owasp-security

owasp-security is a skill for Claude Code, Codex from agamm/claude-code-owasp. It costs 62 tokens per session (3,523 once invoked), scanned A, original, MIT.

A web-security review guide based on OWASP standards, which are widely used checklists for preventing common application security problems. It covers authentication, access permissions, user input, dependencies, encryption, logging, and AI-related risks.

In plain words
What is it for?
Use it when reviewing or writing web code, login and permission systems, input handling, dependency choices, or security controls.
Why use it?
It helps locate security weaknesses that could expose data, let users access the wrong things, or allow harmful input to affect an application.

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/agamm/claude-code-owasp/owasp-security
Any agent
npx skills add agamm/claude-code-owasp --skill owasp-security
Clone the repo
git clone --depth 1 https://github.com/agamm/claude-code-owasp

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 owasp-security

README.md
[![agentmods](https://agentmods.dev/badge/skills/agamm/claude-code-owasp/owasp-security.svg)](https://agentmods.dev/skills/agamm/claude-code-owasp/owasp-security)
Your own site
<a href="https://agentmods.dev/skills/agamm/claude-code-owasp/owasp-security"><img src="https://agentmods.dev/badge/skills/agamm/claude-code-owasp/owasp-security.svg" alt="Measured on agentmods" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,523 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 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 $0.00062 $0.03523
Opus 5 $0.00031 $0.01761
Sonnet 5 $0.00012 $0.00705
Haiku 4.5 $0.00006 $0.00352

Measured 5d ago against content hash 7c7ee6971d97, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

owasp-security scanned grade A 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 5d 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.

Makes network callslowCapability

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

6. **Standard Library:** Historic CVEs in std libs (Python urllib, Java XML, Ruby OpenSSL).

Runs shell commandslowCapability

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

os.system(f"convert {filename} output.png")
.claude/skills/owasp-security/SKILL.md · 304 lines

How it starts

The opening of the file, as written. The whole thing — 304 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OWASP Security Best Practices Skill

Apply these security standards when writing or reviewing code.

Reference files (load on demand):

Quick Reference: OWASP Top 10:2025

# Vulnerability Key Prevention
A01 Broken Access Control Deny by default, enforce server-side, verify ownership
A02 Security Misconfiguration Harden configs, disable defaults, minimize features
A03 Software Supply Chain Failures Lock versions, verify integrity, audit dependencies
A04 Cryptographic Failures TLS 1.2+, AES-256-GCM, Argon2/bcrypt for passwords
A05 Injection Parameterized queries, input validation, safe APIs
A06 Insecure Design Threat model, rate limit, design security controls
A07 Authentication Failures MFA, check breached passwords, secure sessions
A08 Software or Data Integrity Failures Sign packages, SRI for CDN, safe serialization
A09 Security Logging and Alerting Failures Log security events, structured format, alerting
A10 Mishandling of Exceptional Conditions Fail-closed, hide internals, log with context

Before Reporting a Finding

A pattern match is not a vulnerability. The most common failure mode in automated security review is reporting unreachable or already-mitigated code, which buries the real findings. Confirm all three before reporting:

  1. Is the input actually attacker-controlled? Trace it back to a real entry point — a request parameter, header, cookie, uploaded file, webhook, queue message, or third-party API response. A value that only ever comes from a constant, an enum, or trusted internal config is not an injection source.
  2. Is the sink reachable with that input? Check whether validation, an allowlist, an ORM, or a framework-level control already sits between them. Look for auth middleware (middleware.ts, proxy.ts, Express/Django/Rails middleware, a base controller, decorators) before flagging a route as missing authorization — enforcement is often centralized rather than per-route.
  3. What is the blast radius? Who can trigger it, what do they get, and does it cross a trust boundary? An SSRF reaching cloud metadata differs from one reaching localhost only.

Read the full file on GitHub · 304 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. 5d ago First seen · 304 lines · 62 tokens per session scan A 7c7ee6971d97

Subscribe to this mod's changes

owasp-security is a skill published in the GitHub repository agamm/claude-code-owasp (352 stars, last pushed 1mo ago), licensed MIT. It adds 62 tokens to every session and 3,523 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 2 findings (makes network calls, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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