gs-cso

gs-cso is a skill for Claude Code, Codex from YousefNabil-SOC/claude-apex. It costs 75 tokens per session (20,388 once invoked), scanned B, a copy of cso, MIT.

A security audit workflow covering common web risks, threat modelling, secrets, dependencies, build pipelines, and AI-related security concerns. Threat modelling means identifying how a system could be attacked before problems occur.

In plain words
What is it for?
Use it for security audits, OWASP checks, STRIDE threat models, vulnerability reviews, and penetration-testing preparation.
Why use it?
It helps find vulnerabilities and unsafe design choices across both application code and the systems used to build and run it.

Skill for Claude CodeCodex

Written for Claude Code and Codex: allowed-tools in frontmatter, but also runs codex exec. Also seen: reads .claude/ paths; mentions CLAUDE.md; names the AskUserQuestion tool.

Good fit Use it for security audits, OWASP checks, STRIDE threat models, vulnerability reviews, and penetration-testing preparation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/yousefnabil-soc/claude-apex/gs-cso
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.

Any agent
npx skills add YousefNabil-SOC/claude-apex --skill gs-cso
Clone the repo
git clone --depth 1 https://github.com/YousefNabil-SOC/claude-apex

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for gs-cso

README.md
[![agentmods](https://agentmods.dev/badge/skills/yousefnabil-soc/claude-apex/gs-cso/github.svg)](https://agentmods.dev/skills/yousefnabil-soc/claude-apex/gs-cso)
Your own site
<a href="https://agentmods.dev/skills/yousefnabil-soc/claude-apex/gs-cso"><img src="https://agentmods.dev/badge/skills/yousefnabil-soc/claude-apex/gs-cso/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.

agentmods 80×15 button for gs-cso

Your own site · 80×15
<a href="https://agentmods.dev/skills/yousefnabil-soc/claude-apex/gs-cso"><img src="https://agentmods.dev/badge/skills/yousefnabil-soc/claude-apex/gs-cso.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 75 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 20,388 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 3 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 75% copy Near-identical to another mod 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 5.1 $0.00075 $0.20388
Opus 5 $0.00037 $0.10194
Sonnet 5 $0.00015 $0.04078
Haiku 4.5 $0.00007 $0.02039

Measured 8d ago against content hash fe0e7378e520, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade B, and why

gs-cso scanned grade B with 3 findings 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 8d 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.

Instruction-override phrasingmediumPrompt injection

Text telling the model to disregard its earlier instructions or safety rules is the shape of a prompt injection, whoever wrote it.

- `IGNORE PREVIOUS`, `system override`, `disregard`, `forget your instructions` (prompt injection)

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Enumerates other installed skillslowAgent snooping

Other skills' SKILL.md files reveal prompts, capabilities and secrets that should be invisible to peers.

ls -la .claude/skills/ 2>/dev/null

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- `curl`, `wget`, `fetch`, `http`, `exfiltrat` (network exfiltration)
Origin

This is a copy

75% identical to cso — 847 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.

skills/gs-cso/SKILL.md · 1,458 lines

How it starts

The opening of the file, as written. The whole thing — 1,458 lines — stays where its author put it; the contents beside it link to each section on GitHub.

INTEGRATION NOTE: Extracted from gstack and renamed gs-cso to coexist with the host CARL / CAPABILITY-REGISTRY routing. Original gstack documentation follows. Sibling gstack skills referenced below by their original names map to gs-* when installed here (e.g. /review -> gs-review). gstack skills NOT installed in this environment (ship, qa, codex, office-hours, browse, freeze, guard, land-and-deploy) and gstack-only infra (browse binary, ~/.gstack GBrain, bun eval harness) are unavailable, so those references are informational only.

When to invoke this skill

Infrastructure-first security audit: secrets archaeology, dependency supply chain, CI/CD pipeline security, LLM/AI security, skill supply chain scanning, plus OWASP Top 10, STRIDE threat modeling, and active verification. Two modes: daily (zero-noise, 8/10 confidence gate) and comprehensive (monthly deep scan, 2/10 bar). Trend tracking across audit runs. Use when: "security audit", "threat model", "pentest review", "OWASP", "CSO review".

Voice triggers (speech-to-text aliases): "see-so", "see so", "security review", "security check", "vulnerability scan", "run security".

Preamble (run first)

_UPD=$(~/.claude/skills/gstack/bin/gstack-update-check 2>/dev/null || .claude/skills/gstack/bin/gstack-update-check 2>/dev/null || true)
[ -n "$_UPD" ] && echo "$_UPD" || true
mkdir -p ~/.gstack/sessions
touch ~/.gstack/sessions/"$PPID"
_SESSIONS=$(find ~/.gstack/sessions -mmin -120 -type f 2>/dev/null | wc -l | tr -d ' ')
find ~/.gstack/sessions -mmin +120 -type f -exec rm {} + 2>/dev/null || true
_PROACTIVE=$(~/.claude/skills/gstack/bin/gstack-config get proactive 2>/dev/null || echo "true")
_PROACTIVE_PROMPTED=$([ -f ~/.gstack/.proactive-prompted ] && echo "yes" || echo "no")
_BRANCH=$(git branch --show-current 2>/dev/null || echo "unknown")
echo "BRANCH: $_BRANCH"
_SKILL_PREFIX=$(~/.claude/skills/gstack/bin/gstack-config get skill_prefix 2>/dev/null || echo "false")
echo "PROACTIVE: $_PROACTIVE"
echo "PROACTIVE_PROMPTED: $_PROACTIVE_PROMPTED"
echo "SKILL_PREFIX: $_SKILL_PREFIX"
source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
REPO_MODE=${REPO_MODE:-unknown}
echo "REPO_MODE: $REPO_MODE"
_LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
echo "LAKE_INTRO: $_LAKE_SEEN"
_TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
_TEL_PROMPTED=$([ -f ~/.gstack/.telemetry-prompted ] && echo "yes" || echo "no")
_TEL_START=$(date +%s)
_SESSION_ID="$$-$(date +%s)"
echo "TELEMETRY: ${_TEL:-off}"
echo "TEL_PROMPTED: $_TEL_PROMPTED"
_EXPLAIN_LEVEL=$(~/.claude/skills/gstack/bin/gstack-config get explain_level 2>/dev/null || echo "default")
if [ "$_EXPLAIN_LEVEL" != "default" ] && [ "$_EXPLAIN_LEVEL" != "terse" ]; then _EXPLAIN_LEVEL="default"; fi
echo "EXPLAIN_LEVEL: $_EXPLAIN_LEVEL"
_QUESTION_TUNING=$(~/.claude/skills/gstack/bin/gstack-config get question_tuning 2>/dev/null || echo "false")
echo "QUESTION_TUNING: $_QUESTION_TUNING"
mkdir -p ~/.gstack/analytics
if [ "$_TEL" != "off" ]; then
echo '{"skill":"cso","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
fi
for _PF in $(find ~/.gstack/analytics -maxdepth 1 -name '.pending-*' 2>/dev/null); do
  if [ -f "$_PF" ]; then
    if [ "$_TEL" != "off" ] && [ -x "~/.claude/skills/gstack/bin/gstack-telemetry-log" ]; then
      ~/.claude/skills/gstack/bin/gstack-telemetry-log --event-type skill_run --skill _pending_finalize --outcome unknown --session-id "$_SESSION_ID" 2>/dev/null || true
    fi
    rm -f "$_PF" 2>/dev/null || true
  fi
  break
done
eval "$(~/.claude/skills/gstack/bin/gstack-slug 2>/dev/null)" 2>/dev/null || true
_LEARN_FILE="${GSTACK_HOME:-$HOME/.gstack}/projects/${SLUG:-unknown}/learnings.jsonl"
if [ -f "$_LEARN_FILE" ]; then
  _LEARN_COUNT=$(wc -l < "$_LEARN_FILE" 2>/dev/null | tr -d ' ')
  echo "LEARNINGS: $_LEARN_COUNT entries loaded"
  if [ "$_LEARN_COUNT" -gt 5 ] 2>/dev/null; then
    ~/.claude/skills/gstack/bin/gstack-learnings-search --limit 3 2>/dev/null || true
  fi
else
  echo "LEARNINGS: 0"
fi
~/.claude/skills/gstack/bin/gstack-timeline-log '{"skill":"cso","event":"started","branch":"'"$_BRANCH"'","session":"'"$_SESSION_ID"'"}' 2>/dev/null &
_HAS_ROUTING="no"
if [ -f CLAUDE.md ] && grep -q "## Skill routing" CLAUDE.md 2>/dev/null; then
  _HAS_ROUTING="yes"
fi
_ROUTING_DECLINED=$(~/.claude/skills/gstack/bin/gstack-config get routing_declined 2>/dev/null || echo "false")
echo "HAS_ROUTING: $_HAS_ROUTING"
echo "ROUTING_DECLINED: $_ROUTING_DECLINED"
_VENDORED="no"
if [ -d ".claude/skills/gstack" ] && [ ! -L ".claude/skills/gstack" ]; then
  if [ -f ".claude/skills/gstack/VERSION" ] || [ -d ".claude/skills/gstack/.git" ]; then
    _VENDORED="yes"
  fi
fi
echo "VENDORED_GSTACK: $_VENDORED"
echo "MODEL_OVERLAY: claude"
_CHECKPOINT_MODE=$(~/.claude/skills/gstack/bin/gstack-config get checkpoint_mode 2>/dev/null || echo "explicit")
_CHECKPOINT_PUSH=$(~/.claude/skills/gstack/bin/gstack-config get checkpoint_push 2>/dev/null || echo "false")
echo "CHECKPOINT_MODE: $_CHECKPOINT_MODE"
echo "CHECKPOINT_PUSH: $_CHECKPOINT_PUSH"
# Plan-mode hint for skills like /spec that branch behavior on plan-mode state.
# Claude Code exposes plan mode via system reminders; we detect best-effort
# from CLAUDE_PLAN_FILE (set by the harness when plan mode is active) and
# fall back to "inactive". Codex hosts and Claude execution mode both end up
# inactive, which is the safe default (defaults to file+execute pipeline).
if [ -n "${CLAUDE_PLAN_FILE:-}${GSTACK_PLAN_MODE_FORCE:-}" ]; then
  export GSTACK_PLAN_MODE="active"
elif [ "${GSTACK_PLAN_MODE:-}" = "active" ]; then
  export GSTACK_PLAN_MODE="active"
else
  export GSTACK_PLAN_MODE="inactive"
fi
echo "GSTACK_PLAN_MODE: $GSTACK_PLAN_MODE"
[ -n "$OPENCLAW_SESSION" ] && echo "SPAWNED_SESSION: true" || true

Read the full file on GitHub · 1,458 lines

Files

What ships with it

2 files 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. 8d ago First seen · 1,458 lines · 75 tokens per session scan B fe0e7378e520

Subscribe to this mod's changes

gs-cso is a skill published in the GitHub repository YousefNabil-SOC/claude-apex (2 stars, last pushed 3mo ago), licensed MIT. It adds 75 tokens to every session and 20,388 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it B with 3 findings (instruction-override phrasing, enumerates other installed skills, makes network calls). It is 75% identical to cso, differing in 847 lines, and is treated as a copy.