testing-for-xss-vulnerabilities

testing-for-xss-vulnerabilities is a skill for Claude Code from balsm-health/Balsm-AI. It costs 105 tokens per session (2,696 once invoked), scanned A, original, no licence file.

A web security test for cross-site scripting (XSS), where injected JavaScript runs in a user's browser through reflected, stored, or DOM-based input.

In plain words
What is it for?
Use it during authorized application assessments to find injection points, test browser output, and demonstrate client-side code execution.
Why use it?
It helps identify places where attackers could affect users, steal sessions, or act as another user.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the balsm-ai plugin — 66 skills, 1 command, 1 agent, 2 hooks, 3 MCP servers shipped together

Good fit Use it during authorized application assessments to find injection points, test browser output, and demonstrate client-side code execution.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/balsm-health/balsm-ai/testing-for-xss-vulnerabilities
Install

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.

Any agent
npx skills add balsm-health/Balsm-AI --skill testing-for-xss-vulnerabilities
Clone the repo
git clone --depth 1 https://github.com/balsm-health/Balsm-AI

Made for: Claude Code.

Or install balsm-ai, the plugin that ships this one along with the rest of its 66 skills, 1 command, 1 agent, 2 hooks, 3 MCP servers.

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 testing-for-xss-vulnerabilities

README.md
[![agentmods](https://agentmods.dev/badge/skills/balsm-health/balsm-ai/testing-for-xss-vulnerabilities/github.svg)](https://agentmods.dev/skills/balsm-health/balsm-ai/testing-for-xss-vulnerabilities)
Your own site
<a href="https://agentmods.dev/skills/balsm-health/balsm-ai/testing-for-xss-vulnerabilities"><img src="https://agentmods.dev/badge/skills/balsm-health/balsm-ai/testing-for-xss-vulnerabilities/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 testing-for-xss-vulnerabilities

Your own site · 80×15
<a href="https://agentmods.dev/skills/balsm-health/balsm-ai/testing-for-xss-vulnerabilities"><img src="https://agentmods.dev/badge/skills/balsm-health/balsm-ai/testing-for-xss-vulnerabilities.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,696 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.
Origin unknown 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 $0.00105 $0.02696
Opus 5 $0.00053 $0.01348
Sonnet 5 $0.00021 $0.00539
Haiku 4.5 $0.00011 $0.00270

Measured 9d ago against content hash 0bcc31f06c88, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

testing-for-xss-vulnerabilities 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/agent.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

plugin/skills/testing-for-xss-vulnerabilities/SKILL.md · 206 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

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.

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. 9d ago First seen · 206 lines · 105 tokens per session scan A 0bcc31f06c88

Subscribe to this mod's changes

testing-for-xss-vulnerabilities is a skill published in the GitHub repository balsm-health/Balsm-AI (2 stars, last pushed 1mo ago), with no licence file. It adds 105 tokens to every session and 2,696 once invoked, about $0.0005 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 2026-09-03.

Related

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testing-for-xss-vulnerabilities

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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.

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testing-for-xss-vulnerabilities-with-burpsuite

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