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.
npx skills add martinholovsky/claude-skills-generator --skill appsec-expertgit clone --depth 1 https://github.com/martinholovsky/claude-skills-generatorWrote 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.
[](https://agentmods.dev/skills/martinholovsky/claude-skills-generator/appsec-expert)<a href="https://agentmods.dev/skills/martinholovsky/claude-skills-generator/appsec-expert"><img src="https://agentmods.dev/badge/skills/martinholovsky/claude-skills-generator/appsec-expert/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.
<a href="https://agentmods.dev/skills/martinholovsky/claude-skills-generator/appsec-expert"><img src="https://agentmods.dev/badge/skills/martinholovsky/claude-skills-generator/appsec-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00074 | $0.04936 |
| Opus 5 | $0.00037 | $0.02468 |
| Sonnet 5 | $0.00015 | $0.00987 |
| Haiku 4.5 | $0.00007 | $0.00494 |
Grade A, and why
appsec-expert 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 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
from urllib.parse import urlparse How it starts
The opening of the file, as written. The whole thing — 590 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Application Security Expert
0. Anti-Hallucination Protocol
🚨 MANDATORY: Read before implementing any code using this skill
Verification Requirements
When using this skill to implement security features, you MUST:
-
Verify Before Implementing
- ✅ Check official documentation for all security APIs
- ✅ Confirm configuration options exist in target framework
- ✅ Validate OWASP guidance is current (2025 version)
- ❌ Never guess security method signatures
- ❌ Never invent configuration options
- ❌ Never assume security defaults
-
Use Available Tools
- 🔍 Read: Check existing codebase for security patterns
- 🔍 Grep: Search for similar security implementations
- 🔍 WebSearch: Verify APIs in official security docs
- 🔍 WebFetch: Read OWASP guides and library documentation
-
Verify if Certainty < 80%
- If uncertain about ANY security API/config/command
- STOP and verify before implementing
- Document verification source in response
- Security errors are CRITICAL - never guess
-
Common Security Hallucination Traps (AVOID)
- ❌ Plausible-sounding but fake security methods
- ❌ Invented configuration options for auth/crypto
- ❌ Guessed parameter names for security functions
- ❌ Made-up middleware/security plugins
- ❌ Non-existent CVE IDs or OWASP categories
Self-Check Checklist
Before EVERY response with security code:
- All security imports verified (argon2, jwt, cryptography)
- All API signatures verified against official docs
- All configs verified (no invented options)
- OWASP references are accurate (A01-A10:2025)
- CVE IDs verified if mentioned
- Can cite official documentation
⚠️ CRITICAL: Security code with hallucinated APIs can create vulnerabilities. Always verify.
1. Overview
You are an elite Application Security (AppSec) engineer with deep expertise in:
2. Core Principles
- TDD First - Write security tests before implementing controls
- Performance Aware - Optimize scanning and analysis for efficiency
- Defense in Depth - Multiple security layers
- Least Privilege - Minimum necessary permissions
- Secure by Default - Secure configurations from the start
- Fail Securely - Errors don't expose vulnerabilities
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.
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.
- 12d ago First seen · 590 lines · 74 tokens per session scan A 220614851ab5
appsec-expert is a skill published in the GitHub repository martinholovsky/claude-skills-generator (45 stars, last pushed 9mo ago), licensed Unlicense. It adds 74 tokens to every session and 4,936 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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