mcpField
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cron-mcp

cron-mcp

Local
github.com/takeaseatventureDeveloper Tools0Updated 13w ago
Repository

About cron-mcp

An MCP server for AI coding agents that parses, validates, explains, and previews cron schedules. It flags semantic pitfalls such as impossible dates, day-of-month/day-of-week OR behavior, uneven intervals, and midnight spikes before deployment.

Key features

  1. 01Parse and explain cron expressions
  2. 02Detect impossible schedules and semantic pitfalls
  3. 03Preview upcoming fire times
  4. 04Estimate frequency and leap-year edge cases
  5. 05Provide common schedule presets

Use cases

  1. 01Check a cron schedule before deploying a job
  2. 02Understand when an expression will run
  3. 03Find risks in day-of-month and weekday combinations
  4. 04Choose a preset for a recurring schedule

MCP support

Exposes cron parsing, validation, next-run previews, and schedule presets as MCP tools for connected AI agents.

Configuration

Local server config is the same for every client. Copy it into your client’s MCP config file.

mcp.json · Universal config
{
  "mcpServers": {
    "takeaseatventure-cron": {
      "command": "npx",
      "args": [
        "-y",
        "cron-mcp-server"
      ]
    }
  }
}
Run commandnpx -y cron-mcp-server

Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.

Packages
npmcron-mcp-server0.1.2

Tools

4

Saved tool list · updated 3w ago

ParameterTypeRequiredDescription
expressionstringYesThe cron expression to parse, e.g. "*/5 * * * *" or "0 9 * * 1-5".

Details

From the project README

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

Published links

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

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