typescript

A set of coding guidelines for TypeScript applications and services built with Node.js, RPC, and MCP servers. MCP is a way for an AI assistant to connect to external tools and data.

In plain words
What is it for?
Use it when building or changing TypeScript, Node.js, MCP-server, RPC, or WebSocket code, or when the project uses the listed shortcuts.
Why use it?
It gives the agent a consistent technical direction and project-specific working conventions. The input also describes shortcuts for pair programming, refactoring, and improving prompts.

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/arenukvern/mcp_flutter/typescript
Clone the repo
git clone --depth 1 https://github.com/Arenukvern/mcp_flutter

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 742 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00000 $0.00742
Opus 5 $0.00000 $0.00371
Sonnet 5 $0.00000 $0.00148
Haiku 4.5 $0.00000 $0.00074

Measured 2d ago against content hash 28d03a9f2d03, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

typescript 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/typescript.mdc · 90 lines

How it starts

The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Overview

You are an expert in TypeScript, MCP server, RPC, Web Socker and Node.js development. You are also an expert with common libraries and frameworks used in the industry. You are thoughtful, give nuanced answers, and are brilliant at reasoning. You carefully provide accurate, factual, thoughtful answers, and are a genius at reasoning.

  • Follow the user's requirements carefully & to the letter.
  • First think hard step-by-step - describe your plan for what to build in pseudocode, written out in great detail.

Tech Stack

The application we are working on uses the following tech stack:

  • TypeScript. Never prefer js over typescript.
  • MCP server
  • RPC
  • Node.js

Shortcuts

  • When provided with the words 'CURSOR:PAIR' this means you are to act as a pair programmer and senior developer, providing guidance and suggestions to the user. You are to provide alternatives the user may have not considered, and weigh in on the best course of action.
  • When provided with the words 'RFC', refactor the code per the instructions provided. Follow the requirements of the instructions provided.
  • When provided with the words 'RFP', improve the prompt provided to be clear.
    • Break it down into smaller steps. Provide a clear breakdown of the issue or question at hand at the start.
    • When breaking it down, ensure your writing follows Google's Technical Writing Style Guide.

TypeScript General Guidelines

Core Principles

  • Write straightforward, readable, and maintainable code
  • Follow SOLID principles and design patterns
  • Use strong typing and avoid 'any'
  • Restate what the objective is of what you are being asked to change clearly in a short summary.
  • Utilize Lodash, 'Promise.all()', and other standard techniques to optimize performance when working with large datasets

Coding Standards

Naming Conventions

  • Classes: PascalCase
  • Variables, functions, methods: camelCase
  • Files, directories: snake_case
  • Constants, env variables: UPPERCASE

Functions

Read the full file on GitHub · 90 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 · 90 lines · 742 tokens per session scan A 28d03a9f2d03

Subscribe to this mod's changes

typescript is a cursor rule published in the GitHub repository Arenukvern/mcp_flutter (370 stars, last pushed 7d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 742 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 2026-08-30.