Fastmail Email & Calendar Management Skill

OpenCode skill for managing Fastmail email and calendar via JMAP and CalDAV APIs.

Features

🔹 9 Email Management Tools:

🔹 8 Calendar Management Tools:

🔹 4 Reminder/Alarm Tools:

Total: 21 MCP Tools

Setup

1. Generate Fastmail API Token (For Email)

1. Log in to Fastmail
2. Go to Settings → Privacy & Security → Integrations
3. Click New API token
4. Name it: OpenCode Nisha (or any name you prefer)
5. Click Generate
6. Copy the token - you won't see it again!

2. Generate App Password (For Calendar)

1. Go to Settings → Privacy & Security → Integrations
2. Click New app password
3. Name it: Calendar Sync
4. Copy the password - this is different from your main password!

3. Set Environment Variables

Add to your shell profile (~/.zshrc, ~/.bashrc, etc.):

# For Email (JMAP)
export FASTMAIL_API_TOKEN="your-api-token-here"
 
# For Calendar (CalDAV)
export FASTMAIL_USERNAME="your-email@fastmail.com"
export FASTMAIL_PASSWORD="your-app-password-here"

Or create a .env file:

echo "FASTMAIL_API_TOKEN=your-api-token-here" >> .env
echo "FASTMAIL_USERNAME=your-email@fastmail.com" >> .env
echo "FASTMAIL_PASSWORD=your-app-password-here" >> .env

Then reload:

source ~/.zshrc  # or source ~/.bashrc

4. Verify Installation

cd .opencode/skills/fastmail
bun install
bunx fastmail --help

Usage Examples

Email Commands

Check your inbox:

User: "Show me my latest emails"
User: "What's in my inbox?"

Search emails:

User: "Search for emails from john@example.com"
User: "Find emails about 'project alpha'"

Send email:

User: "Send email to sarah@example.com with subject 'Meeting Tomorrow' and body 'Let's meet at 2pm'"

Reply to email:

User: "Reply to the email from John saying 'Thanks, sounds good!'"

Calendar Commands (Thai)

ดูปฏิทิน:

User: "แสดงปฏิทินทั้งหมด"
User: "มีกี่ปฏิทิน"

ดูกิจกรรม:

User: "ดูกิจกรรมวันนี้"
User: "มีนัดอะไรสัปดาห์นี้"
User: "แสดงกิจกรรมเดือนนี้"

สร้างกิจกรรม:

User: "สร้างนัดหมายชื่อ 'ประชุมทีม' วันพรุ่งนี้ 10:00-11:00"
User: "เพิ่มกิจกรรม 'พบลูกค้า' วันที่ 15 กุมภาพันธ์ 14:00-15:30"

ค้นหากิจกรรม:

User: "ค้นหากิจกรรมที่มีคำว่า 'ประชุม'"
User: "หานัดที่เกี่ยวกับโครงการ A"

ลบกิจกรรม:

User: "ลบกิจกรรม [event-id]"

Reminder Commands (Thai)

เพิ่ม reminder:

User: "เพิ่ม reminder ก่อน event [id] 15 นาที"
User: "ตั้ง reminder ก่อน 1 ชั่วโมง"

ดู reminders:

User: "แสดง reminders ของ event [id]"

ลบ reminder:

User: "ลบ reminder ออกจาก event [id]"

สร้าง event พร้อม reminder:

User: "สร้างนัด 'ประชุมทีม' พรุ่งนี้ 10:00-11:00 เตือนก่อน 15 นาทีและ 1 ชั่วโมง"

Timezone Information

Calendar times use your local timezone by default

You can configure the timezone with the FASTMAIL_TIMEZONE environment variable:

# Use local system timezone (default - no configuration needed)
# Or explicitly set a timezone:
export FASTMAIL_TIMEZONE="America/New_York"  # or "Asia/Bangkok", "Europe/London", etc.

• Default: Auto-detects your system's local timezone
• Input: Accept times in configured timezone format
• Storage: Stored as UTC internally
• Display: Converted to configured timezone for display
• DST: Handles Daylight Saving Time automatically

Example (with Asia/Bangkok timezone):

• You say: "สร้างนัด 10:00" (assumed local timezone)
• Stored as: 03:00 UTC
• Displayed as: 10:00+07:00

Technical Details

Architecture

.opencode/skills/fastmail/
├── SKILL.md                    # Skill metadata
├── README.md                   # Documentation
├── package.json                # Dependencies
├── tsconfig.json               # TypeScript config
├── scripts/                    # Executable code
│   ├── cli.ts                 # CLI entry point (21 tools)
│   ├── jmap-client.ts         # JMAP API client (email)
│   ├── caldav-client.ts       # CalDAV client (calendar)
│   └── tools/
│       ├── email.ts           # Email operations
│       └── calendar.ts        # Calendar operations
└── references/
    └── TOOLS.md               # Detailed tool reference

APIs Used

Email - JMAP:

• Modern JSON-based protocol
• Fast batch operations
• Efficient syncing

Calendar - CalDAV:

• Industry standard protocol
• iCalendar (ICS) format
• Full recurring event support

Dependencies

{
  "@modelcontextprotocol/sdk": "^1.0.0",
  "tsdav": "^2.1.2",      // CalDAV client
  "uuid": "^9.0.0"         // Event ID generation
}

Requirements

• Bun - JavaScript runtime (install with curl -fsSL https://bun.sh/install | bash)

Troubleshooting

Email Issues

Error: "FASTMAIL_API_TOKEN environment variable is required"

Solution: Set the environment variable (see Setup above)

Verify it's set:

echo $FASTMAIL_API_TOKEN

Error: "Failed to get session: 401 Unauthorized"

Cause: Invalid or expired API token

Solution: Generate new token from Fastmail Settings

Calendar Issues

Error: "Calendar support disabled"

Cause: FASTMAIL_USERNAME or FASTMAIL_PASSWORD not set

Solution: Set both environment variables

Error: "401 Unauthorized" when using calendar

Cause: Invalid app password

Solution:

1. Check you're using app password (not main password)
2. Generate new app password from Fastmail Settings
3. Verify FASTMAIL_USERNAME includes full email

Error: "Calendar not found"

Solution: Use list_calendars to see available calendars

TypeScript Build Errors

Solution: Rebuild the project:

cd .opencode/skills/fastmail
bun run build

Development

Run in Dev Mode

cd .opencode/skills/fastmail
bunx fastmail --help

Build

bun run build

Project Structure

• scripts/cli.ts - CLI entry point with 21 tool definitions
• scripts/jmap-client.ts - JMAP API client for email
• scripts/caldav-client.ts - CalDAV client for calendar
• scripts/tools/email.ts - Email operations (9 methods)
• scripts/tools/calendar.ts - Calendar operations (8 methods)

Limitations

• Fastmail only: Uses Fastmail-specific APIs
• No attachments: File upload/download not yet implemented
• No contacts: Contact management not yet implemented
• CalDAV only: JMAP Calendar not yet available from Fastmail

Security

• ✅ API token via environment variable (never hardcoded)
• ✅ App password for calendar (separate from main password)
• ✅ HTTPS for all API calls
• ✅ No sensitive data in logs
• ⚠️ Tokens have full account access - keep them secret!

Best practices:

• Use .env file (add to .gitignore)
• Rotate tokens if compromised
• Use unique token per application
• Use app passwords (not main password) for calendar

Resources

• Fastmail API Documentation
• JMAP Specification
• CalDAV RFC
• iCalendar Format

Support

For issues or questions:

1. Check .sisyphus/notepads/fastmail-agent-skill/ for detailed docs
2. Review issues.md for common problems
3. Check Fastmail API status: https://fastmailstatus.com/

License

Part of OpenCode project - follows project licensing.

Built with ❤️ using JMAP, CalDAV, and TypeScript