security

security is a skill for Claude Code, Codex from davidmatousek/tachi. It costs 165 tokens per session (8,338 once invoked), scanned A, original, Apache-2.0.

A security scan for source code and dependency files that looks for common application vulnerabilities and known CVEs, which are publicly recorded software flaws. SAST means analyzing source code, while SCA means checking dependencies.

In plain words
What is it for?
Use it to scan feature-branch changes, write a security audit report, and identify OWASP Top 10 issues or vulnerable dependencies.
Why use it?
It helps find security problems in changed code before they reach production and can stop the workflow when serious findings need action.

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

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

README.md
[![agentmods](https://agentmods.dev/badge/skills/davidmatousek/tachi/security.svg)](https://agentmods.dev/skills/davidmatousek/tachi/security)
Your own site
<a href="https://agentmods.dev/skills/davidmatousek/tachi/security"><img src="https://agentmods.dev/badge/skills/davidmatousek/tachi/security.svg" alt="Measured on agentmods" height="20"></a>
Per session 165 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 8,338 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00165 $0.08338
Opus 5 $0.00082 $0.04169
Sonnet 5 $0.00033 $0.01668
Haiku 4.5 $0.00016 $0.00834

Measured 3d ago against content hash c4e86f44ad04, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

security scanned grade A with 1 finding 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.

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.

Runs shell commandslowCapability

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

- Command Injection: `os.system(var)`, `subprocess.call(f"cmd {var}")`, `exec(user_input)`
Origin

Copies of this mod

1 near-identical copy found in the catalogue:

  • security — 100% identical, 0 lines differ
.claude/skills/security/SKILL.md · 818 lines

How it starts

The opening of the file, as written. The whole thing — 818 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/security — SAST/SCA Security Scan

Purpose: Analyze code files and dependency manifests changed on the feature branch for OWASP Top 10 vulnerabilities and known CVE patterns. Write permanent audit artifacts. Block on CRITICAL/HIGH findings until acknowledged or fixed.

When invoked from /aod.build: Called as the Security Scan step (Step 7) via the Skill tool. --no-security flag in /aod.build bypasses this skill entirely.

When invoked standalone: Run directly as /security from any project directory. security-scan.md is written to specs/{NNN}-*/ if inside an AOD project, or to the current working directory otherwise.


Step 0: Parse Arguments

If invoked standalone, parse optional flags from arguments:

  1. --no-security: If present (standalone invocation context), output "Security scan skipped (--no-security)" and exit cleanly. This flag is normally handled by /aod.build Step 0 before invoking this skill; if present here in standalone mode, honor it.

  2. Feature number extraction: Detect current feature number from branch name (git branch --show-current → extract leading digits) or from specs/*/ directory listing. Used for output path resolution.

  3. Output path resolution:

    • If inside an AOD project (specs/{NNN}-*/ exists): write security-scan.md to specs/{NNN}-*/security-scan.md
    • Otherwise: write security-scan.md to current working directory

Step 1: File Detection

Detect all files changed on the feature branch relative to main.

1a: SAST File Detection (FR-004)

Run: git diff --name-only main...HEAD

Filter the output to code files by including only these extensions: .py .js .ts .jsx .tsx .sh .go .rs .java .rb .swift .kt .php .cs .cpp .c .h

Exclude these patterns from the result:

  • Generated files: *.lock, *.min.js, *.min.css, *.map, *.generated.*
  • Directories: vendor/, dist/, build/, node_modules/, .aod/, docs/

Store result as code_files list. Count as code_file_count.

Read the full file on GitHub · 818 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. 3d ago First seen · 818 lines · 165 tokens per session scan A c4e86f44ad04

Subscribe to this mod's changes

security is a skill published in the GitHub repository davidmatousek/tachi (90 stars, last pushed 21d ago), licensed Apache-2.0. It adds 165 tokens to every session and 8,338 once invoked, about $0.0008 per session on Opus 5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.