Cron Parser Skill

Overview

Cron Expression Parser works by parsing cron expressions and validating their syntax. It returns field-by-field analysis, human-readable descriptions, and frequency information for both 5-field and 6-field cron formats.

Live Test Cron Parser Skill Skill →

The tool

Once your client is connected to the VerveKit server, this appears in its tool list as CronParserSkill. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

{
  "name": "CronParserSkill",
  "arguments": {
    "expression": "0 9 * * 1-5"
  }
}

You do not name the tool yourself; the model picks it. Asking about 0 9 * * 1-5 in the terms this skill covers is enough for it to reach for CronParserSkill on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every skill in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervekit": {
      "url": "https://api.vervekit.com/v1/mcp"
    }
  }
}

https://api.vervekit.com/v1/mcp

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

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{
  "status": "ok",
  "error": null,
  "data": {
    "expression": "0 9 * * 1-5",
    "isValid": true,
    "format": "5-field",
    "fields": {
      "second": {
        "expression": "0",
        "description": "At 0",
        "values": [
          0
        ]
      },
      "minute": {
        "expression": "0",
        "description": "At 0",
        "values": [
          0
        ]
      },
      "hour": {
        "expression": "9",
        "description": "At 9",
        "values": [
          9
        ]
      },
      "dayOfMonth": {
        "expression": "*",
        "description": "Every",
        "values": [
          1,
          2,
          3,
          4,
          5,
          6,
          7,
          8,
          9,
          10,
          11,
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          25,
          26,
          27,
          28,
          29,
          30,
          31
        ]
      },
      "month": {
        "expression": "*",
        "description": "Every",
        "values": [
          1,
          2,
          3,
          4,
          5,
          6,
          7,
          8,
          9,
          10,
          11,
          12
        ]
      },
      "dayOfWeek": {
        "expression": "1-5",
        "description": "From 1 to 5",
        "values": [
          1,
          2,
          3,
          4,
          5
        ]
      }
    },
    "description": "At 9:00 AM on Monday, Tuesday, Wednesday, Thursday, Friday",
    "frequency": {
      "type": "Daily",
      "interval": "day"
    },
    "nextRuns": [
      "2026-02-19T09:00:00.000Z",
      "2026-02-20T09:00:00.000Z",
      "2026-02-21T09:00:00.000Z",
      "2026-02-24T09:00:00.000Z",
      "2026-02-25T09:00:00.000Z"
    ]
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

A call costs 2 credits each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Syntax Validation

Validate cron expressions before deploying them to production to avoid scheduling errors

Schedule Documentation

Generate human-readable descriptions of cron expressions for documentation and team communication

Debugging

Parse and analyze existing cron expressions to understand their timing and identify issues

Migration

Verify cron expressions when migrating between systems or converting from 5-field to 6-field format

Other ways to use Cron Parser Skill

Set up Cron Parser Skill on VerveKit, or reach the same source a different way. Your VerveKit account and credits work on all of them — one key, one balance.

Related

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