security-review

A checklist and set of coding patterns for protecting software that handles logins, user input, secrets, APIs, payments, or other sensitive data.

In plain words
What is it for?
Use it when adding authentication, API endpoints, file uploads, payment features, third-party integrations, or any code that stores or sends sensitive information.
Why use it?
It helps find common security problems such as exposed credentials, unsafe input handling, injection, missing access checks, and data leaks.

Skill for Claude CodeCodex

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/cloudnative-co/claude-code-starter-kit/security-review
Any agent
npx skills add cloudnative-co/claude-code-starter-kit --skill security-review
Clone the repo
git clone --depth 1 https://github.com/cloudnative-co/claude-code-starter-kit

Made for: Claude Code, Codex.

Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 659 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 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 $0.00036 $0.00659
Opus 5 $0.00018 $0.00329
Sonnet 5 $0.00007 $0.00132
Haiku 4.5 $0.00004 $0.00066

Measured 2d ago against content hash b2f6eb63e670, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

security-review 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 2d 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.

skills/security-review/SKILL.md · 68 lines

How it starts

The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security Review Skill

Ensures all code follows security best practices and identifies potential vulnerabilities.

When to Activate

  • Implementing authentication or authorization
  • Handling user input or file uploads
  • Creating new API endpoints
  • Working with secrets or credentials
  • Implementing payment features
  • Storing or transmitting sensitive data
  • Integrating third-party APIs

Security Checklist Categories

Review each category. See references/vulnerability-patterns.md for WRONG/CORRECT code examples.

  1. Secrets Management -- No hardcoded secrets; all in env vars; .env* gitignored
  2. Input Validation -- Schema validation; file upload size/type/extension checks
  3. SQL Injection -- Parameterized queries only; no string concatenation
  4. Auth & Authorization -- httpOnly cookies; RBAC; row-level/object-level authorization where needed
  5. XSS Prevention -- DOMPurify for user HTML; CSP headers configured
  6. CSRF Protection -- CSRF tokens on state-changing ops; SameSite=Strict cookies
  7. Rate Limiting -- All endpoints rate-limited; stricter on expensive operations
  8. Data Exposure -- No secrets in logs; generic error messages to users
  9. High-Risk Integrations -- Payments, wallets, third-party APIs, and webhooks validated when present
  10. Dependencies -- npm audit clean; lock files committed; Dependabot enabled

Full checkbox checklist: assets/security-checklist.md

Pre-Deployment Checklist

Before ANY production deployment, confirm ALL of the following:

  • No hardcoded secrets, all in env vars
  • All user inputs validated
  • All queries parameterized
  • User content sanitized (XSS)
  • CSRF protection enabled
  • Proper token handling (httpOnly cookies)
  • Authorization role checks in place
  • Rate limiting on all endpoints
  • HTTPS enforced
  • Security headers configured (CSP, X-Frame-Options)
  • No sensitive data in error messages or logs
  • Dependencies up to date, no vulnerabilities
  • CORS properly configured
  • File uploads validated (size, type)

Read the full file on GitHub · 68 lines

Files

What ships with it

2 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. 2d ago First seen · 68 lines · 36 tokens per session scan A b2f6eb63e670

Subscribe to this mod's changes

security-review is a skill published in the GitHub repository cloudnative-co/claude-code-starter-kit (147 stars, last pushed 9d ago), licensed MIT. It adds 36 tokens to every session and 659 once invoked, about $0.0002 per session on Opus 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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