sk-worktree-safety

name	sk-worktree-safety
description	Enforces a mandatory 4-step safety protocol (Ignore, Setup, Baseline, Commit) for creating, managing, and destroying git worktrees in pipeline isolation contexts. Use when a pipeline step declares `isolation: worktree`, when parallel pattern tasks require branch isolation, or when the iterative or spec-driven patterns require atomic rollback capability.
disable-model-invocation	true
user-invocable	false

Worktree Safety Protocol — Isolated Execution

Defines the mandatory 4-step protocol (Ignore, Setup, Baseline, Commit) for creating, managing, and destroying git worktrees.

An isolated git workspace sharing the same repository object but operating on a different branch and path. Running the project's test suite before modification to identify pre-existing failures. Committing all uncommitted work before removing the worktree directory.

The 4-Step Safety Protocol

### 1. VERIFY_IGNORED The `.worktrees/` directory must be git-ignored before any worktree is created, to prevent accidental commits or workspace pollution. ```bash git check-ignore -q .worktrees || { echo ".worktrees/" >> .gitignore && git add .gitignore && git commit -m "chore: ignore worktrees"; } ```

2. SETUP_AFTER_CREATE

Manifests are auto-detected (package.json, Cargo.toml, etc.) and the corresponding installation commands (npm install, cargo build) are run to prepare the isolated environment.

3. VERIFY_BASELINE

The project's full test suite is run before any modifications.

• Failures Found: Results are reported to the user. DO NOT PROCEED with implementation without explicit human authorization.
• Goal: Distinguishes between pre-existing issues and pipeline-introduced regressions.

4. COMMIT_BEFORE_DESTROY

All changes are added and committed before any worktree is removed, preserving the work-in-progress state.

cd "$WORKTREE_PATH" && git add -A && git commit -m "wip: pipeline checkpoint"
git worktree remove "$WORKTREE_PATH"

Pattern Integration

<integration_table>

Pattern	Worktree Requirement	Rationale
1. Sequential	Optional	Linear flow may not require isolation.
2. Parallel	Mandatory	Required for fanned-out task isolation.
3. Iterative	Mandatory	Enables atomic rollback on escalation.
4. Gated	Conditional	Required only during the modification phase.
5. Spec-Driven	Mandatory	Enforced per-task during Phase 5 (Implement).
</integration_table>

Detection Signals

Environment state is verified before execution: - **`GIT_DIR != GIT_COMMON`**: Already in a linked worktree; Step 1 is skipped. - **Branch empty**: Detached HEAD detected; branching/pushing is not possible. Escalate to user. - NEVER skip the baseline test; it is the leading cause of false escalations in iterative loops. - NEVER use `git worktree remove --force` without a preceding commit to preserve findings. - ALWAYS verify that `.worktrees/` is ignored before creation.

Red Flags — STOP

• "I'll skip the baseline test, it'll be fine." → STOP. Pre-existing failures will corrupt the pipeline metrics.
• "Just force-remove the worktree, the pipeline failed." → STOP. Commit partial findings first to aid debugging.

Reference Files

• sk-pipeline-patterns/SKILL.md — Topology selection.
• sk-pipeline-state/SKILL.md — metadata.worktree_root tracking.
• finishing-a-development-branch/SKILL.md — Final merge protocol.