| 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.
