modern

A set of coding rules for developing PromptScript, a language that turns standardized AI instructions into formats used by tools such as GitHub Copilot, Claude Code, and Cursor. It defines the project’s TypeScript structure, libraries, and code-style expectations.

In plain words
What is it for?
Use it when editing PromptScript’s parser, resolver, validator, compiler, formatters, command-line interface, or shared core code.
Why use it?
It gives contributors a shared way to organize and implement changes in a multi-package repository, where one project contains several related packages. This reduces inconsistent code and architectural decisions.

Cursor rule

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/mrwogu/promptscript/modern
Clone the repo
git clone --depth 1 https://github.com/mrwogu/promptscript
Per session 1,005 This file is loaded in full into every session.
When invoked 1,005 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 $0.01005 $0.01005
Opus 5 $0.00502 $0.00502
Sonnet 5 $0.00201 $0.00201
Haiku 4.5 $0.00101 $0.00101

Measured yesterday against content hash 50da8344d8c5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

modern 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 yesterday.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

  • multifile — 100% identical, 0 lines differ
packages/formatters/src/__tests__/__golden__/cursor/modern.mdc · 140 lines

How it starts

The opening of the file, as written. The whole thing — 140 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert TypeScript developer working on PromptScript - a language and toolchain for standardizing AI instructions across enterprise organizations.

PromptScript compiles .prs files to native formats for GitHub Copilot, Claude Code, Cursor, and other AI tools.

You write clean, type-safe, and well-tested code following strict TypeScript practices.

Tech stack: typescript, Node.js 20+, Nx, pnpm workspaces

Architecture

The project is organized as a monorepo with these packages:

flowchart TB
  subgraph packages
    core[core - Types, errors, utilities]
    parser[parser - Chevrotain-based parser]
    resolver[resolver - Inheritance & import resolution]
    validator[validator - AST validation rules]
    compiler[compiler - Pipeline orchestration]
    formatters[formatters - Output formatters]
    cli[cli - Command-line interface]
  end

  cli --> compiler
  compiler --> parser
  compiler --> resolver
  compiler --> validator
  compiler --> formatters
  parser --> core
  resolver --> core
  validator --> core
  formatters --> core

Key Libraries

  • Parser: Chevrotain
  • CLI: Commander.js
  • Testing: Vitest
  • Linting: ESLint + Prettier

Code style:

  • Strict mode enabled
  • Never use any type - use unknown with type guards
  • Prefer interface for object shapes
  • Use type for unions and intersections
  • Named exports only, no default exports
  • Explicit return types on public functions
  • Files: kebab-case.ts
  • Classes/Interfaces: PascalCase
  • Functions/Variables: camelCase
  • Constants: UPPER_SNAKE_CASE
  • Use custom error classes extending PSError
  • Always include location information
  • Provide actionable error messages
  • Test files: *.spec.ts next to source
  • Follow AAA (Arrange, Act, Assert) pattern
  • Target >90% coverage for libraries
  • Use fixtures for parser tests
  • Framework: vitest

Git Commits:

  • format: Conventional Commits
  • reference: https://www.conventionalcommits.org/
  • maxSubjectLength: 70
  • types: feat, fix, docs, style, refactor, test, chore
  • example: feat(parser): add support for multiline strings

Read the full file on GitHub · 140 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. yesterday First seen · 140 lines · 1,005 tokens per session scan A 50da8344d8c5

Subscribe to this mod's changes

modern is a cursor rule published in the GitHub repository mrwogu/promptscript (391 stars, last pushed 7d ago), licensed MIT. It adds 1,005 tokens to every session, about $0.0050 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.