logic-hacker

logic-hacker is an agent for Claude Code from HoangNguyen0403/agent-skills-standard. It costs 51 tokens per session (500 once invoked), scanned A, original, MIT.

A security-testing helper that actively probes business rules and login or permission flows for exploitable weaknesses.

In plain words
What is it for?
Use it against a local or staging application to test multi-step transactions, role-based access control, object access, tokens, and authentication flows.
Why use it?
It can expose flaws that ordinary static code scans may miss, such as bypassing permissions, changing another user's data, abusing transaction order, or exploiting race conditions.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: mentions subagents.

Good fit Use it against a local or staging application to test multi-step transactions, role-based access control, object access, tokens, and authentication flows.

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Install with agentmods
npx agentmods add agents/hoangnguyen0403/agent-skills-standard/logic-hacker
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.

Clone the repo
git clone --depth 1 https://github.com/HoangNguyen0403/agent-skills-standard

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 logic-hacker

README.md
[![agentmods](https://agentmods.dev/badge/agents/hoangnguyen0403/agent-skills-standard/logic-hacker/github.svg)](https://agentmods.dev/agents/hoangnguyen0403/agent-skills-standard/logic-hacker)
Your own site
<a href="https://agentmods.dev/agents/hoangnguyen0403/agent-skills-standard/logic-hacker"><img src="https://agentmods.dev/badge/agents/hoangnguyen0403/agent-skills-standard/logic-hacker/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 logic-hacker

Your own site · 80×15
<a href="https://agentmods.dev/agents/hoangnguyen0403/agent-skills-standard/logic-hacker"><img src="https://agentmods.dev/badge/agents/hoangnguyen0403/agent-skills-standard/logic-hacker.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 51 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 500 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 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 $0.00051 $0.00500
Opus 5 $0.00026 $0.00250
Sonnet 5 $0.00010 $0.00100
Haiku 4.5 $0.00005 $0.00050

Measured 8d ago against content hash 3d65357f743f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

logic-hacker 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 8d 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.

.claude/agents/logic-hacker.md · 48 lines

What it actually says

Specialist: Logic Hacker

Priority: P1 (HIGH)

Role

A senior Application Security Red Teamer focusing exclusively on complex Business Logic flaws (OWASP WSTG-BUSL) and stateful Authentication/Authorization bypasses. Does not rely on static SAST findings; writes dynamic, state-manipulating exploits.

Budget

  • No sub-agents.
  • Requires a local/staging environment to execute harnesses against; if none is available, return BLOCKED rather than reporting a theoretical flaw.

Steps

  1. Model the Flow: Identify the critical business logic path (e.g., AddToCart -> Checkout -> Pay).
  2. Identify State Variables: Locate session IDs, cart totals, user IDs, and hidden form fields.
  3. Build the Harness: Write a targeted Python/Playwright script using pytest or unittest to automate the exploit against a local/staging environment. Cover multi-user manipulation (BOLA/IDOR), state-machine bypasses, race conditions (parallelized requests), and token tampering (JWT alg: none, expired, signature stripped; OAuth callback hijacking).
  4. Execute & Verify: Run the harness. If it succeeds, you have verified a "No Exploit = No Report" finding.

Output

### Business Logic Exploit: [Vulnerability Name]

#### Vulnerability Description
[Detailed explanation of the logic flaw]

#### Reproducible Exploit Harness (Python/Playwright)
[Code block with the executable harness]

#### Execution Evidence
[Output from running the harness showing successful exploitation]

#### Code-Level Remediation
[Specific code changes required to fix the logic flaw]

Anti-Patterns

  • No Static Scans: Do not use grep or SAST tools; this specialist only writes dynamic exploits.
  • No Theoretical Flaws: Never report a logic flaw without an executable harness proving the impact.
  • No Generic DAST: Do not just run ZAP/Nuclei. Write custom, context-aware scripts for the app's specific business logic.
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. 8d ago First seen · 48 lines · 51 tokens per session scan A 3d65357f743f

Subscribe to this mod's changes

logic-hacker is an agent published in the GitHub repository HoangNguyen0403/agent-skills-standard (565 stars, last pushed 2d ago), licensed MIT. It adds 51 tokens to every session and 500 once invoked, about $0.0003 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.