typescript

typescript is a cursor rule for Cursor from adonai-labs/agent-runway. It costs 0 tokens per session (1,942 once invoked), scanned A, original, MIT.

A set of best-practice rules for writing safe, maintainable TypeScript, including strict compiler settings, type guards, generics, and common mistakes to avoid. TypeScript adds checks to JavaScript code before it runs.

In plain words
What is it for?
Use it when configuring a TypeScript project, designing types, checking untrusted values, organising imports, or reviewing TypeScript code.
Why use it?
It helps catch type-related errors earlier and keeps large TypeScript codebases easier to understand and change.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc).

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/adonai-labs/agent-runway/typescript
Clone the repo
git clone --depth 1 https://github.com/adonai-labs/agent-runway

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 typescript

README.md
[![agentmods](https://agentmods.dev/badge/rules/adonai-labs/agent-runway/typescript.svg)](https://agentmods.dev/rules/adonai-labs/agent-runway/typescript)
Your own site
<a href="https://agentmods.dev/rules/adonai-labs/agent-runway/typescript"><img src="https://agentmods.dev/badge/rules/adonai-labs/agent-runway/typescript.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 1,942 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 5.1 $0.00000 $0.01942
Opus 5 $0.00000 $0.00971
Sonnet 5 $0.00000 $0.00388
Haiku 4.5 $0.00000 $0.00194

Measured 2d ago against content hash 604bfce5d075, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, 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.

src/stacks/typescript/typescript.mdc · 194 lines

How it starts

The opening of the file, as written. The whole thing — 194 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TypeScript Best Practices

Directives for type-safe, maintainable TypeScript. Australian English spelling throughout.


Strict Configuration

Enable these compilerOptions; do not disable strict mode.

Option Purpose
strict: true Enables strict null checks, no implicit any, strict function types
noUnusedLocals Error on unused variables
noUnusedParameters Error on unused function parameters
noFallthroughCasesInSwitch Require break in switch
noUncheckedIndexedAccess Index access returns T | undefined
exactOptionalPropertyTypes Distinguish undefined from omitted optional props
noImplicitReturns All code paths must return
noImplicitOverride Require override when overriding
allowUnreachableCode: false Error on unreachable code
  • Do not use skipLibCheck: true unless necessary for legacy dependencies
  • Prefer moduleResolution: "bundler" for modern bundlers; "node16" for Node

Path Mapping

  • Use baseUrl: "." and paths for aliases (e.g. @/*, @components/*, @utils/*)
  • Prefer short, consistent aliases over long relative imports
  • For Electron: separate tsconfig.main.json and tsconfig.renderer.json with distinct include/exclude and rootDir/outDir
  • Ensure paths resolve correctly in both IDE and build; extend from a base config if shared

Utility Types

Use case Type
Partial nested object DeepPartial<T>
Require specific keys RequiredFields<T, K> or Required<Pick<T, K>>
Make specific keys optional OptionalFields<T, K> or Partial<Pick<T, K>> & Omit<T, K>
Ensure keys are non-null NonNullableFields<T, K>
Event handler (event: T) => void or Promise<void>
Async/sync function types (...args: TArgs) => Promise<TReturn> vs (...args: TArgs) => TReturn
  • Use Pick<T, K> for a subset of keys; Omit<T, K> when excluding keys
  • Use Record<K, V> for object maps; avoid { [key: string]: T } when keys are known
  • Prefer Awaited<T> over manual unwrapping of Promise<T>

Read the full file on GitHub · 194 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 · 194 lines · 0 tokens per session scan A 604bfce5d075

Subscribe to this mod's changes

typescript is a cursor rule published in the GitHub repository adonai-labs/agent-runway (2 stars, last pushed 16d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,942 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 2026-09-03.