api-pentest

api-pentest is a cursor rule for Cursor from GktuOktay/ai-skills. It costs 0 tokens per session (761 once invoked), scanned A, original, MIT.

A security audit guide for web APIs, which are endpoints that applications use to exchange data. It tests access control, request limits, token-based login, and injection attacks.

In plain words
What is it for?
It is for checking ownership rules, mass assignment, rate limiting, JWT authentication, and SQL or NoSQL injection defenses in API endpoints.
Why use it?
APIs can expose another user's data, accept fields that should be protected, or be overwhelmed by abusive requests. This helps identify those weaknesses before attackers do.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc).

Good fit It is for checking ownership rules, mass assignment, rate limiting, JWT authentication, and SQL or NoSQL injection defenses in API endpoints.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/gktuoktay/ai-skills/api-pentest
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/GktuOktay/ai-skills

Made for: Cursor.

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 api-pentest

README.md
[![agentmods](https://agentmods.dev/badge/rules/gktuoktay/ai-skills/api-pentest.svg)](https://agentmods.dev/rules/gktuoktay/ai-skills/api-pentest)
Your own site
<a href="https://agentmods.dev/rules/gktuoktay/ai-skills/api-pentest"><img src="https://agentmods.dev/badge/rules/gktuoktay/ai-skills/api-pentest.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 761 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 $0.00000 $0.00761
Opus 5 $0.00000 $0.00380
Sonnet 5 $0.00000 $0.00152
Haiku 4.5 $0.00000 $0.00076

Measured 4d ago against content hash 605e6a51e50a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

api-pentest 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.

agents/cursor/rules/api-pentest.mdc · 71 lines

How it starts

The opening of the file, as written. The whole thing — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Penetration Testing & Security

Overview

This skill focuses on ensuring robust API security by preventing common vulnerabilities such as those listed in the OWASP API Security Top 10. It covers Broken Object Level Authorization (BOLA), Mass Assignment, rate limiting, JWT weaknesses, and injection attacks.

Core Principles

1. Authorization and BOLA (Broken Object Level Authorization)

Ensure that users can only access data they own.

  • Always validate ownership: When an endpoint accesses a resource by ID, verify that the authenticated user is authorized to access that specific ID.
  • Use indirect references: Where possible, use non-sequential or random IDs (UUIDs) to prevent enumeration.

2. Mass Assignment

Prevent attackers from updating fields they shouldn't have access to (e.g., isAdmin, balance).

  • Explicit binding: Only allow specific properties to be bound from the request payload to the object.
  • Use DTOs (Data Transfer Objects): Map incoming requests to DTOs rather than directly to domain models.

3. Rate Limiting and DoS Prevention

Protect endpoints from abuse by implementing rate limits.

  • IP & User-based limiting: Limit requests per IP and per authenticated user.
  • Complex endpoints: Apply stricter limits to computationally expensive endpoints (e.g., login, search).

4. JWT Token Validation Weaknesses

Ensure JWTs are generated and validated securely.

  • Use strong algorithms: Enforce strong algorithms like RS256. Do not allow 'none' algorithm.
  • Validate claims: Always validate exp, iss, aud, and nbf claims.
  • Store secrets securely: Never hardcode secrets. Use key management services.

5. Input Sanitization & Injection Prevention (SQL/NoSQL)

Never trust user input.

  • Parameterized queries: Always use parameterized queries or ORMs to prevent SQL injection.
  • Sanitize NoSQL inputs: Ensure NoSQL queries do not accept objects containing operators (e.g., $gt, $ne) from user input directly.

Read the full file on GitHub · 71 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. 4d ago First seen · 71 lines · 761 tokens per session scan A 605e6a51e50a

Subscribe to this mod's changes

api-pentest is a cursor rule published in the GitHub repository GktuOktay/ai-skills (2 stars, last pushed 4d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 761 tokens. 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.