; fi

# Python
if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
if [ -f pyproject.toml ]; then poetry install; fi

# Go
if [ -f go.mod ]; then go mod download; fi

4. Verify Clean Baseline

Run tests to ensure the worktree starts clean:

# Examples - use project-appropriate command
npm test
cargo test
pytest
go test ./...

If tests fail: Report failures and ask whether to proceed or investigate.

If tests pass: Report ready.

5. Report Location

Worktree ready at <full-path>
Tests passing (<N> tests, 0 failures)
Ready to implement <feature-name>

Quick Reference

Situation	Action
.worktrees/ exists	Candidate only; verify ignored + untracked before reuse
worktrees/ exists	Candidate only; verify ignored + untracked before reuse
Both exist	Check .worktrees/ first
Neither exists	Check CLAUDE.md -> ask user
Directory not ignored	Add to .gitignore, commit, re-verify
Directory already tracked	Stop and fix tracked path, or use global location
Post-create status shows worktree path	Stop and fix before implementing
Tests fail during baseline	Report failures + ask
No package.json/Cargo.toml	Skip dependency install

Common Mistakes

Treating an existing directory as automatically safe

• Problem: Reusing .worktrees/ just because it exists can reintroduce a tracked path or gitlink mess
• Fix: Existing directory means candidate only; verify ignored and untracked every time

Checking ignore status but not tracked state

• Problem: git check-ignore alone does not catch an already tracked .worktrees/<branch> entry
• Fix: Always pair it with git ls-files --stage .worktrees worktrees

Missing the post-creation check

• Problem: The worktree gets created, but the main worktree now shows .worktrees/<branch> as modified or tracked
• Fix: Run git status --short .worktrees worktrees immediately after creation

Proceeding with failing tests

• Problem: Can't distinguish new bugs from pre-existing issues
• Fix: Report failures, get explicit permission to proceed

Hardcoding setup commands

• Problem: Breaks on projects using different tools
• Fix: Auto-detect from project files (package.json, etc.)

Example Workflow

You: I'm using the using-git-worktrees skill to set up an isolated workspace.

[Check .worktrees/ - exists]
[Verify ignored - git check-ignore confirms .worktrees/ is ignored]
[Verify untracked - git ls-files --stage .worktrees returns nothing]
[Create worktree: git worktree add .worktrees/auth -b feature/auth]
[Verify post-create status - no .worktrees/auth entry appears in main worktree]
[Run npm install]
[Run npm test - 47 passing]

Worktree ready at /Users/jesse/myproject/.worktrees/auth
Tests passing (47 tests, 0 failures)
Ready to implement auth feature

Red Flags

Never:

• Create a project-local worktree without verifying both ignore status and tracked state
• Reuse .worktrees/ or worktrees/ just because the directory exists
• Ignore a 160000 gitlink entry for .worktrees/<branch>
• Skip the post-creation status check
• Proceed with failing tests without asking
• Assume directory location when ambiguous
• Skip CLAUDE.md check

Always:

• Follow directory priority: existing > CLAUDE.md > ask
• Verify project-local directories are both ignored and untracked
• Run a post-creation git status check from the main worktree
• Auto-detect and run project setup
• Verify clean test baseline

Integration

Called by:

• brainstorming (Phase 4) - REQUIRED when design is approved and implementation follows
• subagent-driven-development - REQUIRED before executing any tasks
• executing-plans - REQUIRED before executing any tasks
• Any skill needing isolated workspace

Pairs with:

• finishing-a-development-branch - REQUIRED for cleanup after work complete