lfe-security-check

lfe-security-check is a skill for Claude Code, Codex from StChiotis/Library-First-Engineering. It costs 60 tokens per session (1,151 once invoked), scanned A, original, MIT.

A read-only security review of code changes using the OWASP Top 10, a widely used checklist of common web-application security risks. It reasons about the code without external scanners and writes findings for a larger inspection step.

In plain words
What is it for?
Use it as part of the inspector workflow to examine a current implementation diff, record possible vulnerabilities, and pass the findings to the main critique.
Why use it?
It provides a structured security check before changes are accepted. Keeping it read-only means the review does not modify the implementation.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

Good fit Use it as part of the inspector workflow to examine a current implementation diff, record possible vulnerabilities, and pass the findings to the main critique.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/stchiotis/library-first-engineering/lfe-security-check
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 StChiotis/Library-First-Engineering --skill lfe-security-check
Clone the repo
git clone --depth 1 https://github.com/StChiotis/Library-First-Engineering

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 lfe-security-check

README.md
[![agentmods](https://agentmods.dev/badge/skills/stchiotis/library-first-engineering/lfe-security-check/github.svg)](https://agentmods.dev/skills/stchiotis/library-first-engineering/lfe-security-check)
Your own site
<a href="https://agentmods.dev/skills/stchiotis/library-first-engineering/lfe-security-check"><img src="https://agentmods.dev/badge/skills/stchiotis/library-first-engineering/lfe-security-check/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 lfe-security-check

Your own site · 80×15
<a href="https://agentmods.dev/skills/stchiotis/library-first-engineering/lfe-security-check"><img src="https://agentmods.dev/badge/skills/stchiotis/library-first-engineering/lfe-security-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,151 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 $0.00060 $0.01151
Opus 5.5 $0.00024 $0.00460
Sonnet 5.5 $0.00012 $0.00230
Haiku 4.5 $0.00006 $0.00115

Measured 1mo ago against content hash 1b678054d6f0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

lfe-security-check 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.

.agents/skills/lfe-security-check/SKILL.md · 98 lines

How it starts

The opening of the file, as written. The whole thing — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.

LFE Security Check — OWASP Top-10 Prompt Analysis

Position in Pipeline

  • Phase: 3 (Inspector sub-skill)
  • Persona: Inspector (read-only; no src/ writes)
  • Trigger: Invoked by /lfe-inspector Sub-Skill Dispatch when lfe-security-check: true in .docs/quality/inspector-config.md
  • Output: .plans/checks/security_findings.md — aggregated by Inspector into critique.md

Mission

Systematically examine the implementation diff for security vulnerabilities using the OWASP Top-10 as a structured checklist. No external scanners, no Semgrep, no platform-specific tooling — reasoning over code only.

Hard Rules

  1. Dispatch Context Required (refuse direct invocation): This skill is dispatched by /lfe-inspector Step 6 — it is not a Brain-typeable skill (per LLM_AGENT_GUIDE.md §8.8 Skill Invocation Authority). If invoked without .plans/builder_done.md AND .plans/tdd_report.md for the current slice, halt immediately and reply: "/lfe-security-check is an Inspector sub-skill dispatched by /lfe-inspector. It cannot be run standalone. Run /lfe-inspector — the dispatcher will invoke this sub-skill if it is enabled in .docs/quality/inspector-config.md (or via an ## Inspector Overrides section in active_plan.md)." Direct invocation produces orphaned findings files and breaks the Inspector's aggregation logic.
  2. Prompt-Only Analysis: All findings come from LLM reasoning over the diff — reason only, with no code execution or external API calls.
  3. Cite Evidence: Every finding must quote the specific code line or pattern that triggers the concern.
  4. Severity Triage: Rate each finding as Critical / High / Medium / Low. Only Critical blocks Builder re-run; others are advisory.
  5. Scope to Diff: Analyse only the files changed in builder_done.md; skip unchanged code.

Inputs

  1. .plans/builder_done.md — list of changed files
  2. .plans/tdd_report.md — context on what was implemented
  3. .plans/active_plan.md — scope boundary
  4. .docs/engineering/engineering-standards.md (if present) — project security baseline

Read the full file on GitHub · 98 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 · 98 lines · 60 tokens per session scan A 1b678054d6f0

Subscribe to this mod's changes

lfe-security-check is a skill published in the GitHub repository StChiotis/Library-First-Engineering (46 stars, last pushed 3mo ago), licensed MIT. It adds 60 tokens to every session and 1,151 once invoked, about $0.0002 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 2026-08-30.

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