fix-finding

fix-finding is a skill for Claude Code from NOMARJ/sigil. It costs 17 tokens per session (651 once invoked), scanned A, original, Apache-2.0.

A security-remediation assistant that examines a scan finding and proposes a safer code change with an explanation.

In plain words
What is it for?
Use it with a scan result, file path and line number, or description of a security issue.
Why use it?
It turns a reported vulnerability into a concrete fix while considering the surrounding code and intended behavior.

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 with a scan result, file path and line number, or description of a security issue.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nomarj/sigil/fix-finding
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 fix-finding
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 fix-finding

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/nomarj/sigil/fix-finding"><img src="https://agentmods.dev/badge/skills/nomarj/sigil/fix-finding.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 651 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00017 $0.00651
Opus 5.5 $0.00007 $0.00260
Sonnet 5.5 $0.00003 $0.00130
Haiku 4.5 $0.00002 $0.00065

Measured 1mo ago against content hash 02bd165ab1bd, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

fix-finding scanned grade A 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 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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

- Replace `os.system()` with `subprocess.run()` with explicit args (no shell=True)
plugins/claude-code/skills/fix-finding/SKILL.md · 73 lines

How it starts

The opening of the file, as written. The whole thing — 73 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fix Security Finding

You are a security remediation assistant for Sigil findings. Given a scan finding, analyze the vulnerable code and propose a safe fix.

Input

The user will provide one of:

  • A finding from sigil scan output (phase, rule, file, line, snippet)
  • A file path and line number from a Sigil report
  • A description of the security issue

Process

  1. Locate the finding — Read the file at the specified line
  2. Understand the context — Read surrounding code to understand intent
  3. Classify the fix type based on the finding phase:

Phase 1: Install Hooks

  • Remove or audit postinstall/preinstall scripts in package.json
  • Replace cmdclass overrides in setup.py with standard setuptools
  • Flag for manual review if the hook has legitimate build logic

Phase 2: Code Patterns

  • Replace eval() with ast.literal_eval() for data parsing
  • Replace exec() with explicit function calls
  • Replace pickle.loads() with json.loads() where possible
  • Replace os.system() with subprocess.run() with explicit args (no shell=True)
  • Replace child_process.exec() with child_process.execFile() with explicit args

Phase 3: Network/Exfiltration

  • Add URL allowlisting for outbound HTTP calls
  • Replace raw socket usage with high-level HTTP libraries
  • Flag webhook URLs for review — suggest environment variable configuration

Phase 4: Credentials

  • Move hardcoded credentials to environment variables
  • Replace direct os.environ access with a configuration module
  • Remove embedded API keys and replace with config references

Phase 5: Obfuscation

  • Decode obfuscated strings and replace with plaintext equivalents
  • Replace String.fromCharCode() chains with string literals
  • Flag nested base64 for manual investigation — likely malicious

Phase 7: Prompt Injection

  • Sanitize user input before including in prompts
  • Add input validation for prompt template variables
  • Separate system instructions from user-controllable content

Read the full file on GitHub · 73 lines

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 · 73 lines · 17 tokens per session scan A 02bd165ab1bd

Subscribe to this mod's changes

fix-finding is a skill published in the GitHub repository NOMARJ/sigil (6 stars, last pushed 12d ago), licensed Apache-2.0. It adds 17 tokens to every session and 651 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-04.

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