Use when starting feature work that needs isolation from current workspace or before executing implementation plans - ensures an isolated workspace exists via native tools or git worktree fallback

Using Git Worktrees Overview Ensure work happens in an isolated workspace. Prefer your platform's native worktree tools. Fall back to manual git worktrees only when no native tool is available. Core principle: Detect existing isolation first. Then use native tools. Then fall back to git. Never fight the harness. Announce at start: "I'm using the using git worktrees skill to set up an isolated workspace." Step 0: Detect Existing Isolation Before creating anything, check if you are already in an isolated workspace. Submodule guard: GIT DIR != GIT COMMON is also true inside git submodules. Before concluding "already in a worktree," verify you are not in a submodule: If GIT DIR != GIT COMMON (and not a submodule): You are already in a linked worktree. Skip to Step 2 (Project Setup). Do NOT create another worktree. Report with 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 time." If GIT DIR == GIT COMMON (or in a submodule): You are in a normal repo checkout. Has the user already indicated their worktree preference in your instructions? If not, ask for consent before creating a worktree: "Would you like me to set up an isolated worktree? It protects your current branch from changes." Honor any existing declared preference without asking. If the user declines consent, work in place and skip to Step 2. Step 1: Create Isolated Workspace You have two mechanisms. Try them in this order. 1a. Native Worktree Tools (preferred) The user has asked for an isolated workspace (Step 0 consent). Do you already have a way to create a worktree? It might be a tool with a name like EnterWorktree , WorktreeCreate , a /worktree command, or a worktree flag. If you do, use it and skip to Step 2. Native tools handle directory placement, branch creation, and cleanup automatically. Using git worktree add when you have a native tool creates phantom state your harness can't see or manage. Only proceed to Step 1b if you have no native worktree tool available. 1b. Git Worktree Fallback Only use this if Step 1a does not apply — you have no native worktree tool available. Create a worktree manually using git. Directory Selection Follow this priority order. Explicit user preference always beats observed filesystem state. 1. Check your instructions for a declared worktree directory preference. If the user has already specified one, use it without asking. 2. Check for an existing project local worktree directory: If found, use it. If both exist, .worktrees wins. 3. If there is no other guidance available , default to .worktrees/ at the project root. Safety Verification (project local directories only) MUST verify directory is ignored before creating worktree: If NOT ignored: Add to .gitignore, commit the change, then proceed. Why critical: Prevents accidentally committing worktree contents to repository. Create the Worktree Sandbox fallback: If git worktree add fails with a permission error (sandbox denial), tell the user the sandbox blocked worktree creation and you're working in the current directory instead. Then run setup and baseline tests in place. Step 2: Project Setup Auto detect and run appropriate setup: Step 3: Verify Clean Baseline Run tests to ensure workspace starts clean: If tests fail: Report failures, ask whether to proceed or investigate. If tests pass: Report ready. Report Quick Reference Situation Action Already in linked worktree Skip creation (Step 0) In a submodule Treat as normal repo (Step 0 guard) Native worktree tool available Use it (Step 1a) No native tool Git worktree fallback (Step 1b) .worktrees/ exists Use it (verify ignored) worktrees/ exists Use it (verify ignored) Both exist Use .worktrees/ Neither exists Check instruction file, then default .worktrees/ Directory not ignored Add to .gitignore + commit Permission error on create Sandbox fallback, work in place Tests fail during baseline Report failures + ask No package.json/Cargo.toml Skip dependency install Common Rationalizations Excuse Reality "I'm obviously not in a worktree — no need to check" Run Step 0. Harness created isolation and submodules both fool eyeballing; the detection commands settle it. " git worktree add is quicker than hunting for a native tool" A native tool (e.g. EnterWorktree ) owns placement, branching, and cleanup. Bypassing it is the 1 mistake — it creates phantom state your harness can't see or manage. "The worktree directory is surely ignored already" Run git check ignore . An unignored worktree directory commits the whole tree into the repo. "Any directory name works" Explicit instructions beat an existing project local directory, which beats the .worktrees/ default. "The workspace is fresh — baseline tests can wait" A dirty baseline makes every later failure ambiguous. Run the tests now; proceeding past failures is your human partner's call.

using-git-worktrees