/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.

Directory Selection Process

Follow this priority order:

1. Check Existing Directories

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 / AGENTS.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 config preference:

No worktree directory found. Where should I create worktrees?

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

Which would you prefer?

Safety Verification

For Project-Local Directories

**MUST verify directory is ignored before creating worktree:**

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

git worktree add "$path" -b "$BRANCH_NAME"
cd "$path"

3. Run Project Setup

Auto-detect and run appropriate setup:

if [ -f package.json ]; then npm install; fi
if [ -f Cargo.toml ]; then cargo build; fi
if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
if [ -f go.mod ]; then go mod download; fi

4. Verify Clean Baseline

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 Mistakes

**Skipping ignore verification** — worktree contents get tracked, pollute git status

**Assuming directory location** — violates project conventions

**Proceeding with failing tests** — can't distinguish new bugs from pre-existing issues

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

Verification

• [ ] Directory choice followed the priority order: existing directory, then config preference, then asking
• [ ] A project-local worktree directory was verified gitignored before the worktree was created
• [ ] Project setup was auto-detected and run in the new worktree
• [ ] The baseline test run happened — failures were reported and confirmed, never skipped past
• [ ] The final report names the worktree path and the test status