Chronos - Date, Time and Calendar Tools

Deterministic date, time and calendar tools for agents over MCP.

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What it can do

  • Describe Date: Get full deterministic facts about a calendar date: weekday, ISO week, day-of-year, leap year, weekend flag. LLMs frequently miscompute the weekday of a date — use this for ground truth
  • Date Difference: Exact difference between two dates: total days/weeks AND a years/months/days breakdown that correctly accounts for leap years and varying month lengths.
  • Business Days Between: Count business days (Mon–Fri) between two dates, optionally excluding holiday dates. Counts the open interval (from, to].

What data it sees

Do you need an account

No: the server works without sign-in

Deterministic date, time and calendar tools for agents over MCP. Parse and format dates, convert time zones, add and diff durations, compute week numbers, business days and calendar arithmetic. Pure computation: no AI, no API keys, no outbound calls, and the same input always returns the same result.

How to connect

How to connect Chronos - Date, Time and Calendar Tools to Claude

The server address to paste into Claude settings:

https://chronos-api--ghdejr11.run.tools

  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 Chronos - Date, Time and Calendar Tools to ChatGPT

The server address to paste into ChatGPT settings:

https://chronos-api--ghdejr11.run.tools

  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 Chronos - Date, Time and Calendar Tools to Cursor

The server address to paste into Cursor settings:

https://chronos-api--ghdejr11.run.tools

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 (7)

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

describe_dateGet full deterministic facts about a calendar date: weekday, ISO week, day-of-year, leap year, weekend flag. LLMs frequently miscompute the weekday of a date — use this for ground truth.
date_differenceExact difference between two dates: total days/weeks AND a years/months/days breakdown that correctly accounts for leap years and varying month lengths.
business_days_betweenCount business days (Mon–Fri) between two dates, optionally excluding holiday dates. Counts the open interval (from, to].
add_daysAdd (or subtract, with a negative value) a number of days to a date. Set business=true to skip weekends and supplied holidays.
nth_weekday_of_monthFind the Nth weekday of a month, e.g. "3rd Monday of January 2026" (MLK Day) or the last Friday (nth=-1). weekday: 0=Sun..6=Sat.
ageExact age (years, months, days, total days) of a birth date as of a given reference date. as_of is required — the tool never reads a wall clock, keeping every result reproducible.
convert_timezoneConvert an instant (ISO-8601 with offset, or unix seconds) into a target IANA time zone, with DST-correct offset. Returns local datetime, offset, weekday and unix ts.