chrono-mcp / rules

---
description: "Chrono MCP Project Standards and Guidelines"
globs: ["**/*.ts", "**/*.js", "**/*.json"]
alwaysApply: true
---

# Chrono MCP Project Guidelines

## Project Overview
This is a Model Context Protocol (MCP) server for time and date operations, providing tools for:
- Getting current time across timezones
- Time calculations and arithmetic
- Date formatting and conversion

## Coding Standards

### TypeScript/JavaScript
- Use TypeScript for all new source files
- Prefer functional programming patterns
- Use proper error handling with try-catch blocks
- Export functions and types explicitly
- Follow the existing project structure in `src/` directory

### MCP Tools
- Each tool should have comprehensive input validation
- Use the existing validation utilities in `src/utils/validation.ts`
- Follow the MCP protocol standards for tool definitions
- Include proper JSDoc comments for all exported functions
- Provide clear error messages for invalid inputs

### Testing
- Write comprehensive tests for all tools using the existing test framework
- Test edge cases and error conditions
- Use descriptive test names that explain the scenario
- Follow the pattern established in existing `.test.ts` files

### Time Handling
- Always use proper timezone-aware date handling
- Leverage the utilities in `src/utils/date-utils.ts`
- Support ISO 8601 datetime strings as input
- Provide multiple output formats when appropriate

### Build Process
- Source files go in `src/` directory
- Compiled output goes to `dist/` directory
- Use `npm run build` to compile TypeScript
- Use `npm test` to run the test suite

## Architecture Notes
- The main entry point is `src/index.ts`
- Tools are organized in `src/tools/` directory
- Shared utilities are in `src/utils/` directory
- Each tool exports its definition and implementation