Using Git Worktrees
Overview
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 ring:using-git-worktrees skill to set up an isolated workspace."
Directory Selection Process
Priority order: (1) Existing .worktrees/ or worktrees/ (2) CLAUDE.md preference (3) Ask user
ls -d .worktrees worktrees 2>/dev/null # Check existing (prefer .worktrees)
grep -i "worktree.*director" CLAUDE.md # Check project preferenceIf none found, ask: .worktrees/ (project-local, hidden) OR ~/.config/ring/worktrees/<project>/ (global)
Safety Verification
Project-local directories: MUST verify.gitignore before creating: grep -q "^\.worktrees/$\|^worktrees/$".gitignore
- If NOT in.gitignore: Add it → commit → proceed (fix broken things immediately)
- Why critical: Prevents accidentally committing worktree contents
Global directory (~/.config/ring/worktrees): No verification needed - outside project.
Creation Steps
# 1. Detect project
project=$(basename "$(git rev-parse --show-toplevel)")
# 2. Create worktree (path = $LOCATION/$BRANCH or ~/.config/ring/worktrees/$project/$BRANCH)
git worktree add "$path" -b "$BRANCH_NAME" && cd "$path"
# 3. Auto-detect and run setup
[ -f package.json ] && npm install
[ -f Cargo.toml ] && cargo build
[ -f requirements.txt ] && pip install -r requirements.txt
[ -f pyproject.toml ] && poetry install
[ -f go.mod ] && go mod download
# 4. Verify clean baseline (npm test / cargo test / pytest / go test ./...)If tests fail: Report failures, ask whether to proceed or investigate. If tests pass: Report: Worktree ready at <path> | Tests passing (<N> tests) | Ready to implement <feature>
Quick Reference
| Situation | Action |
|---|---|
.worktrees/ exists | Use it (verify.gitignore) |
worktrees/ exists | Use it (verify.gitignore) |
| Both exist | Use .worktrees/ |
| Neither exists | Check CLAUDE.md → Ask user |
| Directory not in.gitignore | Add it immediately + commit |
| Tests fail during baseline | Report failures + ask |
| No package.json/Cargo.toml | Skip dependency install |
Common Mistakes
| Mistake | Problem | Fix |
|---|---|---|
| Skip.gitignore verification | Worktree contents tracked, pollute git status | Always grep.gitignore first |
| Assuming directory location | Inconsistency, violates conventions | Follow priority: existing > CLAUDE.md > ask |
| Proceeding with failing tests | Can't distinguish new vs pre-existing bugs | Report failures, get permission |
| Hardcoding setup commands | Breaks on different tools | Auto-detect from project files |
Example Workflow
Announce → Check .worktrees/ exists → Verify.gitignore → git worktree add.worktrees/auth -b feature/auth → npm install → npm test (47 passing) → Report ready
Red Flags
Never:
- Create worktree without.gitignore verification (project-local)
- Skip baseline test verification
- Proceed with failing tests without asking
- Assume directory location when ambiguous
- Skip CLAUDE.md check
Always:
- Follow directory priority: existing > CLAUDE.md > ask
- Verify.gitignore for project-local
- Auto-detect and run project setup
- Verify clean test baseline
Integration
Called by:
- brainstorming (Phase 4) - REQUIRED when design is approved and implementation follows
- Any skill needing isolated workspace
Pairs with:
- finishing-a-development-branch - REQUIRED for cleanup after work complete
- ring:executing-plans or ring:subagent-driven-development - Work happens in this worktree
Blocker Criteria
STOP and report if:
| Decision Type | Blocker Condition | Required Action |
|---|---|---|
| .gitignore Safety | Project-local worktree directory not in.gitignore | STOP and report |
| Baseline Tests | Tests fail during worktree setup | STOP and report |
| Directory Ambiguity | Multiple conflicting worktree locations exist | STOP and report |
| Permission Issues | Cannot create worktree in target directory | STOP and report |
Cannot Be Overridden
The following requirements CANNOT be waived:
- Project-local worktree directories MUST be in.gitignore before creation
- Baseline test verification is REQUIRED before proceeding with work
- Directory selection MUST follow priority order: existing > CLAUDE.md > ask user
- Worktree creation MUST include dependency installation and test verification
Severity Calibration
| Severity | Condition | Required Action |
|---|---|---|
| CRITICAL | Worktree directory not in.gitignore (project-local) | MUST add to.gitignore immediately |
| CRITICAL | Proceeding with failing baseline tests | MUST report failures and get permission |
| HIGH | Skipping dependency installation step | MUST run appropriate package manager |
| HIGH | Assuming directory location when ambiguous | MUST follow priority order or ask user |
| MEDIUM | Missing CLAUDE.md check in priority order | Should check CLAUDE.md preferences |
| LOW | Not auto-detecting project type | Fix in next iteration |
Pressure Resistance
| User Says | Your Response |
|---|---|
| "Skip.gitignore check, just create the worktree" | "CANNOT skip.gitignore verification for project-local directories. Worktree contents would pollute git status." |
| "Tests are failing but proceed anyway" | "CANNOT proceed with failing baseline tests. I need to report failures so we can distinguish pre-existing bugs from new ones." |
| "Put the worktree in this custom location" | "I'll verify that location doesn't conflict with existing conventions and check.gitignore requirements first." |
| "Skip dependency installation, it takes too long" | "CANNOT skip dependency installation. Tests won't run correctly without dependencies, invalidating baseline verification." |
Anti-Rationalization Table
| Rationalization | Why It's WRONG | Required Action |
|---|---|---|
| ".gitignore check is paranoia" | Without it, worktree contents get tracked, polluting every git status. | MUST verify.gitignore first |
| "I know where worktrees go in this project" | Assumption conflicts with existing directories or CLAUDE.md preferences. | MUST follow directory priority order |
| "Failing tests are probably unrelated" | You cannot distinguish new vs pre-existing bugs without clean baseline. | MUST report failures and ask before proceeding |
| "Setup is straightforward, skip auto-detection" | Different projects use different tools. Manual setup misses dependencies. | MUST auto-detect from project files |
| "Global directory doesn't need verification" | Global directories don't need.gitignore verification - this is correct. Only project-local needs it. | MUST distinguish global vs project-local |