Cron Mcp

io.github.takeaseatventurePublished by GitHub account takeaseatventurev0.1.2Updated Oct 25, 2026

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

The publisher's own server: Croncool Cron Jobs

VerifiedSTDIODesktop onlyProductivity & WorkflowDeveloper Tools

Overview

AI-generated overview

A local MCP server that lets an AI assistant parse, validate, explain and preview cron expressions, flagging impossible or risky schedules before deployment.

What you can do
Parse cron expressions into plain-English descriptions of when they fire, including L, W, # and named months/days syntaxes and 5-field standard cron. Validate schedules deeply for impossible dates, day-of-month/day-of-week OR semantics, midnight spikes, uneven steps and leap-year edges, with a frequency estimate. Compute the next N fire times as ISO-8601 timestamps with relative offsets. Look up a library of common, proven preset schedules such as every 5 minutes, hourly, weekdays at 9am, monthly and quarterly.
When to use it
Useful when writing or reviewing cron schedules for jobs, CI pipelines or scheduled tasks and you want an assistant to catch silent bugs such as never-firing dates or the classic day-of-month/day-of-week OR trap before the job is deployed. Also handy for explaining an existing expression or generating a next-fire preview.
Requirements
Runs as a local stdio process on the user's machine, installed from the npm package cron-mcp-server (global install or npx); Node.js is needed. No authentication, environment variables or headers are declared. Desktop clients such as Claude Desktop, Cursor or VS Code Copilot are configured to launch it.
Before you install
The tools are read-only analysis of expressions the user supplies; the README describes no writes, sends or third-party data transfer. It is a thin wrapper around a bundled cron engine, so results reflect that engine's interpretation of cron semantics. No credentials are requested.

Installation

In SourceWeft

  1. Open Cron Mcp in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

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

bash
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:

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

Cursor

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

json
{  "mcpServers": {    "cron": {      "command": "cron-mcp-server"    }  }}

VS Code (Copilot)

json
{  "mcp.servers": {    "cron": {      "type": "stdio",      "command": "cron-mcp-server"    }  }}

Direct (no install)

bash
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

Source: README.md at commit 902a68e

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v0.1.2LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

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