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.
npx skills add tonydzi/second-brain-starter-kit --skill guardgit clone --depth 1 https://github.com/tonydzi/second-brain-starter-kitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/tonydzi/second-brain-starter-kit/guard)<a href="https://agentmods.dev/skills/tonydzi/second-brain-starter-kit/guard"><img src="https://agentmods.dev/badge/skills/tonydzi/second-brain-starter-kit/guard/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/tonydzi/second-brain-starter-kit/guard"><img src="https://agentmods.dev/badge/skills/tonydzi/second-brain-starter-kit/guard.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00019 | $0.00852 |
| Opus 5.5 | $0.00008 | $0.00341 |
| Sonnet 5.5 | $0.00004 | $0.00170 |
| Haiku 4.5 | $0.00002 | $0.00085 |
Grade C, and why
guard scanned grade C with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 22d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Recursive force deletehighDestructive command
rm -rf with a variable or a broad path is one typo away from removing the wrong tree.
Combines /careful (warns before rm -rf, DROP TABLE, force-push, etc.) with This is a copy
100% identical to guard — 38 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.
When to invoke this skill
Combines /careful (warns before rm -rf, DROP TABLE, force-push, etc.) with /freeze (blocks edits outside a specified directory). Use for maximum safety when touching prod or debugging live systems. Use when asked to "guard mode", "full safety", "lock it down", or "maximum safety".
/guard — Full Safety Mode
Activates both destructive command warnings and directory-scoped edit restrictions.
This is the combination of /careful + /freeze in a single command.
Dependency note: This skill references hook scripts from the sibling /careful
and /freeze skill directories. Both must be installed (they are installed together
by the gstack setup script).
mkdir -p ~/.gstack/analytics
echo '{"skill":"guard","ts":"'$(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:
- Resolve it to an absolute path:
FREEZE_DIR=$(cd "<user-provided-path>" 2>/dev/null && pwd)
echo "$FREEZE_DIR"
- 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."
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.
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.
- 22d ago First seen · 91 lines · 19 tokens per session scan C ae1ec65c4256
guard is a skill published in the GitHub repository tonydzi/second-brain-starter-kit (8 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 5.5. A static security scan graded it C with 1 finding (recursive force delete). It is 100% identical to guard, differing in 38 lines, and is treated as a copy.
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