Git Worktree Manager

Tier: POWERFUL Category: Engineering / Developer Tooling Maintainer: Claude Skills Team

Overview

Manage parallel development workflows using Git worktrees with deterministic naming, automatic port allocation, environment file synchronization, dependency installation, and cleanup automation. Optimized for multi-agent workflows where each agent or terminal session owns an isolated worktree with its own ports, environment, and running services.

Keywords

git worktree, parallel development, branch isolation, port allocation, multi-agent development, worktree cleanup, Docker Compose worktree, concurrent branches

Core Capabilities

1. Worktree Lifecycle Management

• Create worktrees from new or existing branches with deterministic naming

• Copy .env files from main repo to new worktrees

• Install dependencies based on lockfile detection

• List all worktrees with status (clean/dirty, ahead/behind)

• Safe cleanup with uncommitted change detection

2. Port Allocation

• Deterministic port assignment per worktree (base + index * stride)

• Collision detection against running processes

• Persistent port map in .worktree-ports.json

• Docker Compose override generation for per-worktree ports

3. Multi-Agent Isolation

• One branch per worktree, one agent per worktree

• No shared state between agent workspaces

• Conflict-free parallel execution

• Task ID mapping for traceability

4. Cleanup Automation

• Stale worktree detection by age

• Merged branch detection for safe removal

• Dirty state warnings before deletion

• Bulk cleanup with safety confirmations

When to Use

• You need 2+ concurrent branches open with running dev servers

• You want isolated environments for feature work, hotfixes, and PR review

• Multiple AI agents need separate workspaces that do not interfere

• Your current branch is blocked but a hotfix is urgent

• You want automated cleanup instead of manual rm -rf operations

Quick Start

Create a Worktree

Create worktree for a new feature branch

git worktree add ../wt-auth -b feature/new-auth main

Create worktree from an existing branch

git worktree add ../wt-hotfix hotfix/fix-login

Create worktree in a dedicated directory

git worktree add ~/worktrees/myapp-auth -b feature/auth origin/main

List All Worktrees

git worktree list

Output:

/Users/dev/myapp abc1234 [main]

/Users/dev/wt-auth def5678 [feature/new-auth]

/Users/dev/wt-hotfix ghi9012 [hotfix/fix-login]

Remove a Worktree

Safe removal (fails if there are uncommitted changes)

git worktree remove ../wt-auth

Force removal (discards uncommitted changes)

git worktree remove --force ../wt-auth

Prune stale metadata

git worktree prune

Port Allocation Strategy

Deterministic Port Assignment

Each worktree gets a block of ports based on its index:

Worktree Index App Port DB Port Redis Port API Port ──────────────────────────────────────────────────────────────── 0 (main) 3000 5432 6379 8000 1 (wt-auth) 3010 5442 6389 8010 2 (wt-hotfix) 3020 5452 6399 8020 3 (wt-feature) 3030 5462 6409 8030

Formula: port = base_port + (worktree_index * stride)

Default stride: 10

Port Map File

Store the allocation in .worktree-ports.json at the worktree root:

{ "worktree": "wt-auth", "branch": "feature/new-auth", "index": 1, "ports": { "app": 3010, "database": 5442, "redis": 6389, "api": 8010 }, "created": "2026-03-09T10:30:00Z" }

Port Collision Detection

Check if a port is already in use

check_port() { local port=$1 if lsof -i :"$port" > /dev/null 2>&1; then echo "PORT $port is BUSY" return 1 else echo "PORT $port is FREE" return 0 fi }

Check all ports for a worktree

for port in 3010 5442 6389 8010; do check_port $port done

Full Worktree Setup Script

#!/bin/bash

setup-worktree.sh — Create a fully prepared worktree

set -euo pipefail

BRANCH="${1:?Usage: setup-worktree.sh <branch-name> [base-branch]}" BASE="${2:-main}" WT_NAME="wt-$(echo "$BRANCH" | sed 's|.*/||' | tr '[:upper:]' '[:lower:]')" WT_PATH="../$WT_NAME" MAIN_REPO="$(git rev-parse --show-toplevel)"

echo "Creating worktree: $WT_PATH from $BASE..."

1. Create worktree

if git rev-parse --verify "$BRANCH" > /dev/null 2>&1; then git worktree add "$WT_PATH" "$BRANCH" else git worktree add "$WT_PATH" -b "$BRANCH" "$BASE" fi

2. Copy environment files

for envfile in .env .env.local .env.development; do if [ -f "$MAIN_REPO/$envfile" ]; then cp "$MAIN_REPO/$envfile" "$WT_PATH/$envfile" echo "Copied $envfile" fi done

3. Allocate ports

WT_INDEX=$(git worktree list | grep -n "$WT_PATH" | cut -d: -f1) WT_INDEX=$((WT_INDEX - 1)) STRIDE=10

cat > "$WT_PATH/.worktree-ports.json" << EOF { "worktree": "$WT_NAME", "branch": "$BRANCH", "index": $WT_INDEX, "ports": { "app": $((3000 + WT_INDEX * STRIDE)), "database": $((5432 + WT_INDEX * STRIDE)), "redis": $((6379 + WT_INDEX * STRIDE)), "api": $((8000 + WT_INDEX * STRIDE)) } } EOF echo "Ports allocated (index $WT_INDEX)"

4. Update .env with allocated ports

if [ -f "$WT_PATH/.env" ]; then APP_PORT=$((3000 + WT_INDEX * STRIDE)) DB_PORT=$((5432 + WT_INDEX * STRIDE)) sed -i.bak "s/APP_PORT=.*/APP_PORT=$APP_PORT/" "$WT_PATH/.env" sed -i.bak "s/:5432/:$DB_PORT/g" "$WT_PATH/.env" rm -f "$WT_PATH/.env.bak" echo "Updated .env with worktree ports" fi

5. Install dependencies

cd "$WT_PATH" if [ -f "pnpm-lock.yaml" ]; then pnpm install --frozen-lockfile elif [ -f "package-lock.json" ]; then npm ci elif [ -f "yarn.lock" ]; then yarn install --frozen-lockfile elif [ -f "requirements.txt" ]; then pip install -r requirements.txt elif [ -f "go.mod" ]; then go mod download fi

echo "" echo "Worktree ready: $WT_PATH" echo "Branch: $BRANCH" echo "App port: $((3000 + WT_INDEX * STRIDE))" echo "" echo "Next: cd $WT_PATH && pnpm dev"

Docker Compose Per-Worktree

docker-compose.worktree.yml — override for worktree-specific ports

Usage: docker compose -f docker-compose.yml -f docker-compose.worktree.yml up

services: postgres: ports: - "${DB_PORT:-5432}:5432" environment: POSTGRES_DB: "myapp_${WT_NAME:-main}"

redis: ports: - "${REDIS_PORT:-6379}:6379"

app: ports: - "${APP_PORT:-3000}:3000" environment: DATABASE_URL: "postgresql://dev:dev@postgres:5432/myapp_${WT_NAME:-main}"

Launch with worktree-specific ports:

DB_PORT=5442 REDIS_PORT=6389 APP_PORT=3010 WT_NAME=auth
docker compose -f docker-compose.yml -f docker-compose.worktree.yml up -d

Cleanup Automation

#!/bin/bash

cleanup-worktrees.sh — Safe worktree cleanup

set -euo pipefail

STALE_DAYS="${1:-14}" DRY_RUN="${2:-true}"

echo "Scanning worktrees (stale threshold: ${STALE_DAYS} days)..." echo ""

git worktree list --porcelain | while read -r line; do case "$line" in worktree\ *) WT_PATH="${line#worktree }" ;; branch\ *) BRANCH="${line#branch refs/heads/}" # Skip main worktree if [ "$WT_PATH" = "$(git rev-parse --show-toplevel)" ]; then continue fi

  # Check if branch is merged
  MERGED=""
  if git branch --merged main | grep -q "$BRANCH" 2>/dev/null; then
    MERGED=" [MERGED]"
  fi

  # Check for uncommitted changes
  DIRTY=""
  if [ -d "$WT_PATH" ]; then
    cd "$WT_PATH"
    if [ -n "$(git status --porcelain)" ]; then
      DIRTY=" [DIRTY - has uncommitted changes]"
    fi
    cd - > /dev/null
  fi

  # Check age
  if [ -d "$WT_PATH" ]; then
    AGE_DAYS=$(( ($(date +%s) - $(stat -f %m "$WT_PATH" 2>/dev/null || stat -c %Y "$WT_PATH" 2>/dev/null)) / 86400 ))
    STALE=""
    if [ "$AGE_DAYS" -gt "$STALE_DAYS" ]; then
      STALE=" [STALE: ${AGE_DAYS} days old]"
    fi
  fi

  echo "$WT_PATH ($BRANCH)$MERGED$DIRTY$STALE"

  if [ -n "$MERGED" ] && [ -z "$DIRTY" ] && [ "$DRY_RUN" = "false" ]; then
    echo "  -> Removing merged clean worktree..."
    git worktree remove "$WT_PATH"
  fi
  ;;

esac done

echo "" git worktree prune echo "Done. Run with 'false' as second arg to actually remove."

Multi-Agent Workflow Pattern

When running multiple AI agents (Claude Code, Cursor, Copilot) on the same repo:

Agent Assignment: ─────────────────────────────────────────────────── Agent 1 (Claude Code) → wt-feature-auth (port 3010) Agent 2 (Cursor) → wt-feature-billing (port 3020) Agent 3 (Copilot) → wt-bugfix-login (port 3030) Main repo → integration (main) (port 3000) ───────────────────────────────────────────────────

Rules:

• Each agent works ONLY in its assigned worktree
• No agent modifies another agent's worktree
• Integration happens via PRs to main, not direct merges
• Port conflicts are impossible due to deterministic allocation

Decision Matrix

Scenario Action

Need isolated dev server for a feature Create a new worktree

Quick diff review of a branch git diff in current tree (no worktree needed)

Hotfix while feature branch is dirty Create dedicated hotfix worktree

Bug triage with reproduction branch Temporary worktree, cleanup same day

PR review with running code Worktree at PR branch, run tests

Multiple agents on same repo One worktree per agent

Validation Checklist

After creating a worktree, verify:

• git worktree list shows the expected path and branch

• .worktree-ports.json exists with unique port assignments

• .env files are present and contain worktree-specific ports

• pnpm install (or equivalent) completed without errors

• Dev server starts on the allocated port

• Database connects on the allocated DB port

• No port conflicts with other worktrees or services

Common Pitfalls

• Creating worktrees inside the main repo directory — always use ../wt-name to keep them alongside

• Reusing localhost:3000 across all branches — causes port conflicts; use deterministic allocation

• Sharing one DATABASE_URL across worktrees — each needs its own database or schema

• Removing a worktree with uncommitted changes — always check dirty state before removal

• Forgetting to prune after branch deletion — run git worktree prune to clean metadata

• Not updating .env ports after worktree creation — the setup script should handle this automatically

Best Practices

• One branch per worktree, one agent per worktree — never share

• Keep worktrees short-lived — remove after the branch is merged

• Deterministic naming — use wt-<topic> pattern for easy identification

• Persist port mappings — store in .worktree-ports.json , not in memory

• Run cleanup weekly — scan for stale and merged-branch worktrees

• Include worktree path in terminal title — prevents wrong-window commits

• Never force-remove dirty worktrees — unless changes are intentionally discarded