Apple Calendar CLI

Manage Apple Calendar events on macOS 14+ using apple-calendar-cli: list, get, create, update, and delete events with ISO 8601 date support.

Security Scan

The instructions and requirements are consistent with a CLI that manages Apple Calendar on macOS — nothing in the skill requests unrelated credentials or system access beyond the expected Calendar permission, but the SKILL.md recommends installing a third‑party Homebrew tap which you should vet before running.

Purpose & Capability

The name/description (manage Apple Calendar events) matches the runtime instructions: all commands operate on calendars/events via a local CLI that uses EventKit. There are no unrelated environment variables, binaries, or config paths requested.

Instruction Scope

SKILL.md is narrowly scoped to running apple-calendar-cli commands (list, get, create, update, delete). It explicitly requires macOS Calendar permission (expected) and does not instruct the agent to read unrelated files, environment variables, or transmit data to external endpoints.

Install Mechanism

This skill is instruction-only (no install spec). SKILL.md recommends: brew install sichengchen/tap/apple-calendar-cli — that is a third‑party Homebrew tap. Installing from a personal/unofficial tap can run arbitrary install scripts; consider vetting the tap or using an official release before installing.

Credentials

No environment variables, credentials, or config paths are requested. The only required permission is macOS Calendar access (read/write) which is proportionate to managing calendars/events.

Persistence & Privilege

The skill is not always-enabled and does not request persistent/global privileges or modify other skills. Agent autonomous invocation remains allowed by default, which is expected behavior and not a concern here by itself.

Assessment

This skill appears to do what it says: it runs a local CLI that uses macOS Calendar access. Before installing: (1) review the Homebrew tap (sichengchen/tap) or the tool's source — third‑party taps can execute install scripts; only install if you trust the author, (2) when granting Calendar permission, understand the tool can read and write your calendars and events, (3) test read-only commands first (list-calendars, list-events) to confirm behavior, and (4) if you prefer to avoid third‑party taps, look for an official release or build from source. No extra credentials are requested by the skill itself.

Apple Calendar CLI — Agent Skill

You have access to apple-calendar-cli, a command-line tool for managing Apple Calendar events via EventKit on macOS.

Prerequisites

• macOS 14+ required
• Install: brew install sichengchen/tap/apple-calendar-cli
• Calendar access permission must be granted (System Settings > Privacy & Security > Calendars)

Date Format

All dates use ISO 8601 format:

• Date only: YYYY-MM-DD (interpreted as start of day in local timezone)
• Date and time: YYYY-MM-DDTHH:MM:SS (local timezone)
• Full ISO 8601: YYYY-MM-DDTHH:MM:SSZ or with offset

Global Options

• --json — Output results as structured JSON (available on all commands)
• --version — Show version
• --help / -h — Show help

Always use --json when calling from an agent for reliable parsing.

Commands

list-calendars

List all available calendars.

apple-calendar-cli list-calendars --json

JSON output — array of objects:

[
  {
    "identifier": "CALENDAR-ID",
    "title": "Work",
    "type": "calDAV",
    "source": "iCloud",
    "color": "#1BADF8",
    "isImmutable": false
  }
]

Use identifier to filter events or target a specific calendar when creating events.

list-events

List events within a date range.

apple-calendar-cli list-events --json
apple-calendar-cli list-events --from 2026-02-22 --to 2026-02-28 --json
apple-calendar-cli list-events --from 2026-02-22 --to 2026-02-28 --calendar CALENDAR-ID --json

Options:

• --from — Start date (default: today)
• --to — End date (default: 7 days from start)
• --calendar — Filter by calendar identifier

JSON output — array of event objects:

[
  {
    "identifier": "EVENT-ID",
    "title": "Team standup",
    "startDate": "2026-02-22T10:00:00-08:00",
    "endDate": "2026-02-22T10:30:00-08:00",
    "isAllDay": false,
    "location": "Conference Room A",
    "notes": null,
    "calendarTitle": "Work",
    "calendarIdentifier": "CALENDAR-ID",
    "url": null,
    "hasRecurrenceRules": true
  }
]

get-event

Get full details of a single event.

apple-calendar-cli get-event EVENT-ID --json

JSON output — single event object (same schema as list-events items).

create-event

Create a new calendar event.

apple-calendar-cli create-event \
  --title "Meeting with Alice" \
  --start "2026-02-23T14:00:00" \
  --end "2026-02-23T15:00:00" \
  --json

apple-calendar-cli create-event \
  --title "All-day conference" \
  --start "2026-03-01" \
  --end "2026-03-02" \
  --all-day \
  --calendar CALENDAR-ID \
  --location "Convention Center" \
  --notes "Bring laptop" \
  --url "https://example.com/conf" \
  --json

Required options:

• --title — Event title
• --start — Start date/time
• --end — End date/time (must be after start)

Optional options:

• --calendar — Calendar identifier (default: system default calendar)
• --notes — Event notes
• --location — Event location
• --all-day — Mark as all-day event
• --url — Event URL
• --recurrence — Recurrence rule: daily, weekly, monthly, yearly
• --recurrence-end — End date for recurrence
• --recurrence-count — Number of occurrences
• --attendees — Comma-separated email addresses
• --alert — Alert offset (e.g., 15m, 1h, 1d)

JSON output — the created event object with its new identifier.

update-event

Update an existing event (partial update — only specified fields change).

apple-calendar-cli update-event EVENT-ID --title "New title" --json
apple-calendar-cli update-event EVENT-ID \
  --start "2026-02-23T15:00:00" \
  --end "2026-02-23T16:00:00" \
  --location "Room B" \
  --json

Required argument:

• <id> — Event identifier

Optional options:

• --title — New title
• --start — New start date/time
• --end — New end date/time
• --calendar — Move to different calendar (by identifier)
• --notes — New notes
• --location — New location
• --url — New URL

JSON output — the updated event object.

delete-event

Delete a calendar event.

apple-calendar-cli delete-event EVENT-ID --json

JSON output:

{
  "deleted": true,
  "event": { ... }
}

Common Agent Workflows

Find and reschedule an event

# 1. List events to find the one to reschedule
apple-calendar-cli list-events --from 2026-02-22 --to 2026-02-28 --json

# 2. Get full details
apple-calendar-cli get-event EVENT-ID --json

# 3. Update the time
apple-calendar-cli update-event EVENT-ID \
  --start "2026-02-24T14:00:00" \
  --end "2026-02-24T15:00:00" \
  --json

Create an event on a specific calendar

# 1. List calendars to find the right one
apple-calendar-cli list-calendars --json

# 2. Create the event on that calendar
apple-calendar-cli create-event \
  --title "Dentist" \
  --start "2026-02-25T09:00:00" \
  --end "2026-02-25T10:00:00" \
  --calendar CALENDAR-ID \
  --json

Check today's schedule

Date-only values resolve to midnight (00:00:00), so --to must be the next day to cover the full day:

# Correct: covers 2026-02-22 00:00 to 2026-02-23 00:00
apple-calendar-cli list-events --from 2026-02-22 --to 2026-02-23 --json

Error Handling

• Calendar access denied: User needs to grant access in System Settings > Privacy & Security > Calendars
• Event not found: The event ID may be stale — list events again to get current IDs
• Invalid date format: Use ISO 8601 (YYYY-MM-DD or YYYY-MM-DDTHH:MM:SS)
• End before start: Ensure the end date/time is after the start date/time