typescript

A set of rules for writing TypeScript code, including file organization, naming, types, functions, and error handling. TypeScript is JavaScript with optional checks that catch many mistakes before the code runs.

In plain words
What is it for?
Reviewing or writing TypeScript files, choosing names and types, organizing imports, documenting public functions, and handling asynchronous errors.
Why use it?
It gives contributors consistent expectations and reduces common problems such as unclear types, unhandled failures, and hard-to-follow imports.

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/arjshiv/localutils-mcp-server/typescript
Clone the repo
git clone --depth 1 https://github.com/arjshiv/localutils-mcp-server

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 339 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 $0.00339
Opus 5 $0.00000 $0.00169
Sonnet 5 $0.00000 $0.00068
Haiku 4.5 $0.00000 $0.00034

Measured yesterday against content hash bb64a2c9ecb7, 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 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.

.cursor/rules/typescript.mdc · 52 lines

What it actually says

TypeScript Coding Standards

File Organization

  • Use named exports over default exports
  • Group imports in the following order:
    1. Node built-in modules
    2. External dependencies
    3. Internal modules
  • Separate import groups with blank lines

Type Safety

  • Avoid using any type
  • Use explicit type annotations for function parameters and return types
  • Prefer interfaces over type aliases for object types
  • Use union types for values that can be one of several types

Naming Conventions

  • Use PascalCase for class names and interfaces
  • Use camelCase for variables, functions, and methods
  • Use UPPER_SNAKE_CASE for constants
  • Prefix interfaces with 'I' (e.g., ITimeService)
  • Prefix type aliases with 'T' (e.g., TTimeFormat)

Functions

  • Keep functions small and focused
  • Use arrow functions for callbacks
  • Implement proper error handling
  • Add JSDoc comments for public functions

Error Handling

  • Use custom error classes for domain-specific errors
  • Always include error messages
  • Implement proper error propagation
  • Use try-catch blocks appropriately

Async Code

  • Use async/await over raw promises
  • Handle promise rejections properly
  • Avoid nested promises
  • Use Promise.all for parallel operations

Code Style

  • Use 2 spaces for indentation
  • Maximum line length: 100 characters
  • Use semicolons
  • Use single quotes for strings
  • Add trailing commas in multiline objects/arrays
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 · 52 lines · 339 tokens per session scan A bb64a2c9ecb7

Subscribe to this mod's changes

typescript is a cursor rule published in the GitHub repository arjshiv/localutils-mcp-server (2 stars, last pushed 8mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 339 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 2026-08-31.