import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import { DateTime, Interval } from "luxon";
export function register(server: McpServer): void {
server.tool(
"date_diff",
"Calculate the difference between two dates/times. Returns the difference in years, months, days, hours, minutes and also total days/hours/minutes.",
{
start: z.string().describe("Start date in ISO 8601 format (e.g. 2024-01-15 or 2024-01-15T10:30:00)"),
end: z.string().describe("End date in ISO 8601 format"),
timezone: z.string().optional().describe("IANA timezone for parsing dates. Defaults to UTC."),
},
async ({ start, end, timezone }) => {
const tz = timezone || "UTC";
const startDt = DateTime.fromISO(start, { zone: tz });
const endDt = DateTime.fromISO(end, { zone: tz });
if (!startDt.isValid) {
return { content: [{ type: "text", text: JSON.stringify({ error: `Invalid start date: ${startDt.invalidExplanation}` }) }] };
}
if (!endDt.isValid) {
return { content: [{ type: "text", text: JSON.stringify({ error: `Invalid end date: ${endDt.invalidExplanation}` }) }] };
}
// Ensure start <= end for interval
const [earlier, later] = startDt < endDt ? [startDt, endDt] : [endDt, startDt];
const isNegative = startDt > endDt;
const interval = Interval.fromDateTimes(earlier, later);
const duration = interval.toDuration(["years", "months", "days", "hours", "minutes", "seconds"]);
const totalDiff = later.diff(earlier, ["days", "hours", "minutes", "seconds"]);
const result = {
start: startDt.toISO(),
end: endDt.toISO(),
timezone: tz,
isNegative,
difference: {
years: duration.years,
months: duration.months,
days: duration.days,
hours: duration.hours,
minutes: duration.minutes,
seconds: Math.floor(duration.seconds),
},
totalDays: Math.floor(totalDiff.as("days")),
totalHours: Math.floor(totalDiff.as("hours")),
totalMinutes: Math.floor(totalDiff.as("minutes")),
totalSeconds: Math.floor(totalDiff.as("seconds")),
};
return { content: [{ type: "text", text: JSON.stringify(result, null, 2) }] };
}
);
}
