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io.github.takeaseatventure/cron-mcp

Official registry AI and agents

MCP cron validator for AI agents; flags impossible schedules and other silent cron bugs.

Source code Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package cron-mcp-server
Claude Code 
claude mcp add cron-mcp -- npx -y cron-mcp-server@0.1.2
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "cron-mcp": {
            "command": "npx",
            "args": [
                "-y",
                "cron-mcp-server@0.1.2"
            ]
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. cron-mcp
  2. Why
  3. Tools exposed
  4. Install
  5. Published links
  6. Configure
  7. Example usage
  8. Engine
  9. License

cron-mcp

An MCP (Model Context Protocol) server that lets AI coding agents — Claude, Cursor, Copilot, Cline — parse, validate, explain, and preview cron expressions.

Built to catch silent cron bugs (impossible schedules, OR-semantics gotchas, midnight spikes) before a job is deployed — a class of mistake that's easy to make and hard to notice until a critical job silently fails to fire.

Why

Cron expressions are deceptively tricky. Common silent failures:

  • 0 0 30 2 * → never runs (February has no 30th). Syntactically valid, semantically dead.
  • 0 0 1,15 * 1 → fires on the 1st OR 15th OR Monday, not "the 1st and 15th if Monday" (the classic dom+dow OR-semantics trap).
  • */7 * * * * → uneven step; intervals drift (:00, :07, :14, …, :56, :00 — not "every 7 minutes" cleanly).
  • 0 0 * * * → midnight spike; every job in the system competes at 00:00.

cron-mcp surfaces these as warnings, observations, and suggestions that the AI agent can act on — before you ship the schedule.

Tools exposed

ToolDescription
parse_cronParse a cron expression → plain-English description of when it fires. Supports 5-field standard cron + L (last), W (nearest weekday), # (nth weekday), named months/days.
validate_cronDeep validation: impossible schedules, OR-semantics, midnight spikes, uneven steps, leap-year edges, frequency estimate (~runs/year).
next_runsCompute the next N fire times as ISO-8601 + relative offsets.
cron_presetsLibrary of common, proven schedules (every 5 min, hourly, weekdays 9am, monthly, quarterly, …).

Install

npm install -g cron-mcp-server

Configure

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or the equivalent on your OS:

{
  "mcpServers": {
    "cron": {
      "command": "cron-mcp-server",
      "args": []
    }
  }
}
Cursor

Add to .cursor/mcp.json (or ~/.cursor/mcp.json for global):

{
  "mcpServers": {
    "cron": {
      "command": "cron-mcp-server"
    }
  }
}
VS Code (Copilot)
{
  "mcp.servers": {
    "cron": {
      "type": "stdio",
      "command": "cron-mcp-server"
    }
  }
}
Direct (no install)
npx cron-mcp-server

Example usage

Once connected, just ask the agent in natural language:

  • "Validate this cron: 0 0 30 2 *"
  • "When does */5 * * * * next fire?"
  • "Give me a cron for every weekday at 9am"
  • "Is there anything risky about 0 0 1,15 * 1?"

The agent calls the tools and returns structured, actionable results.

Engine

The cron engine is battle-tested: 638 lines, zero dependencies, originally extracted from a browser-based cron generator and hardened with 69 unit tests. This MCP server is a thin tool wrapper around it.

License

MIT © takeaseatventure

Frequently asked questions

What is io.github.takeaseatventure/cron-mcp?

MCP cron validator for AI agents; flags impossible schedules and other silent cron bugs.

How do I install io.github.takeaseatventure/cron-mcp?

It runs on your machine. In Claude Code: claude mcp add cron-mcp -- npx -y cron-mcp-server@0.1.2. For other clients, paste the JSON configuration from this page into their MCP settings.

Does io.github.takeaseatventure/cron-mcp need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is io.github.takeaseatventure/cron-mcp open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains io.github.takeaseatventure/cron-mcp?

It is published by takeaseatventure. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.