business-logic

business-logic is a skill for Claude Code from ShulkwiSEC/bb-huge. It costs 207 tokens per session (4,671 once invoked), scanned A, original, MIT.

A guide to testing business logic, meaning the rules that control how an application behaves rather than how its code parses input. It models intended workflows and looks for ways to abuse values, permissions, timing, or state changes.

In plain words
What is it for?
Use it to assess checkout, subscriptions, banking transfers, games, ticketing, and other workflows for race conditions, workflow bypasses, trust-boundary mistakes, and incorrect assumptions.
Why use it?
It helps uncover flaws that automated scanners often miss, such as skipping required steps, reusing one-time actions, or manipulating prices and quantities.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter. Also seen: positional $N argument.

Good fit Use it to assess checkout, subscriptions, banking transfers, games, ticketing, and other workflows for race conditions, workflow bypasses, trust-boundary mistakes, and incorrect assumptions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/shulkwisec/bb-huge/business-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 ShulkwiSEC/bb-huge --skill business-logic
Clone the repo
git clone --depth 1 https://github.com/ShulkwiSEC/bb-huge

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 business-logic

README.md
[![agentmods](https://agentmods.dev/badge/skills/shulkwisec/bb-huge/business-logic/github.svg)](https://agentmods.dev/skills/shulkwisec/bb-huge/business-logic)
Your own site
<a href="https://agentmods.dev/skills/shulkwisec/bb-huge/business-logic"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/business-logic/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 business-logic

Your own site · 80×15
<a href="https://agentmods.dev/skills/shulkwisec/bb-huge/business-logic"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/business-logic.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 207 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,671 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00207 $0.04671
Opus 5 $0.00103 $0.02336
Sonnet 5 $0.00041 $0.00934
Haiku 4.5 $0.00021 $0.00467

Measured 7d ago against content hash b5d7d2db413c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

business-logic 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 7d 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.

| `kali(command=...)` | curl parallel requests (race conditions, replay), python3 analysis scripts |
skills/curated/business-logic/SKILL.md · 423 lines

How it starts

The opening of the file, as written. The whole thing — 423 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Business Logic Security Testing

You are an expert in application-level business logic security. Your goal: understand the application's intended behavior first, then systematically find every way to subvert it — abusing values, bypassing workflows, crossing trust boundaries, replaying operations, and exploiting assumptions the developers made about how users behave.

This skill is domain-agnostic. The same patterns apply to an e-commerce checkout, a SaaS subscription system, a banking transfer flow, a gaming leaderboard, a ticketing system, or a social platform.

Request: $ARGUMENTS


Tools Available

Tool Use for
session(action="start", options={...}) Define target, scope, depth, and hard limits — always call this first
session(action="complete", options={...}) Mark the scan done and write final notes
kali(command=...) curl parallel requests (race conditions, replay), python3 analysis scripts
http(action="request", ...) Raw HTTP — individual probes. Set poc=True for confirmed findings
http(action="save_poc", ...) Save a confirmed exploit as a raw .http file in pocs/
scan(tool="spider", ...) Crawl the app to discover all endpoints and flows
report(action="finding", data={...}) Log a confirmed vulnerability with evidence to findings.json
report(action="diagram", data={...}) Save a Mermaid diagram of workflows and trust boundaries
report(action="dashboard", data={"port": 7777}) Serve dashboard.html at localhost:7777
report(action="note", data={...}) Write a reasoning note or decision to the session log

Test Categories

Category OWASP What it finds
Value / Quantity Logic A04 Negative, zero, overflow, rounding on numeric fields
Workflow Bypass A04 Skipping steps, out-of-order operations, reused one-time tokens
State Machine Abuse A04 Forcing illegal state transitions
Trust Boundary / BOLA API1, A01 Horizontal/vertical access to other users' resources
BFLA API5 Calling functions intended for higher-privilege roles
Idempotency / Replay A04 Duplicate submissions, double-spend, reference reuse
Quota / Limit Bypass A04 Exceeding stated resource, rate, or usage limits
Time / Date Manipulation A04 Exploiting time-based logic (expiry, windows, promotions)
Predictability A07 Sequential IDs, guessable codes, enumerable references
Multi-Tenant Isolation A01 Tenant A accessing Tenant B's data

Read the full file on GitHub · 423 lines

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. 7d ago First seen · 423 lines · 207 tokens per session scan A b5d7d2db413c

Subscribe to this mod's changes

business-logic is a skill published in the GitHub repository ShulkwiSEC/bb-huge (22 stars, last pushed 2mo ago), licensed MIT. It adds 207 tokens to every session and 4,671 once invoked, about $0.0010 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 2026-09-03.

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