# Safe Worktree Slug Validation

> Ensure Git worktree slugs can never escape the managed workspace or inject traversal.

- Skill: `vishuwa2004/safe-worktree-slug-validation` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add vishuwa2004/safe-worktree-slug-validation`
- Raw SKILL.md: https://api.skillmd.com/api/skills/vishuwa2004/safe-worktree-slug-validation/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: vishuwa2004 (https://skillmd.com/u/vishuwa2004)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/vishuwa2004/safe-worktree-slug-validation

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# SKILL: Safe Worktree Slug Validation
**Domain:** git-worktree
**Trigger:** Apply this when accepting user-provided prefixes for enter worktree and you need to guarantee no path traversal or invalid chars slip into the worktree directory.
**Source Pattern:** Distilled from reviewed permission, shell-safety, and worktree-management implementations.

## Core Method
Split a slug on `/`, reject segments that are empty, `.` or `..`, or contain characters outside a za z0 9, and enforce a maximum combined length before joining the cleaned segments into a deterministic branch name and path. Perform this validation synchronously before invoking any git commands so the CLI never creates directories outside claude worktrees.

## Key Rules
- Validate each `/`-separated segment independently so user evil and similar mashups fail early.
- Enforce a total length cap (e.g., 64 chars) before `git worktree add` to prevent excessively long refs or paths.
- Reject slugs with leading/trailing slashes or repeated `..` segments even when a normalization would neutralize them.
- Run this check before any git fetch, mkdir, or hook execution to avoid partial side effects.

## Example Application
Any agent producing a worktree name for a release hotfix can reuse this skill: call the validator on the proposed slug, surface a concise error message if it fails, and refuse to call `git worktree add` until the slug is safe.

## Anti-Patterns (What NOT to do)
- Do not rely on `git worktree add` to detect traversal; it may silently create directories in unexpected locations.
- Do not treat slugs as a single string (e.g., foo bar) without splitting, because multi-segment checks are necessary.
- Avoid waiting until after `mkdir` or config changes—the validation must run before any side effects.