security-audit

A code-security review for web apps, APIs, services, command-line tools, libraries, and other software. It looks for vulnerabilities that an attacker could actually exploit.

In plain words
What is it for?
Use it to review a codebase for security problems, find exploitable bugs, or assess it as part of a penetration test.
Why use it?
It helps separate serious security bugs from theoretical concerns or normal industry behavior. This makes security findings more focused on real impact.

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/cloudflare/security-audit-skill/security-audit
Any agent
npx skills add cloudflare/security-audit-skill --skill security-audit
Clone the repo
git clone --depth 1 https://github.com/cloudflare/security-audit-skill

Made for: Claude Code, Codex.

Per session 70 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,327 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 $0.00070 $0.02327
Opus 5 $0.00035 $0.01163
Sonnet 5 $0.00014 $0.00465
Haiku 4.5 $0.00007 $0.00233

Measured 3d ago against content hash 928503b4eb74, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

security-audit 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 3d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (validate-findings.cjs), 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.

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.

Origin

Copies of this mod

4 near-identical copies found in the catalogue:

skills/security-audit/SKILL.md · 109 lines

How it starts

The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security Audit

You are a security auditor. Your job is to find exploitable vulnerabilities with real impact.

Platform terminology

This skill is agent-neutral. In the methodology:

  • Task tool means the coding agent's delegation or sub-agent mechanism.
  • research agent means a delegated agent optimized for focused codebase exploration and factual verification.
  • general agent means a delegated agent that can investigate broadly and spawn focused research agents.
  • subagent_type means the equivalent delegated-agent role supported by the current platform.

Use the platform's equivalent capabilities while preserving the specified roles, parallelism, prompts, and independence boundaries.

Setup

Before starting, establish two paths:

  • Target: the codebase to audit (from the user's request or the current working directory)
  • Output directory: where all audit artifacts go. Ask the user if not specified, or default to ~/security-audit-skill/<repo-name>/run-<N> where <N> is the next unused integer (check what exists with ls). Create it if it doesn't exist. This ensures multiple runs against the same repo produce separate results.

All files written during the audit go in the output directory:

  • architecture.md — Phase 1 output, fed into Phase 2 agent prompts
  • REPORT.md — human-readable report (Phase 4)
  • FINDINGS-DETAIL.md — detailed data flows for MEDIUM+ findings (Phase 4)
  • findings.json — machine-readable structured output (Phase 5)

Subagents (Phases 1, 2, 3, 6) do NOT write files — they return results to you via the Task tool. You are responsible for writing all files to the output directory.

Coverage and prior runs

Each audit run explores different code paths depending on which agents find what and where they dig. No single run finds everything. Testing shows the best single run finds roughly half the total vulnerabilities across multiple runs.

If prior runs exist for the same repo (check ~/security-audit-skill/<repo-name>/), read their findings.json files before starting Phase 2. Use them to:

  1. Skip known findings — don't waste agents re-discovering the same status bypass. Mention prior findings in the report but focus hunting effort on new ground.
  2. Target gaps — if prior runs focused heavily on injection and auth, weight this run toward business logic, creative attacks, and the wildcard agent. If prior runs missed public endpoints, focus there.
  3. Resolve disagreements — if prior runs gave conflicting verdicts on the same finding, validate it definitively.

Read the full file on GitHub · 109 lines

Files

What ships with it

10 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. 3d ago First seen · 109 lines · 70 tokens per session scan A 928503b4eb74

Subscribe to this mod's changes

security-audit is a skill published in the GitHub repository cloudflare/security-audit-skill (3,192 stars, last pushed 1mo ago), licensed MIT. It adds 70 tokens to every session and 2,327 once invoked, about $0.0003 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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