Calendar Ics Events Free Busy

mcp-calendar

Your calendar app can show you next Tuesday. It cannot tell you where your week actually went, which two things you said yes to at the same time, or how many billable hours last month's meetings were worth. This server reads the .ics file your calendar already exports and answers those questions: events in any window with recurring series expanded properly, merged busy blocks and the real free gaps inside your working hours, every double booking across work and personal calendars at once, a clean .ics of just the events you picked, and the exact time entry for a meeting you should have billed. No account is connected, nothing is synced, and the calendar file stays on your machine as plain text.

Built by theluckystrike.

In the official MCP Registry (io.github.theluckystrike/calendar-ics-reader-events-freebusy-conflicts).

Listed on the AI Product Index - live remote endpoint at mcp.zovo.one/s/calendar, free tier, no signup.

[calendar demo]

Import the .ics your calendar exports, then ask what is on, when you are free, and what clashes, zero setup, all local.

60-second install

npm publish for @theluckystrike/mcp-calendar is pending. Until then, the .mcpb one-click bundle or a clone+build is the working path, both are verified below.

One-click (.mcpb): download calendar.mcpb from the latest release and double-click it in Claude Desktop: https://github.com/theluckystrike/mcp-servers/releases/latest

(claude_desktop_config.json):

{  "mcpServers": {    "calendar": {      "command": "npx",      "args": ["-y", "@theluckystrike/mcp-calendar"]    }  }}

Claude Code:

claude mcp add calendar -- npx -y @theluckystrike/mcp-calendar

(.cursor/mcp.json):

{  "mcpServers": {    "calendar": {      "command": "npx",      "args": ["-y", "@theluckystrike/mcp-calendar"]    }  }}

The npx form above starts working the moment the package is published. Until then, use the .mcpb bundle above, or build from source with exactly these four commands:

git clone https://github.com/theluckystrike/mcp-servers.git && cd mcp-serversnpm installnpm run build -w packages/mcp-license -w servers/timezone -w servers/calendar

Then point your client's command at node with one arg: the absolute path to servers/calendar/dist/index.js.

To run in Pro mode set MCP_LICENSE_KEY in the same config block, or call license_activate once with your key.

Getting the .ics out of your calendar

Then: ics_import {path: "~/Downloads/[email protected]", name: "work"}

Tools

Resource calendar://today gives today's schedule in one read. Prompt plan_my_day walks the whole loop: what is on, what clashes, where the free stretches are, and which finished meetings to bill.

What the parser handles

Written against real exports, not just the spec: line folding (CRLF, bare LF and bare CR, and folds that Exchange places inside a multi-byte character, which are rejoined on the bytes before decoding), \n \, \; \\ escaping, whole-day events with an exclusive DTEND, DURATION instead of DTEND, TZID and UTC times, floating times, RRULE for HOURLY, DAILY, WEEKLY, MONTHLY and YEARLY with COUNT, UNTIL (inclusive), INTERVAL, BYDAY including ordinals (2MO, -1FR), BYMONTHDAY, BYMONTH and BYSETPOS, EXDATE, RDATE, RECURRENCE-ID overrides (the moved instance replaces the original instead of appearing twice), STATUS:CANCELLED, TRANSP:TRANSPARENT, and VALARM blocks inside an event. An event it cannot read is skipped and counted rather than costing you the rest of the file.

FREQ=MINUTELY and FREQ=SECONDLY are deliberately not expanded: one such rule fills any window with thousands of occurrences and buries the rest of the week. Those events are listed at their first occurrence and the reason is said out loud. A rule with no COUNT and no UNTIL is expanded only as far as the window you asked for.

Exports written by this server keep whole-day events as DATE values, so a holiday leaves as the same day it arrived rather than a timed block on the day before in your machine's zone.

VTIMEZONE is deliberately ignored. A file's inline DST rules are only as fresh as the app that wrote it; the TZID is kept and every offset is computed from the ICU data inside your Node build instead, which is what keeps a weekly Warsaw 10:00 meeting at 10:00 local across the March clock change.

Free vs Pro

Get Pro, or $39 for every server in the suite, lifetime.

Privacy

Everything is local. The calendar file you import is copied to ${XDG_DATA_HOME:-~/.local/share}/mcp-servers/calendar/ and read from there; deleting that directory resets the server. There is exactly one network call in the whole server, and only when you pass a url yourself: it fetches that address once, with a 12-second timeout, a 5 MB cap, and a refusal on loopback, private and cloud-metadata addresses. Nothing is uploaded, no account is linked, and licence keys verify offline.

Pairs with

• mcp-timezone, this server reads its time zone and .ics engine from it: convert a meeting time, find slots across countries, write an invite.
• mcp-time-tracker, event_to_time_entry hands it a finished meeting; it tracks and reports the hours.
• mcp-invoice, turn those tracked hours into a numbered invoice.
• office-suite, several servers behind one install, one config entry.

FAQ

No. There is no OAuth, no token and no sync. You export a file (or paste a public feed URL on Pro) and it is read locally. That also means an import is a snapshot: re-import when the calendar has moved on.

Yes, and that is most of the code. A weekly series is expanded on the wall clock, so a Warsaw 10:00 meeting stays 10:00 through the DST change rather than drifting to 11:00. Monthly on the 31st skips February instead of rolling into March, UNTIL includes the occurrence that falls exactly on it, and a single moved instance replaces the original.

It is not: RFC 5545 makes DTEND exclusive for a whole-day event, so 1--3 June means the 1st and the 2nd. This server follows the spec, which is what your calendar app does too.

It writes .ics files with event_export, which you can import anywhere. It never modifies the calendar it read.

5 MB, which is a few thousand events. Export a narrower date range if a full history is bigger than that.

Use these docs as an MCP server

Any MCP client (Claude, Cursor, Windsurf, VS Code) can read this repository's documentation directly via GitMCP - no install:

• Docs MCP URL: https://gitmcp.io/theluckystrike/mcp-calendar