Fastmail

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name: fastmail description: Manages Fastmail email and calendar via JMAP and CalDAV APIs. Use for emails (read, send, reply, search, organize, bulk operations, threads) or calendar (events, reminders, RSVP invitations). Timezone auto-detected from system. compatibility: opencode metadata: author: witooh version: "2.1" api: JMAP, CalDAV

Quick Start

Invoke tools via CLI:

# Install dependencies first
cd .opencode/skills/fastmail && bun install

# Email: List mailboxes
bunx fastmail list_mailboxes

# Email: Send
bunx fastmail send_email \
  '{"to": [{"email": "user@example.com"}], "subject": "Hi", "text_body": "Message"}'

# Calendar: List events
bunx fastmail list_events \
  '{"start_date": "2024-01-01", "end_date": "2024-01-31"}'

# Calendar: Create event with reminder
bunx fastmail create_event_with_reminder \
  '{"title": "Meeting", "start": "2024-01-15T10:00:00", "end": "2024-01-15T11:00:00", "reminder_minutes": [15, 60]}'

# List all available tools
bunx fastmail --list

When to Use This Skill

• 📧 Check inbox or search emails
• 📧 Send, reply, or move emails
• 🏷️ Apply labels or organize mailbox
• 📅 View calendar or events
• 📅 Create, update, or delete events
• 🔔 Set event reminders or alarms

Email Tools (10 total)

Tool	Purpose
list_mailboxes	List all folders
list_emails	List emails in mailbox
get_email	Get full email content
get_thread	Get all emails in a conversation thread
search_emails	Search by text query
send_email	Send new email
reply_email	Reply to email
move_email	Move to folder
set_labels	Apply labels ($seen, $flagged)
delete_email	Delete (move to trash)

Bulk Email Tools (3 total)

Tool	Purpose
bulk_move_emails	Move multiple emails at once
bulk_set_labels	Apply labels to multiple emails
bulk_delete_emails	Delete multiple emails at once

Calendar Tools (10 total)

Tool	Purpose
list_calendars	List all calendars
list_events	List events by date range
get_event	Get event details
create_event	Create new event
update_event	Update existing event
delete_event	Delete event
search_events	Search by title/description
create_recurring_event	Create repeating event
list_invitations	List calendar invitations
respond_to_invitation	Accept/decline/maybe invitations

Reminder Tools (4 total)

Tool	Purpose
add_event_reminder	Add reminder to event
remove_event_reminder	Remove reminder(s)
list_event_reminders	List reminders for event
create_event_with_reminder	Create event + reminder in one call

Common Examples

# Check inbox (limit 10)
bunx fastmail list_emails '{"limit": 10}'

# Search for emails
bunx fastmail search_emails '{"query": "invoice"}'

# Get specific email content
bunx fastmail get_email '{"email_id": "xxx"}'

# Get email thread/conversation
bunx fastmail get_thread '{"email_id": "xxx"}'

# Bulk operations
bunx fastmail bulk_move_emails '{"email_ids": ["id1", "id2"], "target_mailbox_id": "archive"}'
bunx fastmail bulk_delete_emails '{"email_ids": ["id1", "id2", "id3"]}'

# Create recurring event (daily for 10 days)
bunx fastmail create_recurring_event \
  '{"title": "Standup", "start": "2024-01-01T09:00:00", "end": "2024-01-01T09:30:00", "recurrence": "daily", "recurrence_count": 10}'

# Calendar invitations
bunx fastmail list_invitations
bunx fastmail respond_to_invitation '{"event_id": "xxx", "response": "accept"}'

Decision Tree

Need to manage email?

• List/search → list_emails or search_emails
• Read content → get_email
• View conversation → get_thread
• Send/reply → send_email or reply_email
• Organize → move_email, set_labels, delete_email
• Bulk actions → bulk_move_emails, bulk_set_labels, bulk_delete_emails

Need to manage calendar?

• View → list_calendars or list_events
• Create → create_event or create_recurring_event
• Modify → update_event
• Delete → delete_event
• Invitations → list_invitations, respond_to_invitation

Need reminders?

• Add to existing event → add_event_reminder
• Create event + reminder → create_event_with_reminder (faster)
• Manage → list_event_reminders, remove_event_reminder

Output Format

All tools return JSON:

{
  "success": true,
  "data": { /* tool-specific response */ },
  "timestamp": "2024-01-15T10:00:00+07:00"
}

Environment Variables

Variable	Purpose	Required
FASTMAIL_API_TOKEN	Email via JMAP	Yes (for email)
FASTMAIL_USERNAME	Calendar via CalDAV	Yes (for calendar)
FASTMAIL_PASSWORD	Calendar app password	Yes (for calendar)
FASTMAIL_TIMEZONE	Calendar timezone (IANA format)	No (auto-detected)

Setup:

export FASTMAIL_API_TOKEN="your-api-token"
export FASTMAIL_USERNAME="your-email@fastmail.com"
export FASTMAIL_PASSWORD="your-app-password"
# Optional: Override timezone (defaults to system local timezone)
export FASTMAIL_TIMEZONE="America/New_York"  # or "Asia/Bangkok", "Europe/London", etc.

Timezone Support

⏰ Configurable calendar timezone

• Default: Auto-detects your system's local timezone
• Override: Set FASTMAIL_TIMEZONE environment variable
• Uses IANA timezone identifiers (e.g., America/New_York, Asia/Bangkok, Europe/London)
• Input times assumed in configured timezone
• Output times shown in configured timezone
• Stored internally as UTC
• Handles Daylight Saving Time (DST) automatically

See Also

• Detailed reference: .opencode/skills/fastmail/references/TOOLS.md
• Full guide: .opencode/skills/fastmail/README.md
• Setup help: Fastmail Settings → Privacy & Security → Integrations