skill-scanner

skill-scanner is a skill for Claude Code from lxyeternal/MalSkillBench. It costs 72 tokens per session (2,233 once invoked), scanned C, original, no licence file.

A security-review tool for agent skills, which are instruction packages that extend a coding agent. It checks the skill’s instructions and related files for risky behavior.

In plain words
What is it for?
Use it to scan or audit a skill, validate its SKILL.md file, and assess whether it is safe to install.
Why use it?
It helps identify prompt injection, harmful scripts, excessive access requests, and possible exposure of secrets before installation.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to scan or audit a skill, validate its SKILL.md file, and assess whether it is safe to install.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/lxyeternal/malskillbench/skill-scanner
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 lxyeternal/MalSkillBench --skill skill-scanner
Clone the repo
git clone --depth 1 https://github.com/lxyeternal/MalSkillBench

Made for: Claude Code.

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/lxyeternal/malskillbench/skill-scanner.svg)](https://agentmods.dev/skills/lxyeternal/malskillbench/skill-scanner)
Your own site
<a href="https://agentmods.dev/skills/lxyeternal/malskillbench/skill-scanner"><img src="https://agentmods.dev/badge/skills/lxyeternal/malskillbench/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 2,233 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 5.1 $0.00072 $0.02233
Opus 5 $0.00036 $0.01117
Sonnet 5 $0.00014 $0.00447
Haiku 4.5 $0.00007 $0.00223

Measured 8d ago against content hash 49a62edc44db, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, 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 8d 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.

Baselines/skillsecurity/getsentry-skill-scanner/skills/skill-scanner/SKILL.md · 210 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 8d ago First seen · 210 lines · 72 tokens per session scan C 49a62edc44db

Subscribe to this mod's changes

skill-scanner is a skill published in the GitHub repository lxyeternal/MalSkillBench (57 stars, last pushed 2mo ago), with no licence file. It adds 72 tokens to every session and 2,233 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). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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