guard

A combined safety mode that warns before destructive commands and restricts file edits to a chosen directory.

In plain words
What is it for?
Use it when you need maximum protection while debugging or making changes in a narrowly defined part of a project.
Why use it?
It reduces the risk of deleting data or changing unrelated files during work on production systems or live codebases.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/garrytan/gstack/guard
Any agent
npx skills add garrytan/gstack --skill guard
Clone the repo
git clone --depth 1 https://github.com/garrytan/gstack

Made for: Claude Code, Codex.

Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 852 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00019 $0.00852
Opus 5 $0.00010 $0.00426
Sonnet 5 $0.00004 $0.00170
Haiku 4.5 $0.00002 $0.00085

Measured 2d ago against content hash ae1ec65c4256, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

guard scanned grade C with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

Combines /careful (warns before rm -rf, DROP TABLE, force-push, etc.) with
guard/SKILL.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to invoke this skill

Combines /careful (warns before rm -rf, DROP TABLE, force-push, etc.) with /freeze (blocks edits outside a specified directory). Use for maximum safety when touching prod or debugging live systems. Use when asked to "guard mode", "full safety", "lock it down", or "maximum safety".

/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).

mkdir -p ~/.gstack/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/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:

  1. Resolve it to an absolute path:
FREEZE_DIR=$(cd "<user-provided-path>" 2>/dev/null && pwd)
echo "$FREEZE_DIR"
  1. Ensure trailing slash and save to the freeze state file:
FREEZE_DIR="${FREEZE_DIR%/}/"
eval "$(~/.claude/skills/gstack/bin/gstack-paths)"
STATE_DIR="$GSTACK_STATE_ROOT"
mkdir -p "$STATE_DIR"
echo "$FREEZE_DIR" > "$STATE_DIR/freeze-dir.txt"
echo "Freeze boundary set: $FREEZE_DIR"

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 <path>/. Edits outside this directory are blocked."
  • "To remove the edit boundary, run /unfreeze. To deactivate everything, end the session."

Read the full file on GitHub · 91 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 91 lines · 19 tokens per session scan C ae1ec65c4256

Subscribe to this mod's changes

guard is a skill published in the GitHub repository garrytan/gstack (130,427 stars, last pushed 2d ago), licensed MIT. It adds 19 tokens to every session and 852 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it C with 1 finding (recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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