security-audit

security-audit is a skill for Claude Code, Codex from falcoschaefer99-eng/michael-security-agent. It costs 0 tokens per session (3,041 once invoked), scanned A, original, Apache-2.0.

A security review for code changes, with a quick mode for deployment checks and a deeper mode for threat analysis. It can also be used for suspected breaches or newly disclosed security vulnerabilities.

In plain words
What is it for?
Use it before deployment, after feature work that changes trust boundaries, or during an incident to inspect access, data flows, dependencies, and common attack patterns.
Why use it?
It helps identify unsafe code, missing authentication, unvalidated input, vulnerable dependencies, and risks where systems or trust boundaries meet.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: reads .claude/ paths.

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/falcoschaefer99-eng/michael-security-agent/security-audit
Any agent
npx skills add falcoschaefer99-eng/michael-security-agent --skill security-audit
Clone the repo
git clone --depth 1 https://github.com/falcoschaefer99-eng/michael-security-agent

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 security-audit

README.md
[![agentmods](https://agentmods.dev/badge/skills/falcoschaefer99-eng/michael-security-agent/security-audit.svg)](https://agentmods.dev/skills/falcoschaefer99-eng/michael-security-agent/security-audit)
Your own site
<a href="https://agentmods.dev/skills/falcoschaefer99-eng/michael-security-agent/security-audit"><img src="https://agentmods.dev/badge/skills/falcoschaefer99-eng/michael-security-agent/security-audit.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,041 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 5.1 $0.00000 $0.03041
Opus 5 $0.00000 $0.01520
Sonnet 5 $0.00000 $0.00608
Haiku 4.5 $0.00000 $0.00304

Measured 6d ago against content hash 159176c21c4e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

security-audit 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 6d 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.

Sends data to an external URLlowData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

curl -H "Authorization: Bearer $KEY" -d "$(python3 -c 'print("x"*2000000)')" "$URL/endpoint"

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.

5. Test with curl where endpoints are accessible
skills/security-audit/SKILL.md · 249 lines

How it starts

The opening of the file, as written. The whole thing — 249 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security Audit

Invoked via /security-audit, /michael, or when your orchestrator dispatches for security review.

Operating Modes

Quick Audit (deploy gate, ~5 min)

Use before deploys or for rapid pass/fail assessment.

  1. Grep for dangerous patterns (hardcoded secrets, innerHTML, eval, raw SQL)
  2. Check auth on all new/changed endpoints
  3. Verify input validation on new user inputs
  4. Scan for new dependencies with known vulnerabilities
  5. Verdict: PASS, PASS WITH NOTES, or BLOCK

Deep Review (threat model, ~30 min)

Use after feature sprints or when new trust boundaries are introduced.

  1. Map all entry points and data flows
  2. Identify trust boundaries (client/server, server/database, service/service)
  3. STRIDE threat analysis on each boundary
  4. Run full 10-category checklist below
  5. Test with curl where endpoints are accessible
  6. Dependency/supply chain review on new packages
  7. Full findings report with threat model summary

Incident Response

Use when a breach is suspected or a relevant CVE is disclosed. See ~/.claude/agents/references/security-intel.md incident response playbook.


10-Category Audit Checklist

1. Path Traversal & File Access [OWASP A01] [NIST PR.AC, PR.DS]

  • Every handler accepting path/file/territory/namespace params validates input
  • Check for ../, null bytes (%00), URL-encoded traversal (%2e%2e%2f)
  • Paths/keys resolve within expected boundaries (allowlist, not blocklist)
  • Validation on BOTH read AND write operations
  • R2 object keys constructed from user input are validated (key traversal)

2. Authentication & Authorization [OWASP A01, A07] [NIST PR.AC, PR.AA]

  • Every endpoint requires auth (no accidentally public routes)
  • Auth comparison is timing-safe (crypto.timingSafeEqual, crypto.subtle.verify, or equivalent)
  • API keys in Authorization: Bearer header, never in URL parameters
  • Tokens not logged or included in error responses
  • Trust boundary mapping: who authenticates at each boundary?
  • JWT: alg header validated, expected algorithm enforced
  • OAuth: redirect_uri hardcoded, state parameter present, PKCE recommended
  • Role/tier values validated against allowlist at write boundary (never accept from client)
  • WebSocket: auth on connection, not just first message
  • IDOR prevention: verify resource ownership, not just authentication

Read the full file on GitHub · 249 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. 6d ago First seen · 249 lines · 0 tokens per session scan A 159176c21c4e

Subscribe to this mod's changes

security-audit is a skill published in the GitHub repository falcoschaefer99-eng/michael-security-agent (10 stars, last pushed 3mo ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 3,041 tokens. A static security scan graded it A with 2 findings (sends data to an external url, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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