sdd-mcp: Skill for Claude Code

.claude/skills/sdd-security-check/SKILL.md

sdd-security-check is a skill for Claude Code from yi-john-huang/sdd-mcp. It costs 46 tokens per session (1,092 once invoked), scanned A, original, MIT.

A security audit guide based on the OWASP Top 10, a widely used list of common web-application security risks.

In plain words
What is it for?
Use it to review a file or code scope for authentication, authorization, data exposure, injection, and other common security problems.
Why use it?
It helps find issues such as missing access controls, exposed secrets, weak encryption, and injection vulnerabilities before release.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is yi-john-huang/sdd-mcp's own configuration. It tells Claude Code how to work on sdd-mcp itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything sdd-mcp configures →

Part of the sdd-mcp plugin — 11 skills, 6 agents shipped together

Reuse

Borrowing it

Nothing to install: this file belongs to yi-john-huang/sdd-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/yi-john-huang/sdd-mcp/master/.claude/skills/sdd-security-check/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/yi-john-huang/sdd-mcp

Made for: Claude Code.

Or install sdd-mcp, the plugin that ships this one along with the rest of its 11 skills, 6 agents.

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 sdd-security-check

README.md
[![agentmods](https://agentmods.dev/badge/skills/yi-john-huang/sdd-mcp/sdd-security-check/github.svg)](https://agentmods.dev/skills/yi-john-huang/sdd-mcp/sdd-security-check)
Your own site
<a href="https://agentmods.dev/skills/yi-john-huang/sdd-mcp/sdd-security-check"><img src="https://agentmods.dev/badge/skills/yi-john-huang/sdd-mcp/sdd-security-check/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for sdd-security-check

Your own site · 80×15
<a href="https://agentmods.dev/skills/yi-john-huang/sdd-mcp/sdd-security-check"><img src="https://agentmods.dev/badge/skills/yi-john-huang/sdd-mcp/sdd-security-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,092 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 91
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
  • medium MCP Rug Pull · line 130
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 133
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
How audits are shown
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 $0.00046 $0.01092
Opus 5 $0.00023 $0.00546
Sonnet 5 $0.00009 $0.00218
Haiku 4.5 $0.00005 $0.00109

Measured 12d ago against content hash e4ae4c305c2f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

sdd-security-check 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 12d 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.

.claude/skills/sdd-security-check/SKILL.md · 194 lines

How it starts

The opening of the file, as written. The whole thing — 194 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SDD Security Check

Perform comprehensive security audits aligned with OWASP Top 10 and security best practices. Identify vulnerabilities before they reach production.

Security Philosophy

Security is not a feature—it's a requirement. Every code change should be reviewed through a security lens.

OWASP Top 10 Checks (2021)

A01: Broken Access Control

Check for:

  • Missing authorization checks on endpoints
  • Insecure Direct Object References (IDOR)
  • Missing function-level access control
  • CORS misconfiguration
  • JWT validation bypass

Pattern: Ensure every endpoint has explicit authorization checks.

A02: Cryptographic Failures

Check for:

  • Sensitive data transmitted without TLS
  • Weak or deprecated algorithms (MD5, SHA1, DES)
  • Hardcoded secrets or API keys
  • Insufficient key length
  • Missing encryption at rest

Pattern: Use strong algorithms (bcrypt for passwords, AES-256 for data).

A03: Injection

Check for:

  • SQL injection (use parameterized queries)
  • NoSQL injection (validate/sanitize inputs)
  • Command injection (use execFile with array args, not string interpolation)
  • LDAP injection
  • Template injection

Pattern: Never interpolate user input into queries or commands.

A04: Insecure Design

Check for:

  • Missing rate limiting
  • No brute force protection
  • Predictable resource IDs
  • Missing threat modeling

A05: Security Misconfiguration

Check for:

  • Debug mode in production
  • Default credentials
  • Unnecessary features enabled
  • Missing security headers
  • Verbose error messages in production

Required Headers: CSP, X-Frame-Options, X-Content-Type-Options, HSTS

A06: Vulnerable Components

  • Check dependencies with npm audit
  • Review for known CVEs
  • Verify component versions

A07: Authentication Failures

Check for:

  • Weak password requirements
  • Missing MFA where required
  • Session fixation vulnerabilities
  • Credential stuffing exposure
  • Insecure password recovery

Session Config: secure=true, httpOnly=true, sameSite='strict'

Read the full file on GitHub · 194 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. 12d ago First seen · 194 lines · 46 tokens per session scan A e4ae4c305c2f

Subscribe to this mod's changes

sdd-security-check is a skill published in the GitHub repository yi-john-huang/sdd-mcp (52 stars, last pushed 1mo ago), licensed MIT. It adds 46 tokens to every session and 1,092 once invoked, about $0.0002 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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