Using Git Worktrees

Overview

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

Core principle: Systematic directory selection + safety verification = reliable isolation.

When to Use

• Working on multiple features in parallel
• Code review while continuing development
• Testing fixes on different branches
• Isolating experimental work
• Multi-agent development workflows

Directory Selection Process

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: Use that directory. If both exist, .worktrees wins.

2. Check Project Config

Look for worktree directory preference in project documentation (CLAUDE.md, AGENTS.md, etc.).

3. Ask User

If no directory exists and no preference specified:

No worktree directory found. Where should I create worktrees?
1. .worktrees/ (project-local, hidden)
2. ~/worktrees/<project-name>/ (global location)

Which would you prefer?

Safety Verification

For Project-Local Directories

MUST verify directory is ignored before creating worktree:

# Check if directory is ignored
git check-ignore -q .worktrees 2>/dev/null || \
git check-ignore -q worktrees 2>/dev/null

If NOT ignored:

1. Add appropriate line to .gitignore
2. Commit the change
3. Proceed with worktree creation

Why critical: Prevents accidentally committing worktree contents to repository.

Creation Steps

1. Detect Project Name

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

2. Create Worktree

# Determine full path
case $LOCATION in
  .worktrees|worktrees)
    path="$LOCATION/$BRANCH_NAME"
    ;;
  ~/worktrees/*)
    path="~/worktrees/$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 worktree starts clean:

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

If tests fail: Report failures, 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	Use it (verify ignored)
worktrees/ exists	Use it (verify ignored)
Both exist	Use .worktrees/
Neither exists	Check config → Ask user
Directory not ignored	Add to .gitignore + commit
Tests fail during baseline	Report failures + ask

Common Commands

# List all worktrees
git worktree list

# Add worktree with new branch
git worktree add ../feature-branch -b feature/my-feature

# Add worktree with existing branch
git worktree add ../hotfix-branch hotfix/urgent-fix

# Remove worktree (after merging)
git worktree remove ../feature-branch

# Prune stale worktree info
git worktree prune

Common Mistakes

Skipping ignore verification

• Problem: Worktree contents get tracked, pollute git status
• Fix: Always use git check-ignore before creating project-local worktree

Assuming directory location

• Problem: Creates inconsistency, violates project conventions
• Fix: Follow priority: existing > config > ask

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

Cleanup After Work

When branch is merged:

# Remove the worktree
git worktree remove .worktrees/feature-branch

# Or if directory was manually deleted
git worktree prune

# Delete the branch if no longer needed
git branch -d feature/my-feature

Red Flags

Never:

• Create worktree without verifying it's ignored (project-local)
• Skip baseline test verification
• Proceed with failing tests without asking
• Assume directory location when ambiguous

Always:

• Follow directory priority: existing > config > ask
• Verify directory is ignored for project-local
• Auto-detect and run project setup
• Verify clean test baseline

Attribution

Based on obra/superpowers using-git-worktrees skill.