using-git-worktrees

name	using-git-worktrees
description	Use when starting feature work that needs isolation from current workspace or before executing implementation plans - creates isolated git worktrees with smart directory selection and safety verification

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.

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 (PowerShell)
Test-Path .worktrees     # Preferred (hidden)
Test-Path worktrees      # Alternative

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

2. Ask User

If no directory exists:

No worktree directory found. Where should I create worktrees?

1. .worktrees/ (project-local, hidden)
2. worktrees/ (project-local, visible)

Which would you prefer?

Safety Verification

For Project-Local Directories (.worktrees or worktrees)

MUST verify directory is ignored before creating worktree:

# Check if directory is ignored
git check-ignore -q .worktrees

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 = Split-Path -Leaf (git rev-parse --show-toplevel)

2. Create Worktree

# Create worktree with new branch
git worktree add ".worktrees/$BRANCH_NAME" -b "$BRANCH_NAME"
cd ".worktrees/$BRANCH_NAME"

3. Run Project Setup

Auto-detect and run appropriate setup:

# Node.js
if (Test-Path package.json) { npm install }

# Python
if (Test-Path requirements.txt) { pip install -r requirements.txt }
if (Test-Path pyproject.toml) { poetry install }

4. Verify Clean Baseline

Run tests to ensure worktree starts clean:

npm 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	Ask user
Directory not ignored	Add to .gitignore + commit
Tests fail during baseline	Report failures + ask
No package.json	Skip dependency install

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 > 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 (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]
[Create worktree: git worktree add .worktrees/auth -b feature/auth]
[Run npm install]
[Run npm test - 47 passing]

Worktree ready at C:\project\.worktrees\auth
Tests passing (47 tests, 0 failures)
Ready to implement auth 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
• Skip ignore verification

Always:

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

Integration

Called by:

• brainstorming - When design is approved and implementation follows

Pairs with:

• finishing-a-development-branch - Cleanup after work complete
• executing-plans or subagent-driven-development - Work happens in this worktree