chrono-mcp-standards

chrono-mcp-standards is a cursor rule for Cursor from JMoak/chrono-mcp. It costs 392 tokens per session, scanned A, original, MIT.

A set of coding rules for Chrono MCP, a server that provides tools for time zones, date calculations, and date formatting. It covers TypeScript code, validation, error messages, documentation, and tests.

In plain words
What is it for?
Use it when developing or reviewing Chrono MCP features, especially new time-related tools and their tests.
Why use it?
It gives contributors consistent expectations for adding or changing tools in the project. This helps prevent timezone mistakes and inconsistent input handling.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

Good fit Use it when developing or reviewing Chrono MCP features, especially new time-related tools and their tests.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/jmoak/chrono-mcp/chrono-mcp-standards
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.

Clone the repo
git clone --depth 1 https://github.com/JMoak/chrono-mcp

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 chrono-mcp-standards

README.md
[![agentmods](https://agentmods.dev/badge/rules/jmoak/chrono-mcp/chrono-mcp-standards/github.svg)](https://agentmods.dev/rules/jmoak/chrono-mcp/chrono-mcp-standards)
Your own site
<a href="https://agentmods.dev/rules/jmoak/chrono-mcp/chrono-mcp-standards"><img src="https://agentmods.dev/badge/rules/jmoak/chrono-mcp/chrono-mcp-standards/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for chrono-mcp-standards

Your own site · 80×15
<a href="https://agentmods.dev/rules/jmoak/chrono-mcp/chrono-mcp-standards"><img src="https://agentmods.dev/badge/rules/jmoak/chrono-mcp/chrono-mcp-standards.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 392 This file is loaded in full into every session.
When invoked 392 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00392 $0.00392
Opus 5 $0.00196 $0.00196
Sonnet 5 $0.00078 $0.00078
Haiku 4.5 $0.00039 $0.00039

Measured 8d ago against content hash ea77ce620a57, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

chrono-mcp-standards 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 8d 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/chrono-mcp-standards.mdc · 53 lines

What it actually says

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
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. 8d ago First seen · 53 lines · 392 tokens per session scan A ea77ce620a57

Subscribe to this mod's changes

chrono-mcp-standards is a cursor rule published in the GitHub repository JMoak/chrono-mcp (0 stars, last pushed 1mo ago), licensed MIT. It adds 392 tokens to every session, about $0.0020 per session on Opus 5. 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.