development-guidelines

Development rules for a TypeScript project, covering type safety, code layout, linting, formatting, validation, and tests. Linting finds code problems, while formatting keeps code style consistent.

In plain words
What is it for?
Use them when writing or reviewing TypeScript, organising files, validating data with Zod, running ESLint or Biome, formatting code, and writing unit or browser tests.
Why use it?
They give contributors shared standards and commands for checking code quality instead of relying on personal preferences.

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/lazylagom/context-compose-mcp/development-guidelines
Clone the repo
git clone --depth 1 https://github.com/lazylagom/context-compose-mcp

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 512 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 $0.00512
Opus 5 $0.00000 $0.00256
Sonnet 5 $0.00000 $0.00102
Haiku 4.5 $0.00000 $0.00051

Measured 2d ago against content hash 22559b85aec5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

development-guidelines 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/development-guidelines.mdc · 73 lines

What it actually says

Development Guidelines

TypeScript Coding Standards

  • Type Safety: Explicit type definitions for all functions and variables
  • Strict Mode: Enable strict type checking in tsconfig.json
  • Type Guards: Utilize Zod schemas for runtime validation

Code Quality

ESLint Configuration

Prettier Formatting

  • Configuration file: .prettierrc
  • Auto-formatting: npm run format
  • Format check: npm run format:check

Biome Integration

  • Configuration file: biome.json
  • Provides fast linting and formatting

File Structure Rules

src/ Directory Structure

src/
├── cli/          # CLI related code
├── core/         # Core business logic
├── schemas/      # Zod schema definitions
└── types/        # TypeScript type definitions

mcp-server/ Directory

Testing Strategy

Vitest Unit Tests

  • Configuration file: vitest.config.ts
  • Execution: npm test
  • Write tests for all utility functions and core logic

Playwright E2E Tests

Build and Deployment

Build Process

  • TypeScript compilation: npm run build
  • Type checking: npm run type-check
  • Output directory: dist/

Package Deployment

  • NPM public package: npm run publish-public
  • Version management: Apply semantic versioning in package.json

Dependency Management

  • Runtime Dependencies: Keep to minimum
  • Development Dependencies: Development tools and testing frameworks
  • Use pnpm: Lock dependencies with pnpm-lock.yaml
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 · 73 lines · 0 tokens per session scan A 22559b85aec5

Subscribe to this mod's changes

development-guidelines is a cursor rule published in the GitHub repository lazylagom/context-compose-mcp (1 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 512 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.