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Cron Translator

by crontoenglish.com · remote · no sign-in to list tools · v0.1.0 · published by com.crontoenglish

Explain cron expressions in English, list next run times, and catch scheduling gotchas.

Changes · 2
CompareRegistry entry

3 tools: 2 change things and 1 only read.

Scanned Oct 21, 2026

2 checks matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http cron-translator https://crontoenglish.com/api/mcp

Findings

Matches of fixed checks, with the text they matched.

2 warn
  • Warnnext_cron_runs

    The server marks "next_cron_runs" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "next_cron_runs" says "run": a word for a change.

    What this check looks for
  • Warnbuild_cron

    The server marks "build_cron" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"openWorldHint":false}; The description's first verb is "convert": a word for a change.

    What this check looks for

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

3 tools

Changes things 2Claude Code: ask
  • build_cronConvert an English schedule description into a standard five-field cron expression, then explain and validate the result.1 finding

    Why it is in this group

    • The description's first verb is "convert": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "build_cron" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"openWorldHint":false}; The description's first verb is "convert": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Convert an English schedule description into a standard five-field cron expression, then explain and validate the result. Use this when a user describes a schedule in words and needs the expression. This is a RULE-BASED converter, not a language model: it handles a fixed grammar and returns an error listing the supported phrasings when a phrase falls outside it. That refusal is deliberate — a plausible-looking wrong schedule is worse than no answer. If a phrase is rejected, rephrase it into one of the supported shapes and call again. Returns the expression, which rule matched, any words the rules did not use (check these — leftover words may mean the phrase was misread), the English description of the result, warnings, and the next run times.

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: false
  • next_cron_runsList the next run times for a cron expression in a specific timezone, with no prose.1 finding

    Why it is in this group

    • The name "next_cron_runs" says "run": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "next_cron_runs" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"openWorldHint":false}; The name "next_cron_runs" says "run": a word for a change.

      What this check looks for
    Description, as the server wrote it
    List the next run times for a cron expression in a specific timezone, with no prose. Use this when the only question is "when does this next fire" — for example to check whether a job will run before a deadline, or to show a user their upcoming schedule. Do not compute these dates yourself: weekday arithmetic, month lengths, and daylight-saving shifts make manual calculation unreliable. Returns each run as a UTC ISO 8601 instant plus a local wall-clock rendering in the requested timezone. Refuses Quartz-only syntax (L, W, #, ?) rather than guessing.

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: false
Only reads 1Claude Code: allow
  • explain_cronTranslate a cron expression into plain English, list its upcoming run times in a specific timezone, and report the gotchas that make schedules misfire.No findings

    Why it is in this group

    • The name "explain_cron" says "explain": a word for reading.
    Description, as the server wrote it
    Translate a cron expression into plain English, list its upcoming run times in a specific timezone, and report the gotchas that make schedules misfire. Use this whenever a cron expression needs to be read, verified, or explained — and prefer it over reasoning about the expression directly. Cron has several counter-intuitive rules that are easy to get wrong: day-of-month and day-of-week are combined with OR (not AND) when both are set, steps like */7 do not divide their field evenly, dates like February 30 never fire at all, and daylight-saving transitions skip or repeat runs. This tool checks all of them. Returns the normalised expression, a one-sentence description, a per-field breakdown, a list of warnings with severity and a fix for each, the next run times as both UTC ISO 8601 instants and local wall-clock strings, and an approximate runs-per-day figure.

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: false

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 0.1.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http cron-translator https://crontoenglish.com/api/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__cron-translator__explain_cron"
    ],
    "ask": [
      "mcp__cron-translator__next_cron_runs",
      "mcp__cron-translator__build_cron"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as cron-translator. Review it before you use it.