codebase-security-audit

codebase-security-audit is a skill for Claude Code, Codex from d-padmanabhan/agent-engineering-handbook. It costs 172 tokens per session (6,181 once invoked), scanned A, original, MIT.

A structured security review of a software codebase. It checks source code, dependencies, configuration, infrastructure, data flows, exposed secrets, and running behavior for security problems.

In plain words
What is it for?
Use it to audit a repository, scan dependencies and infrastructure, check for committed secrets, investigate security incidents, or add security checks to CI/CD.
Why use it?
It helps find vulnerabilities and leaked credentials before they are abused, then organizes the findings by severity and suggested remediation.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

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/d-padmanabhan/agent-engineering-handbook/codebase-security-audit
Any agent
npx skills add d-padmanabhan/agent-engineering-handbook --skill codebase-security-audit
Clone the repo
git clone --depth 1 https://github.com/d-padmanabhan/agent-engineering-handbook

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 codebase-security-audit

README.md
[![agentmods](https://agentmods.dev/badge/skills/d-padmanabhan/agent-engineering-handbook/codebase-security-audit.svg)](https://agentmods.dev/skills/d-padmanabhan/agent-engineering-handbook/codebase-security-audit)
Your own site
<a href="https://agentmods.dev/skills/d-padmanabhan/agent-engineering-handbook/codebase-security-audit"><img src="https://agentmods.dev/badge/skills/d-padmanabhan/agent-engineering-handbook/codebase-security-audit.svg" alt="Measured on agentmods" height="20"></a>
Per session 172 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,181 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 5.1 $0.00172 $0.06181
Opus 5 $0.00086 $0.03090
Sonnet 5 $0.00034 $0.01236
Haiku 4.5 $0.00017 $0.00618

Measured 2d ago against content hash 2747c94ba0f5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

codebase-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 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/codebase-security-audit/SKILL.md · 570 lines

How it starts

The opening of the file, as written. The whole thing — 570 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codebase Security Audit & Remediation

A systematic, multi-layer security review with actionable fixes. Combines static (SAST), composition (SCA), secrets, data-flow / taint, semantic / CPG, infrastructure (IaC), custom rules, and dynamic (DAST) checks - and wires the results into CI/CD for continuous coverage.

Companion rules:

  • 310-security.mdc - principles + OWASP Top 10 + NHI Top 10
  • 316-zero-trust.mdc - Zero Trust principles (always-on)
  • 160-github-actions.mdc - secure CI workflow patterns

When to invoke

Use when the user asks to:

  • "Security audit" / "harden this repo" / "check for vulnerabilities"
  • "Find committed secrets" / "scan for credentials"
  • "OWASP audit" / "Top 10 review"
  • "SAST scan" / "SCA / dependency audit" / "IaC audit" / "DAST validation"
  • "Set up continuous security scanning"
  • Open / re-open a security incident triage on a codebase

Tooling Stack - Eight Practical Layers

Map every audit to these eight layers so coverage is explicit and gaps are visible.

# Layer Purpose Recommended Tools
1 Secrets scanning Find exposed credentials in code & git history (regex + entropy) gitleaks, trufflehog, detect-secrets, ggshield, ripgrep regex
2 SAST (static) Code-level vulns - injection, crypto, access control semgrep, codeql, bandit (Python), gosec (Go), eslint-plugin-security (JS/TS), spotbugs + find-sec-bugs (Java), brakeman (Ruby), cppcheck / flawfinder (C/C++)
3 SCA (deps) Vulnerable / outdated / license-risky packages pip-audit, safety, npm audit, yarn audit, govulncheck, mvn dependency-check, osv-scanner, grype, trivy fs, Snyk, Dependabot / Renovate
4 Data-flow / taint Track untrusted input through code to a dangerous sink semgrep (mode: taint), CodeQL data-flow libs, Pysa (Python)
5 Semantic / CPG Behavior-aware deep analysis - privilege escalation, auth bypass CodeQL (full DB build), Joern
6 IaC scanning Misconfig in Terraform / K8s / cloud / Dockerfiles checkov, tfsec, terrascan, kube-linter, kubesec, kics, trivy config, hadolint
7 Custom rules Business-specific risks the off-the-shelf rules miss Semgrep custom rules in .semgrep/, CodeQL custom queries in .github/codeql/
8 DAST (dynamic) Validate runtime behavior on the deployed app OWASP ZAP, Nuclei, Burp Suite, sqlmap (targeted)

Read the full file on GitHub · 570 lines

Files

What ships with it

3 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 · 570 lines · 172 tokens per session scan A 2747c94ba0f5

Subscribe to this mod's changes

codebase-security-audit is a skill published in the GitHub repository d-padmanabhan/agent-engineering-handbook (16 stars, last pushed 6d ago), licensed MIT. It adds 172 tokens to every session and 6,181 once invoked, about $0.0009 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 2026-09-03.

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