secure-code-review

A security-focused review of source code using OWASP ASVS, a checklist for application security, and CWE Top 25, a list of common dangerous software weaknesses.

In plain words
What is it for?
Use it during pull-request reviews or when checking authentication, authorization, cryptography, user input, dependencies, and trust boundaries.
Why use it?
It finds security issues in code changes, especially where attackers may affect login, permissions, encryption, or input handling. Findings include severity and guidance for fixing them.

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/unitoneai/securityskills/secure-code-review
Any agent
npx skills add UnitOneAI/SecuritySkills --skill secure-code-review
Clone the repo
git clone --depth 1 https://github.com/UnitOneAI/SecuritySkills

Made for: Claude Code, Codex.

Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,546 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 $0.00074 $0.06546
Opus 5 $0.00037 $0.03273
Sonnet 5 $0.00015 $0.01309
Haiku 4.5 $0.00007 $0.00655

Measured 2d ago against content hash f18fb31b59ac, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

secure-code-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/appsec/secure-code-review/SKILL.md · 579 lines

How it starts

The opening of the file, as written. The whole thing — 579 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Secure Code Review

A structured, repeatable process for performing security-focused code review grounded in OWASP Application Security Verification Standard (ASVS) 4.0.3 and the CWE Top 25 Most Dangerous Software Weaknesses (2024 edition). This skill produces findings with traceable control IDs, severity ratings, and actionable remediation guidance.


Step 1: Scope and Language Identification

If a target is provided via arguments, focus the review on: $ARGUMENTS

Before examining any code, establish the review boundary.

  1. Identify the languages and frameworks present in the changeset (Python, JavaScript/TypeScript, Go, Java, etc.).
  2. Catalog the modules under review -- list every file path and its primary responsibility (route handler, data model, utility, middleware, configuration).
  3. Determine trust boundaries -- mark where user-controlled data enters the system (HTTP parameters, headers, file uploads, message queues, environment variables).
  4. Note dependencies -- third-party libraries that handle security-sensitive operations (auth libraries, ORM layers, crypto packages, templating engines).
  5. Map ASVS sections to scope -- based on what the code does, select which ASVS chapters (V1 through V14) are applicable to this review.

Gate: Do not proceed until the language, trust boundaries, and applicable ASVS sections are documented. This prevents scope creep and ensures coverage.


Step 2: Input Validation and Injection Review

ASVS Reference: V5 -- Validation, Sanitization and Encoding CWE Coverage: CWE-79 (XSS), CWE-89 (SQL Injection), CWE-78 (OS Command Injection), CWE-22 (Path Traversal), CWE-77 (Command Injection), CWE-20 (Improper Input Validation)

2.1 Controls to Verify

ASVS Control Description
V5.1.1 Input validation is applied on a trusted service layer, not solely client-side
V5.1.3 All input is validated against an allowlist of permitted characters or patterns
V5.2.1 All HTML form output is properly encoded to prevent reflected XSS
V5.2.2 Unstructured data is sanitized to enforce safety and allowed characters
V5.3.1 Output encoding is relevant for the interpreter context (HTML, JS, URL, CSS, SQL)
V5.3.4 Data selection or database queries use parameterized queries or ORM
V5.3.7 The application protects against LDAP injection
V5.3.8 The application protects against OS command injection
V5.5.1 Serialized objects use integrity checks or encryption to prevent hostile object creation

Read the full file on GitHub · 579 lines

Files

What ships with it

1 file 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 · 579 lines · 74 tokens per session scan A f18fb31b59ac

Subscribe to this mod's changes

secure-code-review is a skill published in the GitHub repository UnitOneAI/SecuritySkills (58 stars, last pushed 2mo ago), licensed MIT. It adds 74 tokens to every session and 6,546 once invoked, about $0.0004 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.