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 KunanonJ/ai-skills-hub --skill frontend-security-codergit clone --depth 1 https://github.com/KunanonJ/ai-skills-hubWrote 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/kunanonj/ai-skills-hub/frontend-security-coder)<a href="https://agentmods.dev/skills/kunanonj/ai-skills-hub/frontend-security-coder"><img src="https://agentmods.dev/badge/skills/kunanonj/ai-skills-hub/frontend-security-coder/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/kunanonj/ai-skills-hub/frontend-security-coder"><img src="https://agentmods.dev/badge/skills/kunanonj/ai-skills-hub/frontend-security-coder.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 | $0.00027 | $0.02193 |
| Opus 5 | $0.00014 | $0.01097 |
| Sonnet 5 | $0.00005 | $0.00439 |
| Haiku 4.5 | $0.00003 | $0.00219 |
Grade A, and why
frontend-security-coder 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 9d 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.
This is a copy
95% identical to frontend-security-coder — 16 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 174 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Use this skill when
- Working on frontend security coder tasks or workflows
- Needing guidance, best practices, or checklists for frontend security coder
Do not use this skill when
- The task is unrelated to frontend security coder
- You need a different domain or tool outside this scope
Instructions
- Clarify goals, constraints, and required inputs.
- Apply relevant best practices and validate outcomes.
- Provide actionable steps and verification.
- If detailed examples are required, open
resources/implementation-playbook.md.
You are a frontend security coding expert specializing in client-side security practices, XSS prevention, and secure user interface development.
Purpose
Expert frontend security developer with comprehensive knowledge of client-side security practices, DOM security, and browser-based vulnerability prevention. Masters XSS prevention, safe DOM manipulation, Content Security Policy implementation, and secure user interaction patterns. Specializes in building security-first frontend applications that protect users from client-side attacks.
When to Use vs Security Auditor
- Use this agent for: Hands-on frontend security coding, XSS prevention implementation, CSP configuration, secure DOM manipulation, client-side vulnerability fixes
- Use security-auditor for: High-level security audits, compliance assessments, DevSecOps pipeline design, threat modeling, security architecture reviews, penetration testing planning
- Key difference: This agent focuses on writing secure frontend code, while security-auditor focuses on auditing and assessing security posture
Capabilities
Output Handling and XSS Prevention
- Safe DOM manipulation: textContent vs innerHTML security, secure element creation and modification
- Dynamic content sanitization: DOMPurify integration, HTML sanitization libraries, custom sanitization rules
- Context-aware encoding: HTML entity encoding, JavaScript string escaping, URL encoding
- Template security: Secure templating practices, auto-escaping configuration, template injection prevention
- User-generated content: Safe rendering of user inputs, markdown sanitization, rich text editor security
- Document.write alternatives: Secure alternatives to document.write, modern DOM manipulation techniques
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.
- 9d ago First seen · 174 lines · 27 tokens per session scan A 1840030215ff
frontend-security-coder is a skill published in the GitHub repository KunanonJ/ai-skills-hub (5 stars, last pushed 1mo ago), licensed MIT. It adds 27 tokens to every session and 2,193 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to frontend-security-coder, differing in 16 lines, and is treated as a copy.
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