engineering-security-engineer

engineering-security-engineer is a skill for Claude Code, Codex from PeterHdd/agent-skills. It costs 91 tokens per session (4,769 once invoked), scanned B, original, MIT.

A security engineering guide for checking applications, infrastructure, and development pipelines for risks. It covers threat modeling, vulnerability reviews, secure system design, and security operations.

In plain words
What is it for?
Use it to review authentication and authorization, scan for leaked secrets and vulnerable dependencies, plan penetration tests, improve CI/CD security checks, manage secrets, and respond to incidents.
Why use it?
It helps find exposed secrets, weak authentication, unsafe dependencies, and other security problems before they become incidents. It also gives a structured way to assess what attackers could reach.

Skill for Claude CodeCodex

Part of the agent-skills plugin — 9 skills shipped together

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/peterhdd/agent-skills/engineering-security-engineer
Any agent
npx skills add PeterHdd/agent-skills --skill engineering-security-engineer
Clone the repo
git clone --depth 1 https://github.com/PeterHdd/agent-skills

Made for: Claude Code, Codex.

Or install agent-skills, the plugin that ships this one along with the rest of its 9 skills.

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 engineering-security-engineer

README.md
[![agentmods](https://agentmods.dev/badge/skills/peterhdd/agent-skills/engineering-security-engineer.svg)](https://agentmods.dev/skills/peterhdd/agent-skills/engineering-security-engineer)
Your own site
<a href="https://agentmods.dev/skills/peterhdd/agent-skills/engineering-security-engineer"><img src="https://agentmods.dev/badge/skills/peterhdd/agent-skills/engineering-security-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 91 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,769 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. Scan, not verified.
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 $0.00091 $0.04769
Opus 5 $0.00046 $0.02384
Sonnet 5 $0.00018 $0.00954
Haiku 4.5 $0.00009 $0.00477

Measured 4d ago against content hash b85e71526ed3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

engineering-security-engineer scanned grade B 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 4d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/audit_auth_surface.py, scripts/check_security_headers.sh, scripts/scan_secrets.sh), 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.

Cloud metadata endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

- Validate and allowlist all URLs provided by users. Block requests to internal IP ranges: `10.0.0.0/8`, `172.16.0.0/12`, `192.168.0.0/16`, `127.0.0.0/8`, `169.254.169.254` (cloud metadata).

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

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- Disable directory listing, debug endpoints, and stack traces in production. Check with: `curl -v https://yourapp.com/debug`, `curl https://yourapp.com/.env`.
skills/engineering-security-engineer/SKILL.md · 240 lines

How it starts

The opening of the file, as written. The whole thing — 240 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security Engineering Guide

Overview

This guide covers application security, infrastructure hardening, threat modeling, vulnerability management, and security operations. Use it when designing auth systems, reviewing code for security issues, setting up security scanning in CI/CD, responding to incidents, managing secrets, or ensuring compliance with security frameworks.

First 10 Minutes

  • Map the attack surface before suggesting fixes: public routes, auth entrypoints, admin paths, file upload/download flows, third-party callbacks, and secrets-loading paths.
  • Run the bundled scripts from the skill directory first, not the repo under review: engineering-security-engineer/scripts/scan_secrets.sh and engineering-security-engineer/scripts/audit_auth_surface.py.
  • For large mobile/web repos, start with high-signal trees such as src, app, server, api, config, and scripts; only scan the full repo if needed.
  • Use scripts/scan_secrets.sh first. Secret exposure changes priority immediately.
  • Use scripts/audit_auth_surface.py next to inventory auth-related files and session/token patterns before reviewing login or authorization changes.
  • Identify the highest-risk trust boundary in the task: browser to API, API to service, service to database, or CI to cloud.

Refuse or Escalate

  • Refuse to approve security-sensitive changes that skip authorization checks, input validation, or audit logging "for later."
  • Escalate immediately when the task involves credential exposure, insecure direct object access in production, or suspected compromise.
  • Do not recommend weakening CSP, CORS, or cookie settings without documenting the exact breakage and the narrowest safe exception.
  • Escalate if the requested solution conflicts with legal or compliance obligations already named in the system.

Threat Modeling

When to Threat Model

  • Before building any new feature that handles user data, authentication, authorization, payments, or file uploads.
  • When adding a new external dependency, third-party integration, or API endpoint.
  • When changing data flow (new database, new cache, new queue) or access patterns.
  • Quarterly review of existing threat models for systems handling PII, financial data, or health data.

Read the full file on GitHub · 240 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. 4d ago First seen · 240 lines · 91 tokens per session scan B b85e71526ed3

Subscribe to this mod's changes

engineering-security-engineer is a skill published in the GitHub repository PeterHdd/agent-skills (11 stars, last pushed 5mo ago), licensed MIT. It adds 91 tokens to every session and 4,769 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it B with 2 findings (cloud metadata endpoint, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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