testing-application-security

testing-application-security is a skill for Claude Code from jaktestowac/awesome-copilot-for-testers. It costs 91 tokens per session (2,442 once invoked), scanned A, original, MIT.

A structured way to test whether an application protects authenticated features, data, and actions from the wrong users or roles. It focuses on tester-level security checks, not unauthorized penetration testing.

In plain words
What is it for?
Checking role permissions, tenant boundaries, login and session behaviour, input validation, injection risks, and access to protected API endpoints. It helps document security findings safely.
Why use it?
It finds access-control and authentication problems that normal tests may miss, such as hidden API endpoints or one user accessing another user's data. It also requires authorization before testing begins.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

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.

agentmods
npx agentmods add skills/jaktestowac/awesome-copilot-for-testers/testing-application-security
Any agent
npx skills add jaktestowac/awesome-copilot-for-testers --skill testing-application-security
Clone the repo
git clone --depth 1 https://github.com/jaktestowac/awesome-copilot-for-testers

Made for: Claude Code.

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-application-security

README.md
[![agentmods](https://agentmods.dev/badge/skills/jaktestowac/awesome-copilot-for-testers/testing-application-security.svg)](https://agentmods.dev/skills/jaktestowac/awesome-copilot-for-testers/testing-application-security)
Your own site
<a href="https://agentmods.dev/skills/jaktestowac/awesome-copilot-for-testers/testing-application-security"><img src="https://agentmods.dev/badge/skills/jaktestowac/awesome-copilot-for-testers/testing-application-security.svg" alt="Measured on agentmods" height="20"></a>
Per session 91 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,442 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original 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 $0.00091 $0.02442
Opus 5 $0.00046 $0.01221
Sonnet 5 $0.00018 $0.00488
Haiku 4.5 $0.00009 $0.00244

Measured 6d ago against content hash 567683ddf809, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

testing-application-security 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 6d 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.

plugins/testing-application-security/skills/testing-application-security/SKILL.md · 187 lines

How it starts

The opening of the file, as written. The whole thing — 187 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Testing Application Security

Use this skill when a feature's protection matters and the functional suite only proves the happy path works for someone who is allowed to use it.

This is security testing at a tester's depth: systematic verification that the application enforces what it claims, not penetration testing. The highest-value work here is unglamorous and rarely done: a complete authorization matrix, checked server-side, for every role against every endpoint. Broken access control is consistently the most common serious defect class in web applications, and it is found by being thorough rather than by being clever.

Everything in this skill runs after the authorization gate in Phase 0. Testing a system you are not authorized to test is not a testing activity.

When to Use

  • a feature is behind authentication or role-based permissions
  • an exploratory session surfaced something security-shaped
  • a security review needs QA-level coverage of access control
  • API endpoints exist that the UI hides but does not protect
  • a new role, permission, or tenant boundary has been added
  • personal or financial data is handled and the handling needs checking

Operating Principles

  • Authorization first, always. Written permission for this system, this environment, this scope, this window. No exception, including for your employer's own systems.
  • Observe, do not exploit. Confirm the finding with the minimum action that demonstrates it, then stop. Reading one record you should not see proves the point; enumerating the table does not add to it and does add harm.
  • The server decides. A UI that hides a button proves nothing. Every check runs against the API.
  • Systematic beats clever. A complete role-by-endpoint matrix finds more real defects than an inventive payload.
  • Never in production without explicit written approval, and never with real customer data.
  • Report findings through the security path, not the public bug tracker.
  • Depth has a limit. Beyond confirming a class of finding, hand off to a security professional rather than going further.

Read the full file on GitHub · 187 lines

Files

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.

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. 6d ago First seen · 187 lines · 91 tokens per session scan A 567683ddf809

Subscribe to this mod's changes

testing-application-security is a skill published in the GitHub repository jaktestowac/awesome-copilot-for-testers (113 stars, last pushed 10d ago), licensed MIT. It adds 91 tokens to every session and 2,442 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 2026-08-30.