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 byerlikaya/claude-starter-kit --skill security-scangit clone --depth 1 https://github.com/byerlikaya/claude-starter-kitWrote 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/byerlikaya/claude-starter-kit/security-scan)<a href="https://agentmods.dev/skills/byerlikaya/claude-starter-kit/security-scan"><img src="https://agentmods.dev/badge/skills/byerlikaya/claude-starter-kit/security-scan/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/byerlikaya/claude-starter-kit/security-scan"><img src="https://agentmods.dev/badge/skills/byerlikaya/claude-starter-kit/security-scan.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 | $0.00054 | $0.01330 |
| Opus 5 | $0.00027 | $0.00665 |
| Sonnet 5 | $0.00011 | $0.00266 |
| Haiku 4.5 | $0.00005 | $0.00133 |
Grade A, and why
security-scan 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 10d 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.
How it starts
The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Security Scan
Trigger phrases: "security scan", "run a security scan", "OWASP check", "scan for vulnerabilities", "find security vulnerabilities", "security audit", "api key", "secret key", "leaked credential", "credentials leaked", "hardcoded secret", "hardcoded password", "sql injection", "can an attacker"
The core of a security vulnerability fits in a single sentence: an untrusted input reaches a dangerous operation without being adequately checked. This skill chases exactly that sentence — it first looks for where the input comes from, then where it flows, and what gate should sit in between. It is stack-agnostic: whatever the language/framework, the same logic applies; when current tooling and patterns are needed, it runs a web search.
Kit adaptation (local, .claude/):
security-expert-cskapplies this; findings are carried to review-agent-csk in severity order. It also holds for the default stack (.NET/PostgreSQL). Automatic fixes only with explicit approval (§4.4);.claudedoes not go to the repo (§4.3). §4 Prohibitions apply.
What it does, what it doesn't
- Does: surfaces common vulnerability classes, known vulnerable dependencies, and risky configuration; ties each finding to a concrete fix.
- Doesn't: does not replace a professional pentest / SAST / DAST. The report guides, it does not give full assurance — state this at the end of the report.
- Boundary: analysis is local; code/data is not sent to an external service, and the project directory is not left.
Mental model — source → gate → sink
Reduce every check to three questions:
- Source — where does the input enter? (route, API endpoint, form, CLI argument, file upload, WebSocket, queue message, external API response)
- Sink — which dangerous operation does this input reach? (SQL execution, shell, file path, HTML render, deserialization, template)
- Gate — is there validation / parameterization / escaping / authorization in between? If not, that's the finding.
What ships with it
4 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.
- 10d ago First seen · 89 lines · 54 tokens per session scan A d9b131725a23
security-scan is a skill published in the GitHub repository byerlikaya/claude-starter-kit (22 stars, last pushed today), licensed MIT. It adds 54 tokens to every session and 1,330 once invoked, about $0.0003 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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