Use when starting feature work needing isolation from current workspace, before executing implementation plans, or when working on multiple branches simultaneously. Required when brainstorming leads to implementation to avoid polluting main workspace.
Creates isolated Git worktrees for working on multiple branches simultaneously without switching. Automatically detects project setup, verifies safety, and runs baseline tests. Triggered when starting feature work or when brainstorming leads to implementation.
/plugin marketplace add astrosteveo/harness-mp/plugin install harness@harness-mpThis skill inherits all available tools. When active, it can use any tool Claude has access to.
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.
Announce at start: "I'm using the using-git-worktrees skill to set up an isolated workspace."
Follow this priority order:
# Check in priority order
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.
grep -i "worktree.*director" CLAUDE.md 2>/dev/null
If preference specified: Use it without asking.
If no directory exists and no CLAUDE.md preference:
No worktree directory found. Where should I create worktrees?
1. .worktrees/ (project-local, hidden)
2. ~/.config/harness/worktrees/<project-name>/ (global location)
Which would you prefer?
MUST verify directory is ignored before creating worktree:
# Check if directory is ignored (respects local, global, and system gitignore)
git check-ignore -q .worktrees 2>/dev/null || git check-ignore -q worktrees 2>/dev/null
If NOT ignored:
Per Steven's rule "Fix broken things immediately":
Why critical: Prevents accidentally committing worktree contents to repository.
No .gitignore verification needed - outside project entirely.
project=$(basename "$(git rev-parse --show-toplevel)")
# Determine full path
case $LOCATION in
.worktrees|worktrees)
path="$LOCATION/$BRANCH_NAME"
;;
~/.config/harness/worktrees/*)
path="~/.config/harness/worktrees/$project/$BRANCH_NAME"
;;
esac
# Create worktree with new branch
git worktree add "$path" -b "$BRANCH_NAME"
cd "$path"
Auto-detect and run appropriate setup:
# Node.js
if [ -f package.json ]; then npm install; fi
# Rust
if [ -f Cargo.toml ]; then cargo build; fi
# Python
if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
if [ -f pyproject.toml ]; then poetry install; fi
# Go
if [ -f go.mod ]; then go mod download; fi
Run tests to ensure worktree starts clean:
# Examples - use project-appropriate command
npm test
cargo test
pytest
go test ./...
If tests fail: Report failures, ask whether to proceed or investigate.
If tests pass: Report ready.
Worktree ready at <full-path>
Tests passing (<N> tests, 0 failures)
Ready to implement <feature-name>
| Situation | Action |
|---|---|
.worktrees/ exists | Use it (verify ignored) |
worktrees/ exists | Use it (verify ignored) |
| Both exist | Use .worktrees/ |
| Neither exists | Check CLAUDE.md → Ask user |
| Directory not ignored | Add to .gitignore + commit |
| Tests fail during baseline | Report failures + ask |
| No package.json/Cargo.toml | Skip dependency install |
git check-ignore before creating project-local worktreeYou: I'm using the using-git-worktrees skill to set up an isolated workspace.
[Check .worktrees/ - exists]
[Verify ignored - git check-ignore confirms .worktrees/ is ignored]
[Create worktree: git worktree add .worktrees/auth -b feature/auth]
[Run npm install]
[Run npm test - 47 passing]
Worktree ready at /Users/jesse/myproject/.worktrees/auth
Tests passing (47 tests, 0 failures)
Ready to implement auth feature
Never:
Always:
Called by:
Pairs with:
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