Using Git Worktrees

Overview

Work in isolated workspace. Prefer native worktree tools; manual git worktrees only when none.

Core principle: Detect existing isolation first. Then native tools. Then git fallback. Never fight harness.

Announce at start: "I'm using the superpowers-using-git-worktrees skill to set up an isolated workspace."

Step 0: Detect Existing Isolation

Before creating anything, check if already in isolated workspace. Via bash:

GIT_DIR=$(cd "$(git rev-parse --git-dir)" 2>/dev/null && pwd -P)
GIT_COMMON=$(cd "$(git rev-parse --git-common-dir)" 2>/dev/null && pwd -P)
BRANCH=$(git branch --show-current)

Submodule guard: GIT_DIR != GIT_COMMON also true inside submodules. Verify not a submodule before concluding "worktree":

# If this returns a path, you're in a submodule, not a worktree — treat as normal repo
git rev-parse --show-superproject-working-tree 2>/dev/null

If GIT_DIR != GIT_COMMON (and not a submodule): Already in linked worktree. Skip to Step 3, do NOT create another. Report branch state:

• On a branch: "Already in isolated workspace at <path> on branch <name>."
• Detached HEAD: "Already in isolated workspace at <path> (detached HEAD, externally managed). Branch creation needed at finish."

If GIT_DIR == GIT_COMMON (or in a submodule): Normal repo checkout. Preference declared? Honor it, no asking. Else ask consent:

"Would you like me to set up an isolated worktree? It protects your current branch from changes."

Declines: work in place, skip to Step 3 — do NOT start editing feature code on the current branch first.

Step 1: Create Isolated Workspace

1a. Native Worktree Tools (preferred)

Already have a worktree mechanism — a tool named EnterWorktree, WorktreeCreate, a /worktree command, or a --worktree flag? Use it, skip to Step 3.

Native tools handle placement, branch creation, cleanup. Using git worktree add when a native tool exists creates phantom state the harness can't manage. No native tool: proceed to Step 1b.

1b. Git Worktree Fallback

Only use if Step 1a does not apply. Explicit user preference always beats filesystem state.

Directory Selection

1. Check instructions for declared directory preference. Use it, no asking.
2. Check for existing project-local worktree directory:

   ls -d .worktrees 2>/dev/null     # Preferred (hidden)
   ls -d worktrees 2>/dev/null      # Alternative

   Both exist? .worktrees wins.
3. Check for existing global directory:

   project=$(basename "$(git rev-parse --show-toplevel)")
   ls -d ~/.config/reasonix/worktrees/$project 2>/dev/null

4. No other guidance: default to .worktrees/ at project root.

Safety Verification (project-local directories only)

MUST verify directory ignored before creating worktree:

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

If NOT ignored: add to .gitignore, commit, proceed. Why critical: prevents committing worktree contents. Global directories need no verification.

Create the Worktree

# For project-local: path="$LOCATION/$BRANCH_NAME"
# For global: path="~/.config/reasonix/worktrees/$project/$BRANCH_NAME"
git worktree add "$path" -b "$BRANCH_NAME"
cd "$path"

Sandbox fallback: git worktree add fails with permission error (sandbox denial — Reasonix confines writes to [sandbox] workspace_root)? Tell the user the sandbox blocked it, working in the current directory instead. Run setup and baseline tests in place.

Step 3: Project Setup

Auto-detect and run setup, bash:

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 pyproject.toml ]; then poetry install; fi
if [ -f go.mod ]; then go mod download; fi

Step 4: Verify Clean Baseline

Run tests, ensure clean baseline (npm test / cargo test / pytest / go test ./...).

Tests fail: report failures, ask whether to proceed or investigate. Pass: report ready.

Worktree ready at <full-path>
Tests passing (<N> tests, 0 failures)
Ready to implement <feature-name>

Quick Reference

Red Flags

Never:

• Create a worktree when Step 0 detects existing isolation
• Use git worktree add when a native worktree tool exists — #1 mistake
• Skip Step 1a, jump straight to git commands
• Create project-local worktree without verifying it's ignored
• Skip baseline test verification
• Proceed with failing tests without asking

Always: run Step 0 first; prefer native tools; follow directory priority (existing > global legacy > instruction file > default); verify ignored for project-local; auto-detect and run setup; verify clean test baseline.