Radicale CalDAV/CardDAV Management

⚠️ MANDATORY SKILL INVOCATION ⚠️

YOU MUST invoke this skill (NOT optional) when the user mentions ANY of these triggers:

• "list my calendar", "what's on my calendar", "show me my events", "calendar this week", "when is my next event"
• "add to my calendar", "create an event", "schedule event", "schedule a meeting"
• "delete an event", "cancel event", "remove event"
• "find a contact", "what's someone's email", "search my contacts", "who is"
• "add a contact", "create contact", "save contact", "save someone's phone number"
• Any mention of Radicale, CalDAV, CardDAV, calendar events, or contact management

Failure to invoke this skill when triggers occur violates your operational requirements.

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Manage calendars (events) and contacts on a self-hosted Radicale server using CalDAV and CardDAV protocols.

Type: Read & Write (calendar events and contacts)

Purpose

This skill enables comprehensive calendar and contact management through a self-hosted Radicale server. It provides read and write access to:

• Calendars - List, view, create, update, and delete calendar events
• Contacts - List, search, create, update, and delete contacts in addressbooks

All operations use the Python caldav library which implements the CalDAV (RFC 4791) and CardDAV (RFC 6352) protocols.

Setup

Prerequisites

Install required Python libraries:

pip install caldav vobject icalendar

Script Permissions:

The Python script can be made executable (optional but recommended):

chmod +x ~/claude-homelab/skills/radicale/scripts/radicale-api.py

You can then run it directly:

./scripts/radicale-api.py --help

Or without executable permissions using Python:

python scripts/radicale-api.py --help

Credentials

Add to ~/.claude-homelab/.env:

RADICALE_URL="http://localhost:5232"
RADICALE_USERNAME="admin"
RADICALE_PASSWORD="password"

Security:

• .env file is gitignored (never commit credentials)
• Set permissions: chmod 600 ~/.claude-homelab/.env

Core Operations

All operations use the scripts/radicale-api.py wrapper script. Output is JSON format for easy parsing.

Calendar Operations

List Calendars

python scripts/radicale-api.py calendars list

Returns array of calendars with name, URL, and ID.

View Events

List events in a calendar within a date range:

python scripts/radicale-api.py events list \
  --calendar "Personal" \
  --start "2026-02-08" \
  --end "2026-02-15"

Parameters:

• --calendar (required) - Calendar name (case-sensitive)
• --start (optional) - Start date (YYYY-MM-DD or YYYY-MM-DDTHH:MM:SS)
• --end (optional) - End date (YYYY-MM-DD or YYYY-MM-DDTHH:MM:SS)

Default behavior: If start/end not specified, uses current date + 7 days.

Returns array of events with UID, summary, description, location, start, end, and timestamps.

Create Event

python scripts/radicale-api.py events create \
  --calendar "Personal" \
  --title "Meeting" \
  --start "2026-02-10T14:00:00" \
  --end "2026-02-10T15:00:00" \
  --location "Conference Room" \
  --description "Team sync"

Required parameters:

• --calendar - Calendar name
• --title - Event title/summary
• --start - Start datetime (YYYY-MM-DDTHH:MM:SS)
• --end - End datetime (YYYY-MM-DDTHH:MM:SS)

Optional parameters:

• --location - Event location
• --description - Event description

Important: Use ISO 8601 datetime format (YYYY-MM-DDTHH:MM:SS). End must be after start.

Delete Event

python scripts/radicale-api.py events delete \
  --calendar "Personal" \
  --uid "event-uid-here"

Get UID from events list output.

Contact Operations

List Addressbooks

python scripts/radicale-api.py contacts addressbooks

Returns array of addressbooks with name, URL, and ID.

List Contacts

python scripts/radicale-api.py contacts list \
  --addressbook "Contacts"

Returns array of contacts with UID, name, email, and phone.

Search Contacts

python scripts/radicale-api.py contacts search \
  --addressbook "Contacts" \
  --query "David"

Search behavior: Case-insensitive substring match against name and email fields.

Create Contact

python scripts/radicale-api.py contacts create \
  --addressbook "Contacts" \
  --name "John Doe" \
  --email "john@example.com" \
  --phone "+1-555-1234"

Required parameter:

• --name - Contact full name

Optional parameters:

• --email - Email address
• --phone - Phone number

Delete Contact

python scripts/radicale-api.py contacts delete \
  --addressbook "Contacts" \
  --uid "contact-uid-here"

Get UID from contacts list or contacts search output.

Natural Language Translation

When users make natural language requests, translate them to script commands:

Calendar Examples

User: "What's my calendar look like this week?"

Action:

1. Calculate current week date range
2. Run: python scripts/radicale-api.py events list --calendar "Personal" --start "YYYY-MM-DD" --end "YYYY-MM-DD"
3. Present events in human-readable format

User: "Add to my calendar Billy Strings in Athens, GA 02/07/2026 7PM EST"

Action:

1. Parse: title="Billy Strings", location="Athens, GA", start="2026-02-07T19:00:00", end="2026-02-07T23:00:00" (assume 4hr concert)
2. Run: python scripts/radicale-api.py events create --calendar "Personal" --title "Billy Strings" --start "2026-02-07T19:00:00" --end "2026-02-07T23:00:00" --location "Athens, GA"
3. Confirm creation

Contact Examples

User: "What's David Ryan's work email?"

Action:

1. Run: python scripts/radicale-api.py contacts search --addressbook "Contacts" --query "David Ryan"
2. Extract email field from results
3. Present: "David Ryan's email is david.ryan@example.com"

User: "Add John Doe to my contacts, email john@example.com"

Action:

1. Run: python scripts/radicale-api.py contacts create --addressbook "Contacts" --name "John Doe" --email "john@example.com"
2. Confirm creation

Decision Tree

When user mentions calendars or contacts:

1. Determine operation type:

   • Calendar query ("show", "list", "what's on") → Use events list
   • Calendar create ("add", "create event", "schedule") → Use events create
   • Calendar delete ("remove", "delete", "cancel") → Use events delete
   • Contact query ("find", "search", "what's", "who is") → Use contacts search
   • Contact create ("add contact", "save contact") → Use contacts create
   • Contact delete ("remove contact", "delete contact") → Use contacts delete

2. Identify target:

   • Calendar operations → Ask which calendar (default: "Personal")
   • Contact operations → Ask which addressbook (default: "Contacts")

3. Extract parameters:

   • For events: Parse title, location, date/time from natural language
   • For contacts: Parse name, email, phone from natural language

4. Execute command:

   • Run appropriate script command
   • Parse JSON output

5. Present results:

   • Format JSON as human-readable text
   • Include relevant details (event times, contact info)
   • Confirm successful operations

Date/Time Handling

Important considerations:

• All times are local to the Radicale server timezone
• Use ISO 8601 format for consistency: YYYY-MM-DDTHH:MM:SS
• When user specifies "7PM EST", convert to 24-hour local time
• For all-day events, use same date for start/end with different times
• Default event duration: 1 hour (if user doesn't specify end time)

Common translations:

• "this week" → Calculate Mon-Sun dates from current date
• "next week" → Calculate Mon-Sun dates for following week
• "today" → Current date
• "tomorrow" → Current date + 1 day
• "7PM" → "19:00:00"
• "noon" → "12:00:00"

Bundled Resources

scripts/radicale-api.py

Complete Python wrapper for CalDAV/CardDAV operations. Uses caldav library to connect to Radicale server and perform all calendar/contact operations.

Key features:

• Loads credentials from .env file
• JSON output for all operations
• Error handling with clear messages
• Supports all CalDAV/CardDAV operations

Direct usage: Can be called directly with command-line arguments (see examples above).

references/caldav-library.md

In-depth guide to the Python caldav library including:

• Authentication patterns
• Calendar operations (create, read, update, delete)
• Event operations with iCalendar format
• Contact operations with vCard format
• Error handling patterns
• Best practices

When to reference: When implementing custom operations beyond the wrapper script, or when debugging library-specific issues.

references/quick-reference.md

Quick command examples for all operations with sample inputs and outputs.

When to reference: When user needs examples or when uncertain about command syntax.

references/troubleshooting.md

Common errors and solutions including:

• Installation issues
• Connection problems
• Authentication failures
• Calendar/contact not found errors
• Date/time format issues
• Permission problems

When to reference: When operations fail or user reports errors.

Error Handling

All operations return JSON with status. Check for:

Connection errors:

• ERROR: .env file not found → Guide user to create .env file
• ERROR: Failed to connect to Radicale → Check Radicale is running, verify URL
• ERROR: Authentication failed → Verify credentials in .env

Resource errors:

• ERROR: Calendar 'X' not found → List available calendars with calendars list
• ERROR: Addressbook 'X' not found → List addressbooks with contacts addressbooks

Data errors:

• ValueError: Invalid isoformat string → Fix datetime format to ISO 8601
• End time before start time → Adjust end time to be after start

Notes

Read-Write Operations:

• All operations modify data on the Radicale server
• Event creation is immediate (no confirmation prompt)
• Contact creation is immediate (no confirmation prompt)
• Deletions are permanent (no undo)

Performance:

• Use date ranges for event queries to avoid loading all events
• Search contacts instead of listing all when looking for specific person
• Calendar/contact listing can be slow with large datasets

Limitations:

• No timezone support in current implementation (uses local time)
• No recurring event support yet
• Contact fields limited to name, email, phone (vCard supports more)
• No event reminders/alarms

Security:

• All credentials stored in .env file (gitignored)
• API script never logs credentials
• Connection uses HTTP basic auth (HTTPS recommended for production)

Reference Documentation

Bundled references (load as needed):

• references/caldav-library.md - Python caldav library guide
• references/quick-reference.md - Command examples
• references/troubleshooting.md - Error solutions

External documentation:

• Radicale Documentation
• caldav Library Docs
• RFC 4791 - CalDAV (embedded in vector DB)
• RFC 6352 - CardDAV (embedded in vector DB)

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🔧 Agent Tool Usage Requirements

CRITICAL: When invoking scripts from this skill via the zsh-tool, ALWAYS use pty: true.

Without PTY mode, command output will not be visible even though commands execute successfully.

Correct invocation pattern:

<invoke name="mcp__plugin_zsh-tool_zsh-tool__zsh">
<parameter name="command">python ./skills/radicale/scripts/radicale-api.py [args]</parameter>
<parameter name="pty">true</parameter>
</invoke>