skill-scanner

skill-scanner is a skill for Claude Code, Codex from stefaniuk/loadout. It costs 72 tokens per session (2,222 once invoked), scanned C, a copy of skill-scanner, MIT.

A security scanner for agent skills, which are instruction packages that guide coding agents. It checks a skill's instructions and included files for common safety risks.

In plain words
What is it for?
Use it to audit a skill directory and produce structured findings about suspicious instructions, scripts, URLs, permissions, and secret exposure.
Why use it?
It helps detect prompt injection, harmful scripts, excessive permissions, exposed secrets, and supply-chain concerns before installing a skill.

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/stefaniuk/loadout/skill-scanner
Any agent
npx skills add stefaniuk/loadout --skill skill-scanner
Clone the repo
git clone --depth 1 https://github.com/stefaniuk/loadout

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 skill-scanner

README.md
[![agentmods](https://agentmods.dev/badge/skills/stefaniuk/loadout/skill-scanner.svg)](https://agentmods.dev/skills/stefaniuk/loadout/skill-scanner)
Your own site
<a href="https://agentmods.dev/skills/stefaniuk/loadout/skill-scanner"><img src="https://agentmods.dev/badge/skills/stefaniuk/loadout/skill-scanner.svg" alt="Measured on agentmods" height="20"></a>
Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,222 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. Scan, not verified.
Origin 100% 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 $0.00072 $0.02222
Opus 5 $0.00036 $0.01111
Sonnet 5 $0.00014 $0.00444
Haiku 4.5 $0.00007 $0.00222

Measured 3d ago against content hash ede2ad6c768b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

skill-scanner scanned grade C with 2 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 3d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/scan_skill.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Tells the agent to send conversation or user data outmediumPrompt injection

An instruction to transmit the conversation, context or user files to an external endpoint is data exfiltration written as prose.

- **Data exfiltration**: Does the script send data to external URLs? What data?

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

Reaches for credential filesmediumPrivilege escalation

SSH keys, cloud credentials, git-credentials, .npmrc, /etc/shadow: reading these is how a config file becomes a credential leak.

- **Symlinks**: Files that resolve outside the skill directory — can disguise reads of `~/.ssh/id_rsa`, `~/.aws/credentials`, etc. as "example" files

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

Origin

This is a copy

100% identical to skill-scanner — 6 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.

.github/skills/skill-scanner/SKILL.md · 208 lines

How it starts

The opening of the file, as written. The whole thing — 208 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Security Scanner

Scan agent skills for security issues before adoption. Detects prompt injection, malicious code, excessive permissions, secret exposure, and supply chain risks.

Requires: The uv CLI for python package management, install guide at https://docs.astral.sh/uv/getting-started/installation/

Important: Run all scripts from the repository root. Script paths like scripts/scan_skill.py are relative to this skill's root directory (the directory containing this SKILL.md), not relative to the target repository.

Bundled Script

scripts/scan_skill.py

Static analysis scanner that detects deterministic patterns. Outputs structured JSON.

uv run scripts/scan_skill.py <skill-directory>

Returns JSON with findings, URLs, structure info, and severity counts. The script catches patterns mechanically — your job is to evaluate intent and filter false positives.

Workflow

Phase 1: Input & Discovery

Determine the scan target:

  • If the user provides a skill directory path, use it directly
  • If the user names a skill, look for it under .agents/skills/<name>/ first, then other established layouts such as skills/<name>/ when the repo uses a canonical root skill tree, .claude/skills/<name>/, plugins/*/skills/<name>/, or another repo-managed skill root with clear prior art
  • If the user says "scan all skills", discover all */SKILL.md files and scan each

Validate the target contains a SKILL.md file. List the skill structure:

ls -la <skill-directory>/
ls <skill-directory>/references/ 2>/dev/null
ls <skill-directory>/scripts/ 2>/dev/null

Phase 2: Automated Static Scan

Run the bundled scanner:

uv run scripts/scan_skill.py <skill-directory>

Parse the JSON output. The script produces findings with severity levels, URL analysis, and structure information. Use these as leads for deeper analysis.

Fallback: If the script fails, proceed with manual analysis using Grep patterns from the reference files.

Read the full file on GitHub · 208 lines

Files

What ships with it

4 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. 3d ago First seen · 208 lines · 72 tokens per session scan C ede2ad6c768b

Subscribe to this mod's changes

skill-scanner is a skill published in the GitHub repository stefaniuk/loadout (1 stars, last pushed yesterday), licensed MIT. It adds 72 tokens to every session and 2,222 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it C with 2 findings (tells the agent to send conversation or user data out, reaches for credential files). It is 100% identical to skill-scanner, differing in 6 lines, and is treated as a copy.

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