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 withcrux/agentHack-skills --skill detecting-xss-vulnerabilities-in-web-appsgit clone --depth 1 https://github.com/withcrux/agentHack-skillsWrote 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/withcrux/agenthack-skills/detecting-xss-vulnerabilities-in-web-apps)<a href="https://agentmods.dev/skills/withcrux/agenthack-skills/detecting-xss-vulnerabilities-in-web-apps"><img src="https://agentmods.dev/badge/skills/withcrux/agenthack-skills/detecting-xss-vulnerabilities-in-web-apps/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/withcrux/agenthack-skills/detecting-xss-vulnerabilities-in-web-apps"><img src="https://agentmods.dev/badge/skills/withcrux/agenthack-skills/detecting-xss-vulnerabilities-in-web-apps.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 | $0.00057 | $0.01804 |
| Opus 5 | $0.00028 | $0.00902 |
| Sonnet 5 | $0.00011 | $0.00361 |
| Haiku 4.5 | $0.00006 | $0.00180 |
Grade A, and why
detecting-xss-vulnerabilities-in-web-apps 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 11d 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.
curl -I http://localhost:8081/ | grep -i "content-security-policy" The source is not reproduced here
A licence we could not identify
The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.
What ships with it
1 file 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.
- 11d ago First seen · 209 lines · 57 tokens per session scan A 49ae9f67efb6
detecting-xss-vulnerabilities-in-web-apps is a skill published in the GitHub repository withcrux/agentHack-skills (5 stars, last pushed 5mo ago), with no licence file. It adds 57 tokens to every session and 1,804 once invoked, about $0.0003 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 2026-08-31.
Other skills, from other repositories
testing-for-xss-vulnerabilities
Tests web applications for Cross-Site Scripting (XSS) vulnerabilities by injecting JavaScript payloads into reflected, stored, and DOM-based contexts to demonstrate client-side code execution, session hijacking, and user impersonation. The tester identifies all injection points and output contexts, crafts…
Web Application Security Testing
OWASP Top 10 testing, injection vulnerability detection, API security assessment, authentication testing, and web vulnerability reporting for authorized assessments.
dom-based-cross-site-scripting-xss
Identify and exploit DOM-based Cross-Site Scripting (XSS) vulnerabilities where malicious payloads are executed entirely within the victim's browser via insecure JavaScript execution, often bypassing server-side WAFs completely.
javascript-prototype-pollution
Identify and exploit Prototype Pollution vulnerabilities in JavaScript applications to achieve client-side Cross-Site Scripting (XSS), bypass authentication, or execute Remote Code Execution (RCE) on Node.js servers by manipulating the core Object prototype.
dom-based-xss
Exploit Document Object Model (DOM) Based Cross-Site Scripting (XSS) vulnerabilities. Unlike Reflected or Stored XSS, the attack payload is executed purely on the client-side as a result of modifying the DOM environment, often without the payload ever reaching the backend server.
CSP Security Testing
Content Security Policy testing and validation to prevent XSS attacks, data injection, and clickjacking through proper CSP header configuration.