Cron Translator

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

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What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

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

    How to connect

    How to connect Cron Translator to Claude

    The server address to paste into Claude settings:

    https://crontoenglish.com/api/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect Cron Translator to ChatGPT

    The server address to paste into ChatGPT settings:

    https://crontoenglish.com/api/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect Cron Translator to Cursor

    The server address to paste into Cursor settings:

    https://crontoenglish.com/api/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (3)

    Raw names from tools/list. Only developers need these.

    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. 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.
    next_cron_runsList 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.
    build_cronConvert 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.