MCP.Market

guard skill

by garrytan·garrytan/gstack·142k stars·MIT

Full safety mode: destructive command warnings + directory-scoped edits. (gstack)

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Is the guard skill safe?

Clean: nothing in its files matched our rules. We read 1 file in the folder on 2026-10-25.

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Install the guard skill

A skill is a folder. Copy it into your agent's skills folder and the agent loads it when the task matches its description. 

git clone --depth 1 https://github.com/garrytan/gstack.git /tmp/gstack
mkdir -p ~/.claude/skills
cp -r /tmp/gstack/guard ~/.claude/skills/guard
available in every project

In the Claude apps, zip the folder and upload it from the Skills settings. The folder on GitHub

The instructions your agent would load

SKILL.md as published, without the frontmatter. Read it on GitHub

<!-- AUTO-GENERATED from SKILL.md.tmpl — do not edit directly --> <!-- Regenerate: bun run gen:skill-docs -->

/guard — Full Safety Mode

Activates both destructive command warnings and directory-scoped edit restrictions. This is the combination of /careful + /freeze in a single command.

Dependency note: This skill references hook scripts from the sibling /careful and /freeze skill directories. Both must be installed (they are installed together by the gstack setup script).

GSTACK_STATE_ROOT=$(~/.claude/skills/gstack/bin/gstack-paths --get GSTACK_STATE_ROOT); : "${GSTACK_STATE_ROOT:?gstack-paths failed; reinstall with ./setup or /gstack-upgrade}"
mkdir -p "$GSTACK_STATE_ROOT"/analytics
echo '{"skill":"guard","ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'","repo":"'$(basename "$(git rev-parse --show-toplevel 2>/dev/null)" 2>/dev/null || echo "unknown")'"}'  >> "$GSTACK_STATE_ROOT"/analytics/skill-usage.jsonl 2>/dev/null || true

Setup

Ask the user which directory to restrict edits to. Use AskUserQuestion:

  • Question: "Guard mode: which directory should edits be restricted to? Destructive command warnings are always on. Files outside the chosen path will be blocked from editing."
  • Text input (not multiple choice) — the user types a path.

Once the user provides a directory path:

Set the user-selected boundary with the shared writer, which resolves a physical absolute path and serializes replacement with investigation cleanup:

bash "$HOME/.claude/skills/gstack/freeze/bin/freeze-state.sh" set "<user-provided-path>"

On helper failure, do not claim the boundary is active. Preserve the state and report recovery; never bypass the shared writer with a direct write or deletion.

Tell the user:

  • "Guard mode active. Two protections are now running:"
  • "1. Destructive command guard — rm -rf, DROP TABLE, force-push, etc. warn before executing (overridable); catastrophic shapes (recursive delete of / or ~, force-push to the default branch) are hard-denied"
  • "2. Edit boundary — file edits restricted to /. Edits outside this directory are blocked."
  • "To remove the persistent edit boundary, run /unfreeze. Ending the session stops its hooks but does not delete that boundary."

What's protected

See /careful for the full list of destructive command patterns and safe exceptions. See /freeze for how edit boundary enforcement works.

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