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

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 CLAUDE.md

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

If preference specified: Use it without asking.

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/claude/worktrees/<project-name>/ (global location)

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 (respects local, global, and system gitignore)

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

If NOT ignored:

Per standard practice "Fix broken things immediately":

• Add appropriate line to .gitignore

• Commit the change

• Proceed with worktree creation

Why critical: Prevents accidentally committing worktree contents to repository.

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

No .gitignore verification needed - outside project entirely.

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/$BRANCH_NAME" ;; /.config/claude/worktrees/*) path="/.config/claude/worktrees/$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:

Examples - 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 CLAUDE.md -> Ask user

Directory not ignored Add to .gitignore + commit

Tests fail during baseline Report failures + ask

No package.json/Cargo.toml 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 > CLAUDE.md > 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 /Users/dev/myproject/.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 CLAUDE.md check

Always:

• Follow directory priority: existing > CLAUDE.md > ask

• Verify directory is ignored for project-local

• Auto-detect and run project setup

• Verify clean test baseline

Integration

Called by:

• brainstorming (Phase 4) - REQUIRED when design is approved and implementation follows

• Any skill needing isolated workspace

Pairs with:

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

• executing-plans or subagent-driven-development - Work happens in this worktree

Iron Laws

• ALWAYS verify .gitignore includes the worktree directory pattern before creating any worktree

• NEVER create a worktree on a dirty working tree — stash or commit changes first

• ALWAYS use project-local directories inside the project for worktree placement

• NEVER delete a worktree with uncommitted changes without explicit user confirmation

• ALWAYS run git worktree prune after removing worktrees to clean up stale metadata

Anti-Patterns

Anti-Pattern Why It Fails Correct Approach

Creating worktree with dirty working tree Uncommitted changes risk loss or confusion Stash or commit changes before creating worktree

Worktree outside project directory Not covered by .gitignore, leaks to VCS Use project-local paths inside the repo

No .gitignore entry for worktree directory Worktree files pollute git status output Add worktree path pattern to .gitignore first

Deleting worktree without checking changes Uncommitted work silently lost Check for uncommitted changes before removal

Forgetting git worktree prune

Stale lock files block future worktree creation Always prune after removing worktrees

Memory Protocol (MANDATORY)

Before starting: Read .claude/context/memory/learnings.md

After completing:

• New pattern -> .claude/context/memory/learnings.md

• Issue found -> .claude/context/memory/issues.md

• Decision made -> .claude/context/memory/decisions.md

ASSUME INTERRUPTION: If it's not in memory, it didn't happen.