git-worktree-manager（git 工作树管理器）

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

Validation Checklist

After creating a worktree, verify:

1. git worktree list shows the expected path and branch
2. .worktree-ports.json exists with unique port assignments
3. .env files are present and contain worktree-specific ports
4. pnpm install (or equivalent) completed without errors
5. Dev server starts on the allocated port
6. Database connects on the allocated DB port
7. 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

1. One branch per worktree, one agent per worktree — never share
2. Keep worktrees short-lived — remove after the branch is merged
3. Deterministic naming — use wt-<topic> pattern for easy identification
4. Persist port mappings — store in .worktree-ports.json, not in memory
5. Run cleanup weekly — scan for stale and merged-branch worktrees
6. Include worktree path in terminal title — prevents wrong-window commits
7. Never force-remove dirty worktrees — unless changes are intentionally discarded

Troubleshooting

Success Criteria

• Zero port conflicts across all active worktrees measured by lsof checks returning no collisions after setup
• Worktree creation under 60 seconds including dependency installation for projects with warm package caches
• 100% env parity between main repo and worktrees verified by diffing .env keys (values may differ for ports)
• Stale worktree count stays at zero when cleanup automation runs on a weekly schedule with a 14-day threshold
• No cross-worktree interference validated by running concurrent dev servers in 3+ worktrees simultaneously without failures
• Branch-to-worktree traceability maintained via .worktree-ports.json present in every active worktree with correct metadata
• Cleanup safety rate of 100% meaning no worktree with uncommitted changes is ever removed without explicit --force confirmation

Scope & Limitations

This skill covers:

• Git worktree lifecycle: creation, listing, status inspection, and removal
• Deterministic port allocation and collision avoidance for parallel dev servers
• Environment file synchronization and Docker Compose override patterns
• Multi-agent workspace isolation strategies and cleanup automation

This skill does NOT cover:

• Git branching strategies or merge conflict resolution (see pr-review-expert and release-manager)
• Secret rotation, vault integration, or credential management (see env-secrets-manager)
• CI/CD pipeline configuration or automated test orchestration (see ci-cd-pipeline-builder)
• Monorepo package management, workspace linking, or cross-package dependency resolution (see monorepo-navigator)

Integration Points