00-project-core

A project rulebook for the Best Cursor Rules repository, a collection of configuration files that guide Cursor, an AI coding editor. It describes the repository layout, file format, purpose, and key working rules.

In plain words
What is it for?
Use it when adding or updating Cursor rule files, checking the repository structure, or deciding where a rule for a technology or practice should live.
Why use it?
It gives contributors a shared structure to follow, reducing misplaced files and incorrectly formatted rules. It also explains where rules for languages, frameworks, testing, and other areas belong.

Cursor rule for 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/renvia-code/best-cursor-rules/00-project-core
Clone the repo
git clone --depth 1 https://github.com/Renvia-code/best-cursor-rules

Made for: Cursor.

Per session 617 This file is loaded in full into every session.
When invoked 617 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00617 $0.00617
Opus 5 $0.00309 $0.00309
Sonnet 5 $0.00123 $0.00123
Haiku 4.5 $0.00062 $0.00062

Measured 2d ago against content hash 7e1988947f1d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

00-project-core 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 2d 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/00-project-core.mdc · 82 lines

How it starts

The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Best Cursor Rules - Project Core

Critical Rules

NO UNNECESSARY FILES - Don't create files outside the defined structure.

FOLLOW MDC FORMAT - All rules must use proper frontmatter (see 01-rule-format.mdc).

Current Date: December 2025


Overview

Purpose: Comprehensive collection of Cursor AI rules for developers Format: MDC files with frontmatter metadata License: CC0 (Public Domain) Maintainer: Renvia Technologies (community-focused)


Project Structure

best-cursor-rules/
├── .github/assets/        # Logos for README (not for users)
├── .cursor/rules/         # THIS repo's own rules
├── rules/
│   ├── frameworks/        # Next.js, React, Vue, Svelte, etc.
│   ├── languages/         # TypeScript, Python, Go, Rust
│   ├── backends/          # Supabase, FastAPI, Node.js
│   ├── mobile/            # React Native, Flutter, SwiftUI
│   ├── styling/           # Tailwind, shadcn/ui
│   ├── testing/           # Vitest, Playwright, Jest
│   ├── best-practices/    # Clean code, security, a11y
│   └── stacks/            # Combined presets (T3, etc.)
├── SETUP-WIZARD.md        # Master prompt for users
├── README.md
├── CONTRIBUTING.md
└── LICENSE

Key Files

File Purpose
SETUP-WIZARD.md Master prompt users paste into Cursor
README.md Project documentation
CONTRIBUTING.md How to add/edit rules
rules/**/*.mdc Individual cursor rules

Naming Conventions

Rule Files

  • Use lowercase with hyphens: nextjs-15.mdc, react-native.mdc
  • Include version only for major versions: nextjs-15.mdc not nextjs-15.1.0.mdc
  • Keep names short but clear

Directories

  • Lowercase, plural: frameworks/, backends/
  • No version numbers in directories

Core Principles

  1. Quality over Quantity - Each rule should be well-tested and useful
  2. Current Versions - Rules should target 2025 framework versions
  3. Practical Examples - Include real code examples, not just theory
  4. User-Friendly - Rules should help, not overwhelm
  5. No AI Slop - Write like a human, avoid corporate/AI clichés

Read the full file on GitHub · 82 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. 2d ago First seen · 82 lines · 617 tokens per session scan A 7e1988947f1d

Subscribe to this mod's changes

00-project-core is a cursor rule published in the GitHub repository Renvia-code/best-cursor-rules (12 stars, last pushed 9mo ago), licensed CC0-1.0. It adds 617 tokens to every session, about $0.0031 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 2026-08-30.