Worktree Manager Agent Skill

Git Worktree Manager

This skill provides helper scripts and workflows for creating and managing Git worktrees, enabling parallel development across multiple branches without cloning the repository multiple times.

When to Use This Skill

Primary triggers — Create a new worktree when:

• Multiple self-contained issues exist — Different problems should NOT be fixed together in a single branch. Each issue deserves its own branch with isolated commits, separate PR, and independent review.

• Human-Copilot iteration is needed — Step-by-step collaboration requires an isolated environment where:
• Each worktree has its own Copilot chat history and context
• Plan and TODO progress stays scoped to that specific issue
• Commits are atomic and traceable to one problem

• Parallel work avoids branch-switching chaos — Instead of constantly switching branches (which mixes up build artifacts, test results, and Copilot context), worktrees let you:
• Keep each VS Code window focused on one task
• Run builds/tests independently without cross-contamination
• Resume work instantly without stashing or context loss

Anti-patterns — Do NOT use worktrees when:

• A quick one-liner fix can be committed directly
• Changes are tightly coupled and belong in the same PR
• You're just reading code (no commits planned)

Prerequisites

• Git installed and configured
• PowerShell 5.1+ (Windows) or PowerShell Core (cross-platform)
• VS Code installed (for automatic workspace opening)
• Repository must be a Git repository (not inside a worktree already)

Available Scripts

This skill provides focused scripts for each worktree operation.

New-WorktreeFromBranch.ps1

Create or reuse a worktree for an existing local or remote branch.

Location: ./scripts/New-WorktreeFromBranch.ps1

./scripts/New-WorktreeFromBranch.ps1 -Branch <branch-name> [-NoFetch]

| Parameter | Required | Default | Description |

|-----------|----------|---------|-------------|

| -Branch | Yes | - | Branch name (local or origin/<name> form) |

| -NoFetch | No | $false | Skip remote fetch if branch missing locally |

Examples:

# From a local or remote branch
./scripts/New-WorktreeFromBranch.ps1 -Branch feature/login

# From origin remote (normalizes automatically)
./scripts/New-WorktreeFromBranch.ps1 -Branch origin/bugfix/nullref

New-WorktreeFromIssue.ps1

Start a new work item branch with consistent naming and create a worktree for it.

Location: ./scripts/New-WorktreeFromIssue.ps1

./scripts/New-WorktreeFromIssue.ps1 -Number <workitem-number> [-Title <description>] [-Base <ref>]

| Parameter | Required | Default | Description |

|-----------|----------|---------|-------------|

| -Number | Yes | - | Azure DevOps work item number for branch naming |

| -Title | No | - | Descriptive title (slugified into branch name) |

| -Base | No | origin/main | Base ref to branch from |

Examples:

# Work item branch with title
./scripts/New-WorktreeFromIssue.ps1 -Number 1234 -Title "Crash on launch"
# Creates: workitem/1234-crash-on-launch

# Work item branch from different base
./scripts/New-WorktreeFromIssue.ps1 -Number 42 -Base origin/develop

# Simple work item branch (no title slug)
./scripts/New-WorktreeFromIssue.ps1 -Number 999
# Creates: workitem/999

Delete-Worktree.ps1

Remove a worktree and optionally its associated branch.

Location: ./scripts/Delete-Worktree.ps1

./scripts/Delete-Worktree.ps1 -Pattern <pattern> [-Force] [-KeepBranch]

| Parameter | Required | Default | Description |

|-----------|----------|---------|-------------|

| -Pattern | Yes | - | Partial branch name or path to match |

| -Force | No | $false | Force removal even with uncommitted changes |

| -KeepBranch | No | $false | Don't delete the local branch |

Examples:

# Delete worktree by branch pattern
./scripts/Delete-Worktree.ps1 -Pattern feature/perf-tweak

# Force delete with uncommitted changes
./scripts/Delete-Worktree.ps1 -Pattern workitem/1234 -Force

# Delete worktree but keep the branch
./scripts/Delete-Worktree.ps1 -Pattern feature/ui -KeepBranch

List Worktrees

Use Git directly to list worktrees:

git worktree list --porcelain

Step-by-Step Workflows

Workflow 1: Work on an Azure DevOps Work Item

• Note the work item number and title
• Create work item branch and worktree:

   ./scripts/New-WorktreeFromIssue.ps1 -Number 1234 -Title "Fix null reference"

• Build, test, and develop as normal
• Commit, push, and open PR
• Delete worktree when PR is merged:

   ./scripts/Delete-Worktree.ps1 -Pattern workitem/1234

Workflow 2: Parallel Feature Development

• Create worktrees for each feature:

   ./scripts/New-WorktreeFromBranch.ps1 -Branch feature/login
   ./scripts/New-WorktreeFromBranch.ps1 -Branch feature/dashboard

• Work on each independently (different VS Code windows)
• Keep ≤ 3 active worktrees to manage cognitive load

Worktree Naming & Locations

| Source | Local Branch Name | Worktree Folder |

|--------|-------------------|-----------------|

| Local/remote branch | Same as branch | <RepoName>-<hash>/ |

| Work item | workitem/<number>-<slug> | <RepoName>-<hash>/ |

Worktrees are created as sibling folders to the repository root (e.g., MyRepo/ and MyRepo-ab12/).

Best Practices

• Keep ≤ 3 active worktrees per developer to reduce cognitive load
• Delete stale worktrees early — each adds file watchers and build churn
• Avoid editing the same file across multiple worktrees simultaneously
• Run git fetch --all --prune periodically in the primary repo, not every worktree
• Use targeted builds inside worktrees instead of full builds

Troubleshooting

| Symptom | Solution |

|---------|----------|

| Cannot lock ref (*.lock error) | Run git worktree prune or delete stale .lock file manually |

| Worktree already exists | Use git worktree list to find existing path; reuse that folder |

| Local branch missing for remote | Run git branch --track <name> origin/<name> then retry |

| Submodules not initialized | Run git submodule update --init --recursive in the worktree |

Common Commands Reference

# List all worktrees
git worktree list --porcelain

# List local branches with tracking info
git branch -vv

# List remotes
git remote -v

# Prune stale worktree references
git worktree prune

# Force remove a worktree with uncommitted changes
git worktree remove --force <path>

Security Notes

• Scripts do not store credentials — they rely on your existing Git credential helper
• No destructive operations without explicit -Force flag

Script Locations

All implementation is self-contained within this skill folder:

Scripts (master source):

• New-WorktreeFromBranch.ps1 — create worktree from branch
• New-WorktreeFromIssue.ps1 — create worktree for work item
• Delete-Worktree.ps1 — remove worktree and branch
• WorktreeLib.ps1 — shared helper functions

Human-friendly wrappers (in tools/git/):

• tools/git/New-WorktreeFromBranch.cmd — delegates to skill's master script
• tools/git/New-WorktreeFromIssue.cmd — delegates to skill's master script
• tools/git/Delete-Worktree.cmd — delegates to skill's master script
• tools/git/Worktree-Guidelines.md — quick reference for developers