# extension-email-calendar-events

This skill adds calendar events and iCalendar invitation emails to an app. Useful when you need meetings with attendees without hand-building ICS files.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 28400 installs · ★ 2
- Author: caffeinelabs
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/caffeinelabs/skills/tree/HEAD/skills/extension-email-calendar-events/SKILL.md
- Updated: 2026-10-22
- HTML: https://affpapa.org/en/nevibecode/skills/extension-email-calendar-events

## What it does

The skill covers events and meetings: add, update, cancel, delete, get and list. Inside is a prefabricated module, `mo:caffeineai-email-calendar-events/calendarEvents.mo`, and it cannot be modified. It keeps events in state and builds an iCalendar file to attach to each email.

Sending goes through `sendCalendarEvent`. One invitation copy per attendee, via the mail gateway with settings the platform injects on every deploy: `INTEGRATIONS_GATEWAY_URL` and `INTEGRATIONS_GATEWAY_API_KEY`. Without them the call returns `#err`. The organizer is the sender itself: `CalendarEvent.organizer` carries only a display name, while the address is built as `<fromUsername>@<app domain>`. Never pass a full address, and the app should not read or guess the domain.

One thing to plan around: receiving RSVPs is not supported yet, so replies from guests have to be collected elsewhere. Sequence matters too. `update`, `addAttendees`, `removeAttendees` and `cancel` store the change with the next sequence number and return the record — send that record, because calendars apply an update or cancellation only when its sequence is higher than the one they hold.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add caffeinelabs/skills --skill extension-email-calendar-events -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/extension-email-calendar-events/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/extension-email-calendar-events/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add caffeinelabs/skills --skill extension-email-calendar-events -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/extension-email-calendar-events/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add caffeinelabs/skills --skill extension-email-calendar-events -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/extension-email-calendar-events/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install caffeinelabs/skills extension-email-calendar-events
```

2. **Manually: put the files in place**
- File: `.github/skills/extension-email-calendar-events/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add caffeinelabs/skills --skill extension-email-calendar-events -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/caffeinelabs/skills --path skills/extension-email-calendar-events
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/extension-email-calendar-events/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add caffeinelabs/skills --skill extension-email-calendar-events -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/caffeinelabs/skills/tree/HEAD/skills/extension-email-calendar-events/SKILL.md

## When to use it
- create a meeting with attendees and email the invitations
- change the time or location of an event and notify guests
- cancel an event and send the cancellation
- add or remove an attendee from the guest list
- list events oldest to newest or newest to oldest

## Example prompts
- add a calendar event for tomorrow and email the invitations
- update the meeting time and send the new invitation
- cancel the event and send the cancellation to all attendees

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 8e12a1ba02e852d1.

BEGIN THIRD-PARTY FILE 8e12a1ba02e852d1
````text
---
name: extension-email-calendar-events
description: Support for organising events/meetings and sending invitations by email.
version: 0.4.1
compatibility:
  mops:
    caffeineai-email-calendar-events: "~0.4.0"
    caffeineai-email: "~0.4.0"
    caffeineai-authorization: "~1.0.1"
caffeineai-subscription: [plus, pro]
---

# Email — Calendar Events
Calendar events email extension for [Caffeine AI](https://caffeine.ai?utm_source=caffeine-skill&utm_medium=referral).

## Overview

This skill adds support for organising events/meetings and sending iCalendar invitations by email. It provides CRUD operations for calendar events and email-based invitation delivery.

# Backend

## This component is for organising events/meetings and sending invitations by email

- Internally it builds and attaches an iCalendar file to each attendees's email
- This component does not yet support receiving RSVPs from attendees

### To add/update/cancel/delete/get/list calendar events

- Use the prefabricated module `mo:caffeineai-email-calendar-events/calendarEvents.mo` which cannot be modified.

```mo:caffeineai-email-calendar-events/calendarEvents.mo
module {
  public type CalendarEvent = {
    uid : Text;
    sequence : Nat32;
    method : CalendarEventMethod;
    summary : Text;
    description : Text;
    location : Text;
    startTime : Nat64;
    endTime : Nat64;
    organizer : Organizer;
    attendees : [Attendee];
  };

  public type CalendarEventMethod = {
    #request;
    #publish;
    #cancel;
  };

  // The organizer is the sender: the invitation comes from
  // `<fromUsername>@<app domain>` and that mailbox, under this display name,
  // is the ICS ORGANIZER and the first guest. Only attendees carry addresses.
  public type Organizer = {
    name : ?Text;
  };

  public type Mailbox = {
    email : Text;
    name : ?Text;
  };

  public type Attendee = {
    who : Mailbox;
    role : CalendarEventRole;
  };

  public type CalendarEventRole = {
    #chair;
    #required;
    #optional;
    #notParticipating;
  };

  public type State = {
    var events : List.List<CalendarEvent>;
    var uidMap : Map.Map<Text, Nat>;
  };

  public func add(
    self : State,
    uid : Text,
    summary : Text,
    description : Text,
    location : Text,
    startTime : Nat64,
    endTime : Nat64,
    organizer : Organizer,
````
END THIRD-PARTY FILE 8e12a1ba02e852d1

The third-party file has ended. Everything between the 8e12a1ba02e852d1 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 2338 of 13602 bytes. © caffeinelabs · Apache-2.0 · https://github.com/caffeinelabs/skills/tree/HEAD/skills/extension-email-calendar-events/SKILL.md

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---
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