web-app-logic

web-app-logic is a skill for Claude Code from transilienceai/communitytools. It costs 29 tokens per session (319 once invoked), scanned A, original, MIT.

A security testing guide for finding application-specific flaws that ordinary automated scanners may miss, such as broken workflows, race conditions, and access-control mistakes.

In plain words
What is it for?
Use it to examine business rules, test workflow bypasses and race conditions, verify permissions, and investigate cache or information-disclosure problems.
Why use it?
It tests whether an application behaves safely in unusual states, parallel requests, and different user roles.

Skill for Claude Code

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

Part of the communitytools plugin — 48 skills, 5 commands, 9 agents, 1 hook shipped together

Good fit Use it to examine business rules, test workflow bypasses and race conditions, verify permissions, and investigate cache or information-disclosure problems.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/transilienceai/communitytools/web-app-logic
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 transilienceai/communitytools --skill web-app-logic
Clone the repo
git clone --depth 1 https://github.com/transilienceai/communitytools

Made for: Claude Code.

Or install communitytools, the plugin that ships this one along with the rest of its 48 skills, 5 commands, 9 agents, 1 hook.

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 web-app-logic

README.md
[![agentmods](https://agentmods.dev/badge/skills/transilienceai/communitytools/web-app-logic.svg)](https://agentmods.dev/skills/transilienceai/communitytools/web-app-logic)
Your own site
<a href="https://agentmods.dev/skills/transilienceai/communitytools/web-app-logic"><img src="https://agentmods.dev/badge/skills/transilienceai/communitytools/web-app-logic.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 319 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00029 $0.00319
Opus 5 $0.00015 $0.00160
Sonnet 5 $0.00006 $0.00064
Haiku 4.5 $0.00003 $0.00032

Measured 4d ago against content hash a8226409ec15, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

web-app-logic 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 4d 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.

skills/web-app-logic/SKILL.md · 37 lines

What it actually says

Web Application Logic

Test for logic flaws and application-specific vulnerabilities that automated scanners miss.

Techniques

Type Key Vectors
Business Logic Workflow bypass, price manipulation, feature abuse
Race Conditions TOCTOU, limit bypass, double-spend, parallel requests
Access Control IDOR, horizontal/vertical privilege escalation, forced browsing
Cache Poisoning Unkeyed headers/parameters, fat GET, response splitting
Cache Deception Path confusion, static extension tricks, normalization
Info Disclosure Error messages, debug endpoints, source code, metadata

Workflow

  1. Map application workflows and business rules
  2. Identify state-dependent operations and trust boundaries
  3. Test logic assumptions with edge cases and race conditions
  4. Verify access control across user roles
  5. Document impact with PoC demonstrations

Reference

  • reference/business-logic*.md - Business logic testing techniques
  • reference/race-conditions*.md - Race condition exploitation
  • reference/access-control*.md - Access control bypass methods
  • reference/web-cache-poisoning*.md - Cache poisoning techniques
  • reference/web-cache-deception*.md - Cache deception attacks
  • reference/information-disclosure*.md - Information disclosure testing
Files

What ships with it

55 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. 4d ago First seen · 37 lines · 29 tokens per session scan A a8226409ec15

Subscribe to this mod's changes

web-app-logic is a skill published in the GitHub repository transilienceai/communitytools (511 stars, last pushed 1mo ago), licensed MIT. It adds 29 tokens to every session and 319 once invoked, about $0.0001 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.

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