scan-file

scan-file is a skill for Claude Code from NOMARJ/sigil. It costs 108 tokens per session (296 once invoked), scanned A, original, Apache-2.0.

A security scan for one file, such as a script, configuration, skill manifest, or MCP server file. It checks for dangerous code, network access, exposed credentials, obfuscation, and suspicious imports.

In plain words
What is it for?
Use it when someone asks whether a file, skill, or MCP server is safe, or before executing an unfamiliar file.
Why use it?
It lets you vet a specific file before running or installing it instead of auditing an entire project. Findings include a risk level, affected lines, explanation, and suggested fixes.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the sigil-security plugin — 6 skills, 2 agents, 2 hooks shipped together

Good fit Use it when someone asks whether a file, skill, or MCP server is safe, or before executing an unfamiliar file.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nomarj/sigil/scan-file
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 NOMARJ/sigil --skill scan-file
Clone the repo
git clone --depth 1 https://github.com/NOMARJ/sigil

Made for: Claude Code.

Or install sigil-security, the plugin that ships this one along with the rest of its 6 skills, 2 agents, 2 hooks.

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 scan-file

README.md
[![agentmods](https://agentmods.dev/badge/skills/nomarj/sigil/scan-file/github.svg)](https://agentmods.dev/skills/nomarj/sigil/scan-file)
Your own site
<a href="https://agentmods.dev/skills/nomarj/sigil/scan-file"><img src="https://agentmods.dev/badge/skills/nomarj/sigil/scan-file/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 scan-file

Your own site · 80×15
<a href="https://agentmods.dev/skills/nomarj/sigil/scan-file"><img src="https://agentmods.dev/badge/skills/nomarj/sigil/scan-file.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 108 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 296 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00108 $0.00296
Opus 5.5 $0.00043 $0.00118
Sonnet 5.5 $0.00022 $0.00059
Haiku 4.5 $0.00011 $0.00030

Measured 1mo ago against content hash c14238ecb280, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

scan-file scanned grade A with 0 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 1mo 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/claude-code/skills/scan-file/SKILL.md · 29 lines

What it actually says

Scan File with Sigil

Analyze a specific file for security vulnerabilities:

Target: "$ARGUMENTS"

Run: sigil scan <file-path> on the specified file.

Check for:

  1. Code Patterns - eval, exec, pickle, subprocess
  2. Network Access - HTTP requests, webhooks, socket connections
  3. Credential Exposure - API keys, tokens, hardcoded secrets
  4. Obfuscation - base64 encoding, hex strings, charCode
  5. Dangerous Imports - suspicious modules or libraries

Present findings with:

  • Severity level (CLEAN, LOW, MEDIUM, HIGH, CRITICAL)
  • Line numbers and code snippets
  • Risk explanation
  • Remediation recommendations

If the file is CRITICAL or HIGH risk, explain the specific threat and recommend quarantine.

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. 1mo ago First seen · 29 lines · 108 tokens per session scan A c14238ecb280

Subscribe to this mod's changes

scan-file is a skill published in the GitHub repository NOMARJ/sigil (6 stars, last pushed 12d ago), licensed Apache-2.0. It adds 108 tokens to every session and 296 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-04.