security-fundamentals

security-fundamentals is a cursor rule for Cursor from djm204/frankenbeast. It costs 394 tokens per session, scanned A, original, no licence file.

A set of fundamental software-security rules covering zero trust, input validation, OWASP protections, and secrets management. Zero trust means checking every request rather than automatically trusting a user or system.

In plain words
What is it for?
It is for applying baseline security practices while building or reviewing software.
Why use it?
It helps prevent common security mistakes, such as accepting unsafe input or exposing passwords and keys.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

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 rules/djm204/frankenbeast/security-fundamentals
Clone the repo
git clone --depth 1 https://github.com/djm204/frankenbeast

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 security-fundamentals

README.md
[![agentmods](https://agentmods.dev/badge/rules/djm204/frankenbeast/security-fundamentals.svg)](https://agentmods.dev/rules/djm204/frankenbeast/security-fundamentals)
Your own site
<a href="https://agentmods.dev/rules/djm204/frankenbeast/security-fundamentals"><img src="https://agentmods.dev/badge/rules/djm204/frankenbeast/security-fundamentals.svg" alt="Measured on agentmods" height="20"></a>
Per session 394 This file is loaded in full into every session.
When invoked 394 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00394 $0.00394
Opus 5 $0.00197 $0.00197
Sonnet 5 $0.00079 $0.00079
Haiku 4.5 $0.00039 $0.00039

Measured 5d ago against content hash c897bf4040f0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

security-fundamentals 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 5d 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.

.cursor/rules/security-fundamentals.mdc · 42 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 5d ago First seen · 42 lines · 394 tokens per session scan A c897bf4040f0

Subscribe to this mod's changes

security-fundamentals is a cursor rule published in the GitHub repository djm204/frankenbeast (2 stars, last pushed 2d ago), with no licence file. It adds 394 tokens to every session, about $0.0020 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 2026-08-31.